Hypogammaglobulinemia Publications (7607)
Several classes of pattern recognition receptors (PRRs) are involved in the pathogenesis of diseases, including Toll-like receptors (TLRs), C-type lectin receptors (CLRs), and Nod-like receptors (NLRs). Patients with primary immune deficiencies (PIDs) affecting TLR signaling can elucidate the importance of these proteins in the human immune system. Defects in interleukin-1 receptor-associated kinase-4 and myeloid differentiation factor 88 (MyD88) lead to susceptibility to infections with bacteria, while mutations in nuclear factor-κB essential modulator (NEMO) and other downstream mediators generally induce broader susceptibility to bacteria, viruses, and fungi. In contrast, TLR3 signaling defects are associated with susceptibility to herpes simplex virus type 1 encephalitis. Other PIDs induce functional alterations of TLR signaling pathways, such as common variable immunodeficiency in which plasmacytoid dendritic cell defects enhance defective responses of B cells to shared TLR agonists. Altered TLR responses to TLR2 and 4 agonists are seen in chronic granulomatous disease (CGD) and X-linked agammaglobulinemia (XLA). Enhanced TLR responses, meanwhile, are seen for TLRs 5 and 9 in CGD, TLRs 4, 7/8, and 9 in XLA, TLRs 2 and 4 in hyper IgE syndrome (HIES), and for most TLRs in adenosine deaminase deficiency. In this review we provide the reader with an update on the role of TLRs and downstream signaling pathways in PID disorders.
We present the clinical and immunological profile of a young man with Good's syndrome that was initially presumed to be common variable immunodeficiency.
The change in ANCA titers and total immunoglobulin levels over time were evaluated using mixed-effects models. Risk factors for serious infections during maintenance were evaluated with Poisson regression.
During induction, IgG levels fell at a rate of 6% per month (95% CI, 4 to 8%), while ANCA levels declined at 47% per month (95% CI, 42 to 52%) and 48% per month (95% CI, 42 to 54%) for anti-MPO and anti-PR3 titers, respectively. During maintenance treatment, with a median duration of 2.4 (IQR, 1.5- 4.0) years, IgG levels declined at 0.6% per year (95% CI, -0.2 to 1.4%). New significant hypogammaglobulinemia (IgG < 400 mg/dL) during maintenance occurred in 4.6% of patients, all of whom were in the lowest baseline IgG quartile. Serious infections during maintenance occurred at a rate of 0.85 [95% CI, 0.66 to 1.1] per 10 patient years and were independently associated with an IgG level < 400mg/dL.
B cell targeted therapy causes a preferential decline in ANCA titers relative to total IgG levels. Despite prolonged maintenance therapy with rituximab, IgG levels remain essentially constant. Serious infections were rare. This article is protected by copyright. All rights reserved.
9% of the cohort developed all three complications. One hundred and twenty (20%) subjects developed SC, 98 MI (12%) and 80 AD (10%); these complications seem to occur in a mutually exclusive manner. By Kaplan-Meier analysis we estimated that after 20 years from the diagnosis SC, MI and AD occurred in 48%, 42% and 29% of patients, respectively. Furthermore, we showed that some clinical and biological markers are skewed among patients with different complications and that subjects with MI and SC had a worse prognosis than those with AD and all other patients (p < 0.0001).
This study reveals the existence of different clinical subsets of chronic lymphocytic leukaemia patients characterised by an increased and different risk for developing specifically MI, SC and AD.
A 15-month-old Korean boy presented with recurrent sinusitis and otitis media after 6 months of age, and had a family history of 2 maternal uncles with XLA. Laboratory tests revealed a profound deficiency of Ig isotypes, and a decreased count of CD19(+) B cells in the peripheral circulation. Based on his family history and our laboratory test results, he was diagnosed with XLA. We performed BTK gene analysis of peripheral blood samples obtained from family members to confirm the diagnosis. Mutational analysis revealed a novel hemizygous frameshift mutation (c.82delC, p.Arg28Alafs(*)5), in the BTK gene. His mother and maternal grandmother were heterozygous carriers of this mutation and his two maternal uncles were hemizygous at the same position. After XLA diagnosis, intravenous immunoglobulin (400 mg/kg, monthly) treatment was initiated; recurrent sinusitis and otitis media were subsequently brought under control. To our knowledge, this is the first reported case of a Korean pedigree with a novel mutation in the BTK gene.
Immune thrombocytopenic purpura and autoimmune hemolytic anemia are the most common autoimmune disorders in this group of patients. The aim of this review is to describe the proposed mechanisms for autoimmunity and to review the literature with respect to the reported autoimmune disorders in each type of PAD.
Homozygous frameshift or in-frame deletions in CD70 in these patients abolished either CD70 surface expression or binding to its cognate receptor CD27. Blood lymphocyte numbers were normal, but the proportions of memory B cells and EBV-specific effector memory CD8(+) T cells were reduced. Furthermore, although T cell proliferation was normal, in vitro-generated EBV-specific cytotoxic T cell activity was reduced because of CD70 deficiency. This reflected impaired activation by, rather than effects during killing of, EBV-transformed B cells. Notably, expression of 2B4 and NKG2D, receptors implicated in controlling EBV infection, on memory CD8(+) T cells from CD70-deficient individuals was reduced, consistent with their impaired killing of EBV-infected cells. Thus, autosomal recessive CD70 deficiency is a novel cause of combined immunodeficiency and EBV-associated diseases, reminiscent of inherited CD27 deficiency. Overall, human CD70-CD27 interactions therefore play a nonredundant role in T and B cell-mediated immunity, especially for protection against EBV and humoral immunity.
Since 2005, we have offered a comprehensive genetic testing service for PIDs and other immune-related disorders with a published sequence. Here we present results for this program, over the first decade, between 2005 and 2014.
We undertook testing in 228 index cases and 32 carriers during this time. The three most common test requests were for X-linked lymphoproliferative (XLP), tumour necrosis factor receptor associated periodic syndrome (TRAPS) and haemophagocytic lymphohistiocytosis (HLH). Of the 32 suspected XLP cases, positive diagnoses were established in only 2 patients. In contrast, genetic defects in 8 of 11 patients with suspected X-linked agammaglobulinemia (XLA) were confirmed. Most XLA patients were initially identified from absence of B cells. Overall, positive diagnoses were made in about 23% of all tests requested. The diagnostic rate was lowest for several conditions with locus heterogeneity.
Thorough clinical characterisation of patients can assist in prioritising which genes should be tested. The clinician-driven customised comprehensive genetic service has worked effectively for New Zealand. Next generation sequencing will play an increasing role in disorders with locus heterogeneity.