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Published on: December 15, 2011
Evaluation of Specific Antibody Responses in Patients with Selective IgA Deficiency and Ataxia Telangiectasia
Shaghayegh Khanmohammadi1,2, Tannaz Moeini Shad1,2, Samaneh Delavari1,2
1Research Center for Immunodeficiencies, Pediatrics Center of Excellence, Children's Medical Center, Tehran University of Medical Science, Tehran, Iran.
Background:
Specific Antibody Deficiency (SAD) is a primary immunodeficiency disease (PID) characterized by the occurrence of recurrent infections and inadequate antibody response to polysaccharide new antigens.
Objective:
This study aims to determine the titer of specific antibodies against unconjugated 23-valent pneumococcal polysaccharide vaccine (PPSV-23), the presence of SAD, and its association with clinical and laboratory findings in Ataxia-telangiectasia (A-T) and selective immunoglobulin A deficiency (SIgAD) patients.
Methods:
32 A-T patients and 43 SIgAD patients were included in this cross-sectional study. Samples of the patients were obtained before and three weeks after vaccination with PPSV-23. Specific immunoglobulin G (IgG) directed towards pneumococcal capsular antigen and specific antibodies against whole pneumococcal antigens was measured.
Results:
Comparison of the response to vaccination revealed that 81.3% of A-T patients and 18.6% of the SIgAD patients had an inadequate response to PPSV-23 (p<0.001). The prevalence of recurrent infection (p=0.034) and pneumonia (p=0.003) in SIgAD patients was significantly higher in non-responders than responders. Likewise, the number of marginal zone B cells (p=0.037), transitional B cells (p=0.019), plasmablasts (p=0.019), CD8+ naïve T cells (p=0.036), and percentage of CD8+ T cells (p=0.047), switched memory B cells (SMB) (p=0.026) and immunoglobulin M (IgM) memory B cells (p=0.022) in SIgAD patients were significantly lower in non-responder group than responder group. In contrast, the percentage of CD4 T+ cells in A-T patients was lower in the non-responder group than responders (p=0.035).
Conclusion:
SAD is more frequent in A-T patients than SIgAD patients. The role of SMB and T cells should not be underestimated in SAD.

