Objective: To investigate the different outcomes by dexamethasone in adults immune thrombocytopenia purpura (ITP) with different types of platelet 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 specific-autoantibodies 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-GPIIb/IIIa antibody, anti-GPIbα antibody, both antibody positive, and both antibody negative were 87.5%, 50.0%, 68.0%, and 72.3% (χ²=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% (χ²=2.719, P=0.437), respectively. Among the GPIbα 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% (χ²=10.811, P<0.05), respectively. Among the GPIIb/IIIa antibody positive patients, the response rates in the four groups were 73.3%, 71.0%, 78.6%, and 66.3% (χ²=1.374, P=0.719), respectively.
Conclusion: ITP patients with GPIbα-IgG antibody have worse response to dexamethasone treatment.
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GPⅠbα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（χ2=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（χ2=2.719，P=0.437）。②按抗体种类分组：抗GPⅠbα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（χ2=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%、78.6%、66.3%，四组间抗体类型比较差异无统计学意义（χ2=1.374，P=0.719）。
结论: 血小板特异性自身抗体为GPⅠbα-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。