RESUMEN
Haematologic toxicity is the most common adverse effect related to long-term administration of zidovudine (AZT). We evaluated the kinetics of modifications of some haematologic parameters of erythroid series in 65 patients with HIV infection treated with AZT for a mean duration of 7.6 +/- 4.7 months (13 of them with a previous diagnosis of AIDS, 34 with ARC, 18 asymptomatic or with LAS/PGL), in order to correlate the observation and the evolution of these laboratory changes with the onset of severe anaemia. The development of macrocytosis occurs in a large majority of AZT-treated subjects, in spite of folate and vitamin B12 supplementation; the monitoring of erythrocytes distribution according to cellular volume and cellular haemoglobin concentration makes it possible to early recognize the occurrence of modification in erythropoiesis. There is no correlation between an elevated mean corpuscular volume and the development of severe anaemia (Hb less than or equal to 9 g/dl) in an individual patient; a fall in the reticulocyte count appears to be the earliest peripheral blood sign of the development of bone marrow toxicity.