The association of VP1 unique region protein in acute parvovirus B19 infection and anti-phospholipid antibody production.
BACKGROUND
Previous studies have postulated a connection between human parvovirus B19 (B19) infection and anti-phospholipid antibodies (aPL). Recently, the phospholipase domain of B19 has been linked to B19-VP1 unique region (VP1u). To elucidate the roles of VP1u in B19 infection and aPL production, the major reactivity of anti-B19-VP1u, anti-cardiolipin antibody (aCL), and anti-beta2-glycoprotein I (beta2GPI) antibody was evaluated.


METHODS
Sera from 102 clinically suspected cases of B19 infection were analyzed by nested PCR and ELISA. Humoral responses of anti-B19-VP1u and anti-B19-VP1uD175A IgM/IgG antibodies, aCL and the anti-beta2GPI antibody were assessed by Western blot and ELISA. Absorption experiments were also performed to determine the binding specificity of immunoglobulins to B19-VP1u, CL and beta2GPI.


RESULTS
Sera from patients with the diagnostic pattern DNA+/IgM+/IgG+ had a high frequency (57%) for recognition of CL and beta2GPI. Furthermore, adsorption experiments were performed by adding purified B19-VP1u, which partially suppressed the reactivity of anti-B19VP1u to CL and beta2GPI.


CONCLUSIONS
Serum from patients with acute B19 infection has a high frequency in recognition of CL and beta2GPI, and the phospholipase domain observed in the B19-VP1u may have contributed to the production of aPL. These findings may provide a clue for understanding the roles of B19-VP1u in B19 infection and aPL production.
Tzang
Bor-Show
BS
Institute of Biochemistry and Biotechnology, Chung Shan Medical University, and Department of Internal Medicine, Chung Shan Medical University Hospital, Taichung, Taiwan.
Tsay
Gregory J
GJ
Lee
Yi-Ju
YJ
Li
Chin
C
Sun
Yu-Shu
YS
Hsu
Tsai-Ching
TC
D000293:Adolescent; D000328:Adult; D000368:Aged; D017152:Antibodies, Antiphospholipid / Q000096:biosynthesis*; D000914:Antibodies, Viral / Q000097:blood; D036022:Capsid Proteins / Q000235:genetics / Q000276:immunology*; D002308:Cardiolipins / Q000097:blood; D002648:Child; D004279:DNA, Viral / Q000097:blood; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008297:Male; D008875:Middle Aged; D010322:Parvoviridae Infections / Q000276:immunology*; D016732:Parvovirus B19, Human / Q000276:immunology*; D053482:beta 2-Glycoprotein I / Q000276:immunology
D017152:Antibodies, Antiphospholipid; D000914:Antibodies, Viral; D036022:Capsid Proteins; D002308:Cardiolipins; D004279:DNA, Viral; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D053482:beta 2-Glycoprotein I; C095547:capsid protein VP1, parvovirus B19