Placental help

Blood stem cells from the placenta could be a major help in treating leukaemic kids

 
Published: Sunday 15 December 1996

LEUKAEMIA affects thousands of children all over the world, accounting for over a third of all cancers diagnosed for children. The bone marrow tissue, which produces blood cells, churn out faulty products in these kids.

The only option is replacement of the marrow. But replacement of bone marrow requires a donor with matching protein molecules, called human leucocyte antigens (HLA), which sit on the surface of marrow cells. Also, for successful transplantation, at least four of the six hlas should match between the donor and the recipient, otherwise the tissue is promptly rejected by the recipient.

And to compound the problems, hlas are among the most variable proteins known. Therefore, the report of the teams of Joanne Kurtzberg of Durham's Duke University Medical Centre, and Pablo Rubinstein of New York Blood Centre that an entirely new strategy can be followed to save these kids using placental blood has been welcomed widely. They have successfully treated 25 patients, including a variety of non-malignant and malignant conditions (nejm, Vol 335, No 3). The strategy of this team has been to develop an alternate source of cells known as blood stem cells.

Blood stem cells are very difficult to isolate and use for transplantation purposes. While these occur in the marrow, another important source has been overlooked until recently -- a tissue discarded by tonnes every day -- placenta and umbilical cord that come out of the mother's womb along with the babies. Rubenstein, with a $4 million grant from the National Institutes of Health, us started the first placental tissue bank at the Mount Sinai Hospital in New York in 1992, making available to scientists and doctors placental-cord blood (pcb) transplants. Of course, only after each sample had been carefully screened for infectious agents and determining the hla profile.

In 1993, Kurtzberg began dipping into Rubenstein's deep freezer for pcb transplants. The nejm paper reports the results of their three-year collaboration, which turned out to be largely successful. Of the 25 people treated, 12 survived at least a year; one boy is alive for three years. Considering their chances of survival which, according to Rubenstein otherwise were 'near zero', the therapeutic method is being considered quite promising.

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