Isoelectric points of urinary light chains in myelomatosis: Analysis in relation to nephrotoxicity

Abstract

Measurements of the isoelectric point (pI), sialic acid content, and polymerisation were made of 43 light chains isolated from the urine of patients with myelomatosis excreting large amounts of light chains. The pls ranged from 3.5-9.5, and 23 were > 7.0. Sialylation was detected in 62% of light chains, and 69% showed microheterogeneity of charge. There was no clear association between the pl, sialylation, or polymerisation and the presence of renal failure, as assessed by serum creatinine concentrations. Light chains with pl spectrotype in the basic range, however, were found to produce more proximal tubular dysfunction than acidic light chains.