PHENOTYPIC AND FUNCTIONAL CHARACTERIZATION OF PERIPHERAL T CELL POPULATIONS FROM COVID-19 PATIENTS HOSPITALIZED IN HOSPITAL PRIVADO UNIVERSITARIO CÓRDOBA- ARGENTINA.

LUISINA ONOFRIO; OTROS (VER EN RESUMEN); G MORON; GRUPO IMMUNOCOVIDCBA

virtual

Congreso; LXIX REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INMUNOLOGÍA (SAI); 2021

SOCIEDAD ARGENTINA DE INMUNOLOGÍA (SAI)

Luisina Onofrio*, Jeremías Dutto*, Sabrina Bossio*, Ruth E. Baigorri*, María Belén Brugo*, Laura Almada**, ConstanzaMarín**, Federico Ruiz Moreno**, Ximena Volpini**, MarielAlmeida, Carolina Olivera, Nicolás Ponce, Juan Nahuel Quiroz,Silene Silvera Ruiz, Lucia Bofelli, Eva Acosta Rodríguez,Carolina Amezcua Vesely, Daniela Arroyo, Fabio Cerbán,Laura Cervi, Laura Fozzatti, Paula Icely, Pablo Iribarren,Belkys Maletto, Gabriel Morón, Cecilia Rodríguez Galán,Cinthia Stempin, Claudio Abiega#, Daina Escudero#, AdrianKahn#, Juan Pablo Caeiro#, Mariana Maccioni, CristinaMotrán, Laura Chiapello, Carolina Montes, Adriana Gruppi,Claudia E Sotomayor. Grupo ImmunoCovidCBA*All these authors contributed equally. **All these authorscontributed equallyDepartamento de Bioquímica Clínica, CIBICI-CONICET, Facultadde Ciencias Químicas, Universidad Nacional de Córdoba.#Hospital Privado Universitario de Córdoba, IUCBC.SARS-CoV-2 infection results in asymptomatic, mild or severedisease. T cells could contribute to these different outcomes, butit remains unclear whether T cell response is dysfunctional or excessive.Here, we evaluated the phenotypic and functional featuresof circulating T cells from a cohort of 40 COVID-19 patients (Cpts)with moderate (MOD) and severe (SEV) clinical disease (aged 21-80 years) and 14 aged matched healthy controls (HC) by FACS. AllCpts exhibited a reduced frequency of CD3+T and Tregs cells compareto HC (p< 0.05). When exhaustion was evaluated, SEV Cptsshowed higher % of PD-1+ and CD39+ in T conv cells (p<0.05),whereas no differences were found in BTLA or TIGIT expression.Even though, no differences in cytokine production (INF-γ, IL-2 andTNF) were observed, T conv cells from SEV Cpts showed a higher% of GZMB+ and CD107+ cells than MOD Cpts or HC (p<0.05). CirculatingCD8+ T cells express different levels of CD8, where CD8locells represent highly activated cytotoxic T cells. COVID-19 patientspresented a higher % of CD8lo T cells than controls and this incrementwas even more pronounced in SEV Cpts (p=0.04, MD vsHD; p=0.0012, SD vs HD). CD8lo T cells exhibited impaired cytokineproduction and CD107a expression compared to CD8hi T cells, althoughGZMB levels were similar among both CD8+ subsets. CD8lopopulation from HC showed higher % of naïve T cells than effectormemory (EM)(p=0.04) or EMRA (p=0.008) subsets, but this distributionwas not seen in MOD or SEV Cpts. Indeed, MOD or SEV Cptsshowed higher % of EM cells than HC.Conclusion: the disease severity impacts on the phenotype andfunctional features of CD4+ and CD8+ T cells, with a pronouncedincrement in the % of CD8lo T cells as the disease worsens. Thesecells appear to have dysfunctional phenotype with an impairmentof effector cytokines production but maintaining cytotoxic potential.The CD8hi/CD8lo ratio might be a useful parameter to predict thedisease outcome.