Correlation between Histopathological Changes and Pro-Inflammatory Cytokine Expression in Nodular Skin Lesions of LSDV-Infected Cattle

Abstract

Lumpy skin disease virus (LSDV) causes cutaneous lesions whose severity may reflect differences in host immune status. This study evaluated the relationship between histopathological changes in nodular skin lesions and cytokine expression in cattle classified according to clinical severity and neutralising antibody responses. During the 2022–2023 outbreak, skin, blood, and scab samples were examined by histopathology, PCR, serology, and quantitative analysis of IL-6, IL-10, and TNF-α gene expression. Skin lesions were assessed at 5 and 25 days post-lesion onset. Immunodeficient cattle showed more severe early hyperkeratosis, acanthosis, hydropic degeneration, vasculitis, and perivascular lymphocytic infiltration, followed by late epidermal necrosis, deep ulceration, granulation tissue formation, dystrophic calcification, and fibrosis. Immunocompetent cattle showed comparatively mild lesions, including a largely normal epidermis at the early stage and limited inflammatory infiltration. PCR detected LSDV in 31 of 34 selected samples. During secondary infection, immunodeficient cattle had low neutralising antibody titres, whereas immunocompetent cattle maintained higher titres. IL-6 and IL-10 were upregulated in both infected groups relative to controls, with IL-10 highest in immunocompetent cattle. TNF-α expression was highest in the immunodeficient group. These findings indicate an association between lesion severity, humoral immune status, and cytokine expression patterns in LSDV-infected cattle, while supporting cautious interpretation of cytokines as context-dependent indicators of immune status.