The Levels And Significance Of IL-21 And BAFF In Patients With Immune Thrombocytopenic Purpura (ITP)

Objective:To investigate the expression of IL-21,BAFF in immune thrombocyto-penic purpura (ITP) and its significanceMethods:46 cases of ITP patients(ITP group) were recruited:male 14, female 32, aged 16 to 74 years, median age was 36 years.The ITP patients were divided into different groups according to time of onset and severity of bleeding, of which 17 patients newly diagnosed ITP, persistent ITP group of 5 patients,20 cases of chronic ITP,3 patients of severe ITP,1 case of refractory ITP group.10 patients with non-ITP thrombocytopenic patients (NITP group) in the same period hospitalized were aslo recruited:4 males and 6 females, aged 16 to 57 years, the median age 40 years.20 healthy subjects (control group) were recruited:10 males and 10 females, aged 16 to 70 years, the median age 39 years. The levels of IL-21 and BAFF in serum of ITP patients before and after treatment, NITP patients and healthy subjects were measured by enzyme-linked immunosorbent assay (ELISA).Resulrs:1.Compared with the normal controls, the level of serum IL-21 in the patients of untreated immune thrombocytopenic purpura were significantly higher (551.79±48.15pg/ml vs 480.2±28.28pg/ml, p<0.01), but no significant difference with NITP group (551.79±48.15pg/ml vs 567.27±92.64 pg/ml, p＝0.619);2. Compared with the normal controls, the levels of serum BAFF in the patients of untreated immune thrombocytopenic purpura were significantly higher (721.03±117.7pg/ml vs 512.5±86.91pg/ml, p<0.01); but no significant difference with NITP group (721.03±117.7pg/ml vs 782.0±138.08pg/ml, p=0.128);3. The levels of serum IL-21 and BAFF in the patients with ITP after treatment,were significantly decreased (468.05±30.11pg/ml,548.57±88.33pg/ml respectively), and no significant difference with the control group;4.In the disease respectively stage with ITP (the newly diagnosed ITP, persistent ITP, chronic ITP, severe ITP, refractory ITP), the levels of serum IL-21, BAFF and disease severity was positively correlated (r=0.833,0.785;P<0.01).5.There were no significant correlation between the levels of serum IL-21 in patients and the bleeding grade level or the peripheral blood platelet count (r=-0.0246,-0.028respectively); Aslo, there were no significant correlation between the levels of serum BAFF in patients and the bleeding grade level or the peripheral blood platelet count (r= 0.03,0.028 respectively);6.The levels of serum IL-21 with ITP patients showed a positive correlation and regression with the levels of serum BAFF in all subjects(r=0659, p<0.01);7. The levels of serum IL-21 or BAFF with the ITP patients in the high-dose dexamethasone treatment group and the standard dose glucocorticoid treatment group,were not statistically significant.Conclusion:The levels of serum IL-21 and BAFF were significantly increased in ITP patients.Also,the relationship of IL-21 and BAFF was positively correlated. Furthermore, the levels of serum IL-21 and BAFF were significantly decreased after glucocorticoid treatment.The result suggests that IL-21 and BAFF may play a important role in ITP.