Immunochemical studies in four cases of alpha chain disease

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Abstract

Studies of a number of properties of the pathological γA-proteins in the first four cases of the recently recognized alpha-chain disease demonstrate that, as in γ-heavy-chain disease, the abnormal protein is devoid of light chains and represents a portion of the α-heavy chain related to the Fc-fragment. In two patients, serum electrophoresis showed a broad abnormal band, whereas in the two others the pathological protein was not noticeable on the electrophoretic pattern. The diagnosis of α-chain disease can be established without purification of the protein by immuno-electrophoresis and gel diffusion experiments using selected antisera to γA and a reference α-chain disease protein. All four proteins belonged to the α1-subclass, displayed electrophoretic heterogeneity, and showed a strong tendency to polymerize. The polymers occurred in vivo and were held together both by disulfide bonds and by strong noncovalent forces. Two of the three purified proteins had a very high carbohydrate content. The abnormal protein was always found in concentrated urines in variable but generally low amounts. It was not detected in parotid saliva but was present in significant amounts in jejunal fluid of all four patients. The α-chain disease protein was shown to be associated with the secretory piece in external secretions of two patients.

Authors

Maxime Seligmann, Edith Mihaesco, Daniel Hurez, Constantin Mihaesco, Jean-Louis Preud'homme, Jean-Claude Rambaud