Loss of seroreactivity against human papillomavirus (HPV) in bone marrow transplant recipients

Sera from 19 autologous and 35 allogeneic bone marrow transplant (BMT) patients at Huddinge University Hospital were analyzed by different ELISA assays before and 1 year after BMT for the presence of IgG antibodies towards human papillomavirus (HPV). One assay was a peptide-based enzyme-linked immunoadsorbent assay (ELISA). These peptides were derived from the amino acid sequences of the two major viral capsid proteins of HPV 16, p(31) L1 and (p49) L2. The other was an ELISA using HPV-type 16 virus-like particles (VLPs) as antigens. Before BMT 13/19 autologous and 14/35 allogeneic BMT patients were IgG positive towards p49 (L2). Reactivity to p31 (L1) was less frequent and was only observed in 7/19 autologous and 3/35 allogeneic BMT patients. One year after BMT 1/4 of the autologous and 2/3 of the allogeneic BMT patients who were IgG positive to p49 (L2) lost these antibodies as measured by the peptide ELISA assay. Regarding IgG reactivity to p31 (L1), one of the seven p31 (L1) positive autologous BMT patients and all three of the p31 (L1) positive allogeneic BMT patients lost this reactivity 1 year after BMT. Of all the 19 autologous and the 35 allogeneic BMT patients only two allogeneic BMT patients were weakly IgG reactive towards VLPs and 1 year after BMT this activity was lost in one of the two patients.