Soluble triggering receptor expressed on myeloid cells-1 is a biomarker of anti-CCP-positive, early rheumatoid arthritis.

OBJECTIVES: To assess serum soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) levels in disease-modifying antirheumatic drug (DMARD)-naïve early rheumatoid arthritis (ERA), to investigate the association of sTREM-1 levels with Disease Activity Score in 28 joints (DAS28) and seropositivity for anti-cyclic citrullinated peptide (CCP) antibody and to determine the predictive value of sTREM-1 with respect to clinical response to DMARD therapy. METHODS: Twenty-two consecutive patients with DMARD-naïve ERA were prospectively evaluated for serum sTREM-1 by means of ELISA at diagnosis and at the following clinic visit after prednisone and/or DMARD has been administered, and related to DAS28 and serum level of anti-CCP antibody. We compared the sTREM-1 level to that of 31 patients with established RA as well as to 24 controls. RESULTS: Serum sTREM-1 level was significantly higher in the DMARD-naïve ERA group (212.9 ± 388.9 ρg/mL) compared to established RA group (1478.0 ± 280.0 ρg/mL, P = 0.001) and normal control (34.4 ± 7.4 ρg/mL, P < 0.001). In the ERA group, elevated basal sTREM-1 level correlated with higher DAS28-CRP score (P = 0.001, HR 3.23, 95% CI 1.4-8.12), DAS28-ESR (P = 0.04, HR 2.34 95% CI 0.1-8.12), as well as predicted higher DAS28 score at the following encounter after DMARD treatment was administered (P = 0.001, HR 3.2 95% CI 1.1-7.2). Higher serum level of sTREM-1 correlated with higher titres of anti-CCP antibody (P < 0.001). CONCLUSIONS: Our results suggest that serum sTREM-1 may provide a novel biomarker for DMARD-naïve ERA as well as for seropositivity for anti-CCP antibody and RA activity.

Diagnostic performance of 14-3-3η and anti-carbamylated protein antibodies in Rheumatoid Arthritis in Han population of Northern China.

OBJECTIVES: As we already know, Rheumatoid arthritis (RA) cannot be excluded when the rheumatoid factor (RF) or anti-cyclic citrullinated peptide antibody (anti-CCP) is negative. Here, we determined the application value of 14-3-3η protein, anti-carbamylated proteins antibodies (anti-CarP), as well as their potential role to diagnose RA together with RF or anti-CCP. METHOD: Serum levels of anti-CCP, RF, 14-3-3η and anti-CarP antibodies were detected in 291 RA patients, 223 patients with autoimmune diseases except RA, and 156 healthy subjects recruited from Han population of Northern China. We examined the differences in the levels of these indicators among groups and compared the correlations between any two of the indicators. At the same time, a total of 12 testing strategies were established for comparison to maximize the diagnostic value. RESULT: The levels of RF, anti-CCP, anti-CarP and 14-3-3η were significantly higher in RA patients (12.5;[9.36-15.7], 30.7;[25.7-35.6], 1.90;[1.70-2.01], 15.8;[10.8-20.8], respectively) compared with either interference-control group (1.24;[1.07-1.41], 0.64;[0.42-0.86], 0.51;[0.46-0.57], 0.33;[0.23-0.44], respectively) (p < 0.0001) or healthy-control group (1.03;[0.99-1.08], 0.49;[0.38-0.59], 0.28;[0.21-0.35], 0.55;[0.27-0.85], respectively) (p < 0.0001). Among all 12 detection strategies, the YI and κ value of a novel strategy that either double-positive of any 2 markers or single-positive of anti-CCP can be diagnosed as RA had the highest diagnostic value. CONCLUSION: The results of our study demonstrated that in Han population of Northern China, anti-CarP antibodies and 14-3-3η protein can be treated as valuable indicators of RA, especially when combined with RF and anti-CCP, the detection value is maximized.

Membranous nephropathy caused by rheumatoid arthritis.

Membranous nephropathy (MN) caused by disease-modifying antirheumatic drugs is relatively common in patients with rheumatoid arthritis (RA). However, MN rarely occurs due to RA itself. We describe a 61-year-old woman with RA who showed nephrotic syndrome. She was admitted because of systemic edema and severe arthritis. She had a long history of RA successfully treated with methotrexate (MTX), but discontinued all treatments 4 years before hospitalization. She had never been treated with bucillamine or gold. Laboratory test results were positive for anti-cyclic citrullinated peptide antibody and negative for anti-nuclear antibody. Renal pathologic findings were compatible with MN. Immunofluorescence microscopy showed IgG, IgA, κ, λ, and C3 along the glomerular capillary wall, whereas deposition of IgM or C1q was not detected. In terms of the IgG subclasses, only IgG2 findings were positive. Results for glomerular antigen and serum antibody for M-type phospholipase A2 receptor and thrombospondin type 1 domain-containing 7A were negative. HLA type did not include the HLA-DQA1 gene that is a concern in primary MN (PMN). She responded to intensive immunosuppressive therapy consisting of prednisolone, tacrolimus, and MTX with a parallel reduction of proteinuria. Based on assessments for differentiating PMN from secondary MN (SMN), the diagnosis of the present case was incompatible with PMN. Taken together, we consider that SMN in the present case was due to RA itself rather than drug-induced MN.