In primary Sjögren's syndrome (SS), systemic exocrine and non-exocrine organs are frequently affected, in addition to the major target tissues of the lacrimal and salivary glands. This study aimed to examine whether the IQI/Jic mouse, an animal model of SS whose autoimmune dacryoadenitis and sialoadenitis have been documented, develops inflammatory lesions in multiple organs as in primary SS.
Systemic histopathological analysis was performed on IQI/Jic mice at various ages. Phenotypes of infiltrated lymphocytes were determined using immunohistochemical techniques.
Inflammatory lesions were observed not only in the lacrimal and salivary glands, but also in multiple organs, including the lung, pancreas and kidney at advanced ages, and were mainly composed of CD4(+) T cells and B cells. The incidence and severity of the inflammatory lesions increased with age in all these organs. The histological appearance and spreading of lesions were similar to those in human primary SS.
IQI/Jic mice spontaneously develop inflammatory cellular infiltrates in multiple exocrine and non-exocrine organs. This characteristic distinguishes IQI/Jic mice from other murine models, making them favourable for studies on the pathogenesis of systemic involvement in primary SS.