目的 探讨过敏性紫癜(HSP)患儿常见的临床特征,发病机制并寻找特异的实验室诊断指标,为临床HSP的诊断、治疗及预后提供实验室依据和指导.方法 本研究为前瞻性研究.共收集了2010年1月至2013年12月期间在浙江大学医学院附属儿童医院住院的1 232例HSP病例,统计分析了这些患儿的临床信息并检测其免疫球蛋白、补体、T淋巴细胞亚群及CRP在HSP急性期的水平,以探讨细胞免疫及体液免疫在HSP发病机制中的可能作用.此外,本研究还选取了同期在本院住院的200例败血症伴有皮疹的患儿,200例荨麻疹患儿和200例血小板减少性紫癜患儿作为对照,400例来我院体检的健康儿童作为正常对照,并检测他们血清中的IgA水平,采用非参数检验中的Mann-Whitney U检验分析数据,以探讨IgA鉴别过敏性紫癜皮疹与其他类似皮疹的能力.结果 HSP患儿血清的IgA水平2.0(0.6 ~7.5)g/L与健康儿童血清IgA水平1.1(0.6~2.1)g/L相比显著升高(Z =5.928,P<0.01).当IgA> 1.44 g/L时,从伴有皮疹的败血症患儿中区分出HSP患儿的敏感度为77.44%(954/1 232),特异度为80.00%(160/200);当IgA> 1.53 g/L时,从荨麻疹患儿中区分出HSP患儿的敏感度为72.57%(894/1 232),特异度为74.51%(149/200);当IgA>0.91 g/L时,从血小板减少性紫癜患儿中区分出HSP患儿的敏感度为95.14%(1 172/1 232),特异度为79.45%(159/200);当IgA> 1.33 g/L时,从健康儿童中区分出HSP患儿的敏感度为81.25%(1 001/1 232),特异度为95.00%(380/400).结论 HSP患儿存在细胞免疫功能失调.Thl/Th2也存在比例失衡,Th2细胞优势活化,从而使免疫球蛋白合成和释放增加,引起体液免疫异常.HSP患儿血清IgA水平显著升高,能有效与其他类似的皮疹进行鉴别诊断.
Objective To explore the common clinical features and mechanism of HenochSchonlein purpura (HSP) in children,and provide evidence and guidance for clinical diagnosis,therapy and prognosis of HSP.Methods Prospective study.Totally 1 232 HSP children blood samples were collected during January 2010 to December 2013 in the Children's Hospital of Zhejiang University School of Medicine,and the levels of immunoglobulin,complement,T lymphocyte subsets and CRP were detected in the acute phase of HSP.The clinical data were analyzed with these indexes to explore the function of cellular and/or humoral immunity in the pathogenesis of HSP.In addition,this study detected serum IgA levels in 200 cases of sepsis rash,200 cases of urticarial and 200 cases of thrombocytopenic purpura patients and 400 cases of healthy children over the same period to our hospital respectively,in order to find out whether IgA is capable of differentiating allergic purpura rash from other similar skin rashes.Results Compared with healthy children,the IgA level was significantly higher [IgA:2.0 (0.6-7.5) g/L vs 1.1(0.6-2.1) g/L,Z =5.928,P =0.03].When IgA > 1.44 g/L,the diagnostic sensitivity and specificity to differentiate allergic purpura patients from sepsis patients were 77.43 % (954/1 232) and 80.00% (160/200),respectively.When IgA > 1.53 g/L,the diagnostic sensitivity and specificity to distinguish from allergic purpura with urticaria patients were 72.57% (894/1 232) and 74.51% (149/200).When IgA >0.91 g/L,it had a 95.14% sensitivity (1 172/1 232) and a 79.45% specificity (159/200) for the differential diagnosis of allergic purpura and thrombocytopenic purpura patients.When IgA > 1.33 g/L,the sensitivity of distinguishing allergic purpura patients from healthy children was 81.25% (1 001/1 232),while the specificity was 95.00% (380/400).Conclusions HSP children show cellular immune dysfunction.Th1/Th2 imbalance and over-activation of Th2 cells result in the increased synthesis and release of immune globulin,causing abnormalities in humoral immune.An increase in serum IgA level of HSP patients can differentiate HSP from other similar rashes.