We sought to evaluate a possible link between parvovirus B19 infection and the 
clinical and laboratory expression of systemic lupus erythematosus (SLE). SLE 
patients were examined to evaluate their clinical status and disease activity. A 
complete Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score was 
obtained for each patient. In addition, we determined the level of systemic 
involvement throughout the course of the disease. Blood levels of IgM and IgG 
antibodies to parvovirus B19, levels of anti-dsDNA, C3, and C4 were measured. A 
PCR real-time assay was used to determine the presence of parvovirus B19 genetic 
material. The viral genome was found in sera of 2 of 51(3.9%) patients with SLE. 
There was no correlation between viral serology and the clinical and serological 
parameters of the disease. More SLE patients with secondary antiphospholipid 
syndrome (APS) had IgG and IgM antibodies to the virus (p < 0.029 and p < 0.018, 
respectively). These patients also had a higher titer of IgG antibodies to 
parvovirus B19 compared to SLE patients without APS. In this group of SLE 
patients, no association was found between parvovirus infection and the presence 
or activity of SLE. The results of the study suggest an association between 
parvovirus infection and antibody production directed against phospholipids.