To the Editor.
—The letter in the Jan 22/29 issue of JAMA entitled "Altered Folate Metabolism in Early HIV [human immunodeficiency virus] Infection"1 is interesting, since the authors state that the elevated folate levels observed in the majority of their patients were unlikely to have resulted from dietary supplementation.A related letter entitled "Folate Deficiency and Demyelination in AIDS [acquired immunodeficiency syndrome]" by Smith et al2 appeared in the July 25, 1987, issue of Lancet. The authors reported that, although serum and erythrocyte folate levels could be normal, cerebrospinal fluid folate levels were low. Defective folate metabolism is known to cause multifocal perivenular demyelination like that due to vitamin B12 deficiency.We would like to point out that in vitamin B12 deficiency, serum folate levels, measured as 5-methyl tetrahydrofolate, are elevated because vitamin B12 is needed for the demethylation of 5-methyl tetrahydrofolate; in its absence, no
Tilkian SM, Lefevre G. Altered Folate Metabolism in Early HIV Infection. JAMA. 1988;259(21):3128-3129. doi:10.1001/jama.1988.03720210018014