系统性红斑狼疮患者血清IgG水平正常及升高与相关免疫学实验室指标的相关分析

Correlation Analysis between Normal and Elevated Serum IgG Levels and Related Immunological Laboratory Indexes in Patients with Systemic Lupus Erythematosus

目的探讨系统性红斑狼疮患者(systemic lupus erythematosus,SLE)中免疫球蛋白G(immunoglobulin G,IgG)正常与IgG升高的患者,其抗核抗体(antinuclear antibody,ANA)滴度、抗双链DNA(double-strand DNA,ds-DNA)抗体及抗可溶性抗原抗体谱(extractable nuclear antigen,ENA),以便深入对SLE的认识。方法选择2019年6~12月在空军军医大学第一附属医院就诊的初诊SLE患者150例,其中狼疮性肾炎患者62例,采用速率散射比浊法分别检测SLE患者血清中免疫球蛋白IgA,IgG,IgM及补体C3,C4的水平。采用间接免疫荧光法和欧蒙印迹法检测抗核抗体ANA,抗ds-DNA抗体及ENA。比较IgG正常组与IgG升高组患者间实验室指标的差异。结果IgG正常组SLE患者血清中免疫球蛋白IgA,IgM水平低于IgG升高组,补体C3,C4水平高于IgG升高组,其中IgA差异具有统计学意义(z=-3.64,P<0.05)。IgG正常组SLE患者抗ds-DNA抗体、抗舍格伦综合征A(SSA)抗体、抗Ro-52抗体、抗核小体抗体(AnuA)阳性率均低于IgG升高组(χ^2=4.985,7.479,8.974和5.637,均P<0.05);而抗核糖核蛋白/史密斯(nRNP/Sm)抗体、抗Sm抗体、抗舍格伦综合征B(SSB)抗体、抗组蛋白抗体(AHA)、抗核糖体P蛋白抗体(ARPA)在两组之间差异无统计学意义(χ^2=0.005~2.050,均P>0.05)。两组患者的狼疮性肾炎患病率相似,差异无统计学意义(χ^2=1.129,P>0.05)。结论IgG正常SLE患者与IgG升高患者相比,其自身抗体阳性率降低,而狼疮肾炎发病率与IgG升高组无差异,提示临床IgG正常和IgG升高的SLE患者实验室指标之间存在差异,以便加深对SLE的认识。

Objective To compare the characteristics of ANA titer,anti dsDNA and ENA in patients of systemic lupus erythematosus(SLE)with normal level of IgG to those with increased level of IgG.Methods A total of 150 newly diagnosed SLE patients,including 62 patients with lupus nephritis were selected in the study.All patients were obtained from the First Affiliated Hospital of Air Force Military Medical University from June 2019 to December 2019.The rate scatter turbidimetric method was used to detect immunoglobulins IgA,IgG,IgM and complement C3,C4 levels in the serum of SLE patients.Indirect immunofluorescence(IIF)and linear immunoblotting(LIA)were used to detect anti-nuclear antibodies ANA,anti-ds-DNA antibodies and ENA.Comparing the differences in laboratory indicators between patients with normal IgG and increased IgG groups.Results The serum IgA(z=-3.64,P<0.05)and IgM levels of SLE patients in IgG normal group was lower than that in IgG increased group.The level of C3 and C4 was higher in IgG normal group with no statistical significance.The positive percentage of ds-DNA,SSA,Ro-52 and AnuA in IgG normal group was lower than that in IgG increased group(χ^2=4.985,7.479,8.974 and 5.637,all P<0.05),but there was no difference for nRNP/Sm,Sm,SSB,AHA and ARPA between the two groups(χ^2=0.005~2.050,all P>0.05).The incidence rate of lupus nephritis was not different between the two groups.Conclusion The SLE patients with normal IgG could be seen frequently in clinic,the positive rate of autoantibodies was lower,and the incidence rate of lupus nephritis was not different from that of IgG increased group.Therefore,the patients with normal IgG SLE should be paid attention by clinicians to reduce their missed diagnosis and misdiagnosis.