Significant association of past parvovirus B19 infection with cytopenia in both adult-onset Still's disease and systemic lupus erythematosus patients.

BACKGROUND

Human parvovirus B19 (B19) infection has been reported as a possible cause of autoimmune diseases. The association of B19 infection with adult-onset Still's diseases (AOSD) remains unclear.

METHODS

IgM and IgG against B19-VP1/2 were determined using ELISA in 86 patients with AOSD, 58 patients with systemic lupus erythematosus (SLE) and 64 healthy controls. Anti-B19-VP1-unique region (VP1u) and anti-B19-nonstructural protein-1(NS1) antibodies were assessed by Western blot. B19 DNA was detected by nested PCR.

RESULTS

Forty-three (50.0%) of 86 AOSD patients, 27 (46.6%) of 58 SLE patients and 30 (46.9%) of 64 controls had positivity for anti-B19-VP1/2-IgG in the absence of anti-B19-VP1/2-IgM, indicating past infection. None of enrolled subjects had detectable circulating B19 DNA. Significantly higher positivity rates for anti-B19-VP1u and anti-B19-NS1 IgG were observed in AOSD patients (39.5% and 46.5% respectively) and SLE patients (34.5% and 36.2% respectively) than in healthy controls (14.1%, p<0.005 for AOSD and p<0.05 for SLE, and 15.6%, p<0.001 for AOSD and p<0.05 for SLE; respectively). AOSD patients and SLE patients with seropositive results for anti-B19-VP1/2 IgG, anti-B19-VP1u or anti-B19-NS1 antibodies had a higher frequency of leucopenia and thrombocytopenia when compared to those with seronegative results. AOSD patients with anti-B19-VP1u or anti-B19-NS1 antibodies were more likely to have arthritis in comparison with those without these antibodies.

CONCLUSIONS

Higher seroreactivity for anti-B19-VP1u and anti-B19-NS1 IgG were associated with cytopenia in both AOSD and SLE patients with unique correlation to arthritis in the AOSD. Further studies are necessary to determine if these responses correlate with a common genetic risk in patients with AOSD and SLE.