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Aim Interleukin-6 (IL-6), a multifunctional cytokine, exists in several forms ranging from a low molecular weight (MW 20–30 kDa) non-complexed form to high MW (200–450 kDa), complexes. Accurate baseline IL-6 assessment is pivotal to understand clinical responses to IL-6-targeted treatments. Existing assays measure only the low MW, non-complexed IL-6 form. The present work aimed to develop a validated assay to measure accurately total IL-6 (complexed and non-complexed) in serum or plasma as matrix in a high throughput and easily standardized format for clinical testing. Methods Commercial capture and detection antibodies were screened against humanized IL-6 and evaluated in an enzyme-linked immunosorbent assay format. The best antibody combinations were screened to identify an antibody pair that gave minimum background and maximum recovery of IL-6 in the presence of 100% serum matrix. A plate-based total IL-6 assay was developed and transferred to the Meso Scale Discovery (MSD) platform for large scale clinical testing. Results The top-performing antibody pair from 36 capture and four detection candidates was validated on the MSD platform. The lower limit of quantification in human serum samples (n = 6) was 9.77 pg l–1, recovery ranged from 93.13–113.27%, the overall pooled coefficients of variation were 20.12% (inter-assay) and 8.67% (intra-assay). High MW forms of IL-6, in size fractionated serum samples from myelodysplastic syndrome and rheumatoid arthritis patients, were detected by the assay but not by a commercial kit. Conclusion This novel panoptic (sees all forms) IL-6 MSD assay that measures both high and low MW forms may have clinical utility.

Elevated levels of 5α-reduced androgens have been shown to be associated with hyperandrogenism and hyperinsulinemia, the leading causes of ovulatory dysfunction in women. 5α-Dihydrotestosterone reduces ovarian granulosa cell proliferation by inhibiting FSH-mediated mitogenic signaling pathways. The present study examined the effect of insulin on 5α-reductase, the enzyme that catalyses the conversion of androgens to their 5α-derivatives. Granulosa cells isolated from immature rat ovaries were cultured in serum-free, phenol red-free DMEM-F12 media and treated with different doses of insulin (0, 0.1, 1.0, and 10.0 μg/ml) for different time intervals up to 12 h. The expression of 5α-reductase type 1 mRNA, the predominant isoform found in granulosa cells, showed a significant (P < 0.05) increase in response to the insulin treatment up to 12 h compared with control. The catalytic activity of 5α-reductase enzyme was also stimulated in a dose-depended manner (P < 0.05). Inhibiting the Akt-dependent signaling pathway abolished the insulin-mediated increase in 5α-reductase mRNA expression, whereas inhibition of the ERK-dependent pathway had no effect. The dose-dependent increase in 5α-reductase mRNA expression as well as catalytic activity seen in response to insulin treatment was also demonstrated in the human granulosa cell line (KGN). In addition to increased mRNA expression, a dose-dependent increase in 5α-reductase protein expression in response to insulin was also seen in KGN cells, which corroborated well with that of mRNA expression. These results suggest that elevated levels of 5α-reduced androgens seen in hyperinsulinemic conditions might be explained on the basis of a stimulatory effect of insulin on 5α-reductase in granulosa cells. The elevated levels of these metabolites, in turn, might adversely affect growth and proliferation of granulosa cells, thereby impairing follicle growth and ovulation.

The long-term effect of infliximab on endoscopic and histologic disease activity and expression of inflammatory markers was assessed in Crohn's disease patients who received infliximab as episodic or scheduled maintenance therapy therapy over 54 weeks (ACCENT 1).All patients received Infliximab 5 mg/kg at week 0 and at week 2 were then randomized as responders or nonresponders to placebo or infliximab (5 or 10mg/kg). Patients received placebo or infliximab 5 mg/kg at weeks 2 and 6 followed by placebo or infliximab (5 or 10mg/kg) every 8 weeks or episodically on loss of response. Crohn's Disease Activity Index (CDAI), Crohn's Disease Endoscopic Index of Severity (CDEIS), Inflammatory Bowel Disease Questionnaire (IBDQ), and colonic and ileal Global Histologic Disease Activity (CGHAS and IGHAS) scores were determined at weeks 0, 10, and 54. Tumor necrosis factor-alpha (TNF-alpha), gelatinase B, Infliximab, tenascin, clusters of differentiation marker 68 (CD68), and intercellular adhesion molecule-1 (ICAM-1) were detected in mucosal biopsies by immunohistochemistry.At baseline, CDEIS significantly correlated with CGHAS only. Further at baseline, both CDEIS and the worst CGHAS or IGHAS, were significantly correlated with CD68, ICAM-1, and gelatinase B expression. At week 10, improvement in CGHAS only, correlated significantly with better CDAI, CDEIS, and IBDQ scores. Improvements in CDEIS and GHAS at week 10 correlated with reductions in gelatinase B and CD68, whereas only GHAS improvement correlated with decreased TNF-alpha expression. At week 54, decreased gelatinase B expression continued to correlate with improved CDEIS and GHAS while decreased CD68 and TNF-alpha expression correlated with GHAS and CDEIS improvement, respectively.Endoscopic and histologic evidence of mucosal healing was associated with a sustained reduction in the expression of inflammatory markers. Infliximab-induced improvement in the clinical signs and symptoms of Crohn's disease was associated with endoscopic and histologic evidence of sustained mucosal healing.

Infliximab (IFX) is a chimeric IgG1 monoclonal antibody specific for human tumor necrosis factor-alpha that is approved in the United States and Europe for the treatment of rheumatoid arthritis (RA) and Crohn's disease (CD). Approximately 10% of RA and CD patients receiving maintenance treatment with IFX will develop antibodies to IFX. The objective of this study was to develop a model to assess the in vivo formation, distribution, and elimination of immune complexes resulting from a low-level immune response in the presence of the excess concentration of a therapeutic antigen. In this model, cynomolgus monkeys were treated with a single intravenous injection of IFX, followed by injection of either radiolabeled, purified monkey anti-IFX IgG antibody (n = 3, test group) or radiolabeled monkey, nonimmune IgG (n = 3, control group). High-performance liquid chromatography analysis of collected sera revealed a rapid formation of immune complexes comprised of IFX and radiolabeled anti-IFX IgG antibody immune complexes. The terminal half-life of the anti-IFX IgG antibody immune complex was approximately 38 h compared with 86 h for the nonimmune antibody. However, the pharmacokinetic profile of IFX, although slightly lower in concentration over time for the test group, was not notably different relative to the control group. There were no macroscopic or microscopic histological findings in either treatment group. These data confirm that immune complexes between IFX and anti-IFX IgG antibodies can form in vivo and that these immune complexes are eliminated more rapidly than nonimmune antibodies in the presence of excess IFX.

Objective: Infliximab monotherapy provided a rapid and high degree of clinical benefit in patients with moderate to severe psoriasis in a previously conducted trial. Herein we describe the pharmacodynamic and pharmacokinetic results observed in this clinical trial. Methods: Patients with psoriasis received 5 or 10 mg/kg of infliximab or placebo at weeks 0, 2, and 6. Immunohistochemical analysis of lesional (weeks 0, 2, 10) and nonlesional (week 0) biopsies was conducted. Median infliximab half-life and peak serum concentrations over time were calculated. Results: Infliximab immunotherapy resulted in rapid and dramatic decreases in epidermal inflammation and normalization of keratinocyte differentiation in psoriatic plaques; these changes preceded maximal clinical response. Infliximab concentrations were maintained above the detection limit (0.1 mg/mL) in the majority of patients through week 14. Conclusion: The clinical and immunohistologic data demonstrate a pivotal role for tumor necrosis factor-α in the pathogenesis of psoriasis and support further development of drugs targeting tumor necrosis factor-α. (J Am Acad Dermatol 2003;48:68-75.)

Radiopaque contrast media have antiplatelet activities of varying potency. The effect of diatrizoate salts, components of many contrast agents, and of two contrast media (Hypaque-76 [Winthrop Pharmaceuticals] and iopamidol) on the binding of 125l-fibrinogen to activated platelets was examined. Diatr

We assessed whether the addition of anti-tumor necrosis factor (TNF) agent to methotrexate (MTX) therapy might alter the response of patients with rheumatoid arthritis (RA) to pneumococcal vaccination.Seventy patients with early RA (n = 20, 36, and 14 in the infliximab 3 mg/kg plus MTX, infliximab 6 mg/kg plus MTX, and placebo plus MTX groups, respectively) were included in an analysis of patients enrolled in an ASPIRE substudy. Patients received 0.5 ml pneumococcal vaccine (Pneumovax) 34 weeks after initiation of study treatment; patient sera were collected 4 weeks later (week 38). Antibody responses were tested using enzyme immunoassay methods for reactivity to a panel of 12 serotypes of the pneumococcal vaccine.No significant difference in response to Pneumovax was observed between the infliximab plus MTX and placebo plus MTX groups. Roughly 80%-85% of patients responded to at least one serotype; however, only 20%-25% of patients in the different treatment groups responded to at least 6 different serotypes. Comparable proportions of patients in the 3 treatment groups responded to an increasing number (or = 1 toor = 6) of different serotypes. Patients45 years of age and those receiving oral corticosteroids generally appeared to respond better than those age 45 to 65 years and those not receiving oral corticosteroids.All treatment groups in this study had lower responses to vaccine than would be expected in the normal population. However, the addition of the anti-TNF agent infliximab to MTX therapy did not appear to affect the response of patients with RA to pneumococcal vaccination.

The effect of different treatment regimens on antibody responses to infliximab and their clinical significance was examined by using data from ACCENT I.Patients with Crohn's disease (n = 573) received 5 mg/kg infliximab (week 0) and then were randomly assigned to blinded infusions at weeks 2 and 6 and every 8 weeks until week 46 of placebo (group I), 5 mg/kg infliximab (group II), or 5 mg/kg infliximab at weeks 2 and 6, followed by 10 mg/kg thereafter (group III). At week 14 or later, patients losing response could cross over to episodic infliximab treatment increased by 5 mg/kg. Samples for antibody determination were collected before the first infusion and at weeks 14, 22, 54, 62, 72, and, if applicable, before and after crossover.Through week 72, antibodies to infliximab were detected in 30%, 10%, and 7% of groups I, II, and III, respectively (P0.0001). Patients receiving immunomodulators had a lower incidence of antibodies compared with patients receiving infliximab alone (10% and 18%, respectively; P = 0.02). Antibodies were associated with a 12% absolute increase in infusion reactions but no increase in serious infusion reactions or serum sickness-like reactions. In the overall population, similar proportions of antibody-positive and antibody-negative patients achieved clinical response (64% and 62%, respectively; P = NS) or clinical remission (41% and 39%, respectively; P = NS) at week 54. Notably, 86% of patients responded to retreatment, and 63% were in clinical response at week 54; however, fewer antibody-positive group I patients attained clinical remission (31%) compared with those who were antibody negative (37%) or antibody inconclusive (54%) (P = NS).Reduced antibody formation and greater clinical benefit were observed with an induction regimen followed by maintenance treatment compared with a single dose followed by episodic retreatment in Crohn's disease patients treated with infliximab.

Anti-tumor-necrosis-factor-alpha (TNF-alpha) monoclonal antibody was used to treat Tg197 transgenic mice, which constitutively produce human TNF-alpha (hTNF-alpha) and develop a progressive polyarthritic disease. Treatment of both young (7- or 8-week-old) and aged (27- or 28-week-old) mice commenced when at least two limbs showed signs of moderate to severe arthritis. The therapeutic efficacy of anti-TNF-alpha antibody was assessed using various pathological indicators of disease progression. The clinical severity of arthritis in Tg197 mice was significantly reduced after anti-TNF-alpha treatment in comparison with saline-treated mice and in comparison with baseline assessments in both young and aged mice. The treatment with anti-TNF-alpha prevented loss of body weight. Inflammatory pathways as reflected by elevated circulating hTNF-alpha and local expression of various proinflammatory mediators were all diminished by anti-TNF-alpha treatment, confirming a critical role of hTNF-alpha in this model of progressive polyarthritis. More importantly, the amelioration of the disease was associated with reversal of existing structural damage, including synovitis and periosteal bone erosions evident on histology. Repair of cartilage was age dependent: reversal of cartilage degradation after anti-TNF-alpha treatment was observed in young mice but not in aged mice.