Varicella zoster virus reinfection in a patient with refractory nephrotic syndrome: a case report.

Permanent immunity to varicella zoster virus (VZV) develops following infection in most patients, with reinfections extremely rare. Here, we report a 6-year-old boy with refractory nephrotic syndrome who contracted VZV infection during B-cell depletion after rituximab treatment. Although developing febrile neutropenia, he was promptly treated with acyclovir, which was successful. The VZV immunoglobulin G antibody titer was weakly positive (3.3) by enzyme immunoassay performed 42 days after the initial diagnosis of VZV infection, confirming the presence of VZV, although antibody production was insufficient to prevent reinfection. Three years later, he was diagnosed with VZV infection again, along with the 18th relapse of nephrotic syndrome. After promptly recovering from VZV infection with acyclovir, he progressed to refractory nephrotic syndrome, which required multiple immunosuppressive therapies to achieve partial remission. The present case illustrates that antibody production can be severely suppressed not only after vaccination but also after viral infection, during rituximab-induced B-cell depletion.