IgA Fc受体Fc α RI在过敏性紫癜患儿中的表达及意义

Expression of IgA Fc receptor FcαRⅠ in children with Henoch-Schonlein purpura

目的:观察急性期过敏性紫癜(Henoch-Schonlein purpura,HSP)患儿外周血及皮损组织IgA Fc受体FcαRI的表达,并探讨FcαRI与炎症相关细胞因子白细胞介素-6(interleukin-6,IL-6)、肿瘤坏死因子-α(tumor necrosis factor,TNF-α)的关系。方法:纳入急性期HSP患儿50例,其中单纯型HSP 30例,紫癜性肾炎型(Henoch-Schonlein purpura nephritis,HSPN)20例,健康对照20例。采用Sandwich固相ELISA法检测血清可溶性IgA Fc受体(s FcαRI-IgA)水平;免疫组化及Western blot分别检测20例HSP患儿皮损组织中FcαRI的表达和分布,直接免疫荧光检测皮损组织中IgA、C3、纤维蛋白原(fibrinogen,Fib)的沉积;ELISA检测患儿血清细胞因子IL-6、TNF-α的水平。结果:(1)急性期HSP和HSPN患儿血清IgA[(2.32±1.00)g/L,(2.42±1.02)g/L]、C3[(1.17±0.33)g/L,(1.11±0.19)g/L]较正常对照明显升高(F=14.000,P=0.000;F=8.227,P=0.000),HSPN组血清s FcαRIIgA水平[(5.75±5.07)pg/mL]较正常对照组[(3.09±2.08)pg/mL]升高(F=2.891,P=0.022)。(2)FcαRI在急性期HSP患儿皮损表皮及真皮中性粒细胞、血管内皮细胞、附属器周围沉积,组化染色强度(HSCORE=205.00±41.86)及FcαRI蛋白表达(FcαRI/beta actin=0.23±0.07)较正常对照组明显增高(t=8.276,P=0.000;t=3.274,P=0.004)。(3)急性期HSP和HSPN患儿PBMC上清中TNF-α水平[(4.75±2.59)pg/mL,(6.37±2.87)pg/mL]较正常对照组[(3.12±2.01)pg/mL]增高(F=8.309,P=0.028,P=0.000),HSPN组升高较HSP更显著(P=0.030)。结论:IgA Fc受体参与急性期HSP发病,FcαRI可能作为急性期HSP的重要分子标记,但FcαRI通过何种机制参与HSP发病仍需深入研究。

Objective：To observe the IgA Fc receptor FcαRI expression in both serum and skin lesions of children with acute Henoch-Schonlein purpura（HSP）,and to find out the relationship between FcαRI expression and production of inflammatory cytokines interleukin-6（IL-6）,tumor necrosis factor-α（TNF-α）.Methods：Fifty children with acute HSP were included in this study,of which30 were HSP and 20 were Henoch-Schonlein purpura nephritis（HSPN）.Twenty healthy age-matched children were admitted as control.Sandwich solid-phase ELISA was applied to detect the serum soluble IgA Fc receptor（sFcαRI）.FcαRI expression and distribution in skin lesions were assayed by immunohistochemistry and Western blot in 20 patients.Direct immunofluorescence was used in locate IgA,C3,Fib deposition.Serum cytokine IL-6 and TNF-α of PBMC supernatant were also detected.Results：（1）Serum levels of IgA,C3 in acute phase of HSP and HSPN were significantly higher than those of normal controls（F=14.000,P=0.000;F=8.227,P =0.000）;serum s FcαRI-IgA levels were elevated in HSPN group only（F=2.891,P=0.022）.（2） FcαRI deposited predominantly in epidermis and dermal neutrophils,vascular endothelial cells and around appendix;both FcαRI staining intensity and protein expression were significantly increased in HSP lesion（t=8.276,P=0.000;t=3.274,P=0.004）.（3）TNF-α levels of PBMC supernatant were higher in both HSP and HSPN（F=8.309,P=0.028,P=0.000）,with more significant increase in HSPN than in HSP（P=0.030）.Conclusion：IgA Fc receptors FcαRI are involved in HSP pathogenesis and may represent an important marker for acute stage HSP.However,the underline mechanisms remain to be further elucidated.