185例原发免疫性血小板减少症患者特异性自身抗体种类及类型与地塞米松疗效的相关性

Study on the relationship of platelet specific-autoantibodies with therapeutic outcomes by dexamethasone in immune thrombocytopenia purpura

目的 探讨成人原发免疫性血小板减少症（ITP）患者血小板特异性自身抗体种类（GPⅡb/Ⅲa、GPⅠbα）及类型（IgG、IgM）对地塞米松疗效的影响.方法 185例ITP患者纳入研究,男61例,女124例,中位年龄42（18～83）岁.其中新诊断ITP 117例,持续性ITP 35例,慢性ITP 33例.入组患者接受地塞米松（40 mg/d×4 d）治疗,稳定后逐渐减量至5～10 mg/d维持3～4周.采用改良单克隆抗体俘获血小板抗原（MAIPA）法检测患者特异性自身抗体种类及类型,分析抗体种类及类型与地塞米松疗效的相关性.结果 ①按抗体类型分组：IgG组：单一抗GPⅡb/Ⅲa抗体阳性、单一抗GP Ⅰ bα抗体阳性、双抗体阳性、双抗体阴性患者治疗有效率分别为87.5％、50.0％、68.0％、72.3％,四组间抗体种类比较差异有统计学意义（x2=11.489,P=0.009）.IgM组：单一抗GPⅡb/Ⅲa抗体阳性、单一抗GPIbα抗体阳性、双抗体阳性、双抗体阴性患者有效率分别为82.1％、71.4％、61.9％、68.9％,四组间抗体种类比较差异无统计学意义（x2=2.719,P=0.437）.②按抗体种类分组：抗GP Ⅰ bα组：单一IgG抗体阳性、单一IgM抗体阳性、IgG＋IgM双抗体阳性、IgG＋IgM双抗体阴性患者有效率分别为52.4％、59.1％、76.5％、77.9％,抗体类型在四组间比较差异有统计学意义（x2=10.811,P=0.013）.抗GPⅡb/Ⅲa组：单一IgG抗体阳性、单一IgM抗体阳性、IgG＋IgM双抗体阳性、IgG＋IgM双抗体阴性患者治疗有效率分别为73.3％、71.0％、61.9％、68.9％,四组间抗体类型比较差异无统计学意义（x2=1.374,P=0.719）.结论 血小板特异性自身抗体为GP Ⅰ bα-IgG型的成人ITP患者对大剂量地塞米松冲击治疗的治疗反应较差.

Objective To investigate the different outcomes by dexamethasone in adults immune thrombocytopenia purpura （ITP） with different types ofplatelet specific-autoantibodies.Methods A total of 185 ITP were enrolled,61 males and 124 females,with a median age of 42 （18-83） years,including 117 newly diagnosed,35 persistent,and 33 chronic cases.All the patients received the dexamethasone at an initial dose of 40 mg per day for 4 days and a low dose of 5-10 mg for 3-4 weeks.The platelet specificautoantibodies were identified by the modified monoclonal antibody-specific immobilization of platelet antigen （MAIPA） assay.Results Among the IgG positive patients,the response rates in anti-GP Ⅱ b/Ⅲ a antibody,anti-GP Ⅰ bα antibody,both antibody positive,and both antibody negative were 87.5%,50.0%,68.0%,and 72.3% （x2=11.489,P 〈 0.05）,respectively.Among the IgM positive patients,the response rates in the four groups were 82.1%,71.4%,61.9%,and 68.9% （x2=2.719,P=0.437）,respectively.Among the GP Ⅰ bα antibody positive patients,the response rates in IgG alone,IgM alone,both positive,and both negative were 52.4%,59.1%,76.1%,and 77.9% （x2=10.811,P〈 0.05）,respectively.Among the GP Ⅱ b/Ⅲ a antibody positive patients,the response rates in the four groups were 73.3%,71.0%,78.6%,and 66.3% （x2=1.374,P=0.719）,respectively.Conclusion ITP patients with GP Ⅰ bα-IgG antibody have worse response to dexamethasone treatment.