Objective To detect the prevalence of human cytomegalovirus (HCMV) in peripheral blood of patients with systemic lupus erthematosus (SLE) and explore its role in the pathogenesis of SLE.Methods HCMV DNA was isolated from the peripheral blood leucocytes (PBLs) of 60 patients with SLE and 111 healthy controls.Nested polymerase chain reaction (nPCR) technology was used to investigate the gene of HCMV glycoprotein gB (UL55) in these specimens.HCMV infections in the PBLs of SLE patients were confirmed by HCMV-UL55 detection.Two-sample t test,nonparametric test,Chi-square test and Fisher probabilities were used to analyze.Results Agarose gel electrophoresis and sequencing analysis showed that established nPCR could specifically detect HCMV-UL55 gene,the HCMV infection rate was significantly higher in patients with SLE than in the healthy controls (P＜0.01).Positive rates of HCMV infection in SLE group and controls were 41.7％ (25/60) and 1.8％ (2/111),respectively.Compared to the SLE patients with HCMV-negative PBLs,the positive rate of Rib-P [26％(9/35) vs 56％(14/25),x2=5.659,P=0.017],the positive rate of direct Coomb's test [37％(13/35) vs 72％(18/25),x2=7.096,P=0.008] and the level of antiβ2GP1 [21.3 (9.9,51.8) U/ml vs 13.6 (5.9,23.1) U/ml,U=2.017,P=0.044] were significantly higher than those in the SLE patients with HCMV-positive PBLs.Compared to the SLE patients with HCMV-negative PBLs,the number of red blood cells [(3.65±0.10)×1012/L vs (3.17±0.17)×1012/L,t=2.574,P=0.013] and lymphocytes [(1.37±0.14)×1012/L vs (0.90±0.13)×1012/L,t=2.456,P=0.017] in peripheral blood and the hemoglobin levels [(110±19) g/L vs (98±5)g/L,t=2.034,P=0.048] of the SLE patients with HCMV-positive decreased significantly.At the same time,the positive rate of hematuria [40％(14/35) vs 72％(18/25),x2=6.000,P=0.014] and 24 h proteinuria [0.80 (0.53,2.37)g vs 0.48 (0.13,1.21)g,U=2.140,P=0.032],which indicated kidney damage were also significantly increased in SLE patients with HCMV-positive PBLs.Conclusion The infection of HCMV in peripheral blood cells may take part in the development of SLE.