Lymphocyte subpopulations in bancroftian filariasis : activated(DR+) CD8+ T cells in patients with chronic lymphatic obstruction.

Renu Lal, B.; Kumaraswami, V.; Krishnan, N.; Nutman Thomas, B.; Ottesen, E.A.

Clinical and Experimental Immunology; 1989; 77; 77-82.

To examine the relationship between lymphocyte phenotypes and states of activation in patients with Bancroftian filariasis, dual colour flow cytometry and concurrent in vitro cell culture were performed on normal individuals (NV; n=15), and on patients with either asymptomatic microfilarraemia (MF; n=12) or elephantiasis (CP; n=11). In contrast to findings by others in a population with Brugian filarasis, the percentages of total B lymphocytes (CD19). T lymphocytes (CD8) in both patient groups were found to be within the range defined by clinically normal individuals. Furthermore, there were no differences among the groups in the expression of the IL-2 receptors (CD25) on T cells. There was, however, a significantly greater proportion (p < 0.01) of 'activated' cytotoxic suppressor lymphocytes (defined by co-expression of CD8 and HLA-DR) in patients with elephantiasis (16.4±8.6%) than in the MF (8.9±2.6%) or NV (8.3±2.9%) groups. Further, when the expression of this activation antigen was examined in parallel with in vitro mitogen responsiveness, an inverse correlation between the percentage of (CD8 + HLA-DR + lymphocytes and pokeweed mitogen-induced proliferation was seen (r=-0.54; p < 0.001). These data provide further definition of the immunoregulatory abnormalities seen in human filarial infections and suggest that activated CD8 + T lymphocytes may be involved in the pathogenesis of the chronic obstructed lymphatic form of this disease.


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