Lenalidomide enhances myeloma-specific T-cell responses in vivo and in vitro.

Immunomodulation is an important part of lenalidomide's mode of action. We analyzed the impact of lenalidomide on T cells from patients with multiple myeloma during lenalidomide therapy in vivo and in patients with lenalidomide-refractory disease in vitro Patients enrolled in the German Speaking Myeloma Multicenter Group (GMMG) MM5 trial received a consolidation therapy with two cycles of lenalidomide after autologous stem cell transplantation (ASCT). Half of the study population continued treatment with lenalidomide maintenance therapy for 2 y, while the other patients received lenalidomide maintenance therapy until complete remission. We analyzed 58 patients with (n = 30) or without (n = 28) lenalidomide therapy and 12 patients refractory to lenalidomide with regards to their anti-myeloma-specific T-cell responses displayed by IFNγ, Granzyme B, and Perforin secretion. The immunophenotype of T-cells was investigated by flow cytometry. Significantly, more myeloma-specific T-cell responses were observed in patients during lenalidomide therapy, compared to patients without treatment. Furthermore, we found on T-cells from patients treated with lenalidomide a decreased CD45RA expression, indicating a maturated immunophenotype and a decreased expression of CD57, indicating functional T cells. An improved myeloma-specific T-cell response was observed in 6 out of 12 heavily pretreated patients (refractory to lenalidomide) after in vitro incubation with lenalidomide. Complementary to the results in vivo, lenalidomide decreased CD45RA expression on T cells in vitro.

Association of antigen-specific T-cell responses with antigen expression and immunoparalysis in multiple myeloma.

PURPOSE: Cancer testis antigens (CTA) are immunotherapeutical targets aberrantly expressed on multiple myeloma cells, especially at later stages, when a concomitant immunoparesis hampers vaccination approaches. EXPERIMENTAL DESIGN: We assessed the expression of the multiple myeloma antigen HM1.24 (reported present in all malignant plasma cells) and the CTAs MAGE-A2/A3 and NY-ESO-1 (aberrantly expressed in a subset of patients with myeloma), in CD138-purified myeloma cells by qRT-PCR (n = 149). In a next step, we analyzed the antigen-specific T-cell responses against these antigens by IFNγ EliSpot assay (n = 145) and granzymeB ELISA (n = 62) in relation to stage (tumor load) and expression of the respective antigen. RESULTS: HM1.24 is expressed in all plasma-cell samples, whereas CTAs are significantly more frequent in later stages. HM1.24-specific T-cell responses, representing the immunologic status, significantly decreased from healthy donors to advanced disease. For the CTAs, the probability of T-cell responses increased in early and advanced stages compared with healthy donors, paralleling increased probability of expression. In advanced stages, T-cell responses decreased because of immunoparesis. CONCLUSION: In conclusion, specific T-cell responses in myeloma are triggered by antigen expression but suppressed by tumor load. Future CTA-based immunotherapeutical approaches might target early plasma-cell diseases to establish prophylactically a specific T-cell response against late-stage antigens in immunocompetent patients.