Bone marrow histopathological changes in visceral leishmaniasis.

Over a period of two years (June 1989-May 1991), bone marrow trephine biopsies from 16 patients with visceral leishmaniasis were examined histologically to assess the correlation between the peripheral blood counts and bone marrow status. Only 25% of patients had normal peripheral blood counts. Of the remainder, 25% and anemia alone, 25% had anemia with thrombocytopenia, and 25% had pancytopenia. The anemia was microcytic/hypochromic in 88.7% of cases and normocytic in 12.3% of cases. Thrombocytopenia was a notable feature, with mean platelet count of 115 +/- 72.47 x 10(9)/L, and eight patients having thrombocytopenia below 120 x 10(9)/L. There was diffuse bone marrow hypercellularity in 13 cases and focal hypocellularity in three. The increased cellularity was attributable to trilineage hyperplasisa, with a predominance of erythroid activity in most cases. Increase in the histiocytic population was a prominent feature in all the cases. In 10 cases, most of the histiocytes were found to be full of LD bodies, while in the six, the parasite load was much less. Megakaryocytes were abundant in number, forming aggregates in most cases. Other notable features included erythrophagocytosis (nine cases) and moderate perivascular plasmacytosis (13 cases).