Low risk of relapse in aplastic anemia patients after SARS‐CoV‐2 omicron infection: A prospective NICHE cohort

Abstract

To the Editor, Aplastic anemia (AA) is an auto-activated T cell-mediated bone marrow failure, characterized by pancytopenia and hypocellular marrow. 1 With the worldwide spread of the Omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus, patients with AA are at high risk for infection due to disease-related neutropenia and enduring immunosuppressive therapy (IST). 2 Furthermore, AA patients often do not receive the SARS-CoV-2 vaccination due to an ineffective protective specific antibody response to viral antigens and potential immune system activation that may worsen underlying marrow failure.Prior studies have evaluated the clinical manifestation of SARS-CoV-2 infection in severe or very severe AA (SAA/VSAA) patients through case reports or case series, 3-8 but the severity and long-term prognosis of SARS-CoV-2 infection in AA is still not clear.To better explore whether patients with AA experienced more severe symptoms of infection or demonstrated higher relapse rate after infection, we prospectively collected 175 AA patients enrolled in National Longitudinal Cohort of Hematological Diseases (NICHE, NCT04645199) and described the clinical features and outcomes of AA after infecting Omicron SARS-CoV-2 between December 2022 and January 2023. This study demonstrated a low risk of relapse in AA after Omicron infection.In this study, SARS-CoV-2 illness severity was evaluated by the National Institutes of Health COVID-19 Treatment Guidelines. Severe illness was defined as individuals who had SpO 2 < 94% on room air at sea level, a ratio of arterial partial pressure of oxygen to fraction of inspired oxygen <300 mmHg, a respiratory rate > 30 breaths/min, or lung infiltrates >50%. Hematological responses were evaluated based on established criteria. 9 Robust response was defined as not only meeting standard response criteria, 9 but fulfilling more than 50 Â 10 9 /L of platelet and 100 g/L of hemoglobin (Hb). A progressive and substantial decline in blood counts requiring reinitiation of highdose cyclosporine or androgen or thrombopoietin receptor agonists was defined as relapse. Paired t-tests were used to compare the hematological indices before and after Omicron infection, including Hb, platelet, neutrophil, and lymphocyte counts.The study engaged a total of 175 patients, comprising 90 males and 85 females, with a median age of 33 years (range, 10-72). Among these patients, 29.7% had SAA/VSAA, 14.3% had transfusiondependent AA, and 56.0% had transfusion-independent AA. Forty-six