Severe myelosuppression involving HPV‐B19 infection and NUDT15 polymorphisms during therapy for LCH.

The article presents a case study of a seven-year-old boy with Langerhans cell histiocytosis (LCH) who experienced severe myelosuppression during chemotherapy with oral 6-mercaptopurine (6-MP). Topics discussed include the association of NUDT15 polymorphisms with fatal myelosuppression, the risk of human parvovirus B19 (HPV-B19) infection during myelosuppression, and the recommendation for genotyping NUDT15 before initiating thiopurine-containing therapy to avoid excess toxicity.