Normal C-reactive protein in active psoriatic arthritis: results from real-world clinical practice

Comparative profiling of serum biomarkers and ATR-FTIR spectroscopy for differential diagnosis of patients with rheumatoid and psoriatic arthritis - a pilot study

BACKGROUND

Rheumatoid arthritis (RA) and psoriatic arthritis (PsA) are chronic inflammatory diseases in which innate and adaptive responses of the immune system are induced. RA and PsA have complex signaling pathways. Despite the differences in their clinical presentation, there is a great demand for fast and accurate diagnosis of diseases to implement treatment and plan an individual therapeutic strategy quickly. In this report, we present the results of differential diagnosis of patients with RA and PsA and healthy subjects (C, control group), allowing for reliable differentiation of groups of rheumatoid patients based on biochemical parameters, attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectra, and combined data sets.

MATERIALS AND METHODS

Biochemical analyses, ELISA (enzyme-linked immunosorbent assays), and multiplex assays were conducted for blood sera from patients with RA (n = 32), patients with PsA (n = 28), and the control group (n = 18). ATR-FTIR spectra were collected for lyophilized sera.

RESULTS

The combination of six biochemical parameters (WBC, ESR, RF, CRP, HCC-4/CCL16, and HMGB1/HMGB) allowed the development of the partial least squares discriminant analysis (PLS-DA) model with an overall accuracy (OA) of 80% for test samples. The best separation between RA, PsA, and the control group was obtained utilizing spectral data. Using the interval PLS algorithm (iPLS) specific spectral ranges were selected and a classifier characterized by OA value for test set equal to 88% was obtained. This parameter, for the hybrid PLS-DA model constructed using selected biochemical parameters and a significantly reduced number of spectral variables, reached the level of 84%.

CONCLUSIONS

PLS-DA models developed on the basis of spectral data enable effective differentiation of patients with RA, patients with PsA, and healthy subjects. They appeared to be insensitive to existing inflammation processes which opens interesting perspectives for new diagnostic tests and algorithms for identification of patients with RA and PsA.

Sex-specific differences in patients with psoriatic arthritis:a nationwide study from the Chinese Registry of Psoriatic Arthritis (CREPAR IV)

OBJECTIVES

To elucidate the sex-specific differences in demographic features, clinical characteristics, and quality of life in Chinese patients with psoriatic arthritis (PsA).

METHODS

A total of 1,074 patients with PsA registered between December 2018 and June 2021 from the Chinese REgistry of Psoriatic ARthritis (CREPAR) cohort were selected. The baseline data on demographics, clinical characteristics, commonly used laboratory tests, comorbidities, and quality of life assessments were collected for this cross-sectional analysis.

RESULTS

A total of 1,074 patients were included in this study, 585 (54.47%) of them were male and 489 (45.53%) were female. The age at PsA onset in male patients was earlier than that in female patients (38.10 ± 12.79 vs 40.37 ± 13.41, p = 0.005). For clinical characteristics, male patients presented with higher rates of axial involvement (43.89% vs 37.74%, p = 0.044) and nail involvement (66.15% vs 58.08%, p = 0.006), while female patients presented with higher rates of peripheral arthritis (89.57% vs 83.93%, p = 0.007). For laboratory tests, men presented with a higher percentage of HLA-B27 positivity than women (24.65% vs 16.70%, p = 0.002) and had higher levels of CRP (median 9.70 vs 5.65, p < 0.001). Regarding disease assessment indices, male patients scored higher in PASI and BASFI (median 5.00 vs 3.00, p = 0.007 and 1.80 vs 1.40, p = 0.012, respectively). No sex difference was found in rates of achieving remission. Factors associated with disease remission were also analyzed in both sexes.

CONCLUSION

Demographic and clinical characteristics tend to vary between male and female patients with PsA. Male patients reported more functional limitations in daily life. Key Points • The demographic and clinical features vary greatly between male and female patients with PsA. • Male patients reported more functional burden in daily life as measured by BASFI.

Earlier clinical response predicts low rates of radiographic progression in biologic-naïve patients with active psoriatic arthritis receiving guselkumab treatment

OBJECTIVE

Assess relationship between earlier clinical improvement and radiographic progression (RP) over 2 years in guselkumab-treated patients with active psoriatic arthritis (PsA).

METHOD

Post hoc analyses combined data from DISCOVER-2 biologic-naïve adults with active PsA randomized to either guselkumab 100 mg every 4 weeks (Q4W) or guselkumab at W0, W4, then Q8W. Correlations (Spearman's coefficient) between baseline disease parameters and total PsA-modified van der Heijde-Sharp (vdH-S) score were examined. Repeated-measures mixed models, adjusted for known RP risk factors, assessed the relationship between Disease Activity Index in PsA (DAPSA) improvement, DAPSA improvement exceeding the median or the minimal clinically important difference (MCID), or DAPSA low disease activity (LDA) at W8 and RP rate, assessed by change from baseline in vdH-S score through W100.

RESULTS

Baseline age, PsA duration, CRP level, and swollen joint count, but not psoriasis duration/severity, weakly correlated with baseline vdH-S score. Elevated baseline CRP (parameter estimate [β] = 0.17-0.18, p < 0.03) and vdH-S score (β = 0.02, p < 0.0001) significantly associated with greater RP through W100. Greater improvement in DAPSA (β = -0.03, p = 0.0096), achievement of DAPSA improvement > median (least squares mean [LSM] difference: -0.66, p = 0.0405) or > MCID (-0.67, p = 0.0610), or DAPSA LDA (-1.44, p = 0.0151) by W8 with guselkumab significantly associated with less RP through W100. The effect of W8 DAPSA LDA on future RP was strengthened over time among achievers vs. non-achievers (LSM difference enhanced from -1.05 [p = 0.0267] at W52 to -1.84 [p = 0.0154] at W100).

CONCLUSIONS

In guselkumab-treated patients with active PsA, earlier improvement in joint symptoms significantly associated with lower RP rates through 2 years, indicating blockade of the IL-23 pathway may modify long-term disease course and prevent further joint damage. Key Points • Greater improvement in DAPSA at Week 8 of guselkumab treatment was significantly associated with less progression of structural joint damage at 2 years in patients with active psoriatic arthritis (PsA). • Early control of peripheral joint disease activity with blockade of the IL-23 pathway may modify long-term PsA trajectory and prevent further joint damage.

Type-I interferon pathway and DNA damage accumulation in peripheral blood of patients with psoriatic arthritis

Objectives

The abnormal DNA damage response is associated with upregulation of the type-1 interferon (IFN-I) pathway in certain rheumatic diseases. We investigated whether such aberrant mechanisms operate in psoriatic arthritis (PsA).

Methods

DNA damage levels were measured by alkaline comet assay in peripheral blood mononuclear cells from 52 PsA patients and age-sex-matched healthy individuals. RNA expression of IFIT1, MX1 and IFI44, which are selectively induced by IFN-I, was quantitated by real-time polymerase chain reaction and their composite normalized expression resulted in IFN-I score calculation. RNA expression of IL1β, IL6, TNF, IL17A and IL23A was also assessed in PsA and control subgroups.

Results

In PsA, DNA damage accumulation was increased by almost two-fold compared to healthy individuals (olive tail moment arbitrary units, mean ± SD; 9.42 ± 2.71 vs 4.88 ± 1.98, p<0.0001). DNA damage levels significantly correlated with serum C-Reactive-protein and IL6 RNA expression in PBMCs. Despite increased DNA damage, the IFN-I score was strikingly lower in PsA patients compared to controls (-0.49 ± 6.99 vs 4.24 ± 4.26; p<0.0001). No correlation was found between IFN-I pathway downregulation and DNA damage. However, the IFN-I score in a PsA subgroup was lower in those patients with higher IL1β expression, as well as in those with higher TNF/IL23A PBMCs expression.

Conclusion

DNA damage in PsA correlates with measures of inflammation but is not associated with the IFN-I pathway induction. The unexpected IFN-I downregulation, albeit reminiscent to findings in experimental models of spondyloarthritis, may be implicated in PsA pathogenesis and explained by operation of other cytokines.

Serum Calprotectin as a Promising Inflammatory Biomarker in Psoriatic Arthritis: a 1-Year Longitudinal Study

INTRODUCTION

There are few biomarkers correlated with psoriatic arthritis (PsA). We aimed to explore the clinical value of calprotectin (CLP) in PsA in disease activity and treatment targets.

METHODS

Serum CLP was detected by enzyme-linked immunosorbent assay (ELISA) in 71 patients with PsA, 55 patients with psoriasis (PsO), and 10 healthy controls. The association of serum CLP with disease activity index at baseline and follow-up was analyzed. Cox regression and receiver operating characteristic (ROC) analysis were used to evaluate the potential of CLP for predicting the achievement of treatment targets, including low disease activity (LDA), remission, and minimal disease activity (MDA).

RESULTS

Serum CLP levels (μg/ml) were significantly increased in patients with PsA/PsO compared with healthy controls (p < 0.001). Serum CLP levels were positively associated with psoriasis area and severity index (PASI), disease activity in psoriatic arthritis (DAPSA), and its components [including tender joint count (TJC), swollen joint count (SJC), patient's global assessment (PGA), and visual analog scale (VAS)-pain, r 0.290-0.601, all p value < 0.05]. After 1-year follow-up, the number of patients with PsA in remission and MDA increased [17 (23.9%) versus 47 (66.1%) and 21 (29.5%) versus 52 (73.2%) respectively, all p value < 0.001]. Cox regression and Kaplan-Meier survival analysis indicated that patients with lower CLP obtain LDA, MDA, and remission earlier, including remission and MDA within a year (all p-value < 0.05). ROC analysis showed the ability of serum at baseline to predict the achievement of the treatment target in 3 months [area under the curve (AUC) 0.663-0.691, all p-values < 0.05].

CONCLUSIONS

Serum CLP level was correlated with disease activity in PsA. It also possessed the ability to predict the achievement of the therapeutic target. These features of CLP would make it a useful tool in clinical work.