Fifteen-year overview of the International Cell Exchange.

1. Through the International Cell Exchange, 4 cells were shipped for blind typing to tissue typing laboratories on a monthly basis for the past 15 years. As many as 288 laboratories worldwide currently participate in this exercise. 2. The frequency of detection of a total of 85 HLA-A,B,C specificities by the laboratories has been determined. Each specificity has been classified as to the reliability of identification. 3. Lymphocytes from 27 donors were sent for retesting in as long as a 13-year interval. This provided an accurate picture of the advances in percent detection by the laboratories. 4. At least 5 variants were found by shipping cells to the laboratories: variants of A9, B21, B5, Bw52, and B40. 5. B cell lines were sent to investigate the HLA-DR antigens. At least 11 specificities had a concordance rate higher than 80% and 5 had a rate of more than 95%. 6. HLA-A,B antibodies sent for antibody characterization were classified by a new mass program for the likely epitope against which the sera were directed. As many as 28 different epitopes were detected by the sera sent in the serum exchange.

Standardization of HLA through an international cell exchange.

1. In a series of 131 monthly distributions of lymphocytes from 4 persons each, tissue typing done on a blind basis of 486 persons was examined for a 12-year period. The number of participating laboratories was initially 85 and 285 in 1987. 2. It was found that 21 HLA-A,B specificities could be identified by 95-100% of the laboratories. An additional 19 specificities were correctly identified by 80-94%. Less than 80% concordance was found for 27 specificities. 3. All of the 4 new specificities assigned by the WHO committee in 1987 were identified previously by the cell exchange. 4. We conclude that this ongoing program aids tissue typing laboratories throughout the world to standardize their typing reagents, to detect new specificities, to monitor progress in international dissemination of the key sera for antigen definition, and to evaluate the state of development of tissue typing to applications in kidney transplantation.

Use of the ELISA to detect and quantify histocompatibility antigens and their subunits.

A solid phase enzyme immunoassay (ELISA) has been developed for the detection and quantification of human histocompatibility antigens and their subunits. The assay involves the binding to a microELISA plate of a mouse monoclonal antibody reacting with a common antigenic determinant to all HLA (A, B, C) antigens. The standard conditions for the assay and the curves obtained for the quantification of total HLA, free beta 2m, and free heavy chain subunit (alpha) present in a biological sample are described and the sensitivity and potential uses of the method are discussed.

Terminology: nomenclature for factors of the HLA system, 1980. World Health Organization.

This article outlines the decisions made by the WHO nomenclature committee on leukocyte antigens at a meeting held after the 8th International Workshop on Histocompatibility Testing. Particular attention is given to new designations for provisional HLA-B and HLA-DR specificities and the upgrading of certain HLA-D and HLA-DR specificities to full HLA status. The existence of supertypic cross-reacting specificities was confirmed and extended.

HLA standardization and proficiency testing in the Southeastern organ Procurement Foundation.

Five years of experience with cell exchanges between laboratories comprising the Southeastern Organ Procurement Foundation (SEOPF) were analyzed in order to evaluate progress in HLA typing proficiency. The results of the analysis of 15 cell exchanges involving a total of 60 cells indicate that the average detection rate was 95% or greater for HLA-A1, 2, 3, 9, 10, 11, 28, and 29; B7, 8, 12, 13, 14, 15, 17, 27, and 40. HLA-A locus antigens were detected more often (85.8%) than B locus antigens (80.9%). False negative results were more frequent than false positive antigen assignments. Errors in antigen assignments tended to be nonrandomly distributed for certain antigens belonging to cross-reacting groups but usually were randomly distributed for well defined antigens. During the period of the study, SEOPF laboratories demonstrated improved proficiency in the identification of most HLA-A, B, and C provisional (w) specificities. The results demonstrate the benefits of interlaboratory proficiency testing and indicate that cell exchanges can be carried out successfully on a regional basis.