FOLLOW-UP-STUDY OF CLINICAL AND IMMUNOLOGICAL FINDINGS IN PATIENTS PRESENTING WITH ACUTE PARVOVIRUS B19 INFECTION

This study was undertaken to examine the natural history of parvovirus B19 infection in persons without a known immune defect in terms of bo th clinical symptoms and immune responsiveness to the virus. Fifty-thr ee patients with acute B19 infection (positive for serum anti-B19 IgM) were studied; symptoms at acute infection were rash and arthralgia (n = 26), rash (n = 7), arthralgia (n = 16), aplastic crisis (n = 3), an d intrauterine fetal death (n = 1). Patients were followed for 26-85 m onths (mean 57 months) and reassessed for persistent symptoms, anti-B1 9 antibodies, and antibodies to the unique region of B19 VP1. There we re 23 cases of arthralgia persisting for longer than 1 year after acut e infection. One of these patients, a 48-year-old woman at follow-up, had had persistent arthralgia for 4 years following acute B19 infectio n, had rheumatoid factor at a titre of 1920 IU/ml detected at follow-u p, and had been independently diagnosed as having rheumatoid arthritis at the time of follow-up. All 53 patients were positive for serum ant i-B19 IgG compared to 45 of 53 age- and sex-matched control patients, a significant difference (two-tailed P value = 0.008). All test patien ts at follow-up and control patients were negative for serum anti-B19 IgM and antibodies to the unique region of B19 VP1. Serum from acute i nfection from 33 of 53 test patients was tested for antibodies to the unique region of VP1, and 16 of these were positive. The presence of t his antibody did not correlate with subsequent duration of symptoms bu t did correlate with a short interval between symptom onset and blood sampling. The unique region of B19 VP1 is known to be crucial for a su ccessful humoral response to the virus, and it seems that the antigeni c role played by this region is important only during the acute phase of B19 infection. (C) 1996 Wiley-Liss, Inc.