Microbiome, Dietary and Quality of Life Analysis of People Living With CVID Treated With or Without Immunoglobulins.

NCT07844668 | Enrolling By Invitation

• 1 other identifier: DELICIOUS
• Study Type: interventional
• Target: 70
• Locations: 1 country
• Sites: 2

Brief Summary

Our research group focusses on finding evidence-based diet strategies to overcome immune dysregulation either due to immune checkpoint inhibitors (ICI) or common variable immunodeficiency (CVID) (Figure 1). CVID is an inborn error of immunity, which is defined, among other factors, by a low level of immunoglobulins, resulting in an increased risk of infections, auto-immune/inflammatory diseases, and cancer. The gut microbiome (GM) plays a crucial role in maintaining immune homeostasis and modulating the host's innate and adaptive immune responses. Modulation of the GM can be achieved by dietary interventions that have been demonstrated to change the composition of the GM within 2 weeks (Oliver et al., 2021). The intake of more than 30 different plant products (vegetables, fruits, seeds and grains) on a weekly basis is associated with a more diverse microbiome in healthy adults (McDonald et al., 2018). Although direct proof of a link between diet and functioning of the immune system is lacking, it is striking that in a retrospective study, melanoma patients treated with immune checkpoint inhibitors (ICI) had a better overall survival when they consumed enough fibers without taking probiotics (Spencer et al., 2021). Currently, we have included 54 of 60 foreseen patients receiving ICI in an interventional study (FORX-01 (NCT05832606)) at our centre, providing them weekly with 30 different plants to be integrated in their diet (funded by Delhaize and FWO). The aim is to measure if the interventional group develops less immune-related adverse events (= side effects of ICI) by changing their GM. Similarly, we hypothesize that introducing a fiber-rich diet in patients with CVID will result in a more diverse GM leading to a decrease in autoimmune disorders and infections and as such lead to an improvement of quality of life. To challenge this hypothesis, we plan to organize a similar diet trial, called KNIVES. To prepare this study, we will first perform an observational study to describe the microbiome of people with CVID (DELICIOUS) followed at UZ Brussel.

Conditions

CVID; SPAD; Antibody Deficiency

Keywords

CVID; fiber-rich diet; spad; auto-immune

Outcome Measures

Primary Outcomes (1)

• Primary outcomes

  To describe the gut microbiome of people living with CVID followed at UZ Brussel. To perform microbiome analysis through metagenomics (depending on availability, pricing, and emerging literature). To analyze one faecal sample of each participant at inclusion and additionally during infectious or autoinflammatory events. To assess microbiome diversity and composition, including: Alpha-diversity. Beta-diversity. Firmicutes/Bacteroidetes ratio (as a proximal marker for dysbiosis). Abundance of specific short-chain fatty acid-producing genera, including: Prevotella. Lactobacillaceae. Bifidobacteriaceae. Lachnospiraceae.

  1 year

Secondary Outcomes (1)

• Secondary outcome

  1 year

Study Arms (1)

CVID participants of Observational cohort

OTHER

Participants assigned to this arm will follow a high-fiber dietary intervention according to the study protocol. Clinical outcomes, gastrointestinal symptoms, dietary intake, and biological samples will be collected throughout the study to assess the effects of the intervention.

Other: Diet

Interventions

Diet OTHER

Participants receive individualized dietary counseling to increase their dietary fiber intake and follow a high-fiber diet according to the study protocol throughout the intervention period.

CVID participants of Observational cohort

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• CVID diagnosis according to ESID criteria
• y or older

Sponsors & Collaborators

• Universitair Ziekenhuis Brussel: lead

Study Sites (2)

Universitair Ziekenhuis Brussel

Ninove, Belgie, 9400, Belgium

Location

Universitair ziekenhuis Brussel

Brussels, Brussels Capital, 1090, Belgium

Location

MeSH Terms

Interventions

Diet

Intervention Hierarchy (Ancestors)

Nutritional Physiological Phenomena; Diet, Food, and Nutrition; Physiological Phenomena

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: SUPPORTIVE CARE
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: September 21, 2026
• First Posted: September 28, 2026
• Study Start: August 15, 2026
• Primary Completion (Estimated): August 1, 2028
• Study Completion (Estimated): September 1, 2028
• Last Updated: September 28, 2026

Record last verified: 2026-07

Data Sharing

• IPD Sharing: Will not share

Locations

BE (2)