OCCURRENCE OF CIRCULATING IMMUNE-COMPLEXES AND VIRAL-ANTIGENS IN IDIOPATHIC THROMBOCYTOPENIC PURPURA

Abstract

The sera of 72 patients with ITP [idiopathic thrombocytopenic purpura] were tested for their inhibitory activity on the agglutination of Ig[immunoglobulin]G-coated particles by RF [rheumatoid factor] or C1q [q fragment of the 1st complement component]. The majority (83%) displayed an inhibitory effect toward both agglutinators, whereas 17% contained endogenous RF. A negative correlation was observed between the number of platelets and the titers of inhibitory factors. Some sera were fractionated by gel filtration. The inhibitory factors and sometimes trace amounts of IgG were distributed over several peaks eluted before monomeric 7S IgG. The IgG detected in the heavy fractions of 2 ITP sera corresponded to antigen-antibody complexes as shown by dissociation experiments at acid pH. In all ITP sera analyzed by chromatography, DNA was detected in the heavy fractions and appears to be the antigen of certain complexes. The sera from 42 patients with ITP were analyzed by counter-electrophoresis for the presence of viral antigens. HBs [hepatitis B surface] antigen was detected in 20 sera, EBV [Epstein-Barr virus] antigen in 5 and adenovirus antigen in 6.