Thrombocytopenia in the HELLP syndrome is not due to platelet-associated IgG (PAIgG).

The presence of membrane-bound and circulating platelet-associated IgG (PAIgG) in nine pregnant women with hemolysis, elevated liver enzymes, and low platelet count (HELLP syndrome) was investigated. The reference group consisted of 21 patients with chronic idiopathic thrombocytopenic purpura (ITP). In the majority of patients with ITP, thrombocytopenia results from the binding of PAIgG to the platelet membrane with subsequent platelet destruction. In none of the patients with HELLP syndrome membrane-bound or circulating PAIgG was found. By contrast, membrane-bound and circulating PAIgG was detected in 15 of the 21 cases of chronic ITP (71.4%). These findings suggest that platelet destruction in patients with HELLP syndrome does not result from the binding of PAIgG to the platelet membrane. Therefore, the treatment of thrombocytopenia in this syndrome with immunosuppressants (e.g., corticosteroids), as in chronic ITP, does not seem appropriate.