X Xu1,2,3, A Estekizadeh4, B Davoudi1,3, S Varani5, V Malmström6, A Rahbar1,3, C Söderberg-Nauclér1,3. 1. Department of Medicine, Solna, Microbial Pathogenesis Unit, BioClinicum, Karolinska Institutet, Stockholm, Sweden. 2. Division of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden. 3. Division of Neurology, Karolinska University Hospital, Stockholm, Sweden. 4. Department of Laboratory Medicine, Virology Division, University of Washington, Seattle, USA. 5. Department of Experimental, Diagnostic and Specialty Medicine, University of Bologna, Bologna, Italy. 6. Division of Rheumatology, Department of Medicine, Center for Molecular Medicine, Karolinska Institutet and Karolinska University Hospital, Solna, Sweden.
Abstract
Objectives: To examine whether signs of an active human cytomegalovirus (HCMV) infection are present in affected joints of patients with rheumatoid arthritis (RA).Method: Polymorphonuclear leucocytes (PMNLs) were obtained from synovial fluid (SF) of 17 RA patients and were analysed for HCMV-pp65 and HCMV-immediate early (IE) proteins using the antigenemia assay. Peripheral blood (PB) and SF obtained from these 17 patients and from 17 additional RA patients (n = 34) were tested for HCMV-IE and pp150 DNA with Taqman polymerase chain reaction. Plasma samples from the patients were analysed for HCMV-immunoglobulin M (IgM) and immunoglobulin G (IgG) by enzyme-linked immunosorbent assay and compared to 71 healthy gender-matched blood donors. Results: HCMV-pp65 protein was detected in 65% of synovial PMNL samples, but in only 18% of PMNLs from PB. In contrast, HCMV IE protein was not found in any of the analysed PMNL samples. On the DNA level, HCMV-IE and pp150 DNA was detected in SF of 13/32 (41%) and 14/23 (61%) of RA patients, respectively. HCMV-IE and pp150 DNA was also found in 24/33 (73%) and in 16/24 (67%) of PB samples obtained from RA patients, respectively. HCMV IgG seroprevalence was 76% in RA patients as well as in healthy controls, while only one RA patient was positive for specific IgM.Conclusions: HCMV pp65 antigen was found in PMNLs from SF of RA patients, indicating an active infection in the affected joint. Future studies are needed to determine whether HCMV infection can aggravate the inflammatory process in these patients.
Objectives: To examine whether signs of an active human cytomegalovirus (HCMV) infection are present in affected joints of patients with rheumatoid arthritis (RA).Method: Polymorphonuclear leucocytes (PMNLs) were obtained from synovial fluid (SF) of 17 RApatients and were analysed for HCMV-pp65 and HCMV-immediate early (IE) proteins using the antigenemia assay. Peripheral blood (PB) and SF obtained from these 17 patients and from 17 additional RApatients (n = 34) were tested for HCMV-IE and pp150 DNA with Taqman polymerase chain reaction. Plasma samples from the patients were analysed for HCMV-immunoglobulin M (IgM) and immunoglobulin G (IgG) by enzyme-linked immunosorbent assay and compared to 71 healthy gender-matched blood donors. Results:HCMV-pp65 protein was detected in 65% of synovial PMNL samples, but in only 18% of PMNLs from PB. In contrast, HCMV IE protein was not found in any of the analysed PMNL samples. On the DNA level, HCMV-IE and pp150 DNA was detected in SF of 13/32 (41%) and 14/23 (61%) of RApatients, respectively. HCMV-IE and pp150 DNA was also found in 24/33 (73%) and in 16/24 (67%) of PB samples obtained from RApatients, respectively. HCMV IgG seroprevalence was 76% in RApatients as well as in healthy controls, while only one RApatient was positive for specific IgM.Conclusions: HCMV pp65 antigen was found in PMNLs from SF of RApatients, indicating an active infection in the affected joint. Future studies are needed to determine whether HCMVinfection can aggravate the inflammatory process in these patients.