Are the cut-offs of the rheumatoid factor and anti-cyclic citrullinated peptide antibody different to distinguish rheumatoid arthritis from their primary differential diagnoses?

OBJECTIVE: Rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibody (anti-CCP) are commonly used for diagnosis of rheumatoid arthritis (RA), although other rheumatic diseases with arthritis can test positive. This study aimed to determine the cutoff values for RF and anti-CCP with the best diagnostic performance in a sample of patients with RA, compared with other rheumatic diseases. METHODS: This was a descriptive, prospective study. EUROINMMUN enzyme-linked immunosorbent assays for RF isotypes immunoglobulin (Ig) A (IgA), IgG and IgM and third-generation assay IgG for anti-CCP were used in serum samples of patients with RA, other rheumatic diseases and healthy subjects. The cutoff with the best diagnostic performance was determined by the Youden Index and receiver operating characteristic analysis Results: Three hundred and thirty-two serum samples were analysed. The cutoffs proposed in our population were for RF in RA patients versus other rheumatic diseases, and healthy subjects IgM 135 IU/mL, for each disease, compared with RA, were psoriatic arthritis (Psa) IgA 47.2 IU/mL, clinically suspicious arthralgia (CSA) IgA 39.5 IU/mL, primary Sjögren's syndrome (pSS) IgM 180.6 IU/mL, systemic lupus erythematosus (SLE) IgA 42.6 IU/mL, primary fibromyalgia (pFM) IgM 68.6 IU/mL, osteoarthritis (OA) IgM 48 IU/mL, gout IgM 117 IU/mL and healthy IgM 16.3 IU/mL. For anti-CCP, in RA patients versus other rheumatic diseases, and healthy subjects 6.95 IU/mL, for each disease, compared with RA, were Psa 6.8 IU/mL, CSA 9.95 IU/mL, pSS 20.7 IU/mL, SLE 6 IU /mL, pFM 11.8 IU/mL, OA 11.9 IU/mL, gout 5 IU/mL and healthy 5 IU/mL. CONCLUSION: Irrespective of the manufacturer's suggested cutoff, the RA versus differential diagnosis cutoffs must be considered.

Rheumatoid arthritis-associated antibodies in healthy first-degree relatives of RA patients.

Rheumatoid arthritis (RA) affects approximately 1.5% of the population worldwide and 0.5-3.3% of the Mexican population. The presence of rheumatoid factor (RF), anti-citrullinated protein antibodies (ACPA) and anti-carbamylated protein (anti-CarP) antibodies has been described in populations at risk of RA development, such as first-degree relatives (FDR). Anti-CarP antibodies are present in RA patients (44%), FDR of RA patients (18%) and healthy controls (4.7%). Anti-CarP antibodies have not been described in FDR of the Mexican population. The objective of this study was to determine the prevalence of Rheumatoid Factors (RF) isotypes, ACPA and anti-CarP antibodies isotypes in FDR of RA patients. An observational, cross-sectional study, in an FDR of RA cohort, was performed. We measured IgA, IgG and IgM isotypes of RF, ACPA and anti-CarP antibodies. A total of 144 FDRs from 99 RA patients were enrolled. The prevalence of anti-CarP antibodies was 2.8% for IgA, 4.2% for IgG, whereas IgM was not detected. The serologic association was for RF/ACPA 4.48%, RF/anti-CarP 2.7%, FR 64.5%, ACPA 1.3%, ACPA/anti-CarP 0.69%, anti-CarP 3.4%, and no RF/ACPA/anti-CarP was observed. We found a low prevalence of anti-CarP antibodies in our cohort of FDR of RA patients, but the prevalence of ACPA and RF were higher than other cohorts previously reported.

Anti-carbamylated protein antibodies positivity and disease activity in Hispanic patients with established rheumatoid arthritis: An observational study.

OBJECTIVES: We aimed to determine the prevalence of anti-carbamylated protein (anti-CarP) antibodies in Mexican Hispanics with established rheumatoid arthritis (RA) and to assess their relationship with disease activity. METHODS: A cohort study was conducted in 278 patients with established RA during an 18-month follow-up. We measured IgG/IgM/IgA rheumatoid factor (RF), IgG anticitrullinated protein antibodies (ACPA) and IgG/IgM/IgA anti-CarP antibodies using enzyme-linked immunosorbent assay (ELISA). For disease activity, we performed the 28-joint disease activity score with erythrocyte sedimentation rate (DAS28-ESR). Repeated measures one-way ANOVA was used to test the association between anti-CarP IgG antibody status and longitudinal DAS28-ESR scores. Patients were evaluated at baseline and at 6, 12, and 18 months during follow-up. RESULTS: Anti-CarP IgG antibodies were positive in 47.8% of patients and, accounting for all isotypes, in 9.5% of patients with negative RF and ACPA. Triple antibody positivity was present in 42.6% of patients in our sample. Anti-CarP IgG antibody positivity did not show statistically significant differences in mean DAS28-ESR when compared to anti-CarP IgG antibody negative patients at baseline, 6, 12 or 18 months. CONCLUSION: Anti-CarP IgG antibodies are not associated to a higher disease activity in Hispanic patients with established RA. Our findings suggest that the clinical value of measuring anti-CarP antibodies in RA diminishes over time.

Epidermal growth factor enhances osteogenic differentiation of dental pulp stem cells in vitro.

INTRODUCTION: Epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) play an important role in extracellular matrix mineralization, a complex process required for proper bone regeneration, one of the biggest challenges in dentistry. The purpose of this study was to evaluate the osteogenic potential of EGF and bFGF on dental pulp stem cells (DPSCs). MATERIAL AND METHODS: Human DPSCs were isolated using CD105 magnetic microbeads and characterized by flow cytometry. To induce osteoblast differentiation, the cells were cultured in osteogenic medium supplemented with EGF or bFGF at a low concentration. Cell morphology and expression of CD146 and CD10 surface markers were analyzed using fluorescence microscopy. To measure mineralization, an alizarin red S assay was performed and typical markers of osteoblastic phenotype were evaluated by RT-PCR. RESULTS: EGF treatment induced morphological changes and suppression of CD146 and CD10 markers. Additionally, the cells were capable of producing calcium deposits and increasing the mRNA expression to alkaline phosphatase (ALP) and osteocalcin (OCN) in relation to control groups (p < 0.001). However, bFGF treatment showed an inhibitory effect. CONCLUSION: These data suggests that DPSCs in combination with EGF could be an effective stem cell-based therapy for bone tissue engineering applications in periodontics and oral implantology.