Radioimmunoassay for immunoglobulin G autoantibody on the surface of mouse erythrocytes.

A radioimmunoassay (RIA) for the determination of autoantibody on the surface of erythrocytes from New Zealand Black (NZB) mice is described. This method was adapted to hemagglutination plates in order to facilitate the separation of bound and unbound 125I-labeled rabbit anti-mouse immunoglobulin G with an automated cell harvester. Intra- and interday precision, over the useful quantitative range of the standard curve, was 3.9 and 12.9%, respectively. The RIA was five to ten times more sensitive than the direct antiglobulin test which, unlike the RIA, provided little quantitative information on a group of 20 experimental NZB mice. This is publication number 562 from the Department of Basic and Clinical Immunology and Microbiology, Medical University of South Carolina.

Radioimmunoassay of the immunomodulator erythro-9-(2-hydroxy-3-nonyl)-hypoxanthine in human serum and urine.

A radioimmunoassay was developed for the measurement in human serum and urine of erythro-9-(2-hydroxy-3-nonyl)-hypoxanthine. Antisera were produced in rabbits by immunization with an erythro-9-(2-hydroxy-3-nonyl)-hypoxanthine hemisuccinate-bovine serum albumin conjugate. The competitive antigen was erythro-9-(2-hydroxy-3-nonyl)-hypoxanthine labeled with carbon-14 on the purine ring. Cross-reactivities were measured against three metabolites and the naturally occurring purine bases inosine and hypoxanthine. Sensitivity of the method was 1 ng/ml in serum and 10 ng/ml in urine. Precision at clinical levels was +/- 15% in serum at 2 ng/ml and +/- 3% in urine at 200 ng/ml.

Inosiplex therapy in subacute sclerosing panencephalitis. A multicentre, non-randomised study in 98 patients.

Inosiplex was administered to 98 patients with subacute sclerosing panencephalitis (SSPE) in the United States and Canada for variable periods of time up to 9.5 years. Survival data from these 98 patients were compared by life-table analysis with survival in three SSPE control groups drawn from SSPE patients contracting the disease in Israel, Lebanon, or the United States at about the same time as the inosiplex-treated patients but treated differently or not at all. In the inosiplex-treated patients the actuarial probability of survival at 2, 4, 6, and 8 years from onset of SSPE was 78%, 69%, 65%, and 61%, compared with 38%, 20%, 14%, and 8% in a composite control group (p less than 0.01 for all four comparisons). Statistical adjustments for time-to-treatment bias did not affect this result: a modified logrank procedure demonstrated that the risk of dying in the treatment group was 43% of that in the controls. Inosiplex seems to be able to prolong life in patients with SSPE.

Quantitation of rheumatoid factor activity by nephelometry.

Rheumatoid factor activity can be quantitated by use of nephelometric assay system. The data presented show a good correlation between this new method and the older quantitative latex tube rheumatoid factor test. In addition, the nephelometric and latex tube testing of sera from normal, rheumatoid and non-rheumatoid patients yielded similar results, suggesting the two procedures share a similar immunologic specificity. The new nephelometric test for rheumatoid factor is simple to perform, endpoints are objectively determined, and test data are highly reproducible.

Use of laser nephelometry in the measurement of serum proteins.

Measurement of immunoglobulins (Ig) and of complement component C3 in human serum by automated and manual nephelometric techniques is tedious, and the effective linear range is too narrow. We describe a laser nephelometer/reagent system for measuring serum proteins by the use of forward light scatter (which enhances the ratio of reaction/blank), electronic blank subtraction, laser light (632 nm), and electronic signal selection. We report data establishing the range of linearity for immunoglobulins IgG, IgA, IgM, and complement C3 with this system, and correlations with results by a radial immunodiffusion. We also compared an electroimmunodiffusion system for quantitation of albumin and IgG in cerebrospinal fluid to our technique. The nephelometric system described provides a rapid, accurate, precise, and objective way to measure immunoglobulins and C3.