Pathogenesis Of Peripheral Blood Gamma-delta T Cells In The Immune Microenvironment Of Children With Henoch-sch?nlein Purpura

Objective To explore the role of gamma-delta T(??T)cells and its subsets in the immunopathogenesis and clinical significance with Henoch-Sch?nlein purpura(HSP)and Henoch-Sch?nlein purpura nephritis(HSPN)in children,and to provide new ideas for the treatment of HSP in children from the aspect of??T cell regulation.Methods A total of 33 children with HSP were enrolled as the HSP group,admitted in the pediatric department of General Hospital of Ningxia Medical University from April 2018to March 2019,including non-HSPN group(15 cases)and HSPN group(18 cases).Another 33healthy children were enrolled as the control group.Peripheral blood samples were collected to measure the percentages of??T cells and its subsets V?1~+T and V?2~+T cells among peripheral blood mononuclear cells(PBMCs),as well as the apoptosis rate of??T cells by flow cytometry(FCM).Plasma level of interleukin-17(IL-17)were detected by enzyme-linked immunosorbent assay(ELISA).Relevant data were collected and analyzed by Logistic regression,including gender,age,gastrointestinal symptoms,streptococcal infection,complement 3(C3),white blood cell count(WBC),platelet count(PLT),C-reactive protein(CRP),immunoglobulin A(IgA),immunoglobulin G(IgG),??T cells,V?1~+T cells,V?2~+T cells and IL-17.Results 1.Compared with the control group,the percentage of lymphocytes in PBMCs was significantly lower in the HSP group and within its non-HSPN and HSPN subgroups(P<0.05).2.The proportion of??T cells in CD3~+T lymphocytes in the HSP group was not significantly different than the control group.Within the HSP group,the HSPN subgroup had significantly higher percentage of??T cells than the non-HSPN subgroup(P<0.05).The HSP group had a significantly lower overall apoptosis rate of??T cells than the control group.The overall apoptosis rate,including the early apoptosis rate and late apoptosis rate,were significantly lower than those of the control group(P<0.05).3.The HSP group and HSPN subgroup had significantly higher percentage of V?1~+T cells in??T cells than the control group(P<0.05),while the expression of V?1~+T cells in the non-HSPN subgroup was not significantly higher than the control group(P>0.05).Compared with the control group,the HSP group and within its subgroups had significantly lower percentages of V?2~+T cells in??T cells(P<0.05),ascribing the decrease in HSP group mainly to the HSPN subgroup.The ratios of V?1~+/V?2~+T in peripheral blood of the HSP group,HSPN and non-HSPN subgroups were significantly higher than those in the control group(P<0.05).There was not statistically significant of the percentage of V?1~-?2~-T cells in??T cells.(P>0.05).4.The HSP group had significantly higher level of IL-17 in plasma than the control group,as well as the HSPN and non-HSPN subgroups(P<0.05),while the subgroups comparison was not statistically significant(P>0.05).5.Multi-factor logistic regression analysis showed that increased anti-streptolysin O(ASO),combined gastrointestinal symptoms,??T cells,V?1~+T cells,and V?2~+T cells were the influencing factors of renal impairment in children with HSP(P<0.05).Among them,the titer of ASO(OR=6.50,P=0.036)and the expressions of??T cells(OR=2.57,P=0.024),V?1~+T cells(OR=1.08,P=0.029),and V?2~+T(OR=0.56,P=0.005)cells were independent influencing factors of renal impairment in HSP children.6.The percentage of V?2~+T cells was positively correlated with overall apoptosis rate(r_s=0.550,P<0.001),and was negatively correlated with IL-17 level(r_s=-0.403,P=0.010).Within the HSP group,the correlation analysis between??T cells and its subsets with overall apoptosis rate,IL-17,IgA and IgG were not statistically significant(P>0.05).Conclusion 1.In the blood microenvironment of children with HSP,there were immune imbalances of??T cells and its subsets,presented abnormal levels of V?1~+T and V?2~+T cell subsets.The two showed compensatory changes,i.e.the ratio of V?1~+T increases while the ratio of V?2~+T decreases,among which the disturbance of immune tolerance induced by V?2~+T cells plays an important role in the pathophysiology of the disease.2.In the blood microenvironment of children with HSP,there were defects or imbalances in??T cells apoptosis and over-activation of IL-17,which were consistent with the changes in V?2~+T cells and disease severity.3.Increased ASO titers and enhanced expression of??T cells and V?1~+T cells were risk factors for renal impairment in HSP,while the expression of V?2~+T was a protective factor.ASO titers and??T-related immune disorders may increase the risk of HSPN.