The performance of the automated immune chemiluminescent system "IMMULITE 2000XPi for the measurement of serum soluble IL-2 receptor in clinical samples

The performance of a chemical luminescence test reagent "Immulyze IL-2R II" with an automated immune chemiluminescent system "IMMULITE 2000XPi" for the measurement of serum soluble IL-2 receptor in clinical samples was investigated. The satisfactory results were obtained for the reproducibility, precision, linearity, and sensitivity, and no interference with hemolysis, bilirubin, chyle or intrafat was observed. A significant correlation was found between the values of sIL-2R measured by the Cell-free N IL-2R and those obtained by the IMMULYZE IL-2R II. The measurements were stable regardless of the methods of sample preservation, or repeated freeze-thawing procedures. Elevated concentrations of sIL-2R over 1,000 U/mL were found in multiple types of collagen diseases or severe cases of allergic diseases, indicative that sIL-2R levels might correlate with the severity of autoimmune diseases. In patients with lymphoma, sIL-2R levels correlated with the lactate dehydrogenase (LD) activity. Among the lymphoma cases with sIL-2R levels over 1,000 U/mL, the majority (84%) had significantly higher levels of LD, and among them, 81% were at the clinical stage IV. We observed that sIL-2R levels increased from the early stages of lymphoma, while LD activities increased at the advanced stages. Our present findings suggest that sIL-2R is a promising marker for the diagnosis of autoimmune and allergic diseases, and also for the diagnosis and staging of lymphomas.