SYNTHESIS OF ABNORMAL HEAVY AND LIGHT-CHAINS IN MULTIPLE-MYELOMA WITH VISCERAL DEPOSITION OF MONOCLONAL IMMUNOGLOBULIN

  • 1 January 1980
    • journal article
    • research article
    • Vol. 42  (3) , 545-553
Abstract
In a patient treated for IgA .kappa. myeloma, bone marrow relapse and a sharp drop in the serum IgA level paralleled tissue deposition of a non-amyloid material reactive with anti-.kappa. and anti-.alpha. sera in immunofluorescence studies of kidney and liver biopsies. Clinical manifestations were progressive renal failure with nephrotic syndrome, with both tubular and glomerular lesions (including nodular glomerulosclerosis), hepatomegaly, cardiac and neurological symptoms. Biosynthesis experiments showed the production of .alpha. chains diminished in length by about 1 domain which were rapidly degraded predominantly after secretion and of 2 spp. of L chains; normal-sized L chains which assembled with .alpha. chains and abnormally short ones which were secreted as free L chains. The apparent MW of the L chains was larger in secretions than in cytoplasmic extracts, suggesting their glycosylation. A causal relationship between tissue deposition and abnormal Ig production by a variant clone is suggested, the emergence of which was possibly induced by melphalan therapy.