To study the role of T regulatory cells in developing asthma in a birth cohort of babies with family history of allergies

Abstract

Asthma is known to be correlated with TH2 immune response. There is evidence that T-regulatory cells are important to prevent allergic diseases like asthma. There are few studies based on the role of Treg cell in birth cohort babies with family history of allergy. Fifty children with asthma and respiratory allergy (study group), 20 children born with a positive family history and being followed up as a birth cohort (cohort group) and a group of 10 healthy children with no history of allergy in the family were considered to be satisfactory (Control group) were recruited in this study. Total IgE level, pulmonary function test (PFT) was assessed. The levels of TH1, TH2, TH17 and CD4+ CD25high FoxP3+ Treg cells expression were determined by Flow cytometry [FACSCanto (Becton Dickinson, Mountain View, CA, USA) with FACS DivaTM software]. The Ethics Committee of PGIMER approved this study (Micro / 2006 / 754 / 8th May 2006). The average level of total IgE in the studied group was 316.8±189.8 IU/mL and significantly higher than cohort (124±28.5 IU/mL, p<0.0001) and control (50±17.5 IU/mL, p<0.0001). The frequency of TH17 cells and culture supernatant level of IL-17 were 12.09±8.67 pg/ml and significantly higher in study group than corresponding level in cohort [5.91±3.56 pg/mL, p<0.001] and control group [2.01±1.27 pg/mL, p<0.001], whereas the frequency of Foxp3 level were significantly lower in study group [(49.00±13.47) %] and cohort group [(68.22±8.55) %] compare to the control group [(95.91±2.63) %]. The total serum IgE level is negatively correlated with FoxP3 level (r= -0.5273 p<0.0001). The FoxP3 expression is negatively correlated with the IL-17 levels (r= -0.5631, p< 0.0001) and IL-4 levels (r= -0.2836 p=0.0460). Imbalance in TH17/Treg was found in patients with allergic asthma. Elevated IL-17 and IL-4 cytokine response and down regulation of FoxP3 were associated with asthma. We also found that T regulatory cells expression decreases as asthma progression.