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Letters False Positive Parvovirus Serology To the Editor: In July 1999 we submitted for publication a case report that described the association of an acute symmetrical polyarthropathy with cranial mononeuritis. Parvovirus B19 IgM was present in the serum and no other cause for the arthropathy or neuropathy was found. Our report was provisionally accepted, but at the suggestion of a reviewer, the parvovirus B19 IgM and IgG titers were repeated 14 months after the original assay, as well as polymerase chain reaction (PCR) analysis for parvovirus B19 DNA, at the Central Public Health Laboratory (CPHL) in London, UK. The results are given in Table 1.
In view of these findings, a further opinion was sought from Prof. Klaus Hedman at the University of Helsinki, Finland, whose assay results are illustrated in Table 2.
These results are consistent with past parvovirus B19 infection, and the anomalous parvovirus B19 IgM results are probably false-positive due to nonspecific reactions, and are not related to recent infection (personal communications, Dr. B.J. Cohen, CPHL, London, UK, and Prof. K. Hedman, University of Helsinki, Helsinki, Finland). On reviewing the initial serum sample results showing persistent parvoviral IgM titer, we withdrew our report. We now wish to draw attention to this case as an example of the doubtful specificity of parvovirus B19 IgM serology that may be encountered by investigators. We would recommend that, where a positive parvoviral IgM is detected, B19 DNA PCR may be necessary to confirm recent infection, where this is clinically necessary. ALICE H. JOHNSON, MRCP; ANDREW GOUGH, MD, MRCP, Department of Rheumatology, Harrogate District Hospital, Lancaster Park Road, Harrogate HG2 7SX, United Kingdom. E-mail: andrew.gough@hhc-tr.northy.nhs.uk REFERENCE 1. Brown KE, Buckley MM, Cohen BJ, Samuel D. An amplified ELISA for the detection of parvovirus B19 IgM using monoclonal antibody to FITC. J Virol Methods 1989;26:189-98. |
