ABSTRACT
Transfusion-dependent thalassemia patients undergo transfusion immunomodulating effects, which result in a general immune response depression and, consequently, an increase in the frequency of infectious episodes and neoplastic events due to a reduction in phagocytic function. Altered natural killer functions and IL-2-mediated lymphocytic response, defects in antigen presentation due to monocyte–macrophage cells, and decreases in bone marrow precursors and HLA II+ cells all play key roles in immunodepression in thalassemia major. SARS-CoV-2 infection presents marked lymphopenia, occurring in 96.1% of severe cases. COVID-19-related lymphopenia is due to various mechanisms, which lead to an increase in lymphocytic apoptosis. Post-COVID-19 lymphocytic quantitative and functional disorders may compromise immune response and promote the onset of infections via opportunistic pathogens. Herein, we report a case of a thalassemia major patient who developed severe post-COVID-19 lymphocytopenia, which may have facilitated the onset of a severe Klebsiella Pneumoniae infection.