Flow cytometry analysis of circulating and splenic follicular helper T (Tfh) cells in a mouse model of allergic rhinitis
Objective 
To investigate changes in the percentages of circulating and splenic follicular helper T (Tfh) cells and the significance of Tfh cells in a mouse model of allergic rhinitis. 
 
 
Methods 
BALB/c mice were sensitized by injection of OVA and aluminum hydroxide to establish the model of allergic rhinitis. Flow cytometry was performed to measure the percentages of circulating and splenic CD4+ CXCR5+ after staining Tfh cells with anti-mouse CD4-FITC and anti-mouse CXCR5-PE. Concentrations of OVE-specific IgE (OVA-sIgE) in serum samples were measured by enzyme-linked immunosorbent assay (ELISA). Student′s t-test and Pearson′s correlation analysis were used for statistical analysis. 
 
 
Results 
Enhanced infiltration of eosinophils in submucosa was observed in the experimental group. After sensitizing the mice with OVA and aluminum hydroxide, the concentration of OVA-sIgE increased from 43.47 pg/ml [(43.47±2.58) pg/ml] to 50.44 pg/ml [(50.44±1.40) pg/ml] (P=0.029); the percentage of circulating CD4+ CXCR5+ was up-regulated from 6.25% [(6.25±1.19)%] to 13.94% [(13.94±2.77)%] (P=0.026); the percentage of splenic CD4+ CXCR5+ was down-regulated from 18.04% [(18.04±4.97)%] to 7.26% [(7.26±0.96)%] (P=0.019). The concentration of OVA-specific IgE was positively correlated with the percentage of circulating Tfh cells (r=0.954, P=0.002), but negatively correlated with the percentage of splenic Tfh cells (r=-0.801, P=0.028). Moreover, a negative correlation was found between circulating and splenic Tfh cells (r=-0.787, P=0.032). 
 
 
Conclusion 
Tfh cells might be involved in the immune responses against allergic rhinitis in mice. 
 
 
Key words: 
Follicular helper T cell (Tfh); Allergic rhinitis; Flow cytometry; Immunoglobulin E (IgE); Mouse