Autoantibodies to Gastric Parietal Cells in Rheumatoid Arthritis Patients

Presence of Autoantibodies to Gastric Parietal Cells and Subsequent Vitamin B12 Deficiency in Rheumatoid Arthritis Patients

A review of the literature reveals that very few studies have assessed the potential co-existence of vitamin B12 deficiency due to gastric parietal cell autoantibodies. While Segal et al. in 2004 published a study which found that 49% of patients with RA had vitamin B12 deficiency, no assessment of the etiology or the presence of autoantibodies was made. While Goeldner et al. in 2011 and Datta et al. in 1990 demonstrated that anti-gastric parietal cell antibodies (anti-GPC Ab) were found in <5% to 28% of RA patients respectively, no additional testing was implemented to determine the significance, specifically whether or not the presence of anti-GPC Ab related to vitamin B12 deficiency.

The purpose of this study is to determine the prevalence and metabolic significance of anti-GPC Ab in three cohorts: (1) a group of patients with Rheumatoid Arthritis, (2) a group of patients with autoimmune thyroid disease (AITD), and (3) a group of patients with neither RA or AITD. To determine the significance of the presence of anti-GPC Ab, testing of the current serum B12 level along with a metabolite dependent on adequate vitamin B12 levels (Methylmalonic acid) will be tested.

Study Overview

• Status: Completed
• Conditions: Vitamin B12 Deficiency

Detailed Description

Background: Organ specific antibodies such as anti-gastric parietal cell antibodies (anti-GPC Ab) have been found in a variable number of patients with RA, but it is unclear what significance these antibodies have on actual vitamin B12 levels. Patients with RA have been found to have vitamin B12 deficiency up to near 50% but it is unclear if this deficiency is due to anti-GPC Ab.

Hypothesis: By virtue of the aberrant autoimmune process that occurs in RA, patients with RA are more likely to have anti-GPC Ab and more likely than a control arm or participants with autoimmune thyroid disease (AITD) to have vitamin B12 deficiency.

Method: 135 patients will be consented; 45 to the RA arm, 45 to an AITD arm, and 45 to a control arm. Exclusion criteria will filter patients who would have other reasons for altered vitamin B12 absorption, such as inflammatory bowel disease, surgery, or medication use. After obtaining consent subjects will be sent to lab a serum anti-GPC Ab test (obtainable in an SLE panel), RF, B12/folate (as available for ordering in CHCS), methyl malonic acid, and (for the control arm subjects and AITD subjects) an anti-CCP IgG. Patients will also complete a one-sided, one page questionnaire asking them about dietary and medication exposures.

Outcomes: (1) Determine whether evidence of serum vitamin B12 deficiency, as measure by either a low vitamin B12 level or elevated methylmalonic acid, will be more common in RA patients with anti-GPC Ab. (2) Determine the prevalence of anti-GPC Ab in a group of patients with RA as compared to a group of patients with AITD and with no known systemic or organ specific autoimmune condition.

• Study Type: Observational
• Enrollment (Actual): 125

Contacts and Locations

Study Locations

• United States
  • Mississippi
    • Keesler AFB, Mississippi, United States, 39534
      • Keesler Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 16 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Participants will be recruited from the Internal Medicine and Internal Medicine Specialty Clinics at one academic community hospital.

Description

Inclusion Criteria:

• Adult, age 18 and older
• RA arm: History of Rheumatoid Arthritis
• AITD arm: History of an autoimmune thyroid disease without a history or clinically obvious manifestation of an organ specific or systemic autoimmune process.
• Control arm: No history of RA and no history or clinically obvious manifestation of an organ specific or systemic autoimmune process.

Exclusion Criteria:

• Known vitamin B12 deficiency for which the participant was formerly treated or continues to receive therapy.
• Active malabsorptive state to include but not limited to celiac disease, inflammatory bowel disease, etc.
• Surgically induced malabsorptive state to include but not limited to Roux-en-Y Gastric bypass
• Use of medications that may interfere with vitamin B12 absorption
• Patients with a thyroid condition not consistent with an autoantibody process (i.e. congenital absence of the thyroid, infectious thyroiditis, thyroidectomy for non-autoimmune process, toxic multinodular goiter) will be excluded from the autoimmune thyroid arm.

Study Plan

How is the study designed?

Design Details

• Observational Models: Case-Control
• Time Perspectives: Cross-Sectional

Number of groups / cohorts

3

Cohorts and Interventions

Group / Cohort
Rheumatoid Arthritis; Patients with seropositive or seronegative Rheumatoid Arthritis
Autoimmune Thyroid Disease (AITD); Participants with autoimmune thyroid disease without other known systemic or organ specific autoimmune illnesses.
Control; Participants without Rheumatoid Arthritis, AITD, or other systemic or organ specific autoimmune illnesses

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Prevalence of Vitamin B12 Deficiency	Hypothesis: Evidence of serum vitamin B12 deficiency, as measure by either a low vitamin B12 level or elevated methylmalonic acid, will be more common in RA patients with anti-GPC Ab.	7 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Presence of Anti-GPC Antibodies	Hypothesis: Evidence of anti-GPC Ab in a group of patients with RA will be more prevalent as compared to a group of patients with AITD and with no known systemic or organ specific autoimmune condition.	7 months

Collaborators and Investigators

• Sponsor: Keesler Air Force Base Medical Center

Study record dates

Study Major Dates

• Study Start: June 1, 2013
• Primary Completion (Actual): April 1, 2015
• Study Completion (Actual): April 1, 2015

Study Registration Dates

• First Submitted: June 9, 2013
• First Submitted That Met QC Criteria: June 9, 2013
• First Posted (Estimate): June 12, 2013

Study Record Updates

• Last Update Posted (Estimate): May 29, 2015
• Last Update Submitted That Met QC Criteria: May 11, 2015
• Last Verified: May 1, 2015

More Information

Terms related to this study

• Keywords: Rheumatoid Arthritis; Autoantibodies; Vitamin B12 deficiency; Autoimmune Thyroid Disease
• Additional Relevant MeSH Terms: Immune System Diseases; Autoimmune Diseases; Nutrition Disorders; Joint Diseases; Musculoskeletal Diseases; Rheumatic Diseases; Connective Tissue Diseases; Avitaminosis; Deficiency Diseases; Malnutrition; Vitamin B Deficiency; Arthritis; Arthritis, Rheumatoid; Vitamin B 12 Deficiency
• Other Study ID Numbers: FKE20130010H