Letter: Cell-mediated immunity in patients with cystic fibrosis.

We agree with the comment of Dr Feighery and Mr Woods that 
a low migration index signifies sensitivity to an antigen which can 
be achieved only by functionally active immunocompetent cells. However, we must 
emphasise that the functions of active immunocompetent cells may or may 
not be impaired, depending upon the antigens to which such cells 
are sensitised. Since comparative cells from age-matched controls and from blood 
donors did not show such sensitisation to those antigens to which 
the cystic fibrosis cells were sensitised then there is no doubt 
that the normal function of these immunocompetent cells in the patients 
with CF is indeed impaired. When one considers that steroids are 
known immunosuppressants it is certainly not surprising that treatment of the 
CF patients with prednisolone caused a decreased sensitivity of these sensitised 
CF cells to the antigens. Indeed, therapeutic concentrations of steroids were 
able to reduce the ability of sensitised spleen cells and of 
lymph-node cells to destroy target cells in vitro. Apart from this 
inhibition of sensitised cells by steroids, 90% of sensitised lymphocytes were 
killed when prednisolone 1 mg/l was present during the sensitisation phase. 
In addition it was observed in man that if cortisol or 
prednisolone was given two hours before abrading the skin, then there 
occurred a marked reduction of emigrations of both mononuclear cells and 
polymorphs into the area, thus inhibiting the mobilisation of macrophages. We 
believe that the situation with regard to steroid therapy and inhibition 
of migration of leukocytes from CF patients is similar. 