Increased frequency of TH2-type cytokine-producing T cells in microfilaremic loiasis

The frequency of cytokine-producing peripheral blood mononuclear cells was assessed in 28 subjects with microfilaremic loiasis and in 14 amicrofilarem ic individuals. In addition, a subgroup of seven microfilaremic individuals coinfected with Plasmodium malariae was evaluated. By using flow cytometry for the intracellular detection of cytokines, a more pronounced T helper ( Th)2 cell-type response with the expansion of interleukin (IL)-4, IL-10, an d IL-13 expressing CD4(+) cells in the microfilaremic compared with the ami crofilaremic group was noted. Expression of IL-5 was equivalent in both gro ups as was the frequency of Th2-type cytokines expressing CD8(+) cells and of Th1-type cytokines (interferon [IFN]-gamma, IL-2, IFN-gamma/IL-2) produc ing CD4(+) and CD8(+) cells. Th0-type cytokine-expressing cells, represente d by IL-4/IFN-gamma, IL-10/IFN-gamma, and IL-13/IFN-gamma, were equally dis tributed within groups. Coinfection of P. malariae did not significantly al ter the cytokine expression compared with microfilaremic individuals withou t P. malariae infections. By identifying a large panel of cytokine-producin g T cell subpopulations, a Th2-driven immune response in microfilaremic Loa loa patients was noted.