Could a common supplement ease lupus?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Participant Inclusion Criteria * Age ≥ 18; * Male or female; * ≥ 4 ACR SLE classification criteria (104,105); * Positive ANA at a titer of ≥ 1/80; * Stable immunosuppressants (MMF ≤ 3 g/day, azathioprine ≤ 150 mg/day; methotrexate ≤ 25 mg/week; leflunomide ≤ 20 mg/week; cyclosporin 100 mg/day; voclosporin 47.4 mg/day) and/or antimalarials (hydroxychloroquine ≤ 400 mg/day) for 30 days prior to screening; stable oral corticosteroids for 2 weeks prior to screening; ≤ 20 mg/day prednisone or equivalent; stable belimumab or anifrolumab for 90 days prior to screening; * Untreated patients must be off above immunosuppressants and/or antimalarials for 30 days prior to screening; oral corticosteroids for 2 weeks prior to screening; belimumab or anifrolumab for 90 days prior to screening; * BILAG 2004 index (48) level A disease activity in ≥ 1 organ/system except renal or central nervous system or BILAG 2004 index level B disease activity in ≥ 1 organs/systems if no level A disease activity is present and SLEDAI ≥ 6 (106); * Enrollment is approved by adjudication committee within 10 days, which may include retesting and communication with study sites, as necessary. * Patients may be considered for enrollment 12 months after rituximab treatment, or 6 months after rituximab treatment if their B cell counts have normalized. Participant Exclusion Criteria * Acute SLE flare threatening vital organs; * Pregnant or lactating; * Moderately serious or serious comorbidities (e.g., diabetes mellitus, congestive heart failure, chronic obstructive pulmonary disease, chronic renal insufficiency) that in investigator's opinion confers high risk for adverse events; * Patients receiving cyclophosphamide within 3 months; * Active chronic infections (e.g., HIV, hepatitis B virus, hepatitis C virus, mycobacteria); patients with oral steroid-dependent asthma; * Infections requiring intravenous antibiotics within a month or oral antibiotics within two weeks of screening; Patients taking (unwilling or unable to stop) NAC or other antioxidants within 1 month of screening (which is considered sufficient time to revert GSH to pre-treatment levels (29); * Patients who participated in the pilot RCT or are taking daily acetaminophen (≤ 1 g/day prn is allowed if documented); * Patients receiving mTOR inhibitors (rapamycin/sirolimus, everolimus); * Patients enrolled in other interventional trials. * Patients should not take medications containing acetaminophen (Tylenol) as it may reduce the effectiveness of NAC. 1 g/day of acetaminophen is allowed if documented. Patients who are currently taking more than 1 gram of acetaminophen per day may be eligible for participation if they are willing to reduce their intake to 1 gram per day or less prior to enrollment. * Patients should avoid taking more than 500 mg of vitamin C and more than 30 IU of vitamin E daily as both vitamin C and E can confound the study results. However, patients currently taking doses above these thresholds may be eligible for participation if they are willing to reduce their intake to 500 mg or less of vitamin C and 30 IU or less of vitamin E per day prior to enrollment.