MECHANISMS OF ALUMINUM-INDUCED MICROCYTOSIS - LESSONS FROM ACCIDENTALALUMINUM INTOXICATION

Twenty-three hemodialysis patients exposed to an accidental aluminum o verload, showed increased erythropoietin requirements and decreased er ythrocyte mean corpuscular volume (MCV). At the peak of the intoxicati on, MCV and plasma aluminum levels changed from unrelated (r = 0.02) t o strongly related (r = 0.425) variables. The molar proportion of plas ma aluminum to plasma iron increased dramatically (from 1:13.8 to 1:2. 4). This significant increment in the aluminum/iron ratio made higher the relative offer of aluminum with respect to iron to the erythroid p recursor cells. Accordingly, in a subset of 13 randomly selected alumi num-intoxicated patients we found increased intraerythrocytic aluminum , which paralleled the increase in plasma aluminum. Furthermore, in th e aluminum-intoxicated group, intraerythrocytic ferritin, a marker of iron content, and the ratio between erythrocyte and plasma ferritin we re lower (P < 0.01 and <0.001, respectively), than in the control grou p. These findings support the hypothesis that in some cases of aluminu m-related microcytosis, a ferropenic mycrocitosis, as expression of er ythroid ferropenia, may exist in spite of the presence of normal body iron stores.