Identification and Validation of SAA4 as a Rheumatoid Arthritis Prescreening Marker by Liquid Chromatography Tandem-mass Spectrometry

• Published in: Molecules (Basel, Switzerland) Vol. 22; no. 5; p. 805
• Main Authors: Seok, AeEun, Lee, Hyun-Jung, Lee, Sungeun, Lee, Jiyeong, Mun, Sora, Park, Arum, Chun, Yeon-Tae, Lee, Jae-Hyeon, Lim, Hee-Joung, Kang, Hee-Gyoo
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 14.05.2017; MDPI
• Subjects: Adult; Arthritis; Arthritis, Rheumatoid - diagnosis; Arthritis, Rheumatoid - metabolism; Assaying; Biomarkers - metabolism; C-reactive protein; C-Reactive Protein - metabolism; Chromatography; Chromatography, Liquid - methods; Correlation; Diagnosis; Diagnostic systems; Female; Health; Humans; Identification methods; Immune response; Immunoassays; LC-MS/MS; Liquid chromatography; Male; Markers; Mass spectrometry; Mass spectroscopy; Middle Aged; Patients; Pharmaceutical industry; pre-screening; Proteins; Proteomics; Rheumatoid arthritis; Rheumatoid factor; Scientific imaging; Serum Amyloid A Protein - metabolism; serum amyloid A4; Tandem Mass Spectrometry - methods; LC-MS/MS; pre-screening; serum amyloid A4; rheumatoid factor
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules22050805

Rheumatoid arthritis (RA) is a chronic autoimmune disease that progresses into systemic inflammation and joint deformity. RA diagnosis is a complicated procedure, and early diagnostic methods are insufficient. Therefore, in this study, we attempted to identify new markers to improve the accuracy of RA prescreening. e identified differentially expressed proteins (DEPs) by using liquid chromatography tandem-mass spectrometry in health-prescreening sera with high rheumatoid factor (RF) values, and compared the findings with those from sera with normal RF values. We identified 93 DEPs; of these, 36 were upregulated, and 57 were downregulated in high-RF sera. Pathway analysis revealed that these DEPs were related to immune responses. Additionally, four DEPs were statistically analyzed by proteomic analysis; of these, SAA4 was significantly validated in individual enzyme-linked immunosorbent assays. Moreover, SAA4 was significantly upregulated in RA patients (n = 40, 66.43 ± 12.97 ng/mL) compared with normal controls (n = 40, 4.79 ± 0.95 ng/mL) and had a higher area under the curve than C-reactive protein. Thus, we identified SAA4 as a protein that was positively correlated with RF and RA. SAA4 may represent a novel prescreening marker for the diagnosis of RA.