Development of immunoassays for free light chains of human immunoglobulins

Apart from normal immunoglobulins, free immunoglobulin light chains (k, ? – chains) are also present in serum, cerebrospinal fluid and urine of healthy individuals. Normally, small amounts of free k, ? – chains are produced by B-cells as well as by proteolysis of normal immunoglobulins. Recently, it was found that free k, ? – chains exert proteolytic and anti-angiogenic activity, and can specifically bind to mast cells receptors to induce hypersensitivity reactions. Extremely high levels of free immunoglobulin light chains in biological fluids are found in multiple sclerosis, lymphoproliferative disorders, rheumatoid arthritis, SLE, acute nephritis. Free k, ? – chains have short half-life in comparison with normal immunoglobulins – that is why determination of their concentration should be recommended as useful diagnostic tool to control treatment efficiency.

Two ELISA kits are developed: K279K Free kappa-chain, K279L Free lambda-chain

Kit performance data:
Test principle: sandwich, monoclonal antibodies
Total time of analysis: 30/30/15 min
Sensitivity: 0.5 µg/ml for kappa chain, 0.05 µg/ml for lambda chain
Material tested: serum / plasma, cerebrospinal fluid, urine

Application of ELISA kits: clinical monitoring data

Correlation to traditionally used method (nephelometry, Freelite, Binding Site), performed by Phadia GmbH, shown good correlation for K279K Free kappa-chain EIA (see below)