Jones and Thompson have reported that a 12% p-toluene sulfonic acid solution in glacial acetic acid gave a flocculant precipitate in the sera of patients with systemic lupus erythematosus.1 Positive tests were also found in a few patients with hepatitis, multiple myeloma, vertebral coccidioidomycosis, and rheumatoid arthritis but not in any with scleroderma, periarteritis nodosa, and dermatomyositis. The authors believed that some unknown factor in lupus erythematosus serum was responsible for the precipitate and that sera with increased γ-globulin did not always show a positive reaction in the test.
During the past 20 or more years many precipitation tests of a nonimmunologic character have been described for sera in various diseases. The majority have depended on nonspecific changes in the blood proteins, especially an increase in the globulins. In general these can be divided into two types: (1) complex poorly understood colloidal systems, mainly
FELSHER Z, LEVIT F. Serum Precipitation StudiesSulfonates and Thiocyanate in Dermatoses and Other Diseases. AMA Arch Derm. 1959;79(6):656–660. doi:10.1001/archderm.1959.01560180030010
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