Immunopathology of rhino mouse, an autosomal recessive mutant with murine lupus-like disease.

Detection of high incidence of antinuclear antibodies (ANA) was reported in young homozygous rhino mice employing formalinized chicken erythrocyte nuclei as substrate for indirect immunoflourescence (IF) assay. The titers of ANA heightened with increasing age, and attained to 1:1024 by the time mice reached 5 months of age. The occurrence of ANA was associated with development of splenic and hepatic fibrosis, glomerulonephritis and abnormalities of lymphoreticular tissue. The granular deposits of IgG and C3 detected by direct IF were initially found at the basement membrane of dermal-epidermal junction of rhino mice aged 2.5 months. These deposits distributed progressively in the fibrotic areas of spleen and liver, and renal glomerular tufts at 5 months of age. Dense deposits revealed by electron microscopy were found in the regions where IF of IgG and C3 was observed. Acid buffer eluates from liver and kidney contained IgG reactive with nuclear antigens. Importance of homozygous rhino gene was discussed in relation to development of autoimmune disorders of these mice.