|Title:||Identification and characterization of IgA antibodies against beta 2-glycoprotein I in childhood Henoch-Schonlein purpura||Authors:||Yang, Yao-Hsu
Chang, C. J.
Chuang, Y. H.
Hsu, H. Y.
Yu, H. H.
Lee, J. H.
Wang, L. C.
Lin, Y. T.
Chiang, B. L.
|Issue Date:||2012||Journal Volume:||167||Journal Issue:||4||Start page/Pages:||874-881||Source:||Br. J. Dermatol.||Abstract:||
Background Henoch-Schonlein purpura (HSP) is a common IgA-mediated vasculitis in children. The antigenic target for IgA is to be determined.
Objective To test whether beta 2-glycoprotein I (beta 2GPI) is an antigenic target for IgA in childhood HSP, and to evaluate the clinical implications and pathogenic role of such IgA autoantibodies.
Methods The reactivity of patients' plasma samples and purified polyclonal IgA with beta 2GPI, beta 2GPI-derived peptides and endothelial cells was tested by enzyme-linked immunosorbent assay. The association between clinical manifestations and IgA anti-beta 2GPI antibodies was also analysed. Finally, IgA-mediated cytotoxicity on endothelial cells was further evaluated.
Results At the acute stage, patients with HSP had significantly higher plasma levels of IgA antibodies against beta 2GPI than healthy controls [reference units (RU) 1.14 +/- 0.8 vs. 0.42 +/- 0.24, P < 0.001]. IgA anti-beta 2GPI antibodies were associated with the presence of joint manifestations (with vs. without joint involvement, 1.15 +/- 0.64 vs. 0.85 +/- 0.47, P = 0.0341) and heavy proteinuria (with vs. without heavy proteinuria, 2.09 +/- 2.02 vs. 1.04 +/- 0.62, P = 0 0028). Polyclonal IgA from plasma samples positive for IgA anti-beta 2GPI antibodies bound well not only to beta 2GPI with Kd values < 10(-5) mol L-1, but also to some beta 2GPI-dereived linear peptides (P3, P5, P7, P11 and P12). Moreover, beta 2GPI-reactive polyclonal IgA also bound well to endothelial cells and induced complement-dependent cell lysis.
Conclusion These findings reveal the clinical and pathogenic relevance of IgA anti-beta 2GPI antibodies in childhood HSP and suggest that beta 2GPI may be an important autoantigen for HSP.
|Appears in Collections:||醫學系|
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