Assessing the HLA diversity of cord blood units collected from a birth clinic caring for pregnant women in an ethnically diverse metropolitan area.
BACKGROUND
New strategies are emerging in cord blood banking where focusing on birth clinics caring for a high number of mothers belonging to ethnic minorities could offer new possibilities for allotransplantation both for patients of European origin and for patients from ethnic minorities or mixed ancestries.


METHODS
Marseilles Cord Blood Bank works with one university birth clinic caring for a culturally and sociologically diverse population. Stringent French legal restrictions apply to recording the geographic origin of parents. To circumvent this limitation and evaluate the contribution of newly banked cord blood units (CBUs) to increasing HLA diversity, we applied an algorithm that allows for the determination of parents' putative haplotypes and thus grossly deduce information on their ancestry. Generic resolution HLA-A, HLA-B, and allelic resolution HLA-DRB1 genotyping for 328 CBUs and 2691 unrelated donors (UDs) between January 2009 and May 2012 were performed. Enrichment from international CBU registry with nonreferenced generic HLA-A, HLA-B, and allelic HLA-DRB1 phenotypes was compared between CBUs identified with one or two non-European haplotypes and CBUs identified with two European haplotypes.


RESULTS
Marseilles CBUs display an increased proportion of HLA antigens frequently expressed in African populations compared to UDs. Whereas 93% of 199 CBUs identified with one or two non-European haplotypes enrich international CBU registry, this result is reduced to 42% for the 129 CBUs identified with two European haplotypes.


CONCLUSIONS
This study supports a new method to assess HLA diversity. However, such an increased of HLA diversity raises questions about frequencies of CBUs released and clinical relevance from their uses.
Cell Therapy Facility, Institut Paoli-Calmettes, Marseille; Cord Blood Bank, Marseille; Inserm CBT-510, Centre d'Investigations Cliniques en Biothérapie, Marseille.
Jeremy
J
Magalon
Lise Marie
LM
Billard-Daufresne
Chantal
C
Gilbertas
Emmanuelle
E
Hermanche
Sophie
S
Simon
Claude
C
Lemarie
Boris
B
Calmels
Florence
F
Sabatier
Marc
M
Gamerre
Christophe
C
Picard
Christian
C
Chabannon
D001800:Blood Specimen Collection; D002947:Cities; D018864:Cultural Diversity; D003696:Delivery Rooms; D005006:Ethnicity; D005260:Female; D005312:Fetal Blood / Q000276:immunology*; D005602:France; D005787:Gene Frequency; D014644:Genetic Variation; D060005:Genotyping Techniques; D006680:HLA Antigens / Q000235:genetics*; D015234:HLA-A Antigens / Q000235:genetics; D015235:HLA-B Antigens / Q000235:genetics; D006801:Humans; D007231:Infant, Newborn; D011247:Pregnancy
D006680:HLA Antigens; D015234:HLA-A Antigens; D015235:HLA-B Antigens