Optimization of the inventory size of the public cord blood program--the Indian context

There are reportedly more than 250,000 cord blood units [CBU] available in cord blood banks world over, yet, there are many who are unable to get a suitable match. Being the pioneer to set up the first and only public cord blood bank in India, we needed to strategize the pool size that will meet the transplantation needs of the people of Indian origin, worldwide.

To define the optimum size of this public cord blood repository [CBR] that will give at least one 5/6 HLA match to a defined number of cord blood graft requests.

We checked the trend of human Leukocyte antigen [HLA] match graft offerings, to 112 random requests from a database of 1800 CBUs. The HLA match function was performed using an 'in house' built and validated software. The pattern of availability of the matches was used as the basis of our study. We then performed a probability analysis to check the probable pool size that would offer at least one acceptable match to all the 112 requests.

With an inventory of 1800 units, we could offer 4/6 matches to about 99% and 5/6 matches to approximately only 29% and 6/6 matches to only 7% of the 112 random requests. Thus, acceptable matches were offered to about 30% of the requests received in the period and database considered for this study.

By employing probability analysis, we concluded that, by doubling the size, we will probably offer at least one 5/6 match to each requester, and from a pool size of about 55500 grafts, we may offer a full house (6/6 match) to the same number of requisitions. Genetic homology between the recipient and donor base, increases the probability of match availability. A good ethnic representation of the Indian population in our CBR plays a significant role in match availability.