1. INFLUENCE OF HLA MISMATCH ON GRAFT SURVIVAL IN RENAL TRASPLANTATION IN ADULTS IN ARGENTINA Bisigniano Liliana MD., López-Rivera Arturo MD., Tagliafichi Viviana, Fernández Víctor J MD., Soratti Carlos A MD.

2. Introduction HLA matching improves the outcome of cadaveric renal transplantation. However, many allografts function well even in the presence of one or more HLA mismatches, which raises the question of whether some mismatches are better recognised by the recipient's immune system than others.

3. Objective To determine if there are influence of both quality and level of HLA mismatch (MM) between donor and recipient on graft survival in kidney transplantation in adults using deceased donors in Argentina.

4. Materials & Methods Retrospective analysis from January 1998 to December 2009. Kaplan-Meier was used to estimate the survival rates, and Log-rank was used to compare the curves. Cox regression was used to analyze the effect of HLA A, B and DR on graft survival.

5. Materials & Methods Adjustments were made for age and gender of both the donor and the recipient, cause of donor’s death, time on dialysis (TD), cold ischemia time and etiology of recipient’s renal failure. The MM value was coded according to the number of antigens shared by HLA A, B and DR. Adding the 3 antigen types, mismatch values ranged from 0 to 6.

6. Results GENDER 2396 (40%) FEMALES AND 3239 (60%) MALES MEAN AGE 46.9 +13.9 yrs MEDIAN FOLLOW UP 4yr (max 13yr) Mismatch Level 0-327.65% 4-673.25%

7. Results 1 year5 years10 years 81.60%64.70%47.30%

8. Results HLA-DR (0)HLA-DR (1)HLA-DR (2) 1 year84.7%80.4%80.9% 5 years68.2%63.8%63.2% 10 years50.3%46.1%46.5% p=0.001 HR (CI95%) 1.18 (1.06-1.33)1.17 (1.04-1.32) p= 0.0040.010

9. Results HLA-A (0)HLA-A (1)HLA-A (2) 1 year82%83.6%80.1% 5 years70.1%66.7%62.9% 10 years48.2%49.4%45.6% p=0.003 HR (CI95%) 1.02(0.84.1.25)1.18(0.97-1.43) p 0.8110.094

10. Results HLA-B (0)HLA-B (1)HLA-B (2) 1 year81%82.6%81.3% 5 years66.5%65.6%64.1% 10 years49.6%49.9%45.9% p=0.264 HR (CI95%) 1.07(0.87-1.21)1.09(0.91-1.29) p 0.9440.351

11. Results MM 0-3MM 4-6 1 year84.5%80.6% 5 years69.1%63% 10 years53.1%45% p=0.0001 HR (IC95%)0.82 CI 95%0.74-0.91 p=0.0002

12. Results 1 year5 years10 years MM 0-384.50%69.10%53.10% MM 4-680.60%63%45%

13. Conclusions  HLA-DR locus is associated with graft survival  Statistical significant difference in survival curves with mismatch between 0 and 3 vs 4 to 6 was observed and was also associated with graft survival after adjusting for other variables.  These results will be relevant when considering that 73.25% of patients over 18 undergoing that 73.25% of patients over 18 undergoing kidney transplant in Argentina had a mismatch >3 kidney transplant in Argentina had a mismatch >3

14. Thank you for your attention