Hematological Disorders Associated With COVID-19 Infection

Viruses are a form of life that possess genes but do not have a cellular structure. Viruses do not have their own metabolism, and they require a host cell to make new products; therefore, they cannot naturally reproduce outside a host cell (1).

From the hematologist point of view, viruses can play a major role in four conditions: causing infections; causing lymphoproliferations and/or malignancies; causing (pan)cytopenia; and used as vectors in treatment (e.g., gene therapy, CAR-T cells)(2).

Taking into the role of viruses in hematology, pancytopenia, aplastic anemia, and other immune-mediated cytopenias are reported to be related to HIV, Hepatitis viruses, Dengue virus; respiratory infections (community-acquired respiratory virus infections; CARV) caused by Orthomyxoviruses (e.g., influenza A/B), Paramyxoviruses (e.g., human parainfluenza virus PIV-1, -2, -3, and -4; respiratory syncytial virus RSV-A and -B), Picornaviruses (e.g., human rhinovirus), coronaviruses (e.g., human coronavirus), Pneumoviridiae (e.g., human metapneumovirus), and potentially other viruses. (2) A new type of Coronavirus was identified by Chinese authorities in mid-December 2019, named by the Coronavirus Study Group of the International Commission on Virus Classification as "Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)" and the disease was named by the World Health Organization (WHO) as coronavirus disease-2019 (COVID-19). The new virus quickly spread around the world, being declared a pandemic in March 2020.(3) The published data have focused on severe respiratory manifestations, found predominantly in adults, while in children the clinical manifestations are mostly asymptomatic and mild. When the disease is more severe in children, it occurs more frequently in those with less than one year of age or with pre-existing illnesses.(4) Hematological changes are frequent in the COVID-19 disease, such as early lymphopenia and, as the disease progresses, anemia and neutrophilia.(5) Thrombocytopenia can occur secondary to sepsis, disseminated intravascular coagulation or drug-induced,(5) as well as direct bone marrow suppression or immune-mediated destruction.(6)