Abstract:

Objective To explore the roles of follicular helper T cells（Tfh） in the pathogenesis of pemphigus and bullous pemphigoid （BP）. Methods Venous blood was collected from 20 patients （including 10 cases of pemphigus and 10 cases of BP） and 20 age- and sex-matched normal human controls. Enzyme linked immunosorbent assay （ELISA） was performed to measure the levels of serum interleukin （IL）-21 and anti-BP180-NC16A antibody, and flow cytometry to detect the percentage of Tfh in peripheral blood mononuclear cells （PBMCs）. The relationship of anti-BP180-NC16A antibody titer to Tfh and IL-21 levels was assessed by linear correlation analysis. Results The serum IL-21 level and Tfh percentage in PBMCs were significantly higher in patients with pemphigus than in the normal controls （95.33 ± 33.69 vs. 54.50 ± 18.13 pg/ml, t = 3.38, P < 0.01; 12.08% ± 4.74% vs. 6.15% ± 1.62%, t = 3.74, P < 0.01）, and higher in patients with BP than in the normal controls（106.70 ± 44.91 vs. 55.37 ± 15.89 pg/ml, t = 3.41, P < 0.01; 11.85% ± 3.14% vs. 6.03% ± 1.74%, t = 5.13, P < 0.01）. The titer of anti-BP180-NC16A antibody was positively correlated with the percentage of Tfh （r = 0.67, P < 0.05） and serum level of IL-21 （r = 0.77, P < 0.01） in patients with BP. Conclusions There is a significant increase in the percentage of Tfh and serum level of IL-21 in patients with pemphigus and BP, hinting a certain role of Tfh and IL-21 in the pathogenesis of pemphigus and BP.

Key words: autoantibody