For patients with multiple myeloma (MM) who are treated with autologous stem cell transplantation (ASCT), high absolute natural killer (NK) cell counts 2 to 3 months after ASCT are an independent predictor for minimal residual disease (MRD-negativity), according to a study published in Transplant Immunology. Amany R. Keruakous, MD, and colleagues hypothesized an association between NK cell recovery after ASCT and disease outcomes in patients with MM. They conducted a prospective study that started enrolling patients in January 2020 to identify the association between absolute NK cell count 2 to 3 months after ASCT and disease outcomes after ASCT in MM using univariate and multivariate analysis. NK cell recovery was evaluated during the third month after ASCT. Patients had a mean NK cell count of 90.53, ranging from 14 to 282 Cell/μL (SD, 84.64 Cell/μL). The odds of having an MRD-positivity among patients with partial remission before transplantation was four times higher than in patients with very good partial response or better (95% CI, 0.45-35.79).