Incidence of apoptosis in HIV-myelopathy, myelodysplastic syndromes and non-specific inflammatory lesions of the bone marrow

Myelodysplastic syndromes, AIDS-related myelopathy and non-specific inflammatory reactions (mostly rheumatoid myelitis) are characterized by normo to hypercellular bone marrow but frequently display cytopenias in the peripheral blood, In the current study we have addressed the question whether this situation reflects an increased programmed cell death in haemopoiesis. For this purpose, the in situ end-labelling technique was applied to formalin-fixed and paraffin-embedded trephine biopsies derived from patients and a control group without any haematological disorder, Results were evaluated by morphometry. Significantly more apoptotic cell death was observed in the haemopoietic marrow of patients with either disease, Using double-immunohistochemistry with the monoclonal antibody PG-M1 (CD68), we were able to demonstrate that approximately one third of the apoptotic cells were ingested by macrophages, Our findings are in keeping with previously published data that postulated increased frequencies of macrophages in these disorders as well as raised serum levels of TNF-alpha.