Detection in Normal Plasma of Immunoglobulin resembling the Protein of γ-Chain Disease

Abstract

TUMOURS of the lymphoid system have from time to time presented protein products apparently unique to the neoplastic process, but found later to occur in inconspicuous amounts in the normal organism. Thus Bence Jones protein was described in the urine of a patient with multiple myeloma in 1848 (ref. 1), found in about 10⁻⁴ times this amount in normal urine 112 yr later², and soon after recognised in both the pathological and normal circumstances to consist of free immunoglobulin light chains^3,4. More recent discoveries of undescribed myeloma proteins are apt to be followed rapidly by recognition of their normal analogues^5–7. No normal analogue of the protein of the type described in 1963 by Franklin et al. in association with a disseminated lymphoid tumour^8,9 has, however, been described. The tumour was called ‘heavy chain disease’ because it was seen to be secreting^9–11 an unusual protein related to immunoglobulin heavy chains. Heavy chain disease is now divided into three types¹²: according to whether the associated protein is related to the γ, α or μ class of heavy chains the disease is called γ, α or μ chain disease. The original case was of γ chain disease, and up to August 1972 thirty such cases had been recorded¹².