Prevalence of UL97 gene mutations in cytomegalovirus reactivation in the colon associated with or without ulcerative colitis

Background: Cytomegalovirus (CMV) reactivation in the colon is common in patients with severe ulcerative colitis (UC) and in immunocompromised patients, and may be associated with poor prognosis. Ganciclovir (GCV) resistance conferring CMV UL97 gene mutations have been reported in recent years. However, the prevalence of UL97 gene mutations in GCV-naive CMV colitis remains to date unknown. The present study aimed to investigate the prevalence of CMV UL97 gene mutations in Japanese patients with colonic CMV infection associated with or without UC.Methods: Twenty-two GCV-naive patients with colonic CMV infection, 15 with UC and 7 with other diseases, were enrolled. Frozen biopsy samples or formalin-fixed paraffin-embedded samples were used for nested polymerase chain reaction (PCR) amplification of the UL97 gene. Sanger DNA sequencing of the PCR products was performed.Results: UL97 mutations were frequently detected in codons T75A (95.5%), Q126L (86.4%), and D605E (86.4%), and less frequently (Conclusions: We did not detect UL97 gene mutations associated with GCV resistance in GCV-naive patients with or without UC. In contrast, T75A, Q126L, and D605E mutations may be used as genetic markers for CMV in East Asian countries.