Measurement of total and bioactive interleukin-2 in tissue samples by immunoaffinity-receptor affinity chromatography.

The detection and measurement of cytokines is an important issue in the clinico-pathological diagnosis of several clinical entities, including organ transplant rejection. Existing techniques, although sensitive, measure only total cytokine concentrations and cannot measure bioactivity. A chromatographic system combining immunoaffinity chromatography with an immobilized receptor detection cartridge has been developed for measuring total and bioactive interleukin (IL)-2 concentrations in tissue extracts prepared from biopsy materials taken from renal transplant recipients during both rejection and drug-induced nephrotoxic episodes. The technique employs a short high-pressure chromatography column packed with antibody-coated glass beads for the initial analyte separation and concentration, followed by detection of bioactive molecules through their interactions with specific, immobilized receptors. This system compares favourably with both conventional bioassays and immunoassays for measuring IL-2 in tissue samples.