A hereditary immunoglobulin A abnormality: absence of light-heavy—chain assembly

A new immunoglobulin A abnormality, absence of assembly of alpha-chain and light-chain, was found in an adult female suffering from recurrent upper respiratory infection and tonsillitis since childhood, but otherwise healthy. The IgA abnormality was manifest in her serum by the presence of free alpha-chains, in her saliva by the presence of alpha-chains bound to secretory piece, and in her urine by the presence of free alpha-chains and free light-chains. The serum IgG and IgM were found to be complete, containing both heavy-chains and light-chains. Evidence for this immunoglobulin A abnormality was also found in the proposita's mother and elder son, demonstrating it to be a hereditary disorder. Studies performed with patient's tonsillar cells in short-term culture, using amino acids-(14)C, revealed synthesis and secretion of both free alpha-chains and free light-chains, in addition to synthesis and secretion of normally assembled IgG and IgM.