Acute lymphoblastic leukemia after COVID-19 infection: a coincidence or a second hit

Abstract

Since the advent of COVID-19 in 2019, the virus has affected all age groups and has a very wide clinical spectrum, ranging from asymptomatic infection to serious life-threatening complications including multi-organ dysfunction syndrome in children. The virus tends to affect all organ systems including the hematological system. There are many contradictory views on the effect of the COVID-19 pandemic on the incidence of hematological malignancies. Some studies have shown an increased incidence of acute lymphoblastic leukemia (ALL) after COVID-19 infection supporting the Greaves two-hit hypothesis of leukemogenesis, while others have shown a decline in the incidence of ALL postulated to be due to widespread lockdown and decreased exposure to environmental pathogens. We report the cases of three children who were diagnosed with acute lymphoblastic leukemia shortly after the initial diagnosis of multisystem inflammatory syndrome in children (MIS-C) or COVID related transient erythroblastopenia of childhood.