Herpes zoster in children with bone marrow transplantation: Report from a single institution.

Herpes zoster (HZ) has been often observed after bone marrow transplantation (BMT) in childhood. The occurrence of HZ was reviewed in children who received BMT. The clinical features of HZ were reviewed in 44 children who underwent BMT at Kyushu Cancer Center. Among the 35 recipients with a history of varicella before BMT, several factors associated with BMT and the lymphocyte subsets were compared between the patients who developed HZ (HZ+ group) and those who did not (HZ- group). Twenty-two recipients (50%) developed HZ; in two-thirds of these cases (15/22: 68%), HZ occurred between 80 and 120 days after BMT (median 101 days). The recipients treated with busulfan had a higher occurrence of HZ than those treated without it. The patients with Grade II-IV acute graft-versus-host disease (GVHD) developed HZ more frequently. In the HZ+ group, the absolute number of lymphocytes, CD3+, CD4+ or CD8+ cells at 3 months was significantly lower than that observed at 12 months after BMT and the CD4/CD8 ratio was significantly lower at 1 month than after 3 months of BMT. In conclusion, recipients were susceptible to HZ at around 100 days after BMT. The development of HZ may be associated with unbalanced T lymphocytes at that time.