A cross-sectional, observational study aims to evaluate the relationship between Helicobacter pylori infection and disease activity in patients diagnosed with systemic lupus erythematosus (SLE), using a combination of structured patient interviews, standardized disease assessments, and laboratory detection of H. pylori by stool antigen testing .

the study explores the potential role of chronic H. pylori infection as a trigger or aggravating factor in SLE, an autoimmune disorder characterized by overactive immune responses that cause multisystem organ damage . The rationale is based on recent findings suggesting that chronic infections may worsen autoimmune disease activity by persistent immune stimulation and production of cross-reactive autoantibodies . SLE patients attending clinics at Assiut University Hospital will be assessed over one year; inclusion requires confirmed SLE diagnosis per established criteria, absence of recent antibiotics/PPIs, and consent. Clinical data, disease activity (via SLEDAI-2K), and socio-demographic information will be collected through detailed medical interviews and laboratory investigations, particularly focusing on stool-based antigen tests for H. pylori. All data will be securely recorded for statistical analysis assessing the bidirectional impact of infection status and SLE severity .

Inclusion Criteria:

• Adult patients (aged ≥18 years) with a confirmed diagnosis of SLE according to the American College of Rheumatology (ACR) or Systemic Lupus International Collaborating Clinics (SLICC) classification criteria.

Patients who provide written informed consent to participate in the study. Patients who have not received antibiotics or proton pump inhibitors (PPIs) in the four weeks

Exclusion Criteria:

• Patients with a history of gastric surgery or known gastrointestinal malignancy.

  • Patients currently receiving immunosuppressive therapy for conditions other than SLE.
  • Patients with coexisting autoimmune diseases other than SLE.
  • Pregnant or lactating women.
  • Patients with active infections (other than H. pylori) at the time of enrollment.

Eligible participants are adults (at least 18 years old) diagnosed with SLE according to ACR or SLICC criteria, who have not used antibiotics or proton pump inhibitors in the past four weeks, and provide written informed consent . Patients with prior gastric surgery, GI cancer, immunosuppressive therapy for non-SLE conditions, coexisting autoimmune diseases, pregnancy or lactation, or any current active infection other than H. pylori at enrollment are excluded . Of those eligible, the expected sample size is 115 patients, calculated to power the main outcome analysis. Demographic details (age, sex, ethnicity, disease duration, smoking status, and family history) and clinical manifestations (SLE-related symptoms, medications, and organ involvement) will be thoroughly documented to ensure a well-characterized, representative population .