“… 1 – 3 Notably, “booster” doses have been shown to enhance the humoral response of these patients. 4 – 7 We recently reported the greatly improved clinical outcome of breakthrough SARS-CoV-2 infection in MM patients who had received three or more doses of anti-SARS-CoV-2 vaccines during the different phases of the pandemic COVID-19 including the most recent viral variants of concern (VOCs); 8 , 9 most of the tested patients had developed an adequate antibody response (anti-spike IgG) to the virus. 9 Due to the scarcity of data about the role of different lymphocyte subsets in this specific population of patients, in the present study, we aimed to evaluate a possible relationship between antibody response after SARS-CoV-2 infection in “booster” vaccinated (at least 3 doses) MM patients and main circulating lymphocyte subpopulations.…”