Electrophoretic analysis of serum proteins in cystic fibrosis [letter].

We have attempted to reproduce the isoelectric focusing in thin layer polyacrylamide 
gels (IEFAG) method specified by Wilson et al. in our laboratory. 
Since the resolution obtained with their procedure appeared to be inadequate 
for identifying single protein bands in the relevant region, we have 
incorporated several methodologic improvements into the isoelectric focusing technique. These improvements 
have significantly enhanced the resolution and have thus enabled us to 
demonstrate a greater degree of heterogeneity of serum gamma-globulins than is 
visible in the paper of Wilson et al. Despite the significant 
increase in the number of bands resolved by our method, a 
difference among CF, heterozygote, and control sera in the pH 8.4 
- 8.5 region could not be detected. In addition, the two-step 
IEFAG/disc electrophoresis technique of Altland et al. has been tested in 
our laboratory. We have also modified this analytic procedure, enabling the 
fractionation of several small proteins from a portion of the IgG 
fraction. Again, despite an improvement in resolution which reveals more heterogeneity, 
no unique protein has been observed consistently in the CF and 
heterozygote area. 