However, careful examination of the BCR MFI ratio index values of the paired samples in the same batch of experiments revealed the presence of different efficiencies in terms of the capability of B cells to discriminate substrate stiffness: B cells from RA patients exhibited a much weaker discrimination efficiency as indicated by the much lower BCR (or pFAK) MFI ratio index, in comparison with B cells from the paired healthy controls (Figure 9A,B). This evidence concerns the gene BCR and rheumatoid arthritis.