Theoccurrence ofcirculating immunecomplexes andviral antigens inidiopathic thrombocytopenic purpura

SUMMARY Theseraofseventy-two patients withITPweretested fortheir inhibitory activity onthe agglutination ofIgG-coated particles byRForClq. Themajority (83%) displayed aninhibitory effect toward bothagglutinators, whereas 17%werefound tocontain endogenous RF.Anegative correlation wasobserved between thenumber ofplatelets andthetitres ofinhibitory factors. Someserawerefractionated bygelfiltration. Theinhibitory factors andsometimes trace amounts ofIgGweredistributed overseveral peaks eluted before monomeric 7SIgG. TheIgG detected intheheavy fractions oftwoITPseracorresponded toantigen-antibody complexes asshownbydissociation experiments atacid pH.Inall ITPseraanalysed bychromatography, DNAhasbeen detected intheheavy fractions andappears tobetheantigen ofcertain complexes. Theserafromforty-two patients with ITPwereanalysed bycounter-electrophoresis forthe presence ofviral antigens. HBsantigen wasdetected intwenty sera, EBVantigen infive, and adenovirus antigen insix.