High Serum sCD40 and a Distinct Colonic T Cell Profile in Ulcerative Colitis Associated With Primary Sclerosing Cholangitis.

BACKGROUND AND AIMS: There is a strong association between primary sclerosing cholangitis [PSC] and ulcerative colitis [UC], but the immunological link between the two diseases is obscure. We compared serum cytokine profiles of patients with PSC-UC and UC, and investigated a number of selected cytokines in colonic biopsy samples. We also assessed the presence and activation of T cells in peripheral blood and colonic mucosa. METHODS: Serum samples from 22 patients with PSC-UC, 28 patients with UC, and 19 controls were analysed by a proximity extension assay including 92 inflammatory cytokines. Biopsies from caecum, sigmoid colon, and rectum were collected from the same patients. Quantitative analysis for IFN-γ, IL-2, IL-4, IL-5, IL-13, IL-17A/ E/F, IL-21, IL-22, IL-23, and IL-27 was carried out on tissue homogenates. T cell phenotype was evaluated by flow cytometry. RESULTS: By multivariate analysis we identified a cluster of serum cytokines with higher levels in PSC-UC, and sCD40 in particular was strongly associated with this patient group. In contrast, colonic cytokines were only modestly increased in PSC-UC, whereas several Th1-, Th2-, and Th17-associated cytokines were increased in UC. Patients with PSC-UC had increased colonic levels of CXCR3-positive CD8+ T cells but fewer CD25-positive CD4+ T cells. An increased CRTH2/CXCR3-quote indicated a predominance of Th-2 type CD4+ T cells in UC patients. CONCLUSIONS: Our study reveals different cytokine profiles and T cell profiles in PSC-UC and UC, with higher systemic levels of cytokines in PSC-UC, and a more pronounced colonic inflammation in UC. Serum sCD40 could potentially be investigated as a marker for PSC in UC.

Downregulated eosinophil activity in ulcerative colitis with concomitant primary sclerosing cholangitis.

Primary sclerosing cholangitis (PSC) is a chronic bile duct inflammation strongly connected to ulcerative colitis (UC). PSC is associated with an increased risk of colon cancer, but the link between the intestinal and the bile duct inflammation is still unknown. Also, the involvement of intestinal immune cells in the pathogenesis of PSC remains to be determined. The eosinophil granulocyte is one of the immune cells implicated in the inflammatory process of ulcerative colitis. This study was performed to determine how the accumulation and activation of intestinal eosinophils may differ between UC with and without concomitant PSC, and how this may be influenced by the cytokine/chemokine profile of the intestinal compartment. Eosinophils from peripheral blood and multiple parts of the colon were analyzed by flow cytometry. The intestinal level of inflammatory mediators was assessed using a multiplex proximity extension assay and a quantitative immunoassay. We found that colonic eosinophils were more abundant in both UC and PSC-UC compared with controls, but that their expression of activation markers was significantly increased in UC only. The colonic level of pro-inflammatory cytokines was increased in active UC but not in PSC-UC. In conclusion, we show for the first time that eosinophil activation phenotype discriminates between UC and PSC-UC, and that this may depend on the local cytokine profile of the colonic mucosa.

Measurement of urinary cystatin C with a particle-enhanced turbidimetric immunoassay on Architect ci8200.

BACKGROUND: Cystatin C is a low-molecular-weight protein that is freely filtered by the glomerulus and catabolized after reabsorption by the proximal tubular cells in healthy subjects. Urinary cystatin C is a potential biomarker for tubular damage including acute kidney injury (AKI) in the acute phase when patients are submitted to the intensive care unit. METHODS: The aim of this study was to perform a method validation of urinary analysis of cystatin C by particle-enhanced turbidimetric immunoassay (PETIA) on a high-throughput chemical analyzer. Total assay time was 10 min. The antigen excess, linearity, lower limit of quantification (LoQ), recovery, assay precision, stability, and interference caused by hemoglobin were evaluated. RESULTS: The LoQ was calculated to 0.020 mg/l with a coefficient of variation (CV) ≤ 10%. No hook effect was observed and the assay was linear over the studied interval less than 0.020-0.950 mg/l with a regression of R² = 0.9994. The assay had a recovery between 93-100% and the assay precision had a total CV of less than 3.5%. Cystatin C was stable for 3 days in room temperature and 14 days in +4C. The assay did not show any major interference with hemoglobin at a hemoglobin concentration of 10 g/L. The reference interval for urine cystatin C was less than 0.166 mg/l. CONCLUSION: The urinary cystatin C PETIA showed good precision and performance characteristics including short test turnaround times that are necessary qualifications for a biomarker at a routine laboratory.

Particle enhanced turbidimetric immunoassay for the determination of urine cystatin C on Cobas c501.

OBJECTIVE: Urinary cystatin C has been reported to be a good marker for tubular damage and acute kidney injury. The aim of this study was to develop a high throughput assay for the quantification of urine cystatin C. METHODS: Antigen-excess, imprecision, interference, linearity, recovery, sample stability and reference values were evaluated on Cobas c501. RESULTS: The assay was linear over the dynamic range of the study (R²=0.9994). The total assay imprecision was below 5%. The assay recovery was estimated at 87-100%. No tendency to antigen-excess (up to 35 mg/L), nor interference with haemoglobin (1.25-10 g/L) was observed. Cystatin C was stable for 1 day at ambient temperature (19-23°C) but for 2 days at +4°C. The reference interval for cystatin C in urine was <0.414 mg/L. CONCLUSIONS: The urinary cystatin C assay verified to be a reliable assay with convenient performance characteristics, enabling routine testing on clinical chemistry platforms.