One-Year Follow-Up of Natural Killer Cell Activity in Multiple Myeloma Patients Treated With Adjuvant Lenalidomide Therapy

Abstract

Multiple myeloma (MM) is a proliferation of tumoral plasma B cells that is still incurable. Natural killer (NK) cells can recognize and kill MM cells in vitro and can limit MM growth in vivo. Previous reports have shown that NK cell function is impaired during MM progression and suggested that treatment with immunomodulatory drugs (IMIDs) such as lenalidomide (LEN) could enhance it. However, the effects of IMIDs on NK cells have been tested mostly in vitro or in preclinical models and supporting evidence of their effect in vivo in patients is lacking. Here, we monitored NK cell activity in blood samples from 10 MM patients starting after frontline induction chemotherapy (CTX) consisting either of association of bortezomib-lenalidomide-dexamethasone (Velcade Revlimid Dexamethasone) or autologous stem-cell transplantation (SCT). We also monitored NK cell activity longitudinally each month during 1 year, after maintenance therapy with LEN. Following frontline chemotherapy, peripheral NK cells displayed a very immature phenotype and retained poor reactivity toward target cells ex vivo. Upon maintenance treatment with LEN, we observed a progressive normalization of NK cell maturation, likely caused by discontinuation of chemotherapy. However, LEN treatment neither activated NK cells nor improved their capacity to degranulate or to secrete IFN-γ or MIP1-β following stimulation with MHC-I-deficient or antibody-coated target cells. Upon LEN discontinuation, there was no reduction of NK cell effector function either. These results caution against the use of LEN as single therapy to improve NK cell activity in patients with cancer and call for more preclinical assessments of the potential of IMIDs in NK cell activation.

Keywords: immunomodulatory drugs; immunomonitoring; innate immunity; lenalidomide; multiple myeloma; natural killer cells.

Figure 1

Induction CTX impairs natural killer (NK) cell maturation and ADCC functions. Flow cytometry analysis of the indicated parameters in peripheral NK cells from HV and multiple myeloma patients after induction/consolidation CTX (post-Velcade Revlimid Dexamethasone). (A,B) Parameters were clustered in functional categories “antitumor function,” “activation markers,” and “cell surface receptors” as labeled and displayed as heatmaps (black dots are patients who received Velcade Revlimid Dexamethasone and blue dots are patients who received stem-cell transplantation). Stars summarize significance level of the p-values adjusted for multiple testing by the Benjamini–Hochberg method. These p-values were obtained using logistic regression models, which compare each patient group with the HD group. Significance codes: 0 “***” 0.001 “**” 0.01 “*” 0.05 “ ” 1.

Figure 2

LEN treatment neither activates NK cells nor improves their effector functions. Flow cytometry analysis of the indicated parameters in NK cells from patients monitored at different time-points before, during, or after LEN therapy. Data were obtained and analyzed as indicated in Figure 1. (A) Charts of the percentages and absolute counts of NK cells. (B) Charts of the percentages of CD57 and CD94 positive cells within gated NK cells. Each line corresponds to one patient (black dots are patients who received VRD, blue dots are patients who received SCT). (C) Parameters were clustered in functional categories “anti-tumor function”, “activation markers,” and “cell surface receptors” as labeled and displayed in heatmaps. Stars summarize significance level of the p-values obtained using linear mixed effect models analyzing the effect of LEN on each parameter, compared to the pre-treatment time-point (T0, corresponding to 3 weeks after CTX). Our analysis takes into account the fact that data are paired over time-points. Significance codes: 0 “***” 0.001 “**” 0.01 “*” 0.05 “.” 0.1 “ ” 1.