High Levels of IL-10 and CD4+CD25hi+ Treg Cells in Endemic Burkitt's Lymphoma Patients.

Background: The interplay between Epstein-Barr virus infection, malaria, and endemic Burkitt's Lymphoma is not well understood. Reports show diminished EBV-specific Th1 responses in children living in malaria endemic areas and deficiency of EBNA1-specific IFN-γ T cell responses in children with endemic Burkitt's Lymphoma (eBL). This study, therefore, examined some factors involved in the loss of EBNA-1-specific T cell responses in eBL.

Methods: T-cell subset frequencies, activation, and IFN-γ- or IL-4-specific responses were analyzed by flow-cytometry. Plasma cytokine levels were measured by ELISA.

Results: CD4+ and CD8+ cells in age- and sex-matched healthy controls ( = 3) expressed more IFN-γ in response to all immunostimulants than in pediatric endemic BL (eBL) patients ( = 4). In healthy controls, IFN-γ expression was higher than IL-4 expression, whereas in eBL patients the expression of IL-4 by CD4+ cells to EBNA-1 was slightly higher than IFN-γ. Moreover, the blood levels of TNF-α was significantly lower ( = 0.004) while IL-10 was significantly higher ( = 0.038), in eBL patients ( = 21) compared to controls ( = 16). Additionally, the frequency of CD4+CD25hi+ T cells was higher in both age-matched acute uncomplicated malaria ( = 26) and eBL ( = 14) patients compared to healthy controls ( = 19; = 0.000 and = 0.027, respectively).

Conclusion: The data suggest that reduced Th1 response in eBL might be due to increased levels of IL-10 and T reg cells.