Bone Marrow and Peripheral Blood Findings in Patients Infected by SARS-CoV-2

• Published in: American Journal of Clinical Pathology 2021-05, Vol.155 (5), p.627-637
• Main Authors: Harris, Cynthia K, Hung, Yin P, Nielsen, G Petur, Stone, James R, Ferry, Judith A
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Anemia; Biomarkers - blood; Bone marrow; Bone Marrow - immunology; Bone Marrow - pathology; Coronaviruses; COVID-19; COVID-19 - blood; COVID-19 - complications; COVID-19 - immunology; COVID-19 - pathology; Female; Health aspects; Hematologic Diseases - blood; Hematologic Diseases - diagnosis; Hematologic Diseases - pathology; Hematologic Diseases - virology; Humans; Immunohistochemistry; Leukocytes (neutrophilic); Leukocytosis; Lymphohistiocytosis, Hemophagocytic - blood; Lymphohistiocytosis, Hemophagocytic - diagnosis; Lymphohistiocytosis, Hemophagocytic - pathology; Lymphohistiocytosis, Hemophagocytic - virology; Lymphopenia; Male; Medical research; Medicine, Experimental; Middle Aged; Original; Patients; Peripheral blood; Polycythemia; Retrospective Studies; Severe acute respiratory syndrome; Severe acute respiratory syndrome coronavirus 2; Thrombocytopenia
• ISSN: 0002-9173; 1943-7722; 1943-7722
• DOI: 10.1093/ajcp/aqaa274

Abstract Objectives Coronavirus disease 19 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is associated with diverse clinical, including hematologic, abnormalities. We describe peripheral blood and bone marrow findings in deceased and living patients with COVID-19. Methods We examined bone marrows from 20 autopsies and 2 living patients with COVID-19 using H&E-stained slides and immunohistochemical stains. Clinical history and laboratory values were reviewed. HScore was calculated to estimate risk of hemophagocytic lymphohistocytosis (HLH). Results The deceased patients included 12 men and 8 women (aged 32 to >89 years; median, 63 years). Hematologic abnormalities included frequent neutrophilic leukocytosis, lymphopenia, anemia, and thrombocytopenia; one patient showed striking erythrocytosis. The bone marrows were all normocellular to hypercellular, most showing maturing trilineage hematopoiesis with myeloid left shift. In all 19 evaluable bone marrows, hemophagocytic histiocytes were identified. The HScore for secondary HLH ranged from 35 to 269 (median, 125; >169 in 5 patients). Coinfections were identified in 6 patients. In 2 living patients, bone marrow showed maturing trilineage hematopoiesis, including one showing few hemophagocytic histiocytes. Conclusions Peripheral blood from deceased patients with COVID-19 frequently showed neutrophilic leukocytosis, lymphopenia, and, rarely, secondary polycythemia; hemophagocytosis was common in their bone marrow. Consistent with other studies, we provide histopathologic evidence of secondary HLH development in patients with COVID-19.