A SINGLE 210-MU-MOL ORAL DOSE OF RETINOL DOES NOT ENHANCE THE IMMUNE-RESPONSE IN CHILDREN WITH MEASLES

This trial assessed the effect of vitamin A on reversing measles-induc ed unresponsiveness to recall antigens and on enhancing measles antibo dy production. These assessments were pant of a randomized, double-mas ked clinical trial of the efficacy of 210 mu mol of retinol as retinyl palmitate for reducing measles-associated morbidity. Two hundred chil dren between 5 mo and 17 y of age with acute measles were enrolled at the Urban Health Centers in Ndola, Zambia; 110 subjects received a pla cebo and 90 received vitamin A. At enrollment and 2 wk later, blood sa mples were collected to determine measles hemagglutinin antibody titer and, at 1 and 2 wk post-enrollment, cutaneous delayed-type hypersensi tivity tests (DTH) for seven antigens were applied. Both groups of sub jects showed marked DTH unresponsiveness, but vitamin A-treated subjec ts had a significant prolongation of unresponsiveness to tuberculin [o dds ratio (OR) 3.22 and 95% confidence interval (CI) 1.27-8.2], Candid a (OR 5.43, CI 1.13-25.9) and Proteus (OR 5.17, CI 1.14-28.4), after a djustment for previous vaccination and age. DTH unresponsiveness was a ntigen specific, reflecting prior vaccination history, and was not ass ociated with acute respiratory infection status. In addition, children in both treatment groups showed a significant increase in measles ant ibody titer from baseline to wk 2, but this increment was not signific antly different between the groups (P = 0.25). These results indicate that a single oral dose of 210 mu mol of retinol as retinyl palmitate in oil does not enhance the immune system during measles.