Alkaline phosphatase induction in cystic fibrosis fibroblasts [letter].

Hosli has published a hypothesis relating to the primary cause of cystic 
fibrosis (CF) based on his observations that the level of alkaline 
phosphatase (ALP) in CF-derived skin fibroblasts, but not fibroblasts derived from 
normal individuals, could be increased several-fold by growing the cells in 
the presence of the urinary glycoprotein, Tamm-Horsfall protein (THP). However, we 
have not been able to show, in Adelaide, any change or 
induction in the level of ALP activity in CF-derived skin fibroblasts 
when grown in the presence of locally prepared THP under what 
appear to be identical cell culture conditions to those used by 
Hosli. It thus appears that under the conditions currently employed in 
our laboratory, there is no diagnostic discrimination between fibroblasts of CF 
homozygotes and normal individuals. 