Letter from I. D. Marshall of Alpha Therapeutic UK Ltd. to Prof. A. L. Bloom of the University Hospital of Wales RE AIDS and precautionary steps being introduced to minimise the risk of the disease being transmitted via donors to the haemophiliac population, including donor screening and leafleting of donors, and enclosing the text of a press release by Alpha Therapeutic UK Ltd entitled Alpha Therapeutic acts to protect haemophiliacs from AIDS epidemic