Inherited immunologically atypical haptoglobin.

THE presence of three genetically determined haptoglobin types (Hp 1–1; Hp2–1 ;, Hp 2–2) for the Caucasian race was first demonstrated by Smithies using starch-gel electrophoresis1,2. Only a small number of atypical haptoglobins have since been described2,3. Although the three Hp types differ with respect to molecular weight and electrophoretic mobility, they have been shown to be immunologically identical among each other4,5, that is, to possess identical antigenic determinants.