Cross-sectional study of plasma Axl, ferritin, IGFBP4 and sTNFR2 as biomarkers of disease activity in childhood-onset SLE: A study of the Pediatric Nephrology Research Consortium

Analysis of risk factors for the progression and prognosis of connective tissue disease-associated interstitial lung disease

Objectives

This study aimed to investigate the risk factors of lung progression in patients with connective tissue disease-associated interstitial lung disease (ILD).

Patients and methods

A total of 91 ILD patients (28 males, 63 females; mean age: 54.9±11.3 years; range, 30 to 77 years) were included in the prospective follow-up study conducted throughout 2020. They were divided into progressors (n=27) and nonprogressors (n=64) according to whether the pulmonary disease progressed during a six-month follow-up period. The clinical data of the two groups were analyzed, and a logistic regression model was constructed to analyze the risk factors of the progression of ILD in all patients.

Results

Univariate analysis revealed significant differences (p<0.05) between the two groups in smoking history, serum ferritin, FVC% (the percentage of forced vital capacity), DLCO% (the percentage of diffusion capacity for carbon monoxide), and computed tomography involvement range. Further application of a logistic regression model revealed that increased serum ferritin level was an independent risk factor for ILD progression (odds ratio=1.002, 95% confidence interval: 1.000-1.003, p=0.004). The optimal critical value of serum ferritin was 303.25 ng/mL, the sensitivity and specificity were 81.5% and 54.7%, respectively, and the area under the curve was 0.747.

Conclusion

The level of serum ferritin may be an independent predictor for ILD progression.

Clinical significance of serum ferritin in patients with systemic sclerosis

Objective

The purpose of this study was to explore the clinical significance of serum ferritin (SF) in patients with systemic sclerosis (SSc).

Methods

The levels of SF were measured in 115 patients with SSc and 117 healthy controls (HCs). Clinical characteristics and laboratory indexes between the high ferritin SSc group and the normal ferritin SSc group were analyzed.

Results

The level of SF in SSc patients was significantly higher than that in HCs (319.78 [179, 554.33] ng/ml vs. 99 [49.03, 164.29] ng/ml, p < 0.01). Compared with the normal ferritin SSc group, the high ferritin SSc group was more likely to develop skin diffuse cutaneous SSc, fingertip arthralgia, and cardiac involvement. In addition, the levels of glutamine transaminase (GGT), alanine aminotransferase (ALT), creatine kinase (CK), creatine kinase isoenzyme‐MB (CK‐MB), lactate dehydrogenase (LD), immunoglobulin G (IgG), immunoglobulin A (IgA), C‐reactive protein (CRP), erythrocyte sedimentation rate (ESR), and the positive rate of anti‐Scl70 antibody in the high ferritin SSc group were significantly higher (each p < 0.05). SF was positively correlated with GGT, ALT, CK, CK‐MB, LD, IgA, CRP, and ESR (each p < 0.05). Multiple linear regression analysis showed that cardiac involvement, ALT, and ESR were independent influencing factors of SF in SSc.

Conclusion

Our study shows that the level of SF in patients with SSc is increased, and the elevated SF is related to abnormal liver function, myocardial involvement, inflammatory status, and production of autoantibodies in SSc. Cardiac involvement, ALT, and ESR are independent factors affecting SF in SSc.

Urine ALCAM, PF4 and VCAM-1 Surpass Conventional Metrics in Identifying Nephritis Disease Activity in Childhood-Onset Systemic Lupus Erythematosus

Objectives

Serial kidney biopsy for repeat evaluation and monitoring of lupus nephritis (LN) in childhood-onset Systemic Lupus Erythematosus (cSLE) remains challenging, thus non-invasive biomarkers are needed. Here, we evaluate the performance of ten urine protein markers of diverse nature including cytokines, chemokines, and adhesion molecules in distinguishing disease activity in cSLE.

Methods

Eighty-four pediatric patients meeting ≥4 ACR criteria for SLE were prospectively enrolled for urine assay of 10 protein markers normalized to urine creatinine, namely ALCAM, cystatin-C, hemopexin, KIM-1, MCP-1, NGAL, PF-4, Timp-1, TWEAK, and VCAM-1 by ELISA. Samples from active renal (LN) and active non-renal SLE patients were obtained prior to onset/escalation of immunosuppression. SLE disease activity was evaluated using SLEDAI-2000. 59 patients had clinically-active SLE (SLEDAI score ≥4 or having a flare), of whom 29 patients (34.5%) were classified as active renal, and 30 patients (35.7%) were active non-renal. Twenty-five healthy subjects were recruited as controls.

Results

Urine concentrations of ALCAM, KIM-1, PF4 and VCAM-1 were significantly increased in active LN patients versus active non-renal SLE, inactive SLE and healthy controls. Five urine proteins differed significantly between 2 (hemopexin, NGAL, MCP1) or 3 (Cystatin-C, TWEAK) groups only, with the highest levels detected in active LN patients. Urine ALCAM, VCAM-1, PF4 and hemopexin correlated best with total SLEDAI as well as renal-SLEDAI scores (p < 0.05). Urine ALCAM, VCAM-1 and hemopexin outperformed conventional laboratory measures (anti-dsDNA, complement C3 and C4) in identifying concurrent SLE disease activity among patients (AUCs 0.75, 0.81, 0.81 respectively), while urine ALCAM, VCAM-1 and PF4 were the best discriminators of renal disease activity in cSLE (AUCs 0.83, 0.88, 0.78 respectively), surpassing conventional biomarkers, including proteinuria. Unsupervised Bayesian network analysis based on conditional probabilities re-affirmed urine ALCAM as being most predictive of active LN in cSLE patients.

Conclusion

Urinary ALCAM, PF4, and VCAM-1 are potential biomarkers for predicting kidney disease activity in cSLE and hold potential as surrogate markers of nephritis flares in these patients.