“…The reactions of anti-Yt a are not diminished by trypsin treatment of red cells but, in one series, six of six examples failed to react with cells treated with bromelin, chymotrypsin, ficin or papain (Rouger et al 1982) and in another series, 8 out of 14 examples of anti-Yt a failed to react with cells treated with ficin or papain (Vengelen-Tyler and .…”