Thrombocytopenic purpura has recently been noted in sexually active homosexual men. To elucidate the pathogenesis of thrombocytopenic purpura in this population, we compared the disorder in 33 homosexual men with that in 23 patients (15 women and 8 men) thought to have classic autoimmune thrombocytopenic purpura. The homosexual group had 3.8-fold higher levels of platelet-bound IgG and 4.2-fold higher levels of platelet-bound complement than the patients with autoimmune thrombocytopenic purpura. Eluates from the platelets of only 1 of 10 homosexual patients reacted in vitro with normal platelets, as compared with those from the platelets of 12 of 15 patients with autoimmune thrombocytopenic purpura. Twenty-one of 24 homosexual patients (88 per cent) had elevated serum levels of immune complexes that were capable of binding to platelets, whereas none of 5 patients with autoimmune thrombocytopenic purpura had circulating immune complexes. The IgG fraction of positive serum samples from three homosexual patients did not bind to normal platelets, whereas that from the positive serum of two patients with autoimmune thrombocytopenic purpura and one woman in whom isoimmune antiplatelet antibody developed during pregnancy (studied as a positive control) did bind to normal platelets. We conclude that, whereas classic autoimmune thrombocytopenic purpura involves antiplatelet IgG directed against platelet antigenic determinants, the thrombocytopenic purpura that occurs in sexually active homosexual men is usually caused not by antiplatelet IgG but probably by the nonspecific deposition of complement and immune complexes on platelets.

Pediatricians play an important role in the prevention of child maltreatment. Their knowledge of the effectiveness of different programs can help guide parents toward appropriate services.

A group of 44 homosexual patients with immune thrombocytopenia and serologic evidence of infection with the human immunodeficiency virus (HIV) was observed for a total of 844 person-months. The risk of developing the acquired immunodeficiency syndrome (AIDS), an actuarial incidence of 36.5% in 37 months, was no different than that reported for seropositive homosexual men from New York who are nonthrombocytopenic and asymptomatic. A statistical analysis comparing the hazard function with a constant-risk model showed that the hazard of developing AIDS was not constant but increased with duration of seropositivity.

In view of the clear immunomodulatory actions seen in our study and in earlier clinical trials, we believe that MTP-PE deserves further study in the adjuvant setting.