Decrease in Mucosal IL17A, IFNγ and IL10 Expressions in Active Crohn's Disease Patients Treated with High-Dose Vitamin Alone or Combined with Infliximab

Abstract

Background: Vitamin D treatment may reduce Crohn's disease (CD) activity by modulating the mucosal immune function. We investigated if high-dose vitamin D +/- infliximab modulated the mucosal cytokine expression in active CD.

Methods: Forty CD patients were randomized into: infliximab + vitamin D; infliximab + placebo-vitamin D; placebo-infliximab + vitamin D or placebo-infliximab + placebo-vitamin D. Infliximab (5 mg/kg) and placebo-infliximab were administered at weeks 0, 2 and 6. Oral vitamin D was administered as bolus 200,000 international units (IU) per week 0 followed by 20,000 IU/day for 7 weeks or placebo. Endoscopy with biopsies was performed at weeks 0 and 7 where endoscopic activity was measured and mucosal mRNA cytokine expression was examined. C-reactive protein (CRP), fecal calprotectin and Harvey-Bradshaw Index (HBI) were measured at weeks 0, 2 and 6.

Results: High-dose vitamin D treatment alone and combined with infliximab decreased the IL17A, IFNγ and IL10 expression. High-dose vitamin D alone did not significantly decrease the disease activity, CRP or calprotectin. Combined infliximab and vitamin D treatment was not clinically significantly superior to monotherapy with infliximab.

Conclusions: High-dose vitamin D as monotherapy and combined with infliximab decreases IL17A, IFNγ and IL-10 expression in mucosa within treatment groups. This did not induce a statistically significant decreased disease activity. EudraCT no.2013-000971-34.

Keywords: Crohn’s disease; infliximab; vitamin D treatment.

Figure 1

Patient flow during the 7-week study period. Patients who underwent rescue treatment were included in the final analyses. * One patient had an allergic reaction to infliximab at the second infusion and was excluded. Infusion treatment in non-responding patients with on-going endoscopic inflammation was unblinded at week 7, and infliximab treatment was initiated.

Figure 2

Crohn’s Disease Endoscopic Index of Severity (CDEIS) and Harvey-Bradshaw Index (HBI) scores during the active vitamin D treatment. Dots represent medians with 95% CI. (A). CDEIS scores at weeks 0 and 7 (“week 7” includes week 3 rescue colonoscopy) within the four groups. Vitamin D treatment did not affect changes in CDEIS score in neither the Ifx + VitD versus Ifx + placeboVitD groups nor in the placeboIfx + VitD versus placeboIfx + placeboVitD groups. The CDEIS score of both infliximab groups declined significantly compared to the placeboIfx + VitD and placeboIfx + placeboVitD group (p < 0.02). (B). HBI scores at weeks 0, 2 and 6 (week 6 includes rescue week 3 HBI scores). HBI changes were not influenced by vitamin D treatment in either the Ifx + VitD versus Ifx + placeboVitD groups or in the placeboIfx + VitD versus placeboIfx + placeboVitD groups. Similar to the CDEIS scores, the HBI scores of the two infliximab groups declined in comparison to the placeboIfx + VitD (p < 0.03) and placeboIfx + placeboVitD groups (p = 0.05). VitD, vitamin D; Ifx, Infliximab.

Figure 3

Calprotectin and CRP levels during active vitamin D treatment. Week 6 includes data from both patients who underwent rescue treatment (week 3) as well as patients who followed the protocol until week 6. The dots represent median with 95% CI (bars). (A). Changes in calprotectin levels over time are significantly different between the groups. These changes are a direct result of infliximab treatment (p = 0.01). No significant differences were observed between Ifx + VitD and Ifx + placeboVitD (p = 0.17) or between placeboIfx + VitD and placeboIfx + placeboVitD (p = 0.48). (B). Changes in CRP levels over time are significantly different between the groups as a result of the infliximab and not the vitamin D treatment (p = 0.01). Only the Ifx + VitD group (not the Ifx + placeboVitD group) demonstrated a more significant decline in CRP levels compared to the placeboIfx + VitD and placeboIfx + placeboVitD groups. VitD, vitamin D; Ifx, Infliximab.

Figure 4

Vitamin D, calcium and parathyroid levels from week 0 to 6. “Week 6” also comprises rescue treated patients (week 3). A mixed model was used to test for parallel curves. Data are presented as medians with 95% CI. Dotted lines represent the reference range. (A). Changes in 25-hydroxyvitamin D₂ + D₃ (25-vitD) over time were significantly different in the four groups (p < 0.0001) as expected. (B). Changes in active 1.25-dihydroxyvitamin D₃ (1.25-vitD) were also dependent on treatment (p < 0.0001) with higher 1.25-vitD levels in the vitamin D treated groups. (C). Changes in calcium-ion levels over time were dependent on treatment (p = 0.01), again with the highest levels in the vitamin D treated groups. However, all patient levels were within the reference range. (D). Changes in parathyroid hormone levels over time were dependent on treatment (p = 0.018), though all patient levels were within the reference range. VitD, vitamin D; Ifx, Infliximab.