Altered Folate Metabolism in Early HIV Infection-Reply

In Reply. —We appreciate the comments by Tilkian et al regarding our finding of elevated serum and red blood cell folate levels in early HIV infection. We, too, considered vitamin B12deficiency and the vitamin B12—folate trap as a possible cause of the apparent elevation of folate levels.1However, there was no significant correlation between folate and serum vitamin B12levels in our patients (r=.12;P=.51). While approximately 25% of our patients were vitamin B12deficient, they were not consistently the same subjects with the elevated folate levels (Figure). Consequently, an alternative explanation should be sought. As pointed out by Tilkian and coworkers, cellular lysis might result in transient elevation of serum nutrient levels. However, our patients had elevated levels of both serum and, most notably, erythrocyte folate. Therefore, release of intracellular folate alone cannot explain our findings. The binding of folate