Serological distance coefficients.

We define experimentally measurable similarity coefficients S[A,B/C] that specify the extent to which a pair of substances, A and B, are similar in the context of a diverse reagent, C, which can be a non-immune serum. We describe how this definition can be applied to mixtures of antibodies, for example the antibodies of two serum samples, A and B. A "distance coefficient" D[A,B/C] between two sera, A and B, in the context of C, is defined as one minus the similarity coefficient of the two sera in the same context. We discuss the problem of the experimental measurement of these coefficients, and the possible use of the coefficients in the diagnosis and prognosis of disease conditions.