The Haematologist and the Infective Complications of HIV Infection

Patients with AIDS often have haematological abnormalities consequent on opportunistic infections, superimposed on abnormalities caused by HIV itself. It is important for the haematologist to recognize characteristic features such as a marked increase in plasma cells and the presence of pleomorphic lymphoid aggregates in order to avoid misdiagnosis of a plasma cell dyscrasia or a lymphoma. Examination of the peripheral blood and bone marrow can also be useful in permitting the diagnosis of specific infections in patients with AIDS. Mycobacterium avium intracellulare is the most commonly recognized opportunistic infection involving the bone marrow. Less often a diagnosis of tuberculosis, cryptococcosis, histoplasmosis or leishmaniasis is made as the result of bone marrow aspiration or trephine biopsy. Infection by specific viruses, particularly the Epstein-Barr virus and human herpes virus 8, can contribute to lymphomagenesis in patients with AIDS. Other opportunistic infection may contribute to the development of MALT-lymphomas. The haematologist may have a role in the diagnosis of AIDS-related lymphomas involving the bone marrow, particularly Burkitt's and Burkitt-like lymphoma and Hodgkin's disease. Infection with human herpes virus 8 is also an aetiological factor in Kaposi's sarcoma which may be detected, albeit rarely, in a trephine biopsy.