Study On The Quantity And Function Of T Follicular Helper Cells In Immuno-related Pancytopenia

Objective:To study the quantity and function of bone marrow (BM) T follicular helper (Tfh) cells of the patients with immuno-related pancytopenia (IRP) and explore the role of Tfh cells in the pathogenesis of this disease.Methods:Forty-three untreated IRP patients,47 recovered IRP patients and 25 healthy donors were enrolled in this study. The ratio of CD4+CXCR5+/CD4+cells, CD4+CXCR5+ICOS+/CD4+CXCR5+cells,CD4+CXCR5+CD40L+/CD4+CXCR5+cells, intracytoplasm CD4+CXCR5+IL-21+/CD4+CXCR5+cells in BM were examined by flow cytometry (FCM). The expression of Bcl-6 mRNA in bone marrow mononuclear (BMMNC) was measured by semiquantitive RT-PCR. The correlations between the ratio of CD4+CXCR5+/CD4+cells, CD4+CXCR5+CD40L+/CD4+CXCR5+cells, CD4+CXCR5+ICOS+/CD4+CXCR5+cells, CD4+CXCR5+IL-21+/CD4+CXCR5+cells, the expression of Bcl-6 mRNA and the ratio of CD3+CD4+/CD3+CD8+, Th1/Th2, CD19+/BMMNC, the quantity BMMNC-antibody, serum immune globulin, serum complement were analyzed.Results:1. The ratio of CD4+CXCR5+/CD4+cells of untreated IRP patients [(28.79±19.70)%] was significiantly higher than that of recovered IRP patients [(21.15±12.81)%] and normal controls [(13.42±6.72)%], the ratio of CD4+CXCR5+/CD4+cells of the recovered IRP patients was significiantly higher than that of normal controls (P＜0.05). The ratio of CD4+CXCR5+ICOS+/CD4+CXCR5+cells of untreated IRP patients [(5.05±4.71)%] was significiantly higher than that of recovered IRP patients [(2.96±2.89)%] and normal controls [(2.99±2.23)%] (P<0.05), there was no significiant difference between that of recovered IRP patients and normal controls. The ratio of CD4+CXCR5+CD40L+/CD4+CXCR5+cells of untreated IRP patients [(5.87±4.14)%] and recovered IRP patients [(6.52±5.47)%] were significiantly higher than that of normal controls [(2.93±2.92)%] (P＜0.05). The ratio of intracytoplasm CD4+CXCR5+IL-21+/CD4+CXCR5+cells of untreated IRP patients [(8.20±7.41)%] and recovered IRP patients [(6.30±6.03)%] were significiantly higher than that of normal controls [(3.43±3.40)%] (P＜0.05). The relative expressions of Bcl-6 mRNA in BMMNC were [(0.625±0.248), (0.485±0.253), (0.306±0.210)] in three groups, respectively. That in untreated IRP patients was significiantly higher than that in recovered IRP patients and normal controls. That in the recovered IRP patients was significiantly higher than that in normal controls (P<0.05).2. In IRP group, there were significantly positive correlations between the ratio of CD4+CXCR5+/CD4+cells and the expression of Bcl-6 mRNA, the ratio of CD19+/BMMNC, the ratio of CD3+CD8-IL-4+/CD3+CD8-, the ratio of CD34+IgG+/BMMNC, the level of serum IgG (r=0.474,0.252,0.475,0.314,0.376, respectively, P<0.05), there were significantly negative correlations between the ratio of CD4+CXCR5+/CD4+cells and the ratio of Thl/Th2, the level of serum C3(r=-0.276,-0.379, respectively, P＜0.05).3. There was significantly positive correlation between the ratio of CD4+CXCR5+CD40L+/CD4+CXCR5+and CD4+CXCR5+ICOS+/CD4+CXCR5+ (r=0.264, P＜0.05). There were significantly positive correlations between the ratio of CD4+CXCR5+IL-21+/CD4+CXCR5+and CD4+CXCR5+CD40L+/CD4+CXCR5+, CD4+CXCR5+ICOS+/CD4+CXCR5+, the expression of Bcl-6 mRNA(r=0.334,0.263, 0.332, respectively, P＜0.05), there was significantly negative correlation between the ratio of CD4+CXCR5+IL-21+/CD4+CXCR5+and the level of serum C3(r=-0.301, P＜0.05).Conclusions:There exists increased quantity and hyperfunction of Tfh cells in the IRP patients, they may play important role in the pathogencsis of IRP. Tfh cells and their effector molecules may be regarded as potential new therapeutic targets of IRP.