Level of Tumor Necrosis Factor Production by Stimulated Blood Mononuclear Cells Can Be Used to Predict Response of Patients With Inflammatory Bowel Diseases to Infliximab.

BACKGROUND & AIMS: A substantial proportion patients with inflammatory bowel disease (IBD) have a primary non-response to infliximab; markers are needed to identify patients most likely to respond to treatment. We investigated whether production of tumor necrosis factor (TNF) by peripheral blood mononuclear cells (PBMCs) can be used as a marker to predict response. METHODS: We performed a prospective study of 41 adults with IBD (mean age, 38 years; 21 male; 21 with Crohn's disease and 20 with ulcerative colitis) not treated with a biologic agent within the past 6 months; patients were given their first infusion of infliximab at a hospital or clinic in Berlin, Germany. We collected data on clinical scores, levels of C-reactive protein, and ultrasound results (Limberg scores) at baseline (before the first infusion) and after 6 weeks (3rd infliximab infusion). PMBCs were obtained from patients at baseline and 10 healthy individuals (controls) and incubated with lipopolysaccharide. We measured production of cytokines (TNF, interleukin 1 [IL1], IL6, IL8, IL10, IL12p70, and IL22) by ELISA and performed cytometric bead array and flow cytometry analyses. The primary endpoint was clinical response (decrease in Harvey Bradshaw Index scores of 2 or more or decrease in partial Mayo scores of 3 or more at week 6) in patients with PBMCs that produced high vs low levels of TNF. RESULTS: Responders had a shorter median disease duration (P = .018) and higher median Limberg score (P = .021), than nonresponders. Baseline PBMCs from responders produced significantly more TNF (P = .049) and IL6 (P = .028) than from nonresponders; a level of 500 pg/ml TNF identified responders with 82% sensitivity and 78% specificity. In patients with Crohn's disease, this cutoff value (500 pg/ml TNF) identified responders with 100% sensitivity and 82% specificity; TNF levels above this level were independently associated with response to infliximab in multivariate analysis (odds ratio, 16.2; 95% CI, 1.8-148.7; P = .014). The percentage of TNF-positive cells was higher among CD14+ monocytes than lymphocytes after stimulation. CONCLUSIONS: Production of a high level of TNF by PBMCs (specifically CD14+ cells) from patients with IBD can identify those most likely to have a clinical response to infliximab therapy. In patients with Crohn's disease, a cutoff value of 500 pg/ml TNF identified responders with 100% sensitivity and 82% specificity.

Leptin induces TNFα-dependent inflammation in acquired generalized lipodystrophy and combined Crohn's disease.

Leptin has been shown to modulate intestinal inflammation in mice. However, clinical evidence regarding its immune-stimulatory potential in human Crohn's disease remains sparse. We here describe a patient with the unique combination of acquired generalized lipodystrophy and Crohn's disease (AGLCD) featuring a lack of adipose tissue, leptin deficiency and intestinal inflammation. Using mass and flow cytometry, immunohistochemistry and functional metabolic analyses, the AGLCD patient was compared to healthy individuals and Crohn's disease patients regarding immune cell composition, function and metabolism and the effects of recombinant N-methionylleptin (rLeptin) were evaluated. We provide evidence that rLeptin exerts diverse pro-inflammatory effects on immune cell differentiation and function, including the metabolic reprogramming of immune cells and the induction of TNFα, ultimately aggravating Crohn's disease in the AGLCD patient, which can be reversed by anti-TNFα therapy. Our results indicate that leptin is required for human immune homeostasis and contributes to autoimmunity in a TNFα-dependent manner.