Lymphocyte function following radium-223 therapy in patients with metastasized, castration-resistant prostate cancer.

PURPOSE: Therapy with the alpha-emitter radium-223 chloride ((223)Ra) is an innovative therapeutic option in patients with metastasized, castration-resistant prostate cancer. However, radiotherapy can lead to hematopoietic toxicity. The aim of this study was to determine if (223)Ra therapy induces an impairment of cellular antimicrobial immune responses.

METHODS: In 11 patients receiving (223)Ra treatment, lymphocyte proliferation and the production of pro- and anti-inflammatory cytokines (interferon-γ and interleukin-10) were determined, using lymphocyte transformation testing and ELISpot, respectively. Lymphocyte function after stimulation with mitogens and microbial antigens was assessed prior to therapy and at day 1, 7 and 28 after therapy.

RESULTS: Lymphocyte proliferation and the production of interferon-γ and interleukin-10 towards mitogens and antigens remained unchanged after therapy. Consistent with these in vitro data, we did not observe infectious complications after treatment.

CONCLUSIONS: The results argue against an impairment of lymphocyte function after (223)Ra therapy. Thus, immune responses against pathogens should remain unaffected.