[Study on immune status of patients with schistosomiasis japonica in Poyang Lake region III Humoral and cellular immune characteristics between Schistosoma japonicum high and low antibody responders].

OBJECTIVE: To explore the immune mechanism of negative results of immune tests of schistosomiasis japonica patients. METHODS: Totally 142 schistosomiasis patients (positive stool examinations) of Poyang Lake region were tested by ELISA method, and the ROC curve was applied to determine the high and low response of the patients. The levels of cellular immunity and cytokines of high and low responders were compared. RESULTS: Totally eight schistosomiasis patients were found as low responders. Besides SWAP-IgA (t = -1.588, P > 0.1), the levels of isotype antibodies were significantly lower in the low responders compared with those in the high responders (t = -14.517 to -2.866, all P < 0.05). In the low responders, the propor- tion of CD3⁺T was increased; and the proportions of CD4⁺T, CD8⁺T, CD4⁺CD25⁺Treg, and the ratio of CD4⁺/CD8⁺ were all de- creased, but all of them were not significant (t = -1.72 to 0.974, all P > 0.05) compared with those in the high responders. The differences of IFN-γ and IL-10 between the high and low responders were both not significant (t = -2.426 to 0.216, all P > 0.05). CONCLUSIONS: There is a significant difference between the high and low responders only in the levels of isotype antibodies. One of the reasons of low response in the immune tests is the much lower antibody level after the antigen-antibody compound is completely formulated.