Role of Oral and Intestinal Microbiota in Rheumatoid Arthritis (RA)

Inclusion Criteria:

Rheumatoid Arthritis (RA) patients must meet American College of Rheumatology (ACR) criteria for RA
RA patients: duration of disease will be greater than 6 weeks and less than 2 years.
RA patients should have a Disease Activity Score 28 (DAS28) greater than or equal to 5.
PsA patients will be required to have disease duration and DAS28 similar to the RA patients, and to meet Moll and Wright criteria for PsA.
Allowable medications for both groups at study entry will include: prednisone (or equivalent) 5 mg or less per day (stable dose for at least 2 months); methotrexate 15 mg or less per week (stable dose for at least 2 months); and nonsteroidal anti-inflammatory drugs (NSAIDs) at FDA-approved doses.
Healthy controls will be age- and sex-matched individuals with no personal or family history of inflammatory arthritis.

Exclusion Criteria:

Patients who are unable to provide informed consent.
Pregnant or lactating women.
Recent (<3 months prior) use of any antibiotic therapy
Current consumption of probiotics
Current extreme diet (parenteral nutrition, macrobiotic diet, etc.)
Prednisone >5 mg/day or equivalent
Use of other disease-modifying antirheumatic drugs (DMARDs) with known antibiotic properties (Gold salts, hydroxychloroquine, sulfasalazine or minocycline).
Use of biologic DMARDs
Known inflammatory bowel disease
Known gastrointestinal (GI) tract neoplasm.
Recent GI tract infection (gastroenteritis, colitis, diverticulitis, appendicitis)
Chronic unexplained diarrhea.
Any GI tract surgery leaving permanent residua (e.g., gastrectomy; bariatric surgery; colectomy)

Significant liver, renal or peptic ulcer disease, defined as:

Liver: aspartate aminotransferase (AST)/alanine aminotransferase (ALT) > 2 x upper limit of normal (ULN)
Renal: Creatinine >1.5 or endstage renal disease
Peptic ulcer disease: recent ulcer or GI bleed (within past 12 months)
Inability or unwillingness to abstain from alcohol consumption.