Study on the relationship of immune status with severity of schistosomiasis japonica in fishermen in the Dongting Lake

Objective To investigate the relationship of the immune status and the intensity of infection or the severity of the hepatosplenic pathology among fishermen with schistosomiasis japonica in the Dongting Lake region. Methods Inquiring and physical examination (IPE), stool examination, B-ultrasonography of the liver and spleen, flow cytometry, turbidimetry and ELISA were undertaken to acquire or determine the intensity of infection (EPG in stool), pathological change in the liver and spleen and the level of cellular and humoral immunity. Data were analyzed with SPSS 10.0 statistics software. Results Compared with subjects from non-endemic area, the CD4+ T cells and the CD4+/CD8+ ratio in fishing population in the endemic area significantly decreased. The decrease of the CD4+/CD8+ ratio was more significant among population with positive stool exam and with the increase of EPG and/or severity of pathological change in the liver and spleen. Contrarily, the level of the total IgM and the anti-SEA IgG in serum from fishing population in the endemic area was significantly higher than those from non-endemic area. High level serum antibodies in those stool positives were remarkable with the increase of EPG and/or the severity of hepatosplenic pathological change. The total IgA increased considerably in the subjects with significant pathological change of the liver and spleen. A high total IgG was only detected in those stool positives. Conclusion The immune status in fishermen with schistosomiasis in the Dongting Lake showed a suppressed cellular immunity and a hyper functioning humoral immune response. The imbalance of the immunity was related to the increase of the intensity of infection and the progress of the hepatosplenic pathology.