Influence of oral zinc supplementation on the lymphocyte response to mitogens of normal subjects.

Oral zinc sulfate was given for 1 month to 83 normal subjects distributed in four groups according to age (20 to 40; 40 to 60), sex, and oral contraception. Their in vitro lymphocyte response to phytohemagglutinin and Concanavalin A, and their serum zinc and copper levels were measured before and after treatment. They were compared in 20 untreated subjects. Zinc treatment significantly increased the lymphocyte response to phytohemagglutinin and Concanavalin A. In the group of women aged 40 to 60, this resulted in a normalisation of the response to Concanavalin A. The response to zinc was related to the starting value of lymphocyte stimulation obtained by phytohemagglutinin, i.e., in low responders this was enhanced whereas in high responders it tended to be reduced. Treatment increased serum zinc and had no effect on serum copper. There was no correlation between serum zinc or copper and the lymphocyte response. The beneficial effect of zinc supplementation on the lymphocyte response does not result from a correction of latent zinc deficiency.