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Systemic Lupus Erythematosus (SLE): Classification, Criteria & Clinical Features

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1. DEFINITION AND EPIDEMIOLOGY

• ~90% of patients are women, predominantly of childbearing age
• Female:male ratio is 13:1 in the 15-44 years age group but drops to 2:1 in children and the elderly - this makes pediatric SLE distinctive, as boys are relatively more affected than in adults
• Higher prevalence and severity in non-Caucasian populations (Black > Hispanic > White > Asian)
• CDC National Lupus Registry prevalence in the US: ~204,295 cases
• Autoantibodies can precede clinical diagnosis by years

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2. CLASSIFICATION CRITERIA

Critical distinction: Classification criteria are developed for research/clinical trial enrollment, NOT for clinical diagnosis. Diagnosis remains a clinical judgment based on the totality of clinical and laboratory findings. Approximately 5% of SLE patients are ANA-negative and would be excluded from trials using EULAR/ACR 2019 criteria.

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A. 2019 EULAR/ACR Classification Criteria (Current Standard)

ANA titer ≥1:80 on HEp-2 cells by indirect immunofluorescence (IIF), or an equivalent positive test at any time. If ANA is absent, SLE classification cannot be made.

Notable: A renal biopsy showing Class III or IV lupus nephritis alone yields 10 points - the only single criterion sufficient to classify as SLE (plus the mandatory ANA entry criterion).

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B. 2012 SLICC Classification Criteria

• Satisfy at least 4 of 17 criteria (at least 1 clinical + 1 immunologic), OR
• Biopsy-proven lupus nephritis in the presence of ANA or anti-dsDNA antibodies

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C. Historical: 1997 ACR Criteria (Rarely Used Now)

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D. Type 1 vs Type 2 SLE (Emerging Classification - Harrison's 22E)

• Type 1 SLE: Predominant classic immune-inflammatory manifestations (nephritis, arthritis, vasculitis) - responds to immunosuppression
• Type 2 SLE: Predominant fibromyalgia-like symptoms (fatigue, diffuse pain, depression, cognitive dysfunction, sleep disturbance, brain fog) - less responsive to immunosuppressives

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3. CLINICAL FEATURES

A. Constitutional Symptoms

• Fatigue - most common symptom, often the presenting complaint, present in >80%
• Fever (may be low-grade or high-grade, signaling disease flare or infection)
• Anorexia and unintentional weight loss
• Malaise
• ~15% have relatively mild disease with predominant fatigue/arthralgia

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B. Cutaneous Manifestations (~90% of patients)

• Occurs with systemic disease activity
• Classic form: Malar (butterfly) rash - erythematous, slightly raised, photosensitive rash over cheeks and nasal bridge with nasolabial fold sparing (this distinguishes it from rosacea, which involves nasolabial folds)
• Lasts >3 weeks; associated with arthralgias and fatigue
• Generalized ACLE: Maculopapular rash in sun-exposed areas
• Rare variants: Bullous lupus, toxic epidermal necrolysis (TEN)-like variant

• Photosensitive, may occur without systemic disease
• Associated with anti-Ro/SSA antibodies
• Flat, red-rimmed annular or psoriasiform lesions
• Non-scarring, widespread

• Discoid lupus erythematosus (DLE): Rough, circular, slightly raised, dyskeratotic and hyperpigmented with depigmented atrophic centers and erythematous rims. Most common chronic form. Scarring alopecia if scalp involved.
• Other forms: Hypertrophic/verrucous lupus, lupus panniculitis (lupus profundus), tumid lupus, chilblains lupus, discoid/lichen planus overlap

• Non-scarring alopecia (diffuse or patchy "lupus hair")
• Oral and nasal mucosal ulcers (painful or painless)
• Raynaud's phenomenon (~1/3 of patients)
• Leukocytoclastic vasculitis, urticarial vasculitis
• Periungual telangiectasias, livedo reticularis

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C. Musculoskeletal Manifestations (~90% of patients)

• Arthralgia and myalgia: Extremely common, often the presenting complaint
• Lupus arthritis: Symmetric polyarthritis most commonly involving:
  • Wrists
  • Metacarpophalangeal (MCP) joints
  • Proximal interphalangeal (PIP) joints of the hands
  • Knees
• Non-erosive by plain radiograph (unlike RA), but emerging MRI/US data show possible mild erosive changes
• Jaccoud arthropathy: Chronic nonerosive, reversible deviations from periarticular ligament damage leading to MCP subluxation and ulnar deviation - a distinctive feature
• Rhupus: Overlap of RA and SLE
• Avascular necrosis (AVN) of bone: Pain in a single hip, shoulder, or knee out of proportion to other joints should prompt consideration, especially with corticosteroid history
• Inflammatory myopathy: Symmetric proximal weakness, elevated CK and aldolase, inflammatory changes on muscle biopsy

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D. Renal Manifestations (50% of patients; up to 70% in Black patients)

• Class I: Minimal mesangial LN
• Class II: Mesangial proliferative LN
• Class III: Focal LN (<50% glomeruli involved)
• Class IV: Diffuse LN (≥50% glomeruli; most severe; segmental [IV-S] or global [IV-G])
• Class V: Membranous LN (can coexist with III or IV)
• Class VI: Advanced sclerosing LN (>90% sclerosis)

• Proteinuria >0.5 g/24h
• Red blood cell casts in urine (pathognomonic)
• Hypocomplementemia (low C3/C4)
• Rising anti-dsDNA titers
• Hypertension, edema, rising creatinine

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E. Hematologic Manifestations

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F. Neuropsychiatric SLE (NPSLE)

• Seizures (most common NPSLE manifestation)
• Cognitive dysfunction/brain fog (very common, often overlooked)
• Cerebrovascular disease/stroke (up to 19% of SLE patients)
• Aseptic meningitis
• Demyelinating syndrome
• Headache (non-specific, very common)
• Myelopathy/transverse myelitis
• Movement disorders (chorea)
• Acute confusional state/delirium
• Psychosis (corticosteroid-induced vs SLE-mediated - important distinction)
• Mood disorders (depression/anxiety very common)

• Mononeuritis multiplex
• Cranial neuropathies
• Peripheral neuropathy (sensorimotor)
• Autonomic neuropathy

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G. Cardiovascular Manifestations

• Pericarditis: Can be managed with NSAIDs, colchicine, anti-IL-1 agents; rarely tamponade
• Pericardial effusion

• Less common but serious
• Left-sided heart failure and/or arrhythmia

• Fibrinous sterile verrucous endocarditis on mitral and aortic valves
• Associated with antiphospholipid antibodies
• Risk of embolic events

• Significant cause of premature death, especially in young patients without traditional risk factors
• Driven by type 1 IFN, immune complex vascular injury, APS, dyslipidemia, corticosteroid use

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H. Pulmonary Manifestations

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I. Gastrointestinal Manifestations

• Nausea, vomiting, diarrhea during flares (nonspecific)
• Lupus peritonitis - serositis of the peritoneum
• Lupus enteritis/vasculitis - abdominal pain, can lead to ischemia, perforation, bleeding; requires high-dose glucocorticoids
• Pancreatitis - rare but recognized association
• Protein-losing enteropathy
• Elevated liver enzymes (transaminitis from active disease or medications)
• Autoimmune hepatitis overlap
• APS-related: Mesenteric thrombosis, Budd-Chiari syndrome, hepatic venoocclusive disease

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J. Ocular Manifestations

• Keratoconjunctivitis sicca - most common (secondary Sjögren's, or dry eyes from inflammation)
• Retinal vasculitis - rare but aggressive; risk of blindness
• Optic neuritis
• Uveitis, scleritis, episcleritis
• Peripheral ulcerative keratitis
• Drug-related: HCQ maculopathy (with prolonged use), corticosteroid-induced cataracts and glaucoma

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4. AUTOANTIBODIES IN SLE - Clinical Significance

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5. PEDIATRIC-ONSET SLE (cSLE / pSLE) - KEY DIFFERENCES

• Peak onset in pre-adolescent and adolescent age groups (mean onset ~12-13 years)
• Can present before age 5 (consider monogenic forms - C1q, C2, C4 deficiency; TREX1 mutations, etc.)
• Female:male ratio ~4-5:1 (closer than in adult SLE at ~9:1) - boys make up a larger relative proportion
• Higher prevalence in Asian, Black, and Hispanic children

• More frequent renal involvement: LN at onset in 50-75% of cSLE (vs ~50% adult); more class III/IV nephritis
• More frequent hematologic involvement: Cytopenias at presentation more common
• More frequent neuropsychiatric involvement: Seizures, headache, cognitive dysfunction, chorea
• Malar rash is a common presenting feature
• Fever at onset is more common than in adults
• Constitutional symptoms (fever, weight loss, fatigue) very prominent
• Serositis (pleuritis, pericarditis) frequent

• Growth failure and pubertal delay from chronic disease and glucocorticoid use
• Macrophage Activation Syndrome (MAS) as a life-threatening complication - must always be considered in a cSLE patient with persistent fever, pancytopenia, elevated ferritin, elevated LDH, hepatosplenomegaly
• Infection risk from immunosuppression
• Psychosocial impact: Depression, anxiety, school absenteeism, reduced quality of life - longitudinal screening is now recommended

• ANA positivity >95%
• Anti-dsDNA positivity is high (~75-80%)
• Anti-Sm positivity slightly higher than in adults
• Complement consumption (low C3/C4) is a reliable activity marker

• Complement deficiencies (C1q, C2, C4) - most strongly associated with SLE
• TREX1 mutations
• DNASE1L3 mutations
• RNASEH2 defects
• SAMHD1, ADAR mutations (Aicardi-Goutières spectrum) These represent interferonopathies and monogenic lupus-like syndromes.

• SLEDAI-2K (SLE Disease Activity Index) adapted for pediatric use (pSLEDAI)
• BILAG (British Isles Lupus Assessment Group) index
• SLICC/ACR Damage Index
• Urine protein:creatinine ratio at every visit
• Complement levels and anti-dsDNA as activity biomarkers

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6. LABORATORY EVALUATION - COMPLETE WORKUP

• ANA (IIF on HEp-2 cells) - screening
• Anti-dsDNA (Crithidia/ELISA/Farr)
• Anti-Sm, anti-Ro/SSA, anti-La/SSB, anti-U1 RNP, anti-histone
• Antiphospholipid panel: aCL (IgG/IgM), anti-β2GPI (IgG/IgM), lupus anticoagulant
• Complement: C3, C4, CH50
• Direct Coombs test
• CBC with differential
• Comprehensive metabolic panel (LFTs, renal function)
• Urinalysis with microscopy + urine protein:creatinine ratio
• ESR, CRP (often markedly elevated ESR with relatively normal CRP in SLE; very high CRP suggests intercurrent infection)

• C3, C4, anti-dsDNA (disease activity markers - fall with flares)
• CBC, CMP, urinalysis at each visit
• Ophthalmology screening for HCQ maculopathy (baseline then yearly after 5 years of use)
• Blood pressure at every visit

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7. DIFFERENTIAL DIAGNOSIS

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8. SUMMARY TABLE: Comparison of Classification Criteria

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• Harrison's Principles of Internal Medicine 22E (2025, McGraw-Hill), Chapter 368
• Tietz Textbook of Laboratory Medicine 7th Edition, Chapter 94
• Aringer M et al. 2019 EULAR/ACR classification criteria for SLE. Ann Rheum Dis 2019;78:1151-9
• Petri M et al. Derivation and validation of the SLICC classification criteria for SLE. Arthritis Rheum 2012;64:2677-86
• Recent PubMed literature: Genetics of Childhood-Onset SLE (Carlomagno R et al., Arthritis Rheumatol 2025; PMID 40356234)---

1. EULAR/ACR 2019 vs SLICC 2012 in pSLE: The 2019 criteria are more specific but require ANA ≥1:80 as a mandatory entry criterion - this is rarely a problem in pediatric SLE (>95% ANA positive), but early-onset or monogenic forms may be ANA-negative, making SLICC 2012 more inclusive and practically useful.
2. Anti-dsDNA fluctuates with disease activity - useful for monitoring flares, especially renal. Anti-Sm is highly specific but does NOT track activity.
3. Complement consumption pattern (falling C3/C4 + rising anti-dsDNA) is the most reliable combination for predicting lupus nephritis flare.
4. Seronegative SLE (~5% anti-dsDNA negative, ~5% ANA negative): Do not dismiss SLE on serology alone if the clinical picture is convincing.
5. Macrophage Activation Syndrome must be actively ruled out in any cSLE patient with fever, cytopenias, hyperferritinemia (>500 ng/mL, especially >10,000), and hepatosplenomegaly - it is a disease-defining emergency.
6. Psychosocial screening (anxiety, depression) is now recommended longitudinally in cSLE as per 2025-2026 literature (Valente Soto et al., Lupus 2026; PMID 41665227).

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SLE: Treatment and Management

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1. TREATMENT GOALS (EULAR Framework)

• 3-month milestone: ≥25% reduction in urine protein:creatinine ratio (UPCR), eGFR not worsened
• 6-month milestone: ≥50% reduction in UPCR to <3 g/day
• 12-24 month target: UPCR <0.5-0.7 g/day with eGFR within 10% of baseline

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2. GENERAL PROTECTIVE MEASURES (ALL PATIENTS)

• Daily broad-spectrum sunscreen (SPF ≥50) on sun-exposed areas - UV light triggers flares
• Avoid UV light exposure (especially 10am-4pm), wear protective clothing
• Hydroxychloroquine (HCQ) for all patients unless contraindicated (see below)
• Healthy diet, maintain normal weight
• No smoking - tobacco reduces antimalarial efficacy
• Regular aerobic exercise
• Strict BP control (target <130/80 in LN)
• Lipid and glucose monitoring
• Vaccinations: Influenza (annual), pneumococcal (PCV15/20 or PCV13 + PPSV23), COVID-19, HPV, varicella (live vaccines should be given before starting immunosuppression or when off significant immunosuppression)
• Bone protection: Calcium + vitamin D supplementation for all patients on glucocorticoids; bisphosphonates if high fracture risk
• ACE inhibitor or ARB for all patients with proteinuria/hypertension
• SGLT2 inhibitor (e.g., dapagliflozin) for patients with LN + reduced eGFR - reduces glomerular hyperfiltration and proteinuria (new in EULAR 2023/2025)

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3. DRUG CLASSES IN SLE TREATMENT

A. Antimalarials - Backbone of All SLE Therapy

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B. Glucocorticoids

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C. Conventional Immunosuppressives

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D. Biologics - The Modern Era

1. Belimumab (Benlysta) - BLyS/BAFF Inhibitor

• Mechanism: Anti-BLyS (B-lymphocyte stimulator) monoclonal antibody; reduces B-cell survival and autoantibody production
• FDA-approved: Active SLE (2011); active LN (2020, BLISS-LN trial)
• Indications: Active non-renal SLE not controlled by standard therapy; active class III/IV/V LN in combination with MMF or low-dose CYC
• Route/Dose: IV 10 mg/kg at 0, 2, 4 weeks then monthly; or SC 200 mg weekly
• BLISS-LN trial: Belimumab + MMF + low-dose GC vs. MMF + GC - significantly better primary efficacy renal response (43% vs 32%) and complete renal response
• Not recommended in severe NPSLE (CNS lupus) - risk of CNS infections
• Pediatric use: Approved for children ≥5 years with active SLE; PLUTO trial showed efficacy

2. Anifrolumab (Saphnelo) - Type I IFN Receptor Inhibitor

• Mechanism: Monoclonal antibody against IFNAR1 (type I interferon receptor), blocking all type I IFNs (α, β, ω)
• FDA-approved: Moderate-to-severe non-renal SLE (2021, TULIP-2 trial)
• Indications: Active non-renal SLE (skin, musculoskeletal) on standard therapy; particularly effective in high IFN signature patients
• Route/Dose: IV 300 mg every 4 weeks
• Key trial: TULIP-2 - significantly better BICLA response (47.8% vs 31.5%), better skin, reduced GC use
• Not recommended for severe NPSLE or in patients with high infection risk
• Pediatric use: Not yet approved for children; trials ongoing

3. Voclosporin (Lupkynis) - Novel CNI for LN

• Mechanism: Next-generation calcineurin inhibitor; superior pharmacokinetic profile vs tacrolimus (flat exposure-response, less nephrotoxicity)
• FDA-approved: Active LN (2021, AURORA 1 trial)
• Dose: 23.7 mg orally twice daily (in combination with MMF)
• AURORA trial: Voclosporin + MMF + low-dose GC vs MMF + GC - significantly better complete renal response at 52 weeks (40.8% vs 22.5%)
• EULAR 2023: Recommended as add-on to MMF for LN (especially class V or refractory)
• Pediatric use: Emerging evidence, not yet approved in children; voclosporin is listed as "emerging treatment" in Brenner & Rector pediatric LN table

4. Obinutuzumab - Type II Anti-CD20 (NEWEST - 2025)

• Mechanism: Humanized type II anti-CD20 monoclonal antibody; superior B-cell depletion vs rituximab (type I anti-CD20) due to different CD20 binding site and enhanced antibody-dependent cellular cytotoxicity
• Phase III REGENCY trial (NEJM, April 2025 - PMID 39927615):
  • 271 adults with biopsy-proven active LN (all classes)
  • Obinutuzumab 1000 mg + MMF + low-dose prednisone vs MMF + prednisone
  • Complete renal response at week 76: 46.4% vs 33.1% (adjusted difference 13.4 pp; p=0.02)
  • Complete renal response with prednisone ≤7.5 mg/day: 42.7% vs 30.9% (p=0.04)
  • More infections (mainly COVID-related) in obinutuzumab arm
• EULAR 2025 LN update (PMID 41107121): Obinutuzumab now included in the guidelines alongside belimumab and rituximab for LN management
• Pediatric use: Data in children not yet available

5. Rituximab (RTX) - Type I Anti-CD20

• Mechanism: Chimeric anti-CD20; B-cell depletion
• Not FDA-approved for SLE (EXPLORER and LUNAR trials failed to meet primary endpoints), but widely used off-label
• Indications: Refractory SLE not responding to MMF/CYC/belimumab; refractory severe cytopenias (ITP, AIHA); refractory NPSLE (myelitis, optic neuritis)
• Dose in LN: 375 mg/m² weekly ×4, or 1000 mg ×2 (2 weeks apart)
• Pediatric use: Widely used as salvage therapy in refractory pSLE; listed in Brenner & Rector pediatric LN table as "emerging treatment"
• EULAR 2023/2025: Recommended for refractory/relapsing LN, especially after failure of CYC-based regimens

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4. MANAGEMENT BY DISEASE SEVERITY AND ORGAN SYSTEM

A. Non-Renal SLE - By Severity

• Constitutional symptoms, mild arthritis, mild rash (<9% BSA), SLEDAI ≤6, PLT 50-100×10⁹/L
• Step 1: Sunscreen + HCQ + NSAIDs (caution - increased MI, renal, aseptic meningitis risk)
• Step 2: Low-dose prednisone (≤10 mg/day) - short course, taper
• Step 3: MTX, AZA, or MMF as steroid-sparing agent

• Moderate-severe arthritis, rash 9-18% BSA, PLT 20-50×10⁹/L, BILAG B
• Step 1-2: HCQ + prednisone 0.5 mg/kg/day, taper
• Step 3: MTX, AZA, or MMF (equal options)
• Step 4: Belimumab or anifrolumab as add-on

• BILAG A manifestations, widespread skin disease, severe arthritis, severe cytopenias
• Step 1: HCQ + prednisone 0.5-1 mg/kg/day (± IV MP pulse for rapid control)
• Step 2: MMF, AZA, or MTX
• Step 3: Belimumab (preferred for skin/arthritis) or anifrolumab
• For severe skin: Add belimumab or anifrolumab; thalidomide/lenalidomide for refractory cutaneous disease (cautiously)
• For severe NPSLE: Neither belimumab nor anifrolumab recommended; use RTX or CYC

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B. Lupus Nephritis (LN) Treatment - Current Standard

• + Belimumab (10 mg/kg IV) added to MMF or low-dose CYC for all class III/IV/V patients - improves complete renal response, reduces flares
• + Voclosporin (23.7 mg BID) added to MMF - particularly for class V or cases with high proteinuria
• + Obinutuzumab (1000 mg IV) added to MMF - new 2025 EULAR recommendation for active LN
• + SGLT2 inhibitor if eGFR permits - nephroprotective, reduces proteinuria
• + ACEi/ARB for all patients with proteinuria - target BP <130/80

• 3 months: UPCR reduced ≥25% from baseline
• 6 months: UPCR reduced ≥50% and <3 g/g, eGFR stable
• 12-24 months: UPCR <0.5-0.7 g/g, eGFR within 10% of baseline - this defines complete renal response

• If UPCR <1 g/g: ACEi/ARB + HCQ; watch closely
• If UPCR 1-3 g/g: MMF ± CNI (voclosporin/tacrolimus)
• If UPCR >3 g/g (nephrotic): MMF + voclosporin or tacrolimus + GC; consider belimumab add-on

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C. Neuropsychiatric SLE (NPSLE) Treatment

• Belimumab and anifrolumab are NOT recommended in severe NPSLE (CNS infection risk, lack of evidence)
• Rituximab is the preferred biologic for refractory inflammatory NPSLE

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D. Hematologic Manifestations

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E. Serositis

• Mild pericarditis/pleuritis: NSAIDs + colchicine (first-line, as per pericarditis guidelines)
• Unresponsive or moderate: Low-to-moderate dose prednisone (0.5 mg/kg/day)
• Recurrent pericarditis: Anti-IL-1 (anakinra, rilonacept) - emerging use in SLE serositis
• Tamponade: Drainage + aggressive immunosuppression

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5. PEDIATRIC SLE (pSLE) TREATMENT - SPECIFIC CONSIDERATIONS

General Approach

• Growth failure, pubertal suppression, AVN, osteoporosis, cataracts, Cushingoid features
• Target: minimize to ≤5 mg/day prednisone as quickly as possible
• Pulse IV methylprednisolone: 30 mg/kg/day (max 1000 mg) × 1-3 days for severe flares

• Pulse IV methylprednisolone × 3 days then oral prednisone 1-2 mg/kg/day
• MMF preferred over CYC in most centers (equal efficacy, better toxicity profile; pediatric dose ~1200 mg/m²/day)
• CYC (IV) 500-1000 mg/m² monthly × 6 months - reserved for severe/refractory LN, CNS disease, or poor prognostic features
• MESNA given with each CYC infusion (hemorrhagic cystitis prophylaxis)
• GnRH analogs (leuprolide) for gonadal protection in adolescent girls receiving CYC

• MMF (preferred, ~1200 mg/m²/day) or AZA (2 mg/kg/day)
• Duration: At minimum 2 years; most centers continue 3-5+ years given high relapse risk
• Long-term renal relapse-free 10-year survival ~73% in pediatric LN; 10-year overall survival ~90%

Macrophage Activation Syndrome (MAS) in pSLE

• First-line: High-dose IV methylprednisolone (30 mg/kg/day × 3 days); IVIG
• Refractory: Cyclosporine A (3-5 mg/kg/day) - most evidence in pSLE-MAS; rapid B-cell depletion
• Emerging: Anakinra (IL-1 blockade), emapalumab (anti-IFN-γ), ruxolitinib (JAK1/2 inhibitor)
• Etoposide (VP-16) if evolves to full HLH
• Simultaneous management of underlying SLE trigger (often infection + active SLE)

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6. ANTIPHOSPHOLIPID SYNDROME (APS) IN SLE

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7. PREGNANCY IN SLE

• Pre-conception counseling: Achieve remission for at least 6 months before conception
• Contraindicated drugs in pregnancy: MMF, methotrexate, leflunomide (teratogenic), cyclophosphamide (first trimester), voclosporin (insufficient data), belimumab, anifrolumab
• Safe in pregnancy: HCQ (continue throughout - reduces flares, reduces CHB risk), azathioprine, tacrolimus, low-dose prednisone, LMWH
• Low-dose aspirin: 100-150 mg/day from 12 weeks for preeclampsia prevention
• Anti-Ro/La positive mothers: Fetal echocardiography from 18-24 weeks for congenital heart block (CHB); fluorinated dexamethasone if 1st/2nd degree CHB detected
• Monitor with anti-dsDNA, complement (C3/C4), UPCR at each antenatal visit
• Postpartum: High risk of flare; continue/resume immunosuppression; HCQ safe with breastfeeding, AZA compatible

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8. MONITORING IN SLE

• Rising anti-dsDNA (especially >2× upper limit)
• Falling C3/C4
• New UPCR >0.5 g/g or worsening by ≥50%
• New or worsening cytopenias

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9. TREATMENT OF REFRACTORY/RELAPSING SLE

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10. EMERGING/PIPELINE THERAPIES (Fellowship-Level Awareness)

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11. SUMMARY: EULAR 2023 KEY OVERARCHING PRINCIPLES

1. Treat-to-target (remission or LLDAS) is the standard of care
2. HCQ is universal background therapy for all SLE patients
3. Minimise glucocorticoids - combine with immunosuppressives/biologics to taper faster; target ≤5 mg/day or off altogether
4. Anifrolumab and belimumab achieve better control than standard of care in extrarenal SLE
5. Combination therapies with belimumab and voclosporin attain higher response rates in LN
6. Remission and LLDAS are associated with better long-term outcomes - prevention of irreversible damage
7. In patients achieving stable remission, GC and immunosuppressive therapy may be gradually tapered (but relapse risk is real - RCT data show higher relapse rates on withdrawal)

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• Harrison's Principles of Internal Medicine 22E (2025), Chapters 368-369
• Brenner & Rector's The Kidney (10th Ed.), Chapter 72 - Pediatric Lupus Nephritis
• Goldman-Cecil Medicine International Edition, Chapter 245
• Fanouriakis et al. 2023 update of EULAR recommendations for SLE. Ann Rheum Dis 2024 (PMID 38777375)
• Fanouriakis et al. EULAR recommendations for SLE with kidney involvement: 2025 update. Ann Rheum Dis 2026 (PMID 41107121)
• Furie RA et al. Obinutuzumab in active lupus nephritis (REGENCY trial). NEJM April 2025 (PMID 39927615)
• Furie R et al. Belimumab in LN - BLISS-LN open-label extension. CJASN 2022 (PMID 36302567)---

1. Voclosporin vs tacrolimus in LN: Voclosporin has a flat pharmacokinetic profile - no need for drug level monitoring, unlike tacrolimus. This makes it practically easier to use. However it is not yet approved in children.
2. Obinutuzumab vs rituximab: Obinutuzumab is a type II anti-CD20 that depletes B cells more completely and durably than rituximab (type I). The REGENCY Phase III (NEJM 2025) is a landmark trial - it's the first positive Phase III trial for a B-cell depleting agent in LN. EULAR 2025 LN guidelines now include it.
3. The "steroid minimization revolution": The EULAR 2023 update fundamentally shifted the approach - high-dose GC protocols are being replaced. The obinutuzumab trial used prednisone ≤7.5 mg/day by week 12 and ≤5 mg/day by week 24 as a standard arm and still showed excellent response, validating low-GC approaches.
4. DOACs in APS: The TRAPS trial (rivaroxaban) and RAPS trial showed inferiority to warfarin in triple-positive aPL and arterial thrombosis. For high-risk aPL profiles, warfarin remains standard. DOACs are only considered in low-risk aPL profiles where warfarin cannot be used.
5. CAR-T in SLE: Early case series from Germany (Mackensen et al., 2022) showed sustained drug-free remission in refractory SLE after CD19-directed CAR-T. This is a paradigm-shifting concept - "resetting" the immune system. Not yet standard care but watch this space.