Free kappa light chains in urine

The immunoglobulin molecule consists of two types of chains It contains two ideant heavy chains and two identical light chains: kappa or lambda. The kappa and lambda light chains are produced by plasma cells. The light chains are produced in excess of the heavy chains, Therefore, the excess is released into the serum in the form of free kappa and lambda light chains. The kappa molecules are synthesized twice as fast as lambda and filtered three times as fast in the kidneys therefore the concentration of both types of chains is balanced Free light chains are filtered in the glomeruli and metabolized in the proximal tubules of the nephron. Kidney damage increases the half-life of light chains from 2-6 hours to 2-3 days An increase in the concentration of free light chains in the urine is associated with The progression of a disease that causes increased production of chains (e.g., multiple myeloma) and the degree of kidney damage.