Antibodies to Merkel cell polyomavirus correlate to presence of viral DNA in the skin.

To validate whether Merkel cell polyomavirus (MCV) serology correlates with MCV infection, we compared real-time polymerase chain reaction results for MCV DNA on fresh-frozen biopsy specimens from various skin lesions and healthy skin from 434 patients to MCV serology results using viruslike particles (VLPs) and MCV neutralization assays. Sixty-five percent of participants were MCV seropositive and 18% were MCV DNA positive. The presence of antibodies was correlated with the presence of virus DNA (odds ratio, 27.85 [95% confidence interval, 6.6-166.5]), with 97% of patients who tested positive for MCV DNA being MCV seropositive. VLP antibody levels correlated to neutralization titers (r=.72), and high antibody levels correlated to high MCV load (P<.01).