CLINICAL AND EXPERIMENTAL IMMUNOLOGY

p. 424-429The immunological response in HTLV-1 infected individuals is characterized by a prominent Type-1 cytokine response with high production of IFNg and TNFa. In contrast, helminthic infections and in particular chronic schistosomiasis are associated with a predominant production of IL-4, IL-5, IL-10 and IL-13. Liver fibrosis is the main pathological finding in schistosomiasis that occurs after many years of infection. This pathology is T cell dependent but the immune response mechanisms are not completely understood. The North-east region of Brazil is endemic for both HTLV-1 and schistosomiasis. In the present study the immune response, clinical severity, and therapeutic response to praziquantel of patients with schistosomiasis coinfected with HTLV-1 were compared with patients infected only with S. mansoni. Patients with HTLV-1 and S.mansoni had lower levels of IL-5 (P<0·05) and higher levelsof (P