Developing clinically relevant biomarkers in inflammatory arthritis: A multiplatform approach for serum candidate protein discovery.
PURPOSE
To identify candidate biomarkers that have the potential to distinguish between patients with psoriatic arthritis (PsA) or rheumatoid arthritis (RA) and explore the value of combining different protein discovery platforms for the development of a multiplexed protein biomarker panel.


EXPERIMENTAL DESIGN
Serum samples from 32 patients (PsA; n = 16 and RA; n = 16) defined as active, early onset, and treatment naïve were analyzed using unbiased label-free LC-MS/MS, a microsphere bead-based immunoassay (Luminex xMAP) and an aptamer-based assay (SOMAscan).


RESULTS
LC-MS/MS was used to quantify 324 proteins, while the Luminex xMAP targeted 48 proteins and SOMAscan supported the measurement of 1129 proteins. The combined data from these techniques gave reproducible quantification of 1501 proteins in total. Of these, 42 (LC-MS/MS), 3 (Luminex xMAP), and 127 (SOMAscan) proteins were found to be differentially expressed between PsA and RA (p < 0.05).


CONCLUSION AND CLINICAL RELEVANCE
Using three different and potentially complementary proteomic platforms we identified a total of 172 proteins that are differentially expressed in patients with PsA compared to RA. These proteins collectively represent candidates for inclusion in a protein signature that could be developed as a diagnostic test to discriminate patients with PsA from RA and therefore be of clinical utility.
['McArdle|Angela|A|', 'Qasim Butt|Aisha|A|', 'Szentpetery|Agnes|A|', 'de Jager|Wilco|W|', 'de Roock|Sytze|S|', 'FitzGerald|Oliver|O|', 'Pennington|Stephen R|SR|']
D000328:Adult D015535:Arthritis, Psoriatic D001172:Arthritis, Rheumatoid D015415:Biomarkers D001798:Blood Proteins D002853:Chromatography, Liquid D003937:Diagnosis, Differential D005260:Female D015870:Gene Expression D020869:Gene Expression Profiling D006801:Humans D007118:Immunoassay D008297:Male D008875:Middle Aged D053719:Tandem Mass Spectrometry
Multiplexing LC-MS/MS Luminex SOMAscan Psoriatic and Rhuematoid Arthritis