Schistosomiasis is a disease whose pathology is strongly related to the
granulomatous reaction formed around parasite eggs trapped in host tissues.
Studies have shown that the chronic intestinal form (INT) of this infection
is associated with a variety of immunoregulatory mechanisms which lead to a
diminished granulomatous reaction. Using an in vitro model of granuloma
reaction, we show that immune complexes (IC) isolated from sera of INT
patients are able to reduce granulomatous reaction developed by peripheral
blood mononuclear cells (PBMC) from acute (AC), INT and hepatosplenic (HE)
patients to soluble egg antigen (SEA)-conjugated polyacrylamide beads
(PB-SEA). This inhibitory activity is also observed in cell proliferation
assay of PBMC from INT and HE patients stimulated with SEA and adult worm
antigen (SWAP). Furthermore, IC isolated from sera of patients with
different clinical forms of the disease are also able to suppress INT
patients PBMC reactivity. Therefore, our results show that circulating IC
present in sera of patients with different clinical forms of
schistosomiasis may down-regulate PBMC reactivity to parasite antigens
resulting in a diminished granuloma reaction to parasite eggs.