Plasma Protein Profiling to Discern Indolent from Advanced Systemic Mastocytosis.

Mastocytosis is a heterogeneous disorder characterized by abnormal mast cell accumulation, in which the clinical severity may be explained by distinct molecular mechanisms. This study aimed to explore plasma protein biomarkers associated with systemic mastocytosis subtypes, as well as the cellular origin of the identified proteins. Plasma samples from patients with mastocytosis, including cutaneous mastocytosis (CM), indolent systemic mastocytosis (ISM), and advanced systemic mastocytosis (AdvSM), and a reference group of patients with polycythemia vera, were analyzed by Proximity Extension Assay technology targeting 275 proteins. Furthermore, potential cellular origin was explored using an available single-cell RNA-sequencing data set generated from patients with ISM. The study cohort included 16 patients with CM, 92 patients with systemic mastocytosis (ISM, n = 80; AdvSM, n = 12), and 60 patients with polycythemia vera. A principal component analysis based on 275 plasma proteins revealed one cluster of patients with CM and ISM that was separated from patients with AdvSM. Up to 29 proteins were associated with distinct severe activity in patients with systemic mastocytosis (ISM versus AdvSM), including IL-1 receptor type 1 (IL-1RT1) and tumor necrosis factor ligand superfamily member 13B (TNFSF13B) (q < 0.01). Furthermore, single-cell RNA-sequencing analysis from ISM-derived bone marrow cells revealed that the mRNA for the identified proteins was not exclusive of mast cells. Distinct plasma protein profiles show potential to refine ISM and AdvSM diagnoses, possibly reflecting differences in pathogenic mechanisms and diverse clinical manifestations.

Faecal biomarkers for diagnosis and prediction of disease course in treatment-naïve patients with IBD.

BACKGROUND: Faecal biomarkers can be used to assess inflammatory bowel disease (IBD). AIM: To explore the performance of some promising biomarkers in diagnosing and predicting disease course in IBD. METHODS: We included 65 patients with treatment-naïve, new-onset Crohn's disease (CD), 90 with ulcerative colitis (UC), 67 symptomatic controls (SC) and 41 healthy controls (HC) in this prospective observational study. We analysed faecal samples for calprotectin (FC), myeloperoxidase (MPO), human neutrophil lipocalin (HNL), eosinophil cationic protein ECP and eosinophil-derived neurotoxin (EDN) and compared markers among groups. We assessed the diagnostic capability of biomarkers with receiver operating characteristic curves. Clinical disease course was determined for each patient with IBD and analysed the association with biomarkers by logistic regression. RESULTS: All markers were elevated at inclusion in patients with IBD compared with HC (p < 0.001) and SC (p < 0.001). FC (AUC 0.85, 95% CI: 0.79-0.89) and MPO (AUC 0.85, 95% CI: 0.80-0.89) showed the highest diagnostic accuracy in distinguishing IBD from SC. The diagnostic ability of biomarkers differed between IBD subtypes with the highest performance for FC and MPO in CD. The diagnostic accuracy was further improved by combining FC and MPO (p = 0.02). Levels of FC, MPO and HNL at inclusion were predictive of an aggressive disease course with MPO showing the strongest association (p = 0.006). CONCLUSIONS: This study provides new insight into the diagnostic and prognostic capability of neutrophil and eosinophil biomarkers in IBD and suggests that MPO, alone or in combination with FC, may add to the diagnostic power of faecal biomarkers.

Identification and validation of a blood- based diagnostic lipidomic signature of pediatric inflammatory bowel disease.

Improved biomarkers are needed for pediatric inflammatory bowel disease. Here we identify a diagnostic lipidomic signature for pediatric inflammatory bowel disease by analyzing blood samples from a discovery cohort of incident treatment-naïve pediatric patients and validating findings in an independent inception cohort. The lipidomic signature comprising of only lactosyl ceramide (d18:1/16:0) and phosphatidylcholine (18:0p/22:6) improves the diagnostic prediction compared with high-sensitivity C-reactive protein. Adding high-sensitivity C-reactive protein to the signature does not improve its performance. In patients providing a stool sample, the diagnostic performance of the lipidomic signature and fecal calprotectin, a marker of gastrointestinal inflammation, does not substantially differ. Upon investigation in a third pediatric cohort, the findings of increased lactosyl ceramide (d18:1/16:0) and decreased phosphatidylcholine (18:0p/22:6) absolute concentrations are confirmed. Translation of the lipidomic signature into a scalable diagnostic blood test for pediatric inflammatory bowel disease has the potential to support clinical decision making.