ASSOCIATION OF 16 6 AND SA1 ANTI-DNA IDIOTYPES WITH ANTICARDIOLIPIN ANTIBODIES AND CLINICAL MANIFESTATIONS IN A LARGE COHORT OF SLE PATIENTS/

Objective The SA1 and 16/6 idiotypes can be found in some patients wit h systemic lupus erythematosus (SLE) or antiphospholipid syndrome (APS ). The aim of this study was to ascertain the prevalence of these idio types in a large cohort of SLE patients, and to determine whether thei r presence is correlated with the anticardiolipin (aCL) and anti-dsDNA antibodies or with the clinical manifestations of SLE. Methods 492 SL E patients were evaluated for clinical manifestations of SLE and were assigned a disease severity score. ds-DNA autoantibodies, aCL autoanti bodies of the IgM, Ige and IgA isotypes, and SA1 and 16/6 idiotypes we re also determined in these patients. Results The prevalence of the SA 1 and 16/6 idiotypes in the 492 SLE patients was found to be 11% and 5 .1%, respectively, and these idiotypes were significantly more prevale nt in the patients who had aCL antibodies of either the IgG, IgM or Ig A isotypes. Moreover, while the 16/6 idiotype was not associated with the clinical manifestation of either SLE or APS, the SA1 idiotype was found significantly more frequently in patients who had vascular event s, Raynaud's phenomenon or hemolytic anemia (p = 0016, 0.01, 0.01, res pectively). Conclusion SLE patients with the SA1 idiotype may run a hi gher risk of developing vascular events, Raynaud's phenomenon or hemol ytic anemia. These clinical manifestations can be attributed to both S LE and secondary APS when aCL autoantibodies are also found. These res ults indicate that the possible pathogenicity of certain idiotypes in SLE cannot be excluded.