Monomorphic HLA Reactivity in Heroin Addicts and Hydatidosis Patients

The presence of HLA antibodies was tested by a double precipitation test with purified 125I-labeled class I or class II molecules. One hundred sixty-two of the 210 sera from heroin addicts (Fig. la) and 31 of the 32 sera from hydatidosis patients (Fig. lc) showed significant reactivity against the class II molecules from the KT13 (DR4,4) cell line. Only one out of 100 male blood donors was positive (Fig. lb). No positivities were found in patients with malaria, acute schistosomiasis, invasive amebiasis, as well as in HBsAg-positive subjects and in HIV-positive, non-heroin addict male homosexuals (Fig. 1 diag, respectively). Similar reactivity was found against class I and class II molecules irrespective of the HLA phenotype. No reactivity was observed against 132m, BSA, and several glycoproteins. This phenomenon may be associated to repeated or continuous antigenic stimulation and could, conceivably, represent a mechanism underlying the immune hyporeactivity of the two groups of subjects considered.