Measurement and partial characterization of an interleukin-2 inhibitor (IL-2-IN) in human urine.

We observed a human urine-derived protein complex (IL-2-IN) which competitively inhibits interleukin-2 (IL-2) dependent murine lymphocyte proliferation. Measurements of urinary IL-2-IN have been used to stratify the immune response of patients to bacteria in the bladder. Partial characterization of IL-2-IN indicates that it is a heat-stable, 75 kDa complex comprised of interleukin-2 bound to another protein(s). Although the IL-2-IN complex is stable in physiologic buffers, the complex can be disrupted using acidic or low-ionic strength buffers, thereby liberating IL-2. IL-2-IN activity is susceptible to bacterial and endogenous urinary proteolysis. The IL-2 bound in the IL-2-IN complex cannot be detected using a double monoclonal antibody radioimmunoassay for IL-2. Unlike other IL-2 binding proteins, the IL-2 binding protein of the IL-2-IN complex is not a soluble interleukin-2 receptor. A modification of the bioassay for interleukin-2 activity is the method of choice for the detection and quantification of urinary IL-2-IN.

Twin pregnancy: routine use of ultrasound examinations in the prenatal diagnosis of intrauterine growth retardation and discordant growth.

A prospective study was undertaken in 42 normal twin pregnancies to determine the value of routine ultrasound evaluation in the prenatal diagnosis of intrauterine growth retardation (IUGR) and intra-pair growth discordancy in twin gestations. Use of multiple sonographic parameters significantly improved diagnostic accuracy when compared with the use of single parameters, such as biparietal diameter (BPD) alone in the prepartum diagnosis of these two entities.