The Mechanism Of T Follicular Helper Subsets Abnormality In Children With Henoch-sch(?)nlein Purpura

Objective: To examine the frequency of different subsets of T follicular helper(Tfh)cells in children with Henoch-Sch(?)nlein purpura(HSP)and HSP Nephritis(HSPN).Methods: 45 children with HSP were classified into three groups as followed: 21 HSP children without renal involvement(group A),12 HSP Nephritis(HSPN)children with Isolated hematuria(group B),12 HSPN children with hematuria and proteinuria(group C),while 17 healthy controls(HC)were included.The percentage of Tfh(CD3+CD4+CXCR5+)cells,Tfh1(CCR6-CXCR3+Tfh)cells,Tfh2(CCR6-CXCR3-Tfh)cells,Tfh17(CCR6+CXCR3-Tfh)cells,the expression of ICOS and OX40 in Tfh cells and subsets,CD19+B cells,and the percentages of CD19+ICOSL+B cells,CD19+CD27+ICOSL+B cell,CD19+CD86+ICOSL+B cells,CD19+CD138+ICOSL+B cells,CD19+OX40L+B cells,CD19+CD27+OX40L+B cell,CD19+CD86+OX40L+B cells,CD19+CD138+OX40L+B cells were detected by flow cytometry of peripheral blood from the patients.Results: Compared with control,the percentage of circulating Tfh cells were significantly higher in group A and C(P<0.05),Tfh2 cells,the ratio of Tfh2+Tfh17 to Tfh1,the MFI of ICOS in Tfh cells and Tfh2 cells,OX40+Tfh cells,CD19+ICOSL+B cells were significantly increased in group C,MFI of ICOS in Tfh cells were increased in group A(P>0.05).while there were no significant difference in the percentage of Tfh1,Tfh2,Tfh17,the expression of ICOS and OX40 in Tfh subsets.The percentages of CD19+B cells,CD19+OX40L+B cells,CD19+CD27+ICOSL+B cells,CD19+CD86+ICOSL+B cells,CD19+CD138+ICOSL+B cells,CD19+CD27+OX40L+B cell,CD19+CD86+OX40L+B cells,CD19+CD138+OX40L+B cells showed no significant difference among each groups(P>0.05).Moreover,The serum Ig A showed positive correlated with the percentage Tfh cells(R=0.396,P<0.01),Tfh2 cells(R=0.367,P<0.05),MFI of ICOS in Tfh(R=0.457,P<0.01),OX40+Tfh(R=0.353,P<0.05)and ICOSL+CD19+B cells(R=0.331,P<0.05),and the levels of serum Ig A showed positive correlated with the percentage Tfh1(R=-0.418,P<0.05).Conclusion: Serum levels of Ig A rise in children with Henoch-Sch(?)nlein purpura(HSP)/HSP Nephritis(HSPN).Increased circulating Tfh cells and imbalanced subsets play a significant role in children with HSP/HSPN.Overexpression of ICOS-ICOSL in Tfh cells and B cells may be a underlying mechanism of abnormal activation of those cells to secrete serum Ig A.