ANTIHISTAMINE EFFECT OF SUPPLEMENTAL ASCORBIC-ACID AND NEUTROPHIL CHEMOTAXIS

Renewed interest in the antihistamine action of ascorbic acid has emer ged with the recently recognized immunosuppressive role of histamine. We examined the antihistamine effect of acute and chronic vitamin C (V C) administration and its effect on neutrophil chemotaxis in healthy m en and women. In the chronic study, 10 subjects ingested a placebo dur ing weeks 1, 2, 5 and 6, and 2 g/day of VC during weeks 3 and 4. Fasti ng blood samples were collected after the initial 2-week period (basel ine) and at the end of weeks 4 and 6. Plasma ascorbate rose significan tly following VC administration compared to baseline and withdrawal va lues. Neutrophil chemotaxis rose 19% (NS) during VC administration, an d fell 30% after VC withdrawal, but these changes were not correlated to plasma ascorbate levels (r = 0.01). Chemotaxis was inversely correl ated to blood histamine (r = -0.32, p = 0.045), and, compared to basel ine and withdrawal values, histamine levels were depressed 38% followi ng VC supplementation. Blood histamine and neutrophil chemotaxis did n ot change 4 hours following a single 2 g dose of ascorbic acid, althou gh plasma ascorbate rose 150%. These data indicate that VC may indirec tly enhance chemotaxis by detoxifying histamine in vivo.