Impaired adaptive immune response in COVID-19 convalescent patients with hematological malignancies.

OBJECTIVES: The immune dysregulation during SARS-CoV-2 has the potential to worsen immune homeostasis after recovery. Patients with hematological malignancies with COVID-19 have changes both in the innate and adaptive immune responses. Little is known about the severity of immune dysfunction following recovery from COVID-19 in hematological patients. METHODS: Here, we performed a comprehensive analysis of the lymphocyte subsets in peripheral blood mononuclear cells by FACS Canto II in 55 patients, including 42 with hematological malignancies 4-6 weeks after COVID-19. RESULTS: Hematological COVID-19 convalescents had deep reduction in CD3+ T cells, including helper T cells (CD3 + CD4+), naïve helper T cells (CD3 + CD4 + CD45RA+), and memory CD4+ T cells among with extremely low levels of Treg cells and decreased expression of both TCRα/β and TCRγ/δ. Severe immune dysregulation in hematological convalescents was expressed by increased activation of T lymphocytes, both as elevated levels of activated T cells (CD3 + HLA-DR+) and activated cytotoxic T cells (CD3 + CD8 + HLA-DR+). CONCLUSIONS: Our findings showed a profound impairment of the adaptive immune response in hematological convalescents which might be a result of persistent activation of T cells. Convalescents with lymphoid malignancies showed more pronounced depletion of key T lymphocytes subpopulations in creating an effective adaptive response and immune memory.