LAUSR

Patients with acute myeloid leukemia (AML) and myelodysplastic syndromes (MDSs) who are treated with hypomethylating agents (HMAs), alone or in combination with venetoclax, are an extremely vulnerable population due to advanced age, comorbidities, and treatment-induced neutropenia. 1,2 In addition, many of these patients receive HMA therapy in an outpatient setting, which continues until hematological disease progression. 1,2 All of these aspects make these patients very susceptible to breakthrough infection by SARS-CoV-2, especially given the emergence of new and highly contagious variants. 3-5 Because patients with blood cancer have been excluded from vaccine clinical trials, real-world data on vaccine immunogenicity are very important in this setting. 6 In particular, the assessment of antibody (Ab) levels may play a role in establishing a response to vaccination in this frail patient population. It is well known that the seroconversion rate after SARS-CoV-2 vaccination is particularly low in patients with hematological diseases with B-cell malignancies who are treated with monoclonal Ab – depleting B cells (eg, rituxi-mab), as well as in those receiving Bruton tyrosine kinase inhibitors. 7-9 Some recent studies analyzed the anti-Spike Ab responses after SARS-CoV-2 vaccination in different hematologic malignancies and con- fi rmed a low seroconversion rate in lymphoma and chronic lymphocytic leukemia; however, a good seroconversion rate was found after 2 vaccination doses in patients with chronic myeloid leukemia, multiple myeloma, acute lymphocytic leukemia,