CD4+ CD25high FOXP3+ Regulatory T Cells Correlate with FEV1 in North Indian Children with Cystic Fibrosis

Cystic fibrosis (CF) lung disease is characterized by dysregulated inflammatory response in the airways. CD4(+)CD25(+) regulatory T cells play a crucial role in maintaining the immune homeostasis. However their role in the disease pathogenesis of CF remains unexplored. Aim: To determine the percentage of circulating CD4(+)CD25(high), FoxP3(+) T cell expression in children with CF and controls. Furthermore to evaluate the relationship between CD4(+)CD25(high), FOXP3 T cell % and the clinical status of the disease (lung function). Methods: CD4(+)CD25(+), intracellular FoxP3 expression in peripheral blood were estimated using flowcytometry in 20 children with CF and 10 healthy controls. Spirometry was carried out according to the standard guidelines. Results: We observed a significant difference in CD4(+)CD25(+)T cell% in children with CF (5.2 +/- 1.2) versus controls (6.8 +/- 1.4, p<0.05), CD4(+)CD25(high)Tcell% in CF (1.72 +/- 0.36) versus controls (2.59 + 0.42, p<0.003). Similarly a significant difference was observed in FoxP3 T cell% CF: (60.7 +/- 6.19) versus controls (76.8 +/- 5.16), p<0.001. A significant positive correlation between FoxP3 T cell% and FEV1 in children with CF(r = 0.822, p<0.01) was observed. CD4(+)CD25(high) T cell% correlated positively with FEV1 (r = 0.742, p<0.01). Conclusion: Our findings report the first evidence of a decreased expression of circulating CD4(+)CD25(high) FoxP3(+) T cells in children with CF. Furthermore circulating CD4+ CD25(high), FOXP3(+) T cell percentage correlated with FEV1.