Genetic diversity of Umbilical Cord Blood Units for transplant of the National Center of Blood Transfusion (Mexico)

Abstract

Introduction

The Umbilical Cord Blood Units (UCBU) for transplant are a therapeutic possibility for patients with a wide range of onco-hematologic disorders, especially in children. In Mexico, 48.5% of oncological diseases in children from 1 to 4 years old are leukemias; while in patients from 5 to 14 and 15 to 24 years of age lymphomas and leukemias are predominant and represent the second and third causes of death in these age groups, respectively. Therefore, is it necessary to have registries of UCBU to ensure the representation of the genetic diversity in Mexico in order to attend this requirement.

Objective

To estimate the genetic diversity of HLA Class I (A, B) and Class II (DRB1) loci in cryopreserved UCBU of the Cord Blood Bank (CBB) at the National Center of Blood Transfusion (NCBT).

Methods

HLA typing of 533 UCBU for transplant was performed at the Research Department (evaluated by “Los Angeles Ca. Inmunogenetics Center”). Class I HLA-A, HLA-B and Class II HLA-DRB1 typing was performed using medium resolution Sequence-Specific Primer (SSP). In cases of an ambiguity by SSP; Sequence-Specific Oligonucleotide (SSO) method was carried out.

Results

46.5% of the UCBU were obtained from Mexico City donors, 30.95% from the State of Mexico, 8.06% Puebla, 6.37% Morelos and 3.37% from Veracruz. The remaining UCBU 4.75% were represented by other states of the country. The most frequent loci for the HLA-A founded were *02/24, *02/68, *02/02, *02/30, *01/02, *02/31; for HLA-B, *35/39, *15/35, *35/40, *39/44, *07/35, *35/48, *39/40 and for HLA-DRB1, *04/08, *04/07, *04/15, *04/15, *04/03, *04/14. The genetic distances analysis showed that the top five populations analyzed in this study are significatively different from each other.

Conclusions

The majority of the genotypes found suggest Amerindian and European origins and in a lesser proportion Oriental and African. The NCBT is therefore establishing agreements with different states of Mexico to promote the donation of UCBU in order to enrich the genetic diversity in the archives of the NCBT.