Effect of Leishmania major on luminol-dependent chemiluminescence of human whole blood phagocytosis.

The aim of this study is to examine the effect of L. major on human whole blood phagocytosis. The phagocytosis was activated by phorbol myristate acetate (PMA) or opsonized zymosan. Various types of Leishmania antigens were tested on luminol-dependent chemiluminescence. In PMA-activated whole blood phagocytosis group, promastigotes and infected medium significantly (P less than 0.001) depressed the maximum peak of chemiluminescence to 5.77 +/- 1.6 and 5.65 +/- 0.45 mV respectively, compared to 9.85 +/- 22 in control group. In a similar fashion a significant reduction of the area under the curve was noted. On the other hand, opsonized zymosan-activated phagocytosis was significantly (P less than 0.025) inhibited in the promastigote treated group only. The maximum peak response was 4.68 +/- 1.5 and 10.8 +/- 0.46 mV in promastigote and control groups, respectively. The above data indicated; a) an inhibition of whole blood phagocytosis induced by Leishmania and b) a marked reduction of the oxygen-reactive metabolites radicals generated by whole blood phagocyte cells and measured by luminol-dependent chemiluminescence suggesting the important role of oxygen free radicals in the pathogenesis of leishmaniasis.