Molecular tissue typing in renal transplantation: Initial experience from a tertiary care Naval Hospital

Background:During the last five years the proportion of living unrelated kidney transplants has increased and DNA tissue-typing methods have become popular in India. This study was carried out to compare the results of tissue - typing by serology and sequence specific primers (SSP) and study the usefulness of 'episode' allograft biopsies for diagnosis of acute graft dysfunction.
Materials and Methods:DNA was extracted from whole blood using Qiagen kit. Samples from 60 individuals including thirty patients and their donors were typed by serology and SSP. Fifteen allograft biopsies were performed for suspected acute rejection (AR) cases.
Results: Both alleles of HLA - A, B and DR antigen could be determined in 86, 65 and 90% of samples by SSP respectively. There was a discrepancy of 16-40% between SSP and serology. Acute rejection was confirmed in 8/15 biopsies. Graft survival rates were 83 and 76% at one and two years respectively. Neither the graft survival nor the number of AR episodes showed any correlation with the extent of HLA mismatch. SSP was useful in defining A*68, A*66, A*69 and A*33 alleles at private level and A*36, A*74 and A*03 alleles which were blank on serology.
Conclusions: SSP has become popular in India due to its simplicity, superior results especially for class II HLA alleles: and episode allograft biopsy is adequate for follow-up of kidney recipients.