Anti-Antiserum Antibody as a Cause of Double Precipitin Rings in Immunoglobulin Quantitation and Its Relation to Milk Precipitins

Abstract During the process of quantitating immunoglobulins by the Mancini technique (1) double precipitin rings were observed in a number of instances despite the use of well-absorbed monospecific antisera (Fig. 1). At first these were attributed to lipemic sera, but double precipitin rings continued to be observed even with the use of agarose and nonlipemic sera. Non-antigen antibody precipitation was also considered as a possibility. Several observations suggested that the double rings might be true antigen-antibody reactions. Buckley and Dees (2) reported that individuals with selective IgA deficiency had an increased incidence of anti-milk antibodies, and Tomasi (3) and Schlegel et al. (4) observed that patients with selective IgA deficiency had antibodies against normal goat serum. We noted that double rings occurred with greatest frequency among patients with selective IgA deficiency who had anti-milk antibodies, and that double rings were present only with certain antisera. These observations suggested that anti-antiserum antibodies might be the cause of double precipitin rings and that they might bear a relationship to milk precipitins. Diffusion studies were designed to investigate this possibility.