Fibromyalgia-associated hepatitis C virus infection.

The objective was to determine whether there might be an association between hepatitis C virus (HCV) chronic infection and fibromyalgia (FM). We determined the prevalence of HCV infection in 112 FM patients, in comparison with matched rheumatoid arthritis (RA) patients from the out-patient clinic of a teaching tertiary care general hospital. Furthermore, we looked for evidence of FM in 58 patients diagnosed with chronic hepatitis due to HCV, compared with matched surgery clinic patients, HCV antibodies were determined by enzyme-linked immunosorbent assay (ELISA) and recombinant immunoblot assay (RIBA). Serum RNA of HCV (HCV-RNA) was determined by polymerase chain reaction. In the group of FM patients, HCV antibodies were found by ELISA in 17 (15.2%) patients and in six (5.3%) of the RA controls (P < 0.05). RIBA was positive in 16 and indeterminate in one of the FM patients. Serum HCV-RNA was found in 13 of these FM patients. In eight (47%) FM patients, alanine aminotransferase (ALT) was normal, although HCV-RNA was detected in four (50%) of them. In the group of patients with chronic hepatitis due to HCV, all patients had HCV antibodies and the presence of HCV-RNA in serum. Within these patients, 31 (53%) had diffuse musculoskeletal pain, while six (10%) fulfilled FM diagnostic criteria. In the control group, 13/58 (22%) had diffuse musculoskeletal pain (P < 0.001), whereas only one female patient (1.7%) fulfilled FM criteria (P < 0.05). Serum ALT was 51.7 +/- 38.4 in FM patients, whereas it was 122 +/- 76.3 in patients with HCV chronic hepatitis but without FM (P < 0.001). There were no statistical differences in autoimmune markers between patients with and without FM. These data suggest that there exists an association between FM and active HCV infection in some of our patients. FM is not associated with liver damage or autoimmune markers in these patients. HCV infection should be considered in FM patients even though ALT elevations were absent.