Typing for HLA class I gene products using plasma as source

Soluble HLA class I proteins have been found in serum or plasma of healthy and diseased individuals. Here we present evidence that these molecules can be readily used for determination of the HLA type by biochemical methods. Immunoprecipitation of the soluble class I gene products using monomorphic monoclonal antibodies coated to immunobeads and one-dimensional isoelectric focusing followed by immunoblotting represents a feasible and reproducible technique for typing. Analysis of these gene products in families (n = 12, with a total of 62 individuals) as well as in the population (n = 82) showed that all serologically defined antigens tested to date were present in plasma. A reference chart established primarily for the membrane-bound antigens could also be used for the soluble ones.