[Influence of hypergammaglobulinemia on antiphospholipid antibodies titres].

Purpose: Antiphospholipid antibodies (aPL), anticardiolipin antibodies (aCL) or lupus anticoagulant (LA), are indispensable for the diagnosis of antiphospholipid syndrome (APS). However, antiphospholipid assays can generate false positive results.

Materials: We have studied the influence of hypergammaglobulinemia (HG) on aPL antibodies titers in 232 patients twice as positive for aPL antibodies.

Results: Out of 232 patients, 93 have an APS (76 primary APS, 17 secondary APS). Thrombosis occurred 138 times in APS patients. Of 139 patients without APS, 95 have an auto-immune disease, 28 have an isolated prolonged KCT and 16 an evolutive neoplasia. LA seems to be the best marker of APS. On the other hand aCL IgG and M, anti-beta2-GP1 IgM titers are significantly higher in patients without APS but with HG.

Conclusion: Those results suggest that biological APS diagnosis should be carefully performed in patients with HG. In this case, other additional risk factors must be considered for the etiological diagnosis of thrombosis.