Heroic measures have been employed to prevent infection in the hospital setting.Bone marrow transplantation from a suitable donor is effective.Compatible donors can be obtained , however ,in only a quarter of the cases. A palliative mode of therapy is treatment with chemically modified bovine adenosine deaminase. The enzyme , modified by covalently attaching polyethylene glycol to the protein, has a longer half-life than the unmodified enzyme (days compared with minutes to hours) and is a poor immunogen. The poor immunogenicity retards the formation of antibodies against the foreign enzyme. Bovine adenosine deaminase must be given by injection.