Pattern of urinary proteins and peptides in patients with rheumatoid arthritis investigated with the Iso-Dalt technique.

Characteristic differences in the pattern of urinary proteins and peptides have been found in patients with rheumatoid arthritis, compared with patterns from healthy controls. These differences have been demonstrated with a two-dimensional gel electrophoretic technique (Iso-Dalt) involving isoelectric focusing in the first dimension, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the second dimension. Using simple photographic techniques, one can obtain a composite pattern of the individual protein-stained gels for each group. Comparison of the composite patterns from the rheumatoid arthritis group and the control group revealed several proteins in the urine of the rheumatoid arthritis patients not found in the control group. Two groupings of these proteins were identified: acidic, high-Mr proteins and more basic, low-Mr proteins.