Fig. 1: Box plots showing the percentages of the analyzed immune cell populations at inclusion (T1), after induction therapy (T2), and during consolidation and maintenance therapy (T3) by treatment arms.

A Flow chart of the GMMG-HD6 trial and sample collection time points. MM patients were randomized into one of four arms (RVd/R, RVd/Elo-R, Elo-RVd/R, and Elo-RVd/Elo-R). Patients in the RVd/R or RVd/Elo-R arm received induction therapy consisting of four cycles of RVd. Patients in the Elo-RVd/R or Elo-RVd/Elo-R arm additionally received the monoclonal antibody elotuzumab in the four cycles of RVd. After induction therapy, patients underwent mobilization therapy followed by peripheral blood stem cell collection and melphalan high-dose chemotherapy/autologous stem cell transplantation. Consolidation therapy was performed with two cycles of RVd (RVd/R and Elo-RVd/R) or RVd/elotuzumab (RVd/Elo-R und Elo-RVd/Elo-R), followed by two years of lenalidomide maintenance therapy with elotuzumab for the RVd/Elo-R and Elo-RVd/Elo-R arms or without elotuzumab for the RVd/R and Elo-RVd/R arms. For the present study, peripheral blood samples were collected and analyzed at three different time points: at inclusion (T1), after induction therapy (T2), and during consolidation or maintenance therapy (T3). Box plots of the percentage of (B) effector CD8⁺ T cells and (C) regulatory CD8⁺ T cells (CD8⁺ CD28^-) at T1 and T2 in study arm RVd/R + RVd/Elo-R and study arm Elo-RVd/R + Elo-RVd/Elo-R. D, E The percentage of effector CD8⁺ T cells at T2 and T3 in study arms RVd/R, RVd/Elo-R, Elo-RVd/R and Elo-RVd/Elo-R. F, G The percentage of regulatory CD8⁺ T (CD8⁺ CD28^-) cells at T2 and T3 in study arms RVd/R, RVd/Elo-R, Elo-RVd/R and Elo-RVd/Elo-R. Differences between groups were evaluated using Student’s t-test; ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001.