VITAMIN-A-DEFICIENCY INCREASES INFLAMMATORY RESPONSES

The authors studied the influence of vitamin A deficiency on immediate and delayed type hypersensitivity as well as granulocyte-mediated inf lammatory reactions in vitamin A depleted and control rats. The number of circulating leukocytes was 43% higher in the vitamin A deficient t han in the control animals. The leucocytosis was a result of a general increase of while blood cells and was not due to an increase in one p articular type. The ratio between CD4(+) and CD8(+) T cells was unchan ged. The vitamin A deficient rats had a four times higher T-cell proli ferative response and a two times higher interferon-gamma production i n vitro than the control animals. In accordance, the DTH reaction was consistently higher in thr vitamin A deficient rats. The granulocyte d ependent inflammation, induced by olive oil injection, was also strong ly enhanced in the vitamin A deficient rats compared with the controls . In addition, the spontaneous release of nitric oxide from the perito neal phagocytes was five times higher in the vitamin A deficient anima ls. The number of peritoneal mast cells was about one and a half times higher in the vitamin A deficient than in the control animals. The de nsity of IgE-receptors oil the mast cells, the IgE receptor occupancy and the histamine release from the mast cells did not differ between t he groups, however. Tho vitamin A deficient immunized rats displayed a consistently stronger immediate skin reaction after intracutaneous an tigen injection than the immunized control rats, despite lower IgE ant ibody levels. The skill reaction after intracutaneous injection of his tamine was also significantly greater in the deficient animals. Despit e the stronger reaction to antigen and histamine, the passive cutaneou s anaphylaxis reaction was lower in that vitamin A deficient rats. In conclusion the study shows that vitamin A deficiency aggravates the cl inical manifestations of inflammatory reactions, Thus, vitamin A defic iency might lead to a higher risk of acquiring irreversible tissue dam age and disabling destruction.