Impact of DNA Typing on a Living-Related Donor Renal Transplant Program M.N. Zafar, N. Ahmed, A. Naqvi, and A. Rizvi M OLECULAR typing of HLA class I and II antigens has improved the quality of typing and has been shown to be relevant for renal allograft survival. 1–3 This paper describes the impact of molecular DNA typing methods in a live-related program. PATIENTS AND METHODS Seven hundred recipients and donors for renal transplantation were typed for HLA-A, B, DR, and DQ by serologic methods between January 1996 and December 1997. Five hundred were typed by Collaborative Transplant Study (CTS), Heidelberg. Cell trays included 120-well HLA-A and B trays and 60-well HLA-DR trays, and 200 by One Lamda 72-well class I and II trays. DNA typing using polymerase chain reaction-single-strand polymor- phism (PCR-SSP) was performed for determination or confirma- tion of doubtful serologic typing. Five hundred HLA-DRB1 typing using 24 primer mixes, 150 HLA-A using 24 primer mixes, and 60 HLA-B using 48 primer mixes were performed on CTS primers. Procedure for PCR-SSP was essentially as described by Olerup and Zellerquist. 4 Statistical analysis included standard normal devia- tion. RESULTS Comparison of serologic methods with DNA typing showed error rates of 30% in class II specificities 1 to 18, 24% in HLA-A, and 14% in HLA-B locus. Alleles most effected in HLA-DR were DR1, 16, 4, 8, 10, 13, and 14. In the HLA-A locus, antigens effected were A29, 31, 32, 33, 24, 68, and 74. All these were missed on serology. Effected alleles in the B locus were B7, B49, and B15. Comparison of graft function grades, rejection episodes, and patient survival at 1 year in 120 molecular typed and 94 serology typed one haplotype- matched transplants showed better results in those matched by molecular method (Table 1). The average cost of DNA typing of HLA ABDR was $80 as compared with $70 for serology. Repeats on serologic typing for HLA-A was 5%, B 5%, and DR 20%. DISCUSSION Molecular methods have shown that serologic methods are problematic with error rates of up to 20%. These are in the form of wrong assignment or missed alleles, that is, sero- logic blanks. Since better matching has shown improved survival, 2,3 the relevance of molecular typing in live-related transplants is all the more important as this is a once in a life time donor and indeed transplant. In a developing country like Pakistan where the majority of the consum- ables are imported, molecular DNA typing is the method of choice in terms of quality and cost effectiveness. The improvement in graft function and survival as shown in our experience is of clinical relevance. This is specially so in terms of class II matching where high discrepancy rates in serology are most likely due to antisera raised in non-Asian Caucasians. REFERENCES 1. Zafar N, Ahmed N, Khan S, et al: Transplant Proc 28:1270, 1996 2. Opelz G, Mytilineos J, Scherer, et al: Lancet 338:461, 1991 3. Mytilineos J, Lempert D, Meddletin F, et al: Tissue Antigens 50:355, 1997 4. Olerup O, Zellerquist H: Tissue Antigens 39:225, 1992 From the Sindh Institute of Urology and Transplantation, Dow Medical College, Karachi, Pakistan. Address reprint requests to Dr Mirza Naqi Zafar, Sindh Insti- tute of Urology and Transplantation, Dow Medical College, Karachi, Pakistan. E-mail: info@siut.org. Table 1. Graft Function Grades, Rejection Episodes, and Patient Survival Rates in One Haplotype-Matched Transplants at 1 Year Function Grades* A (%) B (%) C (%) D (%) F (%) Rejection Episode (%) Patient Survival (%) DNA (n = 120) 50 (39) 33 (42) 22 (18) 2 (1.6) 6 (5) 30 (25) 113 (94) Serology (n = 94) 26 (28) 26 (28) 25 (27) 4 (4) 8 (8) 37 (39) 85 (90) p  0.05 p  0.05 *A, 1.5; B, 2.0; C, 3.0; D, 3.0; F, failed. © 1999 by Elsevier Science Inc. 0041-1345/99/$–see front matter 655 Avenue of the Americas, New York, NY 10010 PII S0041-1345(99)00815-5 Transplantation Proceedings, 31, 3335 (1999) 3335