The Expression Of Tfh Cell And Its Pathogenic Role Of In Patients With Immune Thrombocytopenia

Objective: Immune thrombocytopenia, is a kind of autoimmune disease,increasing antiplatelet antibodies in quantity lead to platelet destruction whichcause excessive bleeding. Bleeding events due to ITP accounted for about30%of the total number of hemorrhagic disease. Any age are at risk of thedisease, The incidence has no difference between children and adults. There isnot any radical treatment methods of ITP, Now commonly used clinical drugsor therapy such as glucocorticoid, human immunoglobulin for intravenousinjection,immunosuppressor and splenectomy. All of those only have shortterm effect,it is difficult to achieve the ideal long-term remission.Hormonotherapy as the first choice therapy for adult in ITP, although efficientis as high as70%~80%,but only46.15%patients can achieve long-termremission. Cohen’s survey found that ITP patients with whose platelets belowthan30×109／L, have a fatal bleeding risk of1.62%~1.62%, Patients withITP have worse life quality even than patients with cancer. Therefore, studythe pathogenesis of ITP and do effective targeted therapy is the key to improveprognosis.Traditional view that, excessive proliferation, activation and maturationof B cells which produce various platelet autoantibody in humoral immune.Platelet autoantibody cause platelet destruction increase which be seemed asthe center of the ITP pathogenesis mechanism. But in recent years, a growingnumber of studies have shown that the abnormal immune regulationmechanism caused by anomalous CD4+T cells may be original cause of thepathogenesis in ITP. Exceptional CD4+T cells subgroups with their abnormalfunction and abnormal quantity proportion, provide abnormalities of theauxiliary signals to B cells, then activate B cells participate in the humoralimmune response of ITP. According to the phenotype and the secretion of cytokines, CD4+Tlymphocytes be divided into Th1,Th2, Th17, Tfh and Treg cells subgroups.Among them, the Thl cells can promote T-cell mediated immune response;Th2cells can enhance the immune response of the antibody; Thl7cells canmediate inflammatory reaction such as autoimmune disease, transplantrejection and tumor; Treg cells can inhibit activation and proliferation ofautoactive T and B cells, then reduce the autoantibody production. In recentyears, studies have reported that patients with ITP have a high proportionThl/Th2and decrease in the number of Treg cells. All of this revealed patientswith ITP have a CD4+T cell subsets abnormal, include proportion andfunction. Yet for Tfh cells, as a new member of the family CD4+T cell,neither at home nor abroad the expression and function in patients with ITP isstill few research reports. Tfh cells located in the lymphoid follicles, oncegerminal centers are formed, Tfh cells are needed to maintain them andregulate germinal center B cell differentiation into plasma cells and memory Bcells. Tfh cells or its effector molecular abnormalities, both can causedisorders of the immune system, result in immunodeficiency diseases such asautoimmune diseases and tumors.Methods: All cases of this research was devided into4groups:pre-treatment group is40initial diagnosed patients with ITP come from thesecond hospital, hebei medical university.38cases of pre-treatment groupwith platelet recovery to normal after treated (include12cases using scalarglucocorticoid treatment,16cases of large dose glucocorticoid treatment,10cases using combine treatment of glucocorticoid and IVIG)be defined ascomplete reaction group. Via regular treatment10cases relapse,were set asrelapsed group, Selection of gender age-matched normal control group,30cases. real-time fluorescent quantitative polymerase chain reaction, detectBcl-6mRNA in PBMC, and enzyme linked immunosorbent assay were usedto detect IL-21protein expression level in serum respectively. Results:1The expression level of Bcl-6mRNA.RQ-PCR result display: The expression level of Bcl-6mRNA in serum,pre-treatment group was(3.83±1.00); in complete reaction group was(2.09±0.74); in relapsed group was (3.42±0.64); in normal group was (1.04±0.41).In all patients with ITP, the Bcl-6mRNA expression levels were relativelyhigher than that in normal control group, and had statistically significantdifference (P<0.01); After treatment the Bcl-6mRNA levels droped, but stillhigher than that in normal control group; Expression level of Bcl-6mRNAwas increased in relapsed group, and compared with pre-treament group hadno statistically difference (P>0.01). Bcl-6mRNA expression level afterdifferent therapy in completely reaction group, was like that, in scalarglucocorticoid treatment group was(2.11±0.69); in large dose glucocorticoidtreatment group was(1.97±0.86); in combine treatment group ofglucocorticoid and IVIG was(2.24±0.60), had no statistically difference indifferent therapy groups(P>0.01).2The expression level of IL-21proteinELISA result display: The expression level of IL-21protein inpre-treatment group was(167.37±14.20) pg/ml; in complete reaction groupwas(121.93±9.96) pg/ml; in relapsed group was(163.47±10.84) pg/ml; innormal group was(91.00±33.09) pg/ml. In all patients with ITP, the IL-21expression levels were relatively higher than that in normal control group, andhad statistically significant difference (P<0.01); After treatment the IL-21levels droped, but still higher than that in normal control group, and hadstatistically significant difference (P<0.01); Expression level of Bcl-6mRNAwas increased in relapsed group, and compared with pre-treament group hadno statistically difference (P>0.01). IL-21expression level after differenttherapy in completely reaction group, was like that, in scalar glucocorticoidtreatment group was(123.08±9.51) pg/ml; in large dose glucocorticoidtreatment group was (122.31±11.22) pg/ml; in combine treatment group ofglucocorticoid and IVIG was(119.66±18.63) pg/ml, had no statisticallydifference after different therapy (P>0.01). 3The correlation between the expression of Bcl-mRNA and IL-21proteinsBy the Pearson correlation analysis: The Bcl-6mRNA expression andserum IL-21protein expression in pre-treatment was significantly positivelyrelated（,r=0.510, p<0.01）. In relapsed group, there was no correlation betweenthe expression of Bcl-6mRNA and serum IL-21protein expression(r=0.355,P>0.01).4The correlation between platelet count and the expression ofBcl-mRNA and IL-21proteinsBy the Pearson correlation analysis: Both in pre-treatment group andrelapsed group, have no correlation between the expression of Bcl-6mRNAand the platelet count (r=0.202, P>0.01; r=0.097, P>0.097). Both inpre-treatment group and relapsed group, have no correlation between theexpression of IL-21and the platelet count(r=-0.059，P>0.01; r=-0.869，P>0.01）.Conclusions:1In patients with ITP, the increase Bcl-6mRNA in PBMC prompt thatTfh cells involves in the pathogenesis of ITP.2Tfh cells may through high expression of IL-21whose main effectfactor inducing the proliferation and differentiation of B cells, and promote theactivation of humoral immune response to ITP patients.3High-dose glucocorticoid may inhibit the migration of Tfh cells fromfollicle, thereby inhibiting excessive activation of B cells, reduce plateletspecific antibody production.