Vitamin D: does it help Tregs in active rheumatoid arthritis patients

ABSTRACT

Background

Regulatory T cells

(Tregs) play an important role in the maintenance of immunological tolerance. Tregs deficiency or suppressor functions reduction may be associated with autoimmune diseases development.

Objectives

To estimate the effect of vitamin D supplementation on Tregs level in the peripheral blood of active rheumatoid arthritis (RA) patients.

Methods

40 active RA patients were randomly assigned into two groups. Group I received methotrexate (MTX) plus hydroxychloroquine, group II received MTX, hydroxychloroquine plus vitamin D supplementation for 3 months, and 30 healthy volunteers as control group. Peripheral blood Tregs were measured at baseline and after 3 months by Flow Cytometry.

Results

At baseline, Tregs percentage was significantly decreased (p<0.001) in both RA patient groups (13.52±1.95%, 13.65±2.98% respectively), compared to controls (28.44±7.37%) with no significant difference between the two patient groups (p=0.866). After 3 months, there was a significant elevation in Tregs percentage in group II compared to group I (p<0.001). Tregs elevation was associated with significant DAS-28 score reduction (p<0.001).

Conclusion

Vitamin D appears to have important immunomodulatory functions. Vitamin D supplementation can be combined safely with traditional DMARDs to regulate the immune system.

Clinical trial registration

Tanta University Protocol Record 33846, Vitamin D Effect in Rheumatoid Arthritis, http://www.clinicaltrials.gov, NCT04472481.

KEYWORDS:

• Regulatory T cells
• foxp3+
• vitamin D supplementation
• rheumatoid arthritis
• DMARDs

Article highlights

• Regulatory T cells play an important role in the maintenance of immunological tolerance.

• Regulatory T cells significantly decrease in the peripheral blood of rheumatoid arthritis patients.

• Vitamin D has an immunomodulatory and anti-inflammatory effect in rheumatoid arthritis.

• Vitamin D supplementation significantly enhances Tregs percentage in the peripheral blood of RA patients.

• Vitamin D supplementation improves rheumatoid arthritis disease activity.

Declaration of interest

We have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Author contributions

H El-Banna had performed the conception and S Ezzat made design, H El-Banna had analyzed and interpreted of the data; S Ezzat performed the draft of paper and revised it for intellectual content; and performed the final approval of the version to be published; and all authors agree to be accountable for all aspects of the work.

Ethics approval and consent to participate

The study was approved by the local Ethics Committee of Faculty of Medicine, Tanta University. Approval Code 33,846. The written informed consent from all the patients was obtained and the trial was conducted according to the Declaration of Helsinki principles.

Declaration of interest

This original work has not been previously published or simultaneously submitted for publication elsewhere. The manuscript has been read and approved by all the authors, and all the conditions as previously stated by the ICMJE have been met.

Declaration of interest

We declare no conflicts of interest.

Additional information

Funding

This paper was not funded.This research did not receive any specific grant from funding agencies. All authors agree to the content and to submit the manuscript. All authors have read and approved the final article.