Analysis of clinical characteristics of patients with systemic lupus erythematosus complicated with decreased level of IgG / 中华风湿病学杂志

ABSTRACT

Objective:To analyze the clinical features and prognostic factors of patients with systemic lupus erythematosus (SLE) complicated with IgG decrease.Methods:Thirty-five newly diagnosed patients with systemic lupus erythematosus with decreased IgG (<7 g/L) admitted to the Department of Rheumatology of Tangdu Hospital of the Air Force Medical University of the Chinese People′s Liberation Army from January 2016 to March 2022 were included, and 38 hospitalized patients with SLE complicated with elevated or normal IgG during the same period were included as the control group. The clinical data were statistically analyzed. Independent sample t test and χ2 test were used. Results:In the SLE group combined with IgG, the incidence of edema was decreased (31.4% vs. 2.6%, χ2=11.00, P=0.001), and the white blood cell count was decreased [(5.8±0.9)×10 9/L vs. (4.2±0.3)×10 9/L, t=2.49, P=0.015], neutrophil [(4.10±0.48)×10 9/L vs. (2.65±0.25)×10 9/L, t=2.75, P=0.008], the ratio of neutrophil and lymphocyte (4.18±0.65 vs. 2.71±0.24, t=2.18, P=0.032), the ratio of neutrophil and serum albumin (0.186±0.025 vs. 0.071±0.068, t=4.58, P<0.001), the ratio of blood urea nitrogen and serum albumin (0.550 6±0.079 4 vs. 0.048 7±0.002 4, t=6.59, P<0.001), erythrocyte sedimentation rate [(59±7)mm/1 h vs. (33±5)mm/1 h, t=3.06, P=0.003], total cholesterol [(5.95±0.40)mmol/L vs. (3.78±0.14)mmol/L, t=5.26, P<0.001], low density lipoprotein cholesterol [(2.93±0.24)mmol/L vs. (1.84±0.09)mmol/L, t=4.30, P<0.001], creatinine [(178.0±45.2)mmol/L vs. (46.8±1.8)mmol/L, t=3.02, P=0.004], urea nitrogen [(11.92±1.62)mmol/L vs. (4.54±0.25)mmol/L, t=4.67, P<0.001], uric acid [(436±31)mmol/L vs. (278±20)mmol/L, t=4.40, P<0.001], lactate dehydrogenase [(356±72)U/L vs. (208±12)U/L, t=2.11, P=0.038], and α-hydroxybutyrate dehydrogenase [(282±35)U/L vs. (175±11)U/L, t=3.05, P=0.003] were higher than that in normal or elevated IgG groups. Red blood cell [(3.35±0.17)×10 12/L vs. (3.96±0.11)×10 12/L, t=-3.03, P=0.003], hemoglobin [(95±4)g/L vs. (113±4)g/L, t=-3.32, P=0.001], serum albumin [(24.5±1.3)mg/L vs. (38.3±0.9)mg/L, t=-8.79, P<0.001], complement C3 [(0.58±0.04)g/L vs. (0.75±0.05)g/L, t=-2.53, P=0.014], the positive rate of anti-SSA antibody (45.7% vs. 73.7%, χ2=5.95, P=0.015), and the course of disease [(5.6±0.9)year vs. (7.7±0.8) year, t=-7.51, P<0.001] were lower than that of combined normal or elevated IgG groups. The ratio of blood urea nitrogen to serum albumin ( r=-0.47), blood urea nitrogen ( r=-0.36) and uric acid ( r=-0.56) were negatively correlated with complement C3 in patients with IgG reduction group ( P<0.05). Conclusion:Most patients with SLE combined with IgG reduction had edema as the first clinical symptom. Kidney involvement,white blood cell count, neutrophil, the ratio of neutrophil to lymphocyte, the ratio of neutrophil to serum albumin, the ratio of blood urea nitrogen to serum albumin, erythrocyte sedimentation rate, total cholesterol, low density lipoprotein cholesterol, creatinine, urea nitrogen, uric acid, lactate dehydrogenase, and α-hydroxybutyrate dehydrogenase were increased, but red blood cell, hemoglobin, serum albumin, and complement C3 were decreased.Edema was the first clinical presentation, and these patients tend to have more rapidly progression of the disease, and their disease were more severe.