RESUMEN
<p><b>OBJECTIVE</b>To investigate the feasibility of peptide mass fingerprinting for non-invasive differential diagnosis of IgA nephropathy (IgAN) from the non-IgA nephropathy (IgAN).?</p><p><b>METHODS</b>According to the results of renal biopsy, 56 patients were divided into IgAN group (n=28) and non-IgAN group (n=28), and peptide mass fingerprints were acquired from these patients using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS).</p><p><b>RESULTS</b>Nine different peptides were identified between IgAN and non-IgAN. The two most distinctive differentially expressed peptides, with peptide peak values of 4476.46 and 1968.10, showed area under curve values of 86.18% and 79.77%. Principal component analysis demonstrated that the accumulated explained variance of the first 8 differential peptides reached 95%, suggesting the feasibility of differential diagnosis of IgAN from non-IgAN. Comparison with the Matrix protein database identified the peptide with a relative molecular mass of 5338.08 as a fragment of mucin 4 inform and the 2082.77 peptide as fragment of α1-II type collagen inform.</p><p><b>CONCLUSION</b>MALDI-TOF MS is feasible for differential diagnosis of IgAN and non-IgAN and also has great potentials in the classification of the subtypes of other systemic diseases.</p>