Revue Frangaise de Transfusion et Immuno-h6matologie Tome XIX. - - N ° 4. - - 1976 629

LETTRES A LA REDACTION

D U

p a r B .P .L . M O O R E

C a n a d i a n R e d Cross , B l o o d T r a n s f u s i o n Service , TORONTO ( C a n a d a ) .

I h a v e b e e n r e a d i n g t h e r e p o r t s o n D U in ~ R e v u e f r a n q a i s e de T r a n s f u s i o n , , , t o m e X V I I , w i t h g r e a t i n t e r e s t . I t h o u g h t t h a t you m i g h t w i s h to h a v e o n h a n d s o m e of o u r r e s u l t s ( w h i c h a p p e a r in o u r l a b o r a t o r y m a n u a l , 7 TM ed, 1972).

F o r e x a m p l e , t h e r o u t i n e m e t h o d w h i c h we u s e f o r m a n u a l R h t y p i n g - a one - s t age e n z y m e t e c h n i q u e - d e t e c t s a b o u t h a l f t h e n u m b e r of D U d e t e c t e d b y t h e i n d i r e c t a n t i g l o b u l i n t e c h n i q u e . A m o n g t h o s e d o n o r s w h o a r e D - - , C - - , E - b y a one - s t age e n z y m e m e t h o d ( p h e n o t y p e r r ) t h e i n c i d e n c e of D U as j u d g e d b y t h e i n d i r e c t a n t i g l o b u l i n m e t h o d u s i n g a n ant i -D r e a c t i n g we l l w i t h C a t e g o r y VI cel ls is 0.248 % (38 D U a m o n g 15,313 d o n a t i o n s ) . An e a r l i e r s u r v e y s h o w e d 72 D U a m o n g 43,407 r r s a m p l e s , a f r e q u e n c y of 0.166 %.

B e c a u s e of t h i s low f r e q u e n c y of D U a m o n g ~ r r ,, donor s , w e do n o t r o u t i n e l y t e s t f o r D U. We k n o w of on ly one o r two cases of ant i -D b e i n g f o r m e d in a D U - p o s i t i v e p e r s o n , b u t w e h a v e i d e n t i f i e d ant i -D in six o r s e v e n D - p o s i t i v e people .

T h e s e f i n d i n g s f i t in we l l w i t h t h e r e s u l t s r e p o r t e d in t h e R e v u e ; we a r e in c o m p l e t e a g r e e m e n t w i t h t h e c o n c l u s i o n s of Mr . J o u v e n c e a u x .

Biological and clinical significance of di/[erences between RBC membrane (Rh ) and non

membrane (ABH, MN, P) antigenic sites

I n h i s r e c e n t a r t i c l e in t h i s j o u r n a l , Lev ine (1) h a s l a id e m p h a s i s o n the f ac t t h a t " a t 37°C al l cell m e m b r a n e s h a v e c h a r a c t e r i s t i c s of f l u i d i t y

(I) Levine, P. - - This journa l X I X , 213, 1976.

630 MOORE B.P.L.

and mobi l i ty" whereas " a t lower temperatures. . , the mobil i ty of the membranes is considerably compromised by the tendency of the liquid wi thin erythrocyte m e m b r a n e to gel and hense lose its fluidity ". The use of surface antigens as indicators of lipid viscosity in the cell membrane has been studied and reviewed by Edidin (2), whose findings are consistent with those cited by Levine.

I t would seem, therefore, that we should not speak, colloquially, of "co ld antibodies ", bu t ra ther of "cold an t igens" when we refer to those sites whose physical "goodness of f i t " is opt imal at lower temperatures .

B.P.L. MOORE,

Canadian Red Cross Blood Transfus ion Service National Reference Laboratory, 95 Wellesley street east TORONTO (Canada).

(2) Edidin, M. m ~, An arrangement and rearrangement of cell surface antigens in a fluid plasma membrane in Cellular Selection and Regulation in the Immune Response (ed. G.M. Edelman) Raven Press, New York, 1974, p. 121.