Splenocytes from 25 patients with severe hepatosplenic
schistosomiasis mansoni were obtained after therapeutic
splenectomy. Spleen cells were phenotyped and analysed for responsiveness to
mitogens or heterogeneous schistosome-derived antigenic preparations (eggs, SEA; adult worms, SWAP; cercariae, CERC) in blastogenesis assays and lymphokine production systems, and were compared with peripheral blood mononuclear cells (PBMN). Splenic lymphocytes were 55% T lymphocytes (sheep erythrocyte rosette-positive) and 37%
surface immunoglobulin-positive B lymphocytes. The mean T4+:T8+ ratio of these splenocytes was 1.0. Phytohaemagglutinin stimulated spleen cell production of the lymphokine mitogenic factor, but exposure to SEA or SWAP did not. Spleen cell and PBMN blastogenic responses to SEA and SWAP were sometimes, but not always in accord. Removal of
plastic adherent cells allowed the non-adherent spleen cells of 30-40% of the patients to respond substantially more vigorously to SEA, SWAP and CERC. Spleen cells from a subgroup of 20-30% of the patients failed to respond to the schistosomal
antigens regardless of removal of adherent cells. Spleen cell responses to gram-negative
lipopolysaccharide peaked on day 5 or 6 of culture, and were augmented by adherent cell removal. Pokeweek
mitogen-stimulated responses were optimal on day 5 of culture. Spleen cells from most severe, hepatosplenic
schistosomiasis mansoni patients do not respond well to schistosomal
antigens or B-cell
mitogens. The splenic responses of many of these patients were elevated by the removal of adherent spleen cells.