Clinical Trial: Desensitising Celiac Disease Patients With the Human Hookworm

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Combining Necator Americanus With Trace Gluten to Restore Tolerance in Coeliac Disease: a Pilot Clinical and a Detailed in Vitro Immunological Study.

Brief Summary: We have established that the hookworm Necator americanus (Na) dramatically alters the local and systemic immune landscape of the infected human host. Consistent with the principle of desensitisation, diet managed celiac disease subjects previously infected by us with Na will be invited to receive small incremental doses of gluten as pasta (3-25 mm straw of spaghetti) over 16 weeks. Each participant will then be carefully re-assessed to determine if it is appropriate to undertake a 12-week gluten challenge.

Detailed Summary:

Hypothesis The adaptive Th2/regulatory profile imposed by Na will promote gluten tolerance following a micro-dose desensitising programme.

Primary Aim: To determine the safety and efficacy of Na as a tolerising agent in celiac subjects

Specific Aim 1. Undertake a therapeutic pilot study comparing mucosal histopathology before and after a gluten challenge, to be preceded by a programmed desensitising micro-challenge using Na as a tolerising agent.

Specific Aim 2. Assess systemic and mucosal immune responses to gluten micro-challenge, Na infection, and gluten re-challenge throughout the pilot study, to be referenced against hookworm-naive people with treated and untreated celiac disease.

Specific Aim 3. Utilising blood and tissue from hookworm-naive celiac disease volunteers, undertake in vitro studies focusing on the effects of Na-derived excretory/secretory (ES) products on gluten-stimulated gut mucosal cell apoptosis, cytokine and gene profiles.

Current Primary Outcome: Duodenal Villus Height:Crypt Depth [ Time Frame: Week -24 to -36 ]

Original Primary Outcome: Duodenal Villus Height:Crypt Depth [ Time Frame: up to 36 weeks ]

Current Secondary Outcome:

• Intraepithelial Lymphocyte Count [ Time Frame: Week-24 and -36 ]
  Biopsies were fixed in neutral buffered formalin, processed and carefully orientated and embedded in paraffin wax. Sections (3 µm) were stained with anti-CD3. All slides were de-identified and graded by Dr John Croese. The IEL percentages were measured on 2 or more randomly selected well-orientated villi. The null hypothesis is that hookworm infection will not protect against mucosal IEL influx following 12-week exposure to gluten in celiac disease.
• Number of Participants With 2 Points Increase in Marsh Score Post GC-1g [ Time Frame: Longitudinal change between week-24 and week-36 ]
  The Marsh score is a defined but qualitative assessment assigned a value to allow for comparison. The scores were evaluated by consensus between the primary (chief) investigator and the study pathologist. The Marsh score was graded 0, 1, 2, 3A (assigned-4), 3B (-5) and 3C (-6); rage 1-6 with normal=0 and severe inflammation=6. Because the scoring is vulnerable to artefact, only a 2-point shift was regarded as a significant intra-individual change. The scores were graded after week-36 on biopsies de-identified shuffled. An upward shift was interpreted to reflect a significant worsening of gluten-associated inflammation. The comparison reported evaluated changes from baseline (week-24) to post-low-dose gluten challenge (week-24; GC-1g). The objective for using the Marsh score was to identify individuals who might have experienced a severe worsening in pathology due to GC-1g that might not be reflected in the Vh:Cd group analysis.
• Serum Anti-tissue Transglutaminase Antibodies Measured as International Units/mL (IU/mL) [ Time Frame: Anti-tTG IU/mL levels pre-trial, mid-trial and after 3 gram/day gluten challenge ]
  The trial was extended with pre-trial and mid-trial anti-tTG antibody levels used to compare with the post-trial levels. Anti-tTG is a serological measure of tissue transglutaminase-2 antibodies. In active celiac disease, levels are increased. In treated disease, levels are low (normal cut-off was <15 IU/mL). A significant increase compared to baseline in tTG can be expected 2 weeks after consuming 3g of gluten daily for 2 weeks in people with celiac disease who have been maintaining a gluten-free diet, but who are not taking other treatment.

Original Secondary Outcome:

• Intraepithelial Lymphocyte Count [ Time Frame: Week-24 and -36 ]
  See above
• Marsh Score [ Time Frame: Week-24 and -36 ]
  As above

Dates:
Date Received: August 6, 2012
Date Started: August 2012
Date Completion:
Last Updated: October 10, 2014
Last Verified: October 2014