Immune reactivity during COVID-19: Implications for treatment

• Published in: Immunology letters Vol. 231; pp. 28 - 34
• Main Authors: Napoli, Claudio, Benincasa, Giuditta, Criscuolo, Clelia, Faenza, Mario, Liberato, Cinzia, Rusciano, Mariangela
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.03.2021; European Federation of Immunological Societies. Published by Elsevier B.V
• Subjects: Antibodies, Monoclonal, Humanized - therapeutic use; Anticoagulants - therapeutic use; COVID-19; COVID-19 - complications; COVID-19 - diagnosis; COVID-19 - immunology; COVID-19 - therapy; COVID-19 Drug Treatment; COVID-19 Serotherapy; Cytokine Release Syndrome - immunology; Cytokine Release Syndrome - prevention & control; Drug Repositioning; drug therapy; Drug Therapy, Combination - methods; Glucocorticoids - therapeutic use; Hospital Mortality; Humans; immune response; Immunization, Passive - methods; Immunoglobulins, Intravenous - therapeutic use; Immunosuppressive Agents - therapeutic use; Immunotherapy - methods; laboratory indexes; Prognosis; Randomized Controlled Trials as Topic; SARS-CoV-2 - immunology; SARS-CoV-2 - isolation & purification; Severity of Illness Index; Treatment Outcome; COVID-19; laboratory indexes; drug therapy; immune response
• ISSN: 0165-2478; 1879-0542
• DOI: 10.1016/j.imlet.2021.01.001

•Lymphopenia and eosinopenia are associated with the severe form of COVID-19.•Increased levels of D-dimer, procalcitonin, and C reactive protein are prognostic biomarkers predicting coagulopathy.•Corticosteroids resulted the best therapy for the immune dysregulation in severe form of COVID-19.•Anticoagulative therapy is associated with reduced in-hospital mortality for COVID-19. Clinical symptoms of COVID-19 include fever, cough, and fatigue which may progress to acute respiratory distress syndrome (ARDS). The main hematological laboratory findings associated with the severe form of disease are represented by lymphopenia and eosinopenia which mostly occur in the elderly population characterized by cardiovascular comorbidities and immunosenescence. Besides, increased levels of D-dimer, procalcitonin, and C reactive protein (CRP) seem to be powerful prognostic biomarkers helping to predict the onset of coagulopathy. The host immune response to SARS-CoV-2 can lead to an aberrant inflammatory response or “cytokine storm” which contributes to the severity of illness. At immunological level, patients affected by a severe form of COVID-19 show poor clinical trajectories characterized by differential “immunotypes” for which T cell response seems to play a critical role in understanding pathogenic mechanisms of disease. Also, patients with mild to severe COVID-19 displayed macrophage activation syndrome (MAS), very low human leukocyte antigen D related (HLA-DR) expression with a parallel reduction of CD04+ lymphocytes, CD19 lymphocytes, and natural killer (NK) cells. Corticosteroids resulted the best therapy for the immune dysregulation whereas repurposing of tocilizumab (IL-6 receptor antagonist) appears to have mixed results in patients with COVID-19. Besides, anticoagulative therapy was associated with reduced in-hospital mortality and need of intubation among COVID-19 patients. Furthermore, the beneficial use of intravenous immunoglobulin (IVIG) and passive immunotherapy with convalescent plasma needs to be validated in large controlled clinical trials. In this review, we summarize the main hematological parameters with a prognostic value in COVID-19 and the basis of immunological reactivity during COVID-19, with a focus on ongoing clinical trials evaluating immune targets as possible therapeutic strategies.