SARS-CoV-2-associated T-cell infiltration in the central nervous system

Area of Science:

• Neurology
• Immunology
• Virology

Background:

• Coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, is primarily a respiratory illness but can lead to neurological symptoms.
• The exact mechanisms of COVID-19 neuropathogenesis, including the role of T cells in the central nervous system (CNS), are not fully understood.
• Endothelial dysfunction, triggered by viral infection or inflammatory cytokines, is a suspected contributor to neurological complications.

Purpose of the Study:

• To investigate the presence and characteristics of T cells within distinct anatomical brain regions of patients who died from COVID-19.
• To determine if T cells found in the brain show SARS-CoV-2 specificity.

Main Methods:

• Analysis of distinct anatomical brain regions from deceased COVID-19 patients.
• T cell receptor Vβ repertoire sequencing was performed on brain tissue.
• Clonotypes were analyzed for SARS-CoV-2 association using public TCR repertoire data.

Main Results:

• SARS-CoV-2-associated T cells were detected in nearly all analyzed brain areas of patients with fatal COVID-19.
• The olfactory bulb, medulla, and cerebellum exhibited the highest prevalence of SARS-CoV-2 specific T cell sequence patterns.
• Neuropathological examination revealed a primary infiltration of CD8+ T cells, predominantly with a perivascular pattern.

Conclusions:

• This study demonstrates widespread SARS-CoV-2-specific T cell infiltration in the brain following fatal COVID-19.
• Further research is required to elucidate the precise relationship between T cell infiltration and the development of neurological symptoms and long-term cognitive effects in COVID-19 patients.