VirusesApr 27, 2026

Immune System Roles and Organ-Specific Immune Responses in Long COVID

Long Covid Weekly Brief ↗PubMed ↗DOI ↗OA ↗

Updated Apr 28, 2026

Abstract

Long COVID may involve persistent symptoms affecting multiple organ systems for at least two months after initial COVID-19 infection.

Symptoms often arise in individuals who initially had mild to moderate COVID-19.
The condition presents a diverse range of symptoms linked to respiratory, cardiovascular, neurological, renal, gastrointestinal, and endocrine systems.
LC may result from a combination of factors, including ongoing viral presence, chronic immune system activation, and immune system dysregulation.
Evidence suggests that systemic immune disturbances vary across different organs, contributing to the varied clinical presentations.
Challenges in understanding LC include differences in study designs, a lack of long-term data, and the need for standardized immune profiling.

Simplified

Long COVID (LC), also referred to as post-acute sequelae of SARS-CoV-2 infection, is characterized by persistent symptoms originating 3 months following acute COVID-19, lasting for at least two months and frequently affecting individuals who initially experienced mild to moderate disease. The clinical spectrum is heterogeneous, involving respiratory, cardiovascular, neurological, renal, gastrointestinal, and endocrine systems, thereby posing substantial diagnostic and therapeutic challenges. Despite extensive investigation, the precise immunopathogenic mechanisms underlying LC remain incompletely defined. Accumulating evidence suggests that LC is driven by a multifactorial interplay of persistent viral antigen reservoirs, chronic immune activation, dysregulated innate and adaptive immune responses, autoimmunity, endothelial dysfunction, microvascular injury, and aberrant tissue repair. These systemic immune perturbations manifest variably across different organs, contributing to the diverse clinical phenotypes observed. However, mechanistic clarity is hindered by heterogeneity in study designs, limited longitudinal data, and the absence of standardized immunological profiling. This narrative review provides integrative insights into the immunopathogenesis of LC, synthesizing current evidence on systemic immune dysregulation and organ-specific immunological mechanisms. A conceptual framework is proposed to facilitate a structured understanding of this complex syndrome and to guide future research toward targeted immunomodulatory strategies.

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Competing interests

There are no conflicts of interest.

PubMed

Immune System Roles and Organ-Specific Immune Responses in Long COVID

Abstract

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Funding

Competing interests

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