Theoretical aspects of the immunopathogenesis of coronavirus infection in cats

Feline Infectious Peritonitis (FIP) is a severe and specific coronavirus infection caused by a mutated feline coronavirus (Feline Infectious Peritonitis Virus (FIPV)). FIP is frequently associated with high mortality rates and a complex multisystem immuno p a thogenesis. This article provides a comprehensive review of contemporary theoretical knowledge on the pathogenesis of FIP, i n cluding the molecular and cellular mechanisms of the immune response underlying disease development. Special attention is given to the analysis of factors determining the virulence of FCoV, mechanisms of viral (FIPV) interaction with macrophages, the role of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) in the progression of the infectious process, and the potential connection of the Arthus reaction to the intricate immunopathological mechanisms involved in FIP. The article discusses the significance of ant i body-dependent enhancement (ADE) in stimulating viral replication in target cells and the role of class G immunoglobulins in disease pathogenesis. The article summarises key aspects of FIP pathogenesis, including the immunological mechanisms respons i ble for the clinical manifestations of the disease. It details the pathogenesis of primary clinical forms of FIP, with an analysis of specific changes occurring in various systems of the body (digestive, respiratory, renal, nervous, and cardiovascular). Additionally, it addresses microcirculatory disturbances and increased vascular wall permeability contributing to systemic inflammation. The text also delves into the cytokine storm induced by hyperactivity of virus-infected immune-competent cells, primarily macrophages. The interplay between pathogen virulence and its ability to modulate the host's immune response by suppressing adaptive immunity is explored. This review synthesises current research, focusing on theoretical insights into the immunopathogenesis of FIP and emphasising the significance of a pathogenetic approach to its diagnosis and prevention.