Zinc status and interleukin-2 production in cystic fibrosis

Zinc (Zn) deficiency may occur in a subset of CF children, which may potent ially contribute to the impairment of their growth and immune functions. Ma ny of the studies that investigated the status of Zn in CF relied exclusive ly on plasma Zn level-which is not a reliable indicator of Zn status in the body. In this study, we evaluated cellular and plasma Zn levels in both CF and control subjects. In addition, IL-2 production and several T lymphocyt e subsets were also measured in both groups. A total of 16 CF patients and 17 age-matched normal subjects were included in this study. Zinc levels wer e assayed using flameless atomic absorption spectrophotometry, cellular IL- 2 production was assayed by ELISA, and T cell subtypes were measured by flo w cytometry. CF patients showed significantly lower granulocyte and lymphoc yte Zn levels than normal subjects (P < 0.01). There was no statistical dif ference between the CF patients and the control subjects in their platelets and plasma Zn levels. There was also no difference between the two groups in the proportions of their T lymphocyte subsets. IL-2 production was highe r in the normal subjects than in the CF patients (P = 0.05). Based on cellu lar Zn criteria, ten CF patients were classified as Zn-deficient. When comp ared to all the Zn-sufficient subjects in the study, the Zn-deficient CF pa tients had significantly lower IL-2 production (P = 0.03). In conclusion, o ur results showed that a mild Zn deficiency, manifested by low cellular Zn levels, can occur in a subset of CF patients, and this may lead to a reduct ion in their lymphocyte IL-2 production. (C) 1999 Wiley-Liss, Inc.