Author(s): Us T, Cetin E, Kaifolu N, Kaifolu T, Akgn Y
Rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) which are autoimmune diseases usually questioned for their association with many infectious agents have etiopathogenesis related to genetic, immunologic, hormonal and even environmental factors. The most commonly attributed etiologic agents are herpes group viruses. The aim of this study was to investigate the role of Epstein-Barr virus (EBV) and herpes simplex (HSV) viruses in the etiology of RA and SLE. A total of 137 patients (87 RA and 50 SLE; mean age: 33 ± 12 years) who were admitted to Eskisehir Osmangazi University Medical Faculty Rheumatology Department between January 2007-January 2008 and diagnosed according to 1987 ACR (American College of Rheumatology) criteria have been included in the study, together with 50 healthy blood donors (mean age: 35 ± 14 years) as control group. Serum samples obtained from all of the cases were tested for EBV VCA-IgG, VCA-IgM, EA/D-IgG and EBNA-IgG (Trinity Biotech, USA); IgM and IgG antibodies against HSV-1 and HSV-2 by ELISA method (Dia-Pro Diagnostic, Italy), and the presence of viral nucleic acids in blood samples were investigated by real-time quantitative polymerase chain reaction (RTPCR; Qiagen, USA). EBV VCA-IgM was negative in all of the RA, SLE and control group patients. VCA-IgG positivity were 98% and 96%, and for EBNA-IgG 98.5% and 100%, in patient and control groups, respectively. There was no statistically significant difference between the groups regarding VCA-IgG and EBNA- IgG positivity (p> 0.05). On the other hand, EBV EA/D-IgG positivity rate found in the SLE group (34%) was significantly higher than RA (7%) and control (12%) groups (p< 0.001 and p< 0.05, respectively). There was no significant difference between RA and control groups in terms of EA/D-IgG positivity (p> 0.05). Regarding herpes simplex virus serology, HSV1-IgG seropositivity were 99% and 94% and HSV2-IgG positivity were 8% and 12% in the patient and control groups, respectively. There was no statistically significant difference between the groups according to the positivity rates of IgM and IgG specific for HSV-1 and HSV-2 (p> 0.05). All of the cases were found negative in terms of EBV, HSV-1 and HSV- 2 DNAs according to double-checked RT-PCR results. In conclusion, no significant difference was determined for EBV and HSV serologic markers in RA and SLE patients compared to the control group. However, significantly higher rate of EBV EA/D-IgG positivity in SLE patients might have indicated a possible association between SLE and EBV infection. Larger scale, prospective studies including examination of the synovial fluid/tissue samples are required to enlighten the association between SLE and EBV.