[Feasibility of peptide mass fingerprinting for differential diagnosis of IgA and non-IgA nephropathy].

Objective To investigate the feasibility of peptide mass fingerprinting for non-invasive differential diagnosis of IgA nephropathy(IgAN) from the non-IgA nephropathy(IgAN).Methods 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).Results 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.Conclusion 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.