Excerpt:

Results
27 different non-specific bands were detected in both groups. Six
of 27 (22%) of the non-specific bands were detected significantly
more in the western blot positive patients compared to the
western blot negative patients (20 kDa, p<0.0001; 28 kDa,
p<0.002; 36 kDa, p<0.002; 37 kDa, p<0.007; 48 kDa, p<0.023; 56
kDa, p<0.028; two-tailed F test). 

Conclusion
Results suggest that the 20, 28 and 48 kDa bands should be
regarded as specific.