Publications by authors named "Stephen J Harding"

17 Publications

  • Page 1 of 1

Parameter Identification for a Model of Neonatal Fc Receptor-Mediated Recycling of Endogenous Immunoglobulin G in Humans.

Front Immunol 2019 8;10:674. Epub 2019 Apr 8.

School of Engineering, University of Warwick, Coventry, United Kingdom.

Salvage of endogenous immunoglobulin G (IgG) by the neonatal Fc receptor (FcRn) is implicated in many clinical areas, including therapeutic monoclonal antibody kinetics, patient monitoring in IgG multiple myeloma, and antibody-mediated transplant rejection. There is a clear clinical need for a fully parameterized model of FcRn-mediated recycling of endogenous IgG to allow for predictive modeling, with the potential for optimizing therapeutic regimens for better patient outcomes. In this paper we study a mechanism-based model incorporating nonlinear FcRn-IgG binding kinetics. The aim of this study is to determine whether parameter values can be estimated using the limited human data, available in the literature, from studies of the kinetics of radiolabeled IgG in humans. We derive mathematical descriptions of the experimental observations-timecourse data and fractional catabolic rate (FCR) data-based on the underlying physiological model. Structural identifiability analyses are performed to determine which, if any, of the parameters are unique with respect to the observations. Structurally identifiable parameters are then estimated from the data. It is found that parameter values estimated from timecourse data are not robust, suggesting that the model complexity is not supported by the available data. Based upon the structural identifiability analyses, a new expression for the FCR is derived. This expression is fitted to the FCR data to estimate unknown parameter values. Using these parameter estimates, the plasma IgG response is simulated under clinical conditions. Finally a suggestion is made for a reduced-order model based upon the newly derived expression for the FCR. The reduced-order model is used to predict the plasma IgG response, which is compared with the original four-compartment model, showing good agreement. This paper shows how techniques for compartmental model analysis-structural identifiability analysis, linearization, and reparameterization-can be used to ensure robust parameter identification.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fimmu.2019.00674DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6465738PMC
September 2020

Remediation of IgG4 Cross-Reactivity in IgG1 and IgG2 Subclass Assays.

Clin Chem 2018 08 6;64(8):1253-1255. Epub 2018 Jun 6.

Department of Research and Development The Binding Site Group Ltd. Birmingham, UK

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1373/clinchem.2018.289124DOI Listing
August 2018

Association between urinary free light chains and progression to end stage renal disease in chronic kidney disease.

PLoS One 2018 9;13(5):e0197043. Epub 2018 May 9.

Department of Renal Medicine, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom.

Background: Patients with chronic kidney disease (CKD) are at an increased risk of developing end-stage renal disease (ESRD). We assessed for the first time whether urinary free light chains (FLC) are independently associated with risk of ESRD in patients with CKD, and whether they offer incremental value in risk stratification.

Materials And Methods: We measured urinary FLCs in 556 patients with CKD from a prospective cohort study. The association between urinary kappa/creatinine (KCR) and lambda/creatinine (LCR) ratios and development of ESRD was assessed by competing-risks regression (to account for the competing risk of death). The change in C-statistic and integrated discrimination improvement were used to assess the incremental value of adding KCR or LCR to the Kidney Failure Risk Equation (KFRE).

Results: 136 participants developed ESRD during a median follow-up time of 51 months. Significant associations between KCR and LCR and risk of ESRD became non-significant after adjustment for estimated glomerular filtration rate (eGFR) and albumin/creatinine ratio (ACR), although having a KCR or LCR >75th centile remained independently associated with risk of ESRD. Neither KCR nor LCR as continuous or categorical variables provided incremental value when added to the KFRE for estimating risk of ESRD at two years.

Conclusions: Urinary FLCs have an association with progression to ESRD in patients with CKD which appears to be explained to a degree by their correlation with eGFR and ACR. Levels above the 75th centile do have an independent association with ESRD, but do not improve upon a current model for risk stratification.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0197043PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5942781PMC
August 2018

Serum IgG4 Concentration in IgG4-Related Disease.

Clin Lab 2017 Sep;63(9):1323-1337

Background: IgG4-related disease (IgG4-RD) is an immune-mediated and chronic fibroinflammatory condition that affects almost any organ and often involves multiple organs in the same patient. In this review article, we address the clinical utility of measuring serum immunoglobulin G subclass 4 concentration ([IgG4]) in IgG4-RD diagnosis and in disease monitoring.

Methods: We discuss the latest literature on the relevance of [IgG4] to the investigation and management of IgG4RDs. In addition, we discuss the potential role of serum [IgG4] measurements in other inflammatory conditions and cancers.

Results: Increasing awareness of IgG4-RD among clinicians has led to a growing list of organ systems that can be affected by this chronic condition and the development of new organ-specific diagnostic guidelines. Diagnosis of IgG4-RD depends on multiple clinical and laboratory tests, including serology. Quantification of serum [IgG4] is included in all IgG4-RD diagnostic guidelines available to-date. The scientific literature supports the idea that elevated serum [IgG4], typically > 135 mg/dL, identifies patients with a more active form of the disease, which correlates with increased concentrations of inflammatory serum biomarkers and hypocomplementemia, increased number of organs affected by the disease, and more extensive organ involvement. These patients seem more resistant to treatment and experience a shorter time to disease relapse compared to IgG4-RD patients with normal serum [IgG4] at the time of diagnosis.

Conclusions: Despite better understanding of how to diagnose IgG4-RD, monitoring for accurate prediction of disease relapse, which may involve organs not affected at the time of presentation, is poorly understood. Timely diagnosis and early detection of disease relapse is important to avoid delayed treatment and potential organ damage.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.7754/Clin.Lab.2017.170403DOI Listing
September 2017

Serum Free Light Chain (FLC) Analysis: A Guiding Light in Monoclonal Gammopathy Management.

J Appl Lab Med 2017 Jul;2(1):98-106

The Binding Site Group, Birmingham, UK.

Background: Monoclonal free light chains (FLCs) were first reported by Dr. Henry Bence Jones over 150 years ago in the urine of patients with multiple myeloma. Now established as important tumor markers, they aid not only in the diagnosis of monoclonal gammopathies but also in their clinical management by indicating the response to treatment and persistence of residual disease.

Content: A particular focus over the past 15 years has been on the replacement of urine with serum analysis for monoclonal FLC measurement. Because of the limited sensitivity and practical constraints of urine assessment, a combination of serum electrophoresis and serum FLC analysis has been adopted by many laboratories as a first-line screen for patients with a suspected monoclonal gammopathy. Early myeloma diagnosis may translate into improved clinical outcomes, and a new study, iStopMM, is underway to ascertain the benefit of population-wide screening protocols for early detection of the disease in its asymptomatic phase. Laboratory algorithms that include measurement of both monoclonal intact immunoglobulins and FLCs are important for assessing possible changes in myelomic clones in response to treatment, and recent data from Intergroupe Francophone du Myelome trials validate serum FLC as a clinically relevant disease biomarker. Whether sensitive serum techniques such as FLC analysis can be used to guide the use of more invasive procedures for detection of minimal residual disease is the subject of emerging studies.

Summary: Here we review the current and evolving utility of serum FLC measurements for the management of patients with monoclonal gammopathies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1373/jalm.2016.021352DOI Listing
July 2017

Serum tryptase concentration and progression to end-stage renal disease.

Eur J Clin Invest 2016 May 15;46(5):460-74. Epub 2016 Apr 15.

Department of Renal Medicine, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK.

Background: Mast cell activation can lead to nonclassical activation of the Renin-Angiotensin-Aldosterone System. However, the relevance of this to human chronic kidney disease is unknown. We assessed the association between serum tryptase, a product of mast cell activation, and progression to end-stage renal disease or mortality in patients with advanced chronic kidney disease. We stratified patients by use of angiotensin-converting enzyme inhibitors/angiotensin receptor II blockers (ACEi/ARB).

Materials And Methods: This was a prospective cohort study of 446 participants recruited into the Renal Impairment in Secondary Care study. Serum tryptase was measured at recruitment by sandwich immunoassay. Cox regression analysis was undertaken to determine variables associated with progression to end-stage renal disease or death.

Results: Serum tryptase concentration was independently associated with progression to end-stage renal disease but not with death. In patients treated with ACEi or ARB, there was a strong independent association between higher tryptase concentrations and progression to end-stage renal disease; when compared to the lowest tertile, tryptase concentrations in the middle and highest tertiles had hazard ratios [HR] of 5·78 (95% confidence interval [CI] 1·19-28·03, P = 0·029) and 6·19 (95% CI 1·49-25·69, P = 0·012), respectively. The other independent risk factors for progression to end-stage renal disease were lower age, male gender, lower estimated glomerular filtration rate and higher urinary albumin creatinine ratio.

Conclusion: Elevated serum tryptase concentration is an independent prognostic factor for progression to end-stage renal disease in patients with chronic kidney disease who are receiving treatment with an ACEi or ARB.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/eci.12622DOI Listing
May 2016

Analytical issues of serum free light chain assays and the relative performance of polyclonal and monoclonal based reagents.

Clin Chem Lab Med 2016 Jun;54(6):997-1003

Serum free light chain (FLC) assays have been incorporated into routine clinical practice and their use is recommended in international guidelines for the management of monoclonal gammopathies. Given that FLCs are not simple analytes, laboratories should be aware of potential analytical issues when using FLC assays, including antigen excess, lot-to-lot variation and non-linearity. Whilst manufacturers of monoclonal antibody-based assays claim that they overcome such issues, the evidence available to date does not support this. Here we review and compare the technical performance of both polyclonal and monoclonal antibody-based assays. The evidence suggests that the Freelite assay, based on polyclonal antisera, gives a broader recognition of monoclonal FLCs than the N Latex assay, based on monoclonal antisera, and despite being cited as a technical concern, we show that lot-to-lot variation of the Freelite assay is good. Both non-linearity and antigen excess are characteristic of FLC analysis and laboratories should be aware of these phenomena regardless of the assay system they use. Comparisons of the absolute values of sFLCs determined using monoclonal and polyclonal antibody-based assays show poor quantitative agreement and, because current guidelines have been established using the polyclonal antibody-based Freelite assay, it should not be assumed that assays utilizing monoclonal antibodies will give compliance with these guidelines.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1515/cclm-2015-1068DOI Listing
June 2016

Quantification of β-region IgA monoclonal proteins - should we include immunochemical Hevylite® measurements? Point.

Clin Chem Lab Med 2016 Jun;54(6):1053-7

Accurate measurement of IgA monoclonal proteins presents a significant challenge to laboratory staff. IgA heavy/light chain (Hevylite, HLC) analysis is an alternative methodology for monoclonal protein assessment, giving an independent measure of IgAκ and IgAλ concentrations. Clonality is assessed by calculating the ratio of involved immunoglobulin to background uninvolved immunoglobulin concentrations (e.g. IgAκ/IgAλ in an IgAκ patient). Here we discuss the challenges faced by the laboratory in IgA monoclonal protein assessment, and compare the performance of Hevylite assays with electrophoresis and total IgA results. We present data which validates the use of Hevylite for response assessment: in most cases, Hevylite provides comparable response assignment to that provided by serum protein electrophoresis (SPE) and total IgA; in other cases Hevylite provides additional information, such as detection of residual disease or relapse.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1515/cclm-2015-0696DOI Listing
June 2016

IgA kappa/IgA lambda heavy/light chain assessment in the management of patients with IgA myeloma.

Cancer 2014 Dec 12;120(24):3952-7. Epub 2014 Aug 12.

Clinical Hematology Department, Huriez Hospital, Regional University Medical Center, Lille, France.

Background: Accurate quantification of immunoglobulin A (IgA) monoclonal immunoglobulins by serum protein electrophoresis (SPEP) can be difficult and can impact the assessment of response among patients with multiple myeloma (MM). Therefore, there is a need to identify new assays that better reflect disease burden and response to treatment, and correlate with patient outcome. IgA Hevylite (HLC) measures IgA kappa and IgA lambda separately and provides precise quantitative measurements of the monoclonal IgA expression and polyclonal-isotype matched suppression. In the current study, the authors assessed the usefulness of these assays in the diagnosis of IgA MM and sought to comment on the prognostic value of the assays.

Methods: A study of 157 patients with IgA MM for whom diagnostic samples were available was performed. HLC measurements were performed on a nephelometer and the results were compared with those of electrophoresis.

Results: All presentation sera (100 IgA kappa specimens and 57 IgA lambda specimens) were found to have abnormal IgA HLC ratios (IgA kappa median ratio: 336.2 [range, 8.2-7353] and IgA lambda ratio: 0.011 [range, 0.0003-0.45]). In comparison, SPEP bands were quantifiable in only 105 of 157 samples (67%) (median, 28.5 g/L [range, 2.2 g/L-98 g/L]). Of the total of 157 patients, 12 patients (8%) presented with oligosecretory myeloma (<10 g/L; including 4 patients with nonquantifiable SPEP bands). HLC uniquely allows for the measurement of isotype paired suppression, which was found to be associated with shortened overall survival in the current study.

Conclusions: In the current study, IgA HLC ratios were found to be abnormal in all patients and the assay was able to produce quantifiable results in more MM sera than either SPEP or total IgA, potentially representing a solution to the issue of comigration and oligosecretory MM. These preliminary data require confirmation in larger prospective trials to validate the usefulness of IgA HLC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cncr.28946DOI Listing
December 2014

Quantification of polyclonal free light chains in clinical samples using a single turbidimetric immunoassay.

Clin Chem Lab Med 2014 Nov;52(11):1605-13

Background: Elevated polyclonal serum free light chain (FLC) levels have been associated with increased mortality and disease activity in many conditions. Currently, polyclonal FLC quantification requires summation of individual FLCκ and FLCλ assays. Here we present a single assay for combined FLC (cFLC, Combylite) which reduces assay time and eliminates potential imprecision errors incurred by summating FLC assays (ΣFLC).

Methods: Sheep FLCκ- and FLCλ-specific antibodies were conjugated to latex microparticles to quantify FLCκ and FLCλ in a single assay. Combylite results were compared to ΣFLC (Freelite) in 132 healthy controls and 1127 patient samples. The utility of cFLC for predicting all-cause mortality in a haematological referral population was evaluated.

Results: cFLC and ΣFLC results were highly concordant (Passing-Bablok equation y=0.98x-1.59 mg/L, R²=0.96). Combylite assay imprecision was low at concentrations around the upper normal range [coefficient of variation (CV) 5.5%, 54 mg/L] and the upper limit of the measuring range (CV 5.5%, 170 mg/L). cFLC levels were significantly raised in disease states compared with healthy controls. Additionally, cFLC >65 mg/L was associated with shorter overall survival in a haematological referral population (hazard ratio=4.5, p<0.001).

Conclusions: cFLC values obtained using Combylite were comparable to ΣFLC results over a wide concentration range, were elevated in diseases characterised by B cell activation and were associated with increased mortality in a haematological referral population. These observations indicate the Combylite assay has value for investigating the role of B cell activation in disparate disease groups and could be considered as a surrogate indication of B cell function.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1515/cclm-2014-0279DOI Listing
November 2014

Serum polyclonal immunoglobulin free light chain levels predict mortality in people with chronic kidney disease.

Mayo Clin Proc 2014 May;89(5):615-22

Department of Renal Medicine, Queen Elizabeth Hospital Birmingham, Mindelsohn Way, Birmingham, United Kingdom; Division of Immunity and Infection, University of Birmingham, Medical School, Birmingham, United Kingdom. Electronic address:

Objective: To determine whether elevated serum polyclonal free light chain (FLC) levels predict mortality in a population of individuals with chronic kidney disease (CKD).

Patients And Methods: From January 2, 2006, through July 31, 2007, we recruited a cohort of 848 people with CKD who were not receiving renal replacement therapy and did not have monoclonal gammopathy. We measured serum kappa FLC and lambda FLC isotype levels to determine combined FLC (cFLC) levels. The cohort was prospectively followed up for a median of 63 months (interquartile range, 0-93 months). Cox regression analysis was performed to determine variables predictive of mortality.

Results: High cFLC levels were an independent risk factor for death (hazard ratio [HR], 2.71; 95% CI, 1.98-3.70; P<.001). Other independent risk factors were age (HR, 1.79; 95% CI, 1.52-2.10; P<.001), South Asian ethnicity (HR, 0.33; 95% CI, 0.14-0.64; P=.02), preexisting cardiovascular disease (HR, 1.59; 95% CI, 1.09-2.31; P=.02), and high-sensitivity C-reactive protein (HR, 1.13; 95% CI, 1.00-1.28; P=.04). Neither estimated glomerular filtration rate nor albuminuria was an independent risk factor for death.

Conclusion: High cFLC levels independently predict mortality in people with CKD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.mayocp.2014.01.028DOI Listing
May 2014

Elevated serum free light chains predict cardiovascular events in type 2 diabetes.

Diabetes Care 2014 Jul 17;37(7):2028-30. Epub 2014 Apr 17.

Diabetes Centre, Heart of England NHS Foundation Trust, Birmingham, U.K.University of Birmingham, Birmingham, U.K.

Objective: Elevated polyclonal serum immunoglobulin free light chains (FLCs; combined FLCκ+FLCλ [cFLC]) are associated with adverse clinical outcomes and increased mortality; we investigated cFLC and cardiovascular disease (CVD) events in type 2 diabetes.

Research Design And Methods: In a cohort study of 352 south Asian patients with type 2 diabetes, serum cFLC, high-sensitivity C-reactive protein (hsCRP), and standard biochemistry were measured. CVD events over 2 years were recorded and assessed using multiple logistic regression.

Results: cFLC levels were elevated significantly in 29 of 352 (8%) patients with CVD events during 2 years of follow-up (50.7 vs. 42.8 mg/L; P = 0.004). In multivariate analysis, elevated cFLC (>57.2 mg/L) was associated with CVD outcomes (odds ratio 3.3 [95% CI 1.3-8.2]; P = 0.012) and remained significant after adjusting for age, albumin-to-creatinine ratio, diabetes duration, or treatment.

Conclusions: cFLC elevation is a novel marker for CVD outcomes in type 2 diabetes that warrants further investigation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2337/dc13-2227DOI Listing
July 2014

Ratio of involved/uninvolved immunoglobulin quantification by Hevylite™ assay: clinical and prognostic impact in multiple myeloma.

Exp Hematol Oncol 2012 Apr 23;1(1). Epub 2012 Apr 23.

Haematology Section of 1st Department of Propedeutic Internal Medicine, Athens Medical School, Athens, Greece.

Unlabelled:

Background: HevyLite™ is a new, recently developed method that facilitates separate quantification of the kappa- and lambda-bounded amounts of a given immunoglobulin (Ig). Using this method, we measured intact immunoglobulin (heavy/light chain; HLC) IgG-kappa, IgG-lambda, IgA-kappa, IgA-lambda individually, as well as their deriving ratios (HLCR) in a series of IgG or IgA multiple myeloma (MM) patients, to investigate and assess the contribution of these tests to disease evaluation.

Patients And Methods: HevyLite™ assays were used in sera from 130 healthy individuals (HI) and 103 MM patients, at time of diagnosis. In patients, the level of paraprotein was IgG in 78 (52 IgG-kappa, 26 IgG-lambda) and IgΑ in 25 (13 IgΑ-kappa, 12 IgΑ-lambda). Durie-Salmon and International Staging System stages were evenly distributed. Symptomatic patients (n = 77) received treatment while asymptomatic ones (n = 26) were followed. Patients' median follow-up was at 32.6 months. HLCR was calculated with the involved Ig (either G or A) as numerator.

Results: In HI, median IgG-kappa was 6.85, IgG-lambda 3.81, IgA-kappa 1.19 and IgA-lambda 0.98 g/L. The corresponding median involving HLC values in MM patients were 25.8, 23.45, 28.9 and 36.4 g/L. HLC-IgG related to anemia, high serum free light chain ratio and extensive bone marrow infiltration, while high HLCR correlated with the same plus increased β2-microglobulin. In addition, increased HLCR and the presence of immunoparesis correlated with time to treatment. Patients with high HLCR had a significantly shorter survival (p = 0.022); HLCR retained its prognostic value in multivariate analysis.

Conclusions: HLC and HLCR quantify the precise amount of the involved immunoglobulin more accurately than other methods; moreover, they carry prognostic information regarding survival in MM patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/2162-3619-1-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3514091PMC
April 2012

Activation of ASK1, downstream MAPKK and MAPK isoforms during cardiac ischaemia.

Biochim Biophys Acta 2010 Sep 13;1802(9):733-40. Epub 2010 Jun 13.

Department of Biochemistry, Henry Wellcome Building, University of Leicester, Leicester, UK.

p38 MAPK is activated potently during cardiac ischaemia, although the precise mechanism by which it is activated is unclear. We used the isolated perfused rat heart to investigate the signalling pathways activated upstream of p38 during global cardiac ischaemia. Ischaemia strongly activated p38alpha but not the JNK pathway. The MAPKKs, MKK3, MKK4 and MKK6 have previously been identified as potential upstream activators of p38; however, in the ischaemic perfused heart, we saw activation of MKK3 and MKK6 but not MKK4. MKK3 and MKK6 showed different temporal patterns of activity, indicating distinct modes of activation and physiological function. Consistent with a lack of JNK activation, we saw no activation of MKK4 or MKK7 at any time point during ischaemia. A lack of MKK4 activation indicates, at least in the ischaemic heart, that MKK4 is not a physiologically relevant activator of p38. The MAPKKK, ASK1, was strongly activated late during ischaemia, with a similar time course to that of MKK6 and in ischaemic neonatal cardiac myocytes ASK1 expression preferentially activated MKK6 rather than MKK3. These observations suggest that during ischaemia ASK1 is coupled to p38 activation primarily via MKK6. Potent activation of ASK1 during ischaemia without JNK activation shows that during cardiac ischaemia, ASK1 preferentially activates the p38 pathway. These results demonstrate a specificity of responses seldom seen in previous studies and illustrate the benefits of using direct assays in intact tissues responding to physiologically relevant stimuli to unravel the complexities of MAPK signalling.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.bbadis.2010.06.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2954285PMC
September 2010

Serum free light chain immunoassay as an adjunct to serum protein electrophoresis and immunofixation electrophoresis in the detection of multiple myeloma and other B-cell malignancies.

Clin Chem Lab Med 2009 ;47(3):302-4

The Binding Site Ltd., Birmingham, UK.

Background: Protein and immunofixation electrophoresis of serum and urine are established as diagnostic aids for identifying monoclonal gammopathies. However, many patient sera sent to laboratories are not accompanied by urine samples and recent reports suggest the use of serum free light chain (sFLC) analysis in combination with serum protein electrophoresis (SPE) and immunofixation electrophoresis (lFE) could eliminate the need for urinalysis. The aim of the study was to assess the utility of sFLC measurement in addition to serum protein electrophoresis in the identification of patients with B-cell malignancies.

Methods: A total of 952 serum samples were analysed by serum protein electrophoresis and those with abnormal bands were analysed by immunofixation. sFLCs were measured in a retrospective manner by automated assay.

Results: In our study of 952 patient sera, it was found that FLC analysis identified 23 additional cases of B-cell malignancies which were missed by SPE.

Conclusions: The additional malignancies identified by sFLC analysis add support for its inclusion in the routine screening protocol for B-cell malignancies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1515/CCLM.2009.084DOI Listing
August 2009

Assessment of monoclonal gammopathies by nephelometric measurement of individual immunoglobulin kappa/lambda ratios.

Clin Chem 2009 Sep 17;55(9):1646-55. Epub 2009 Jul 17.

Department of Immunity and Infection, Medical School, University of Birmingham, UK.

Background: Currently, monoclonal immunoglobulins are identified and quantified from bands on electrophoretic gels. As an alternative, clonality might be determined by measuring the separate light chain types of each Ig class to allow numerical assessment of Ig'kappa/Ig'lambda ratios, analogous to free light chain kappa/lambda ratios.

Methods: Using immunization, tolerization, and adsorption procedures, we prepared sheep antibodies against each of the 6 separate molecules, IgGkappa, IgGlambda, IgAkappa, IgAlambda, IgMkappa, and IgMlambda. Antibody targets comprised the junctional epitopes between the heavy chain and light chain domains. After purification, we assessed the antisera on a Siemens Dade-Behring BN II nephelometer for analytical quality and clinical utility.

Results: High-avidity, specific antibodies allowed the production of automated nephelometric immunoassays for each Ig light chain type. Laboratory comparison with serum protein electrophoresis, using dilution experiments, showed lower analytical sensitivity for monoclonal IgG detection but similar or greater sensitivity for IgA and IgM, particularly when the monoclonal bands overlaid transferrin. Results obtained from typing of monoclonal proteins into IgG, A, or M types were comparable with results obtained by immunofixation-electrophoresis methods. Initial clinical studies, in multiple myeloma patients, indicated that Ig'kappa/Ig'lambda ratios were sometimes more sensitive than immunofixation electrophoresis, provided numerical results, and correlated with changes in disease.

Conclusions: Immunoassays for intact Ig kappa/lambda pairs are possible and should assist in the management of patients with monoclonal gammopathies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1373/clinchem.2009.123828DOI Listing
September 2009

A new anticancer glycolipid monoclonal antibody, SC104, which directly induces tumor cell apoptosis.

Cancer Res 2006 Jun;66(11):5901-9

Institute of Infections, Immunity, and Inflammation, Cancer Research UK Department of Clinical Oncology, University of Nottingham and Scancell Ltd., BioCity, Nottingham, United Kingdom.

A novel monoclonal antibody was raised by immunization of mice with colorectal tumor cell lines. The fusion was screened by immunohistochemistry for binding to primary colorectal tumors. Subsequent analysis on primary disaggregated colorectal tumors show that the antibody recognizes a cell surface antigen expressed by the majority of colorectal tumors. Antigen characterization has shown that the antibody recognizes a sialyltetraosylceramide but does not bind to GM1, GD1a, GT1b, or sialyl Lewis(X) antigens. Binding to a frozen panel of tumor and normal tissue sections revealed that the antigen was also strongly expressed on esophageal, gastric, and endometrial tumors. Its normal tissue distribution was largely restricted to moderate staining of large intestine. Surprisingly, SC104 antibody directly induces tumor cell death without the need for immune effector cells or complement. This may be related in part to its homophilic binding properties that allow cross-linking of antibody and receptors on the cell surface. Caspase activation can be detected following SC104 treatment of colorectal cells, and cotreatment with caspase inhibitors has been shown to inhibit cell death. This suggests that SC104 induces death by a classic apoptotic pathway. Furthermore, SC104 antibody shows additive killing with complement and 5-fluorouracil/leucovorin in vivo, suggesting a new therapeutic approach for this class of antibodies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1158/0008-5472.CAN-05-3812DOI Listing
June 2006