Helminthic parasites cause widespread, persistent infections in humans. Schistosomiasis
mansoni infected patients being in a chronic immune-activation state enabled us to
investigate the effects of such immune activation on immune responses. We performed
by flow cytometry a phenotypic analysis of peripheral blood T lymphocytes from 64
Schistosoma mansoni infected patients, in different clinical forms of the chronic disease.
The main findings in the patient group in comparison with the non-infected controls
were: (i) decreased CD3, CD4 and CD8 lymphocyte counts; (ii) elevated levels of
activated T cells (CD4 expressing HLA-DR); (iii) decreased numbers of CD28+ CD8+
lymphocytes. These findings support the notion that chronic helminthic infections cause
persistent immune activation that result in hyporesponsiveness and anergy. Such
impaired immune functions may diminish the capacity of these individuals to cope with
infections and to generate cellular protective immunity after vaccination. |
