过敏性紫癜并肺炎支原体感染患儿免疫球蛋白和补体的研究

Immunoglobulin and complement levels of children with henoch-schonlein purpura concurrent with mycoplasma infection

目的检测过敏性紫癜(HSP)合并肺炎支原体(MP)感染的患儿血清免疫球蛋白及补体的水平,探讨MP感染与HSP的体液免疫学关系。方法研究对象为55例HSP患儿,检测MP-IgM抗体,分为MP-IgM阳性组20例、MP-IgM阴性组35例,并以20名正常儿童作为对照组。采用全自动生化分析仪检测血清免疫球蛋白IgA、IgM、IgG、IgE及补体C3、C4。结果 HSP患儿MP感染阳性率达36.36%,合并MP感染的患儿临床症状更严重。与正常对照组相比,MP-IgM阴性组IgA、IgE明显增高(P<0.01),C3水平降低(P<0.05),同时IgE明显高于MP-IgM阳性组(P<0.01),IgG、IgM、C4无明显变化。MP-IgM阳性组与正常对照组相比,IgA增高,IgM、C3、C4水平降低,且其中IgM、C3低于MP-IgM阴性组,差异均有统计学意义(P<0.05),而IgG、IgE水平无明显改变。结论在HSP儿童中有较高MP感染率,所有HSP患儿存在血清IgA增高及C3水平降低,说明体液免疫参与HSP的发病。伴MP感染的HSP患儿体液免疫功能更加紊乱,表现在C4水平下降,IgM、C3明显低于MP-IgM阴性组,IgE增高仅见于MP-IgM阴性组,提示MP感染的HSP患儿可能更多伴有低补体血症的自身免疫紊乱参与,说明MP感染引起的免疫紊乱可能在HSP发生、发展中具有重要作用。

Objective To observe the changes of immunoglobulin and complement levels of children with Henoch-Schonlein pur- pura （HSP） concurrent with mycoplasma （MP） infection, and explore the correlation between MP infection and HSP in humoral immuni- ty. Methods 55 children with HSP were chosen and divided into two groups based on the MP detection results ： 20 cases in MP-IgM pos- itive group, and 35 cases in MP-IgM negative group, with 20 healthy children as the control. The plasma immunoglobulin IgA, IgM, IgG and IgE as well as complement C3 and C4 were detected by automatic biochemistry analyzer. Results The infection rate of MP in chil- dren with HSP was 36.36%. The clinical symptoms of children with HSP and current MP were more serious. Compared with the controls, the levels of IgA and IgE significantly increased （ P 〈 0.01 ） in MP-IgM negative group, while C3 level decreased （ P 〈 0.05 ）. The lgE level of MP-IgM negative group was significant higher than that of MP-IgM positive group, but the levels of IgG, IgM and C4 showed no significant differences. In MP-IgM positive group, the level of lgA significantly increased while the levels of IgM, C3 and C4 decreased compared with the control group, and the levels of IgM and C3 were significantly lower than those in MP-IgM negative group. But the lev- els of IgG and IgE showed no significant changes. Conclusion The infection rate of MP is higher in children with HSP. Increase of IgA and decrease of C3 in plasma appear in all children with HSP, which indicates that humoral immunity may participate in the pathogenesis of HSP. The disorder of humoral immune function is more obvious in children with HSP concurrent with MP infection, whose level of C4 decreased, with the levels of IgM and C3 lower than those with no MP infection. Increase of IgE exists only in MP-IgM negative group, suggesting that autoimmunity disorder with hypocomplementemia may participate in the pathogenesis of HSP concurrent with MP infection. It indicates immunologic derangement caused by MP infection may possibly play an important role in the pathogenesis of HSP.