Figure 2. Cross-reactivity between trichodysplasia spinulosa–polyomavirus (TSV), Merkel cell polyomavirus (MCV), and BKV polyomavirus viral protein 1 (VP1). Correlation between seroreactivity against TSV VP1 and MCV VP1 (A) and BKV VP1 (B) was analyzed by using Bio-Plex 100 analyzer (Bio-Rad Laboratories, Hercules, CA, USA) with 30 serum samples from renal transplant patients, the Netherlands. Each circle represents 1 serum sample, and the line represents results of linear regression analyses. Correlation coefficients (r2) were determined by using GraphPad Prism software (GraphPad Software Inc., La Jolla, CA, USA). MFI, median fluorescent intensity.