Alterations of Blood Immune Cells in Elderly Patients with COVID-19 and with or without Pre-Existing Type 2 Diabetes

SALVA, SUSANA; KOLLING, YANINA; ARGAÑARAZ, NICOLÁS; NOVILLO, MARÍA PÍA ROCCHIA; NOVILLO, MARÍA DEL MILAGRO ROCCHIA; ALBARRACIN, LEONARDO; CHARUBI, JACQUELINE; CASEN, ALEJANDRA; GOBBATO, NADIA; RACHID, MIRTA; ALVAREZ, SUSANA; KITAZAWA, HARUKI; VILLENA, JULIO; VALDEZ, JUAN CARLOS

Open Journal of Immunology

Scientific Research

Año: 2022 vol. 12 p. 41 - 63

2162-450X

Elderly individuals, especially those with pre-existing conditions like type 2diabetes mellitus (T2DM), have a high risk for developing severe cases ofCOVID-19. The aim of this work was to characterize the alterations of bloodimmune cells (BIC) in patients with symptomatic COVID-19 and confirmedSARS-CoV-2 infection, ≥60 years and who needed hospitalization in theCentro de Salud Hospital of Tucuman, Argentina, during the second peak ofthe pandemic in Argentina. Ten patients were enrolled from December 2020to May 2021. Blood samples were taken at the time of admission (day 0) andfive days after (day 5) for routine laboratory tests and the characterization ofBIC by flow cytometry. Most of the patients were men (70%) aged between 60and 78 years. The 70% of patients had T2DM while 50% had arterial hypertension.At day 0, all the patients had increased neutrophils and inflammatorymarkers (C reactive protein and D-dimers) and reduced numbers of lymphocytes,HLA-DRhi monocytes, CD16+CD56+ NK cells, CD3+HLA−DR+CD25+cells, CD4+ and CD8+ T cells in blood. Patients received a standard treatment for COVID-19 care (O2, corticosteroids and antibiotics). The hospital treatmentnormalized the levels of BIC (day 5) in 30% of patients who were thosewith no comorbidities. In patients with T2DM, BIC recovery was variable. InT2DM patients who required administration of plasma (30%), prolonged O2therapy (40%) or referral to the intensive care unit (10%) significant reductionsof CD16+CD56+, CD3+HLA−DR+CD25+, CD4+ and CD8+ cells were observedbetween days 0 and 5. In line with previous studies, our results showthat absolute counts of major lymphocyte subsets in blood are significantlyand substantially decreased during the course of severe COVID-19 disease inelderly patients. These BIC alterations may persist despite clinical care in elderlypatients with T2DM. Further studies are needed to investigate the utilityof early lymphocyte subset measurements as prognostic biomarkers of diseaseseverity, mortality, and response to treatment in COVID-19 elderly patientswith T2DM.