title: HLA match likelihoods for Indian patients seeking unrelated donor transplantation grafts: a population-based study.
abstract: BACKGROUND
  For patients who do not have a suitable human leukocyte antigen (HLA)-matched family donor, unrelated donor registries of adult volunteers and banked umbilical cord blood (UCB) units provide the potential for successful haemopoietic stem-cell transplantation. The size and genetic composition of such registries determines the proportion of patients who will be able to find a suitable match. We aimed to assess the proportion of positive matches for Indian patients.
  
  
  METHODS
  Using HLA data from ten existing donor and UCB registries and clinical transplant centres in India, we built population-based genetic models for 14 Indian regions to model Indian registry growth to predict the likelihood of identifying a suitable donor-either an adult donor or UCB-for Indian patients. We computed ranking tables of the top ten haplotypes in each regional group and compared these with four US samples from the National Marrow Donor Program (NMDP) registry.
  
  
  RESULTS
  The mean proportion of individuals who would have a 10/10 adult donor match within India ranged from 14·4% with a registry size of 25 000 to 60·6% with a registry size of 1 000 000. Only when donor registries increased to 250 000 did the match rate within India exceed that found by searching the US-NMDP registry combined with an Indian registry of 25 000 donors. The proportion of matches increased logarithmically with increased registry size (R(2)=0·993). For a UCB registry size of 25 000, 96·4% of individuals would find a 4/6 match; however, only 18·3% would have a 6/6 match.
  
  
  CONCLUSIONS
  Serial match modelling and follow-up comparisons can identify the relative and progressively greater value of an India-based donor registry and UCB banking network to serve the Indian population. Understanding regional HLA haplotype diversity could guide registry growth and maximise benefit to patients. Similar modelling could guide planning for the needs of other ethnically distinct populations.
  
  
  BACKGROUND
  University of Minnesota and the Indian Council for Medical Research.
authors.affiliation: National Marrow Donor Program, Minneapolis, MN, USA. Electronic address: mmaiers@nmdp.org.
authors.forename: Martin
authors.initials: M
authors.lastname: Maiers
authors.affiliation: National Marrow Donor Program, Minneapolis, MN, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Halagan
authors.affiliation: Manipal Hospital, Bangalore, India.
authors.forename: Sangeeta
authors.initials: S
authors.lastname: Joshi
authors.affiliation: Manipal Hospital, Bangalore, India.
authors.forename: H Sudarshan
authors.initials: HS
authors.lastname: Ballal
authors.affiliation: Rotary Bangalore-TTK Blood Bank, Bangalore Medical Services Trust, Bangalore, India.
authors.forename: Latha
authors.initials: L
authors.lastname: Jagannatthan
authors.affiliation: Narayana Hrudayalaya, Bangalore, India.
authors.forename: Sharat
authors.initials: S
authors.lastname: Damodar
authors.affiliation: Jeevan Stem Cell Bank, Chennai, India.
authors.forename: Periathiruvadi
authors.initials: P
authors.lastname: Srinivasan
authors.affiliation: Jeevan Stem Cell Bank, Chennai, India.
authors.forename: Saranya
authors.initials: S
authors.lastname: Narayan
authors.affiliation: Tata Memorial Hospital, Mumbai, India.
authors.forename: Navin
authors.initials: N
authors.lastname: Khattry
authors.affiliation: Post Graduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Pankaj
authors.initials: P
authors.lastname: Malhotra
authors.affiliation: Post Graduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Ranjana W
authors.initials: RW
authors.lastname: Minz
authors.affiliation: Gujarat Cancer and Research Institute, Civil Hospital Campus, Ahmedabad, India.
authors.forename: Sandip A
authors.initials: SA
authors.lastname: Shah
authors.affiliation: DATRI, Chennai, India.
authors.forename: Raghu
authors.initials: R
authors.lastname: Rajagopal
authors.affiliation: DATRI, Chennai, India; Histogenetics, New York, NY, USA.
authors.forename: Nezih
authors.initials: N
authors.lastname: Cereb
authors.affiliation: DATRI, Chennai, India; Histogenetics, New York, NY, USA.
authors.forename: Soo Young
authors.initials: SY
authors.lastname: Yang
authors.affiliation: Marrow Donor Registry (India), Mumbai, India.
authors.forename: Sunil
authors.initials: S
authors.lastname: Parekh
authors.affiliation: Christian Medical College, Vellore, India.
authors.forename: Joy
authors.initials: J
authors.lastname: Mammen
authors.affiliation: Christian Medical College, Vellore, India.
authors.forename: Dolly
authors.initials: D
authors.lastname: Daniels
authors.affiliation: Division of Hematology, Oncology and Transplantation, University of Minnesota, MN, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Weisdorf