Comparison of Mouse Liver Sections and Cultured Mouse Fibroblasts as Substrates for the Detection of Antinuclear Antibodies

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Abstract
Immunofluorescent antinuclear antibody tests were performed on selected sera representing various connective-tissue diseases using mouse liver sections and mouse connective-tissue fibroblasts cultivated in vitro. Substrate sensitivities and patterns of staining were compared by indirect immunofluorescent methods employing sera from 92 patients. Sensitivity (geometric mean serum endpoint titer) was significantly greater with the cultured cell substrate. This greater sensitivity was also detected with sera from 46 patients with systemic lupus erythematosus (SLE). No significant difference was observed in other clinical groups tested (rheumatoid arthritis, polyarthritis, drug-induced SLE, degenerative joint diseases, and progressive systemic sclerosis). Sera from 107 of 109 normal controls were negative on the mouse fibroblast substrate. The two substrates were equally sensitive in detecting homogenous, peripheral, or speckled patterns of fluorescence in patients’ sera having antinuclear activity. Nucleolar staining was observed in only one serum specimen as a minor pattern. Neither substrate demonstrated a predominant immunofluorescent pattern with sera from SLE, polyarthritis, and progressive systemic sclerosis. Sera of patients with clinically diagnosed rheumatoid arthritis, drug-induced SLE, and degenerative joint diseases usually manifested homogeneous staining patterns. However, these differences in staining pattern among the various clinical groups were not statistically significant. The mouse connective-tissue fibroblast represents a standardized alternative to mouse tissue sections of equal specificity and significantly increased sensitivity for the detection of antinuclear antibody.