Distinct B-cell populations are present in hepatic and intestinal Schistosoma mansoni granulomas.

Although it is generally accepted that schistosomal granuloma formation results from a T-cell dependent host response towards the parasite egg, attention has recently been focused on the involvement of B-cells in the induction of schistosome-induced pathology. In this study we investigated the involvement of two functionally different B-cell populations in the formation of the Schistosoma mansoni granuloma: naive and antigen-stimulated B-cells. In liver granulomas two distinct B-cell populations were found, namely unstimulated B-cells at the periphery of the granuloma and antigen-stimulated, syndecan-1 positive B-cells in the inner part near the deposited egg. Intestinal granulomas differed by their relative lack of unstimulated B-cells at the granuloma periphery, but like hepatic granulomas intestinal granulomas also have syndecan-1 positive B-cells. From our results, we conclude that B-cells are important constituents of the S. mansoni granuloma.