Follicular helper T (Tfh) cells involves in the pathogenesis of Henoch-Schönlein purpura through affecting CD40/CD40L axis

Abstract

Objective To investigate whether follicular helper T (Tfh) cells were involved in the development of Henoch-Schonlein purpura (HSP) and Henoch-Schonlein purpura nephritis (HSPN) in children through affecting CD40/CD40L axis. Methods Fifty-five subjects were enrolled in this study and divided into four groups as follows: 22 children with HSP but without renal involvement (Group A), 11 children with HSPN presenting with microhematuria (Group B), 11 children with HSPN presenting with microhematuria and proteinuria (Group C) and 11 healthy children (control group). Flow cytometry was performed to detect the percentages of CD19+ B cells and their subsets, CD19+ B cells and CD19+ CD38+ B cells secreting different Ig classes, CD19+ CD40+ B cells and their subsets and Tfh cells expressing CD40 ligand (CD40L). Results Compared with the control group, the percentages of CD19+ CD86+ B, CD19+ CD138+ B and CD40L+ Tfh cells significantly increased in Group C (P 0.05). No significant difference in the percentages of CD19+ B cells, CD19+ CD27+ B cells, CD19+ B cells or CD19+ CD38+ B cells expressing IgG, IgM, IgD, CD19+ B cells or CD19+ B cell subsets secreting CD40 was found between the control group and Groups A, B and C (P>0.05). Moreover, the percentages of CD19+ B and CD19+ CD38+ B cells secreting IgA and IgE in Groups A, B and C were higher than those in the control group (P<0.05). Secretion of IgA by CD19+ B and CD19+ CD38+ B cells were positively correlated with the expression of CD40L by Tfh cells (P<0.05). Conclusion Tfh cell-mediated abnormal expression of CD40/CD40L might play an important role in the development of HSP and be related to the clinical severity of renal involvement in HSPN. Key words: Henoch-Schonlein purpura; Immunoglobulin; B cell; Follicular helper T cell; CD40/CD40 ligand