Varicella-zoster virus-specific cell-mediated immunity and herpes zoster development in multiple myeloma patients receiving bortezomib- or thalidomide-based chemotherapy

Background: The incidence of herpes zoster is substantial during bortezomib treatment in patients with multiple myeloma (MM). Objectives: This study aimed to elucidate the effect of chemotherapy with or without bortezomib in MM patients on their herpes zoster incidence and varicella zoster virus (VZV)-specific cell-mediated immunity (CMI). Study design: Peripheral blood mononuclear cells were collected at baseline and after 1 month of bortezomib-based or thalidomide-based chemotherapy and then analyzed using VZV-specific interferon-gamma (IFN-γ) enzyme-linked immunospot (ELISPOT) assay. The clinical data from these patients were analyzed in relation to the ELISPOT results. Results: Of 58 patients analyzed, 39 patients received bortezomib and the other 19 patients, thalidomide. Among them, 5 patients developed herpes zoster during chemotherapy; all 5 were being treated with the bortezomib-based regimen and were not receiving prophylactic anti-viral agents. The median onset of herpes zoster was 32 days (range, 15-95 days) from the initiation of chemotherapy. Among patients who received bortezomib therapy, acyclovir prophylaxis significantly reduced the risk for herpes zoster (100-day cumulative incidence, 0% vs. 49.5%; p<0.001). Spot-forming cell (SFC) counts in the IFN-γ ELISPOT assay decreased from baseline after bortezomib (p=0.011) or thalidomide (p=0.096) treatment. Patients with baseline SFCs greater than 20/10⁶ mononuclear cells exhibited significantly higher incidence of herpes zoster (100-day cumulative incidence, 34.8% vs. 0%; p=0.040). Conclusions: Bortezomib treatment significantly reduced VZV-specific CMI, and high baseline SFC counts in patients receiving this treatment without acyclovir prophylaxis were associated with a significantly increased risk for herpes zoster.