Publications by authors named "A M Balderacchi"

10 Publications

The Importance of N186 in the Alpha-1-Antitrypsin Shutter Region Is Revealed by the Novel Bologna Deficiency Variant.

Int J Mol Sci 2021 May 26;22(11). Epub 2021 May 26.

Department of Molecular and Translational Medicine, University of Brescia, viale Europa 11, 25123 Brescia, Italy.

Alpha-1-antitrypsin (AAT) deficiency causes pulmonary disease due to decreased levels of circulating AAT and consequently unbalanced protease activity in the lungs. Deposition of specific AAT variants, such as the common Z AAT, within hepatocytes may also result in liver disease. These deposits are comprised of ordered polymers of AAT formed by an inter-molecular domain swap. The discovery and characterization of rare variants of AAT and other serpins have historically played a crucial role in the dissection of the structural mechanisms leading to AAT polymer formation. Here, we report a severely deficient shutter region variant, Bologna AAT (N186Y), which was identified in five unrelated subjects with different geographical origins. We characterized the new variant by expression in cellular models in comparison with known polymerogenic AAT variants. Bologna AAT showed secretion deficiency and intracellular accumulation as detergent-insoluble polymers. Extracellular polymers were detected in both the culture media of cells expressing Bologna AAT and in the plasma of a patient homozygous for this variant. Structural modelling revealed that the mutation disrupts the hydrogen bonding network in the AAT shutter region. These data support a crucial coordinating role for asparagine 186 and the importance of this network in promoting formation of the native structure.
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http://dx.doi.org/10.3390/ijms22115668DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8198886PMC
May 2021

COVID-19 infection in severe Alpha 1-antitrypsin deficiency: Looking for a rationale.

Respir Med 2021 07 30;183:106440. Epub 2021 Apr 30.

Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Laboratory of Biochemistry and Genetics, Institute for Respiratory Disease, Department of Internal Medicine and Therapeutics, University of Pavia, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.

The clinical manifestations of COVID-19 are heterogeneous: 46.4% of patients admitted into hospital reported to have at least one comorbidity. Comorbidities such as COPD, diabetes, hypertension and malignancy predispose patients with Covid-19 to adverse clinical outcomes. Alpha 1-antitrypsin deficiency (AATD) is a genetic disorder caused by pathological mutation(s) in the SERPINA1 gene resulting in an imbalance in proteinase activity which may lead to premature emphysema and COPD. Our aim was to investigate whether people with severe AAT deficiency (AATD) have an increased risk of (severe) COVID-19 infection. We collected data on COVID-19 symptoms, laboratory-confirmed infection, hospitalization and treatment by means of a telephone survey, directly administered to Italian severe AATD subjects in May 2020. We then compared our findings with data collected by the Istituto Superiore di Sanità on the total population in Italy during the same period. We found an higher frequency of SARS-CoV-2 infection in our cohort (3.8%) compared to national data regarding infection, thus giving severe AATD a relative risk of 8. 8 (95%CI 5.1-20,0; p<0.0001) for symptomatic SARS-CoV-2 infection. Moreover, the relative risk (RR) was higher in AATD patients with pre-existing lung diseases (RR 13.9; 95%CI 8.0-33.6; p<0.001), but with a similar death rate (1 in 8, 12.5%) compared to the general population (13.9%; RR 0.9). These preliminary findings highlight the importance of close surveillance in the spread of COVID-19 in patients with severe AATD and underlines the need for further studies into the role of the antiprotease shield in preventing SARS-Cov-2 infection.
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http://dx.doi.org/10.1016/j.rmed.2021.106440DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8086383PMC
July 2021

Comparison of different algorithms in laboratory diagnosis of Alpha1-antitrypsin deficiency.

Clin Chem Lab Med 2021 Mar 5. Epub 2021 Mar 5.

Centre for Diagnosis of Inherited Alpha-1 Antitrypsin Deficiency, Laboratory of Biochemistry and Genetics, Institute for Respiratory Disease, Department of Internal Medicine and Therapeutics, University of Pavia, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.

Objectives: Alpha1-antitrypsin deficiency (AATD) is an inherited condition that predisposes individuals to an increased risk of developing lung and liver disease. Even though AATD is one of the most widespread inherited diseases in Caucasian populations, only a minority of affected individuals has been detected. Whereas methods have been validated for AATD testing, there is no universally-established algorithm for the detection and diagnosis of the disorder. In order to compare different methods for diagnosing AATD, we carried out a systematic review of the literature on AATD diagnostic algorithms.

Methods: Complete biochemical and molecular analyses of 5,352 samples processed in our laboratory were retrospectively studied using each of the selected algorithms.

Results: When applying the diagnostic algorithms to the same samples, the frequency of False Negatives varied from 1.94 to 12.9%, the frequency of True Negatives was 62.91% for each algorithm and the frequency of True Positives ranged from 24.19 to 35.15%. We, therefore, highlighted some differences among Negative Predictive Values, ranging from 0.83 to 0.97. Accordingly, the sensitivity of each algorithm ranged between 0.61 and 0.95. We also postulated 1.108 g/L as optimal AAT cut-off value, in absence of inflammatory status, which points to the possible presence of genetic AATD.

Conclusions: The choice of the diagnostic algorithm has a significant impact on the correct diagnosis of AATD, which is essential for appropriate treatment and medical care. The fairly large number of possible false negative diagnoses revealed by the present paper should also warn clinicians of negative results in patients with clinically-suspected AATD.
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http://dx.doi.org/10.1515/cclm-2020-1881DOI Listing
March 2021

Molecular diagnosis of alpha1-antitrypsin deficiency: A new method based on Luminex technology.

J Clin Lab Anal 2020 Jul 17;34(7):e23279. Epub 2020 Mar 17.

Center for Diagnosis of Inherited Alpha1-antitrypsin Deficiency, Laboratory of Biochemistry and Genetics, Institute for Respiratory Disease, Department of Internal Medicine and Therapeutics, University of Pavia, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.

Background: Alpha1-antitrypsin deficiency (AATD) is an under-diagnosed hereditary disorder characterized by reduced serum levels of alpha1-antitrypsin (AAT) and increased risk to develop lung and liver diseases at an early age. AAT is encoded by the highly polymorphic SERPINA1 gene. The most common deficiency alleles are S and Z, but more than 150 rare variants lead to low levels of the protein. To identify these pathological allelic variants, sequencing is required. Since traditional sequencing is expensive and time-consuming, we evaluated the accuracy of A1AT Genotyping Test, a new diagnostic genotyping kit which allows to simultaneously identify and genotype 14 deficiency variants of the SERPINA1 gene based on Luminex technology.

Methods: A total of 418 consecutive samples with AATD suspicion and submitted to the Italian Reference laboratory between January and April 2016 were analyzed both by applying the diagnostic algorithm currently in use, and by applying A1AT Genotyping Test.

Results: The assay gave the following results: 101 samples (24.2%) were positive for at least one of the 14 deficiency variants, 316 (75.6%) were negative for all the variants analyzed. The identified mutations showed a 100% correlation with the results obtained with our diagnostic algorithm. Seventeen samples (4%) resulted negative for the assay but sequencing identified other rare pathological variants in SERPINA1 gene.

Conclusion: The A1AT Genotyping Test assay was highly reliable and robust and allowed shorter diagnostic times. In few cases, it has been necessary to sequence the SERPINA1 gene to identify other rare mutations not included in the kit.
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http://dx.doi.org/10.1002/jcla.23279DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7370739PMC
July 2020

Peripheral CD19+CD24CD38 B-regulatory cells in lung transplant recipients.

Transpl Immunol 2019 12 14;57:101245. Epub 2019 Sep 14.

Department of Internal Medicine, Section of Pneumology, University of Pavia, Pavia, Italy; Department of Medical Sciences and Infective Diseases, Unit of Respiratory Diseases, IRCCS Policlinico San Matteo Foundation, Pavia, Italy.

Background: The role of CD19+CD24CD38 B-regulatory cells in solid-organ Transplant (Tx) in acceptance are still scarce. In previous studies on kidney transplant recipients may suggest a protective role of this cell subtype in graft tolerance and the existence of a cross talk between B-and T-regulatory clones. In lung transplantation, the role of B-regulatory cells has never been investigated. In a murine tracheal transplantation model, this subset seems able to prevent tracheal obliteration when in combination with rapamycin. Aim of this study is to analyze peripheral CD19+CD24CD38 B-reg cells counts in a cohort of lung recipients, their association with several clinical and pharmacological variables and their possible association with T regulatory cell.

Methods: From Jan 2009 to Dec 2014, 117 lung Tx recipients were submitted to an immunological follow up I-FU(median: 108.7 months (6.7-310.5)). Immunological follow up consisted of a complete blood peripheral immuno-phenotype, inclusive of CD19+CD24CD38 B-cells (globally 1106 determinations). We tested the association between B-reg and relevant variables by linear or regression models for repeated measures, adjusting for time from Tx.

Results: Among all variables analyzed at multivariate analysis: chronic rejection (OR - 0.19, p = .039), use of Mycophenolate (OR - 0.38, p < .001) and the presence of a concomitant pulmonary infection of S. aureus (OR 0.66, p = .002) and A. fumigatus (OR 0.50, p = .009) were significantly associated to B-reg cell. No significant correlation between CD19+CD24CD38 B-reg cells and T-reg cells counts was found in our cohort.

Conclusions: Our present data highlight, for the first time, that this cell subset might participate in long-term lung graft acceptance mechanisms.
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http://dx.doi.org/10.1016/j.trim.2019.101245DOI Listing
December 2019