During 1987 and 1988, we identified 9 adults at the Medical and Rheumatology Services of the University of Iowa Hospitals and Clinics who had a clinical diagnosis of fifth disease; 8 of the 9 had symptoms of joint involvement. Another 12 adults with serologic positivity for anti-parvovirus B19 IgM antibody presented with polyarthralgidpolyarthritis. Patients were usually found to be seronegative for rheumatoid factor, and none developed nodules or erosive disease. Many patients with chronic disease met criteria for a diagnosis of rheumatoid arthritis. A diagnosis of parvovirus B19 infection should be considered during the initial visit of patients with polyarthralgia/polyarthritis.Human parvovirus B19 causes childhood exanthem erythema infectiosum, or fifth disease (1-3, a similar syndrome in adults (6), a chronic arthropathy (7,8), aplastic crisis in patients with chronic hemolytic anemia (9)(10)(11)(12)(13)(14)(15)(16)
PATIENTS AND METHODSAntigen-positive sera. Sera were obtained from sickle cell anemia patients presenting with aplastic crisis. Sera containing high-titer B19 virus were identified in a parvovirus B19 antigen-capture enzyme-linked immunosorbent assay (ELISA), as previously described (29). Serum from patient 1 1 was initially found to be anti-B19 IgM and IgG antibody-positive by Drs. L. J. Anderson and G . W. Gary, Jr. (Centers for Disease Control [CDC], Atlanta, GA) by an antibody-capture ELISA, and was subsequently used to initially screen sera for B19 virus in an antigen-capture ELISA in our laboratory (29). Serum from a child in Florida with sickle cell anemia was obtained during the areticulocytosis phase of aplastic crisis; this serum was obtained prior to the onset of endogenous anti-B 19 antibody response and, therefore, was intensely viremic and lacked anti-B19 antibodies, which would interfere with an antibody-capture ELISA. The presence of B19 virus in antigen-capture ELISA-positive sera was confirmed by electron microscopy and by polymerase chain reaction amplification of B19 target DNA sequences. Electron microscopy. Serum was examined for virus using a pseudoreplicate technique of virus fixation, as previously described (19). Briefly, a 25-pl sample of serum was allowed to absorb into an agarose block, leaving the viral particles on the surface. The agarose was layered with plastic (Formvar; Electron Microscopy Sciences, Fort Washington, PA), and after hardening, the plastic was floated off the agarose, applied to a support grid, and negatively stained with uranyl acetate. Examination of sera used as a source of B19 viral antigen demonstrated abundant nonenveloped, icosahedral viral particles -23 nm in diameter, a finding that is consistent with the presence of parvovirus B19 (Figure 1).Polymerase chain reaction. Parvovirus B19 DNA was detected following polymerase chain reaction amplification of target B19 DNA sequences in sera using standard methods (30,31). A 130-basepair sequence in the open reading frame encoding the structural viral proteins VP1 and VP2 was amplified using sy...