Impaired T-cell Reactivity in Hematological Malignancy Patients: Insights into SARS-CoV-2 Omicron Infection and Clinical Implications

The SARS-CoV-2 Omicron variant has posed global health challenges, particularly for individuals with haematological malignancies. This study aimed to characterize clinical and immunological aspects of Omicron-infected haematological malignancy patients and compare them to the general population. In a retrospective study from Dec 3, 2022, to Apr 30, 2023, we assessed SARS-CoV-2-positive patients in the Haematology Department (study group) and randomly selected control patients from other departments. Clinical symptoms were similar, but pneumonia was more common in the patients with haematological malignancies. Haemoglobin and platelet levels were notably lower in the study group, and they had a higher viral load with lower intracellular ATP levels in CD4+ and CD8+ T cells. CD8+ ATP levels were further reduced in lymphocytic malignancies. Risk factors for mortality included age >60 years, ECOG score >3, CRP >50 mg/L, and NLR ≥6.5. This study emphasizes the significance of cellular immune responses in Omicron-infected haematological malignancy patients. Tailored clinical strategies and close monitoring are crucial for this vulnerable group due to potential immune impairments and associated risks.