The 1993 cell typings of the International Cell Exchange

1. This is a summary of the typings for 40 cells for Class I antigens and 20 cultured cell lines for Class II antigens through the International Cell Exchange. Serological typings were compared with DNA typing reports for Class II specificities. Presently, 283 laboratories participate in the monthly Class I exchange. Class II results were received from 124 serology labs and 81 DNA labs on a monthly basis. 2. In 1993, 12 A-locus antigens were typed and 8 specificities reached levels of 95% or greater average detection. Thirteen of the 33 B-locus antigens showed 95% or better mean agreement levels. There was an improvement in detection of B76 and B7801. 3. Discrepancy rates of 7 A-locus and 9 B-locus antigens typed 3 or more times were compared with the overall rates for each respective locus. The discrepancy rate of false negatives, ie, how often the antigen was missed for the recognized B-locus specificities, continued to be greater than those for the A-locus antigens. The discrepancy rates, especially the percent false-positive, decreased for A33 during the recent 6-year period. 4. We showed the number of labs with their total of false-negatives and false-positives. Twelve labs attained a final total of no misses for all antigens. In 1993, 11 labs achieved impressive perfect records (zero false negative and false positive) for all analyzed antigens. 5. Retyping results of 2 donors showed improved antigen detection, particularly of A2403, B70, and B76. 6. Eleven cells typed in previous cell exchanges as having new or rare variants were sequenced recently. The B*5102 and B*5901 cells were retyped as reference cells. A new A-locus variant detected in previous exchanges was recently confirmed by sequence work as A*8001. New variants of B5 and B22 were discussed. 7. In addition to the mean detection rates, the low and high levels were determined for 15 broad (11 DR & 4 DQ) specificities by serology and compared with those attained for the respective generic (low-resolution) DNA typing. Only 2 broad antigens (DR10 and DQ4) had less than a 90% agreement level by serology. All of the generic types reached over 95% average detection levels, with the exception of DQB1*04, which reached 90% mean detection. 8. Detection of 8 Class II splits (4 DR & 4 DQ) continued to pose problems in serology, ranging from as low as 15% for DQ5 and DQ9 to an average detection level of 61% for DR15.(ABSTRACT TRUNCATED AT 400 WORDS)