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Autoimmune Disorders

Last updated 31 May 2026 · Immunology clinical guideline

📋 Key Information Summary

📋
  • Autoimmune disorders arise from loss of self-tolerance, leading to immune-mediated damage of specific organs or systemic tissues.
  • Broadly classified as organ-specific (e.g., Type 1 diabetes, Hashimoto's thyroiditis) or systemic (e.g., SLE, rheumatoid arthritis).
  • Key immunological mechanisms include autoantibody production, immune complex deposition, and T-cell mediated cytotoxicity.
  • Diagnosis requires correlation of clinical features with specific autoantibody and inflammatory marker profiles.
  • First-line investigations include ANA, RF, anti-CCP, ESR, CRP, and organ-specific antibodies (e.g., anti-TPO, GAD65).
  • Treatment is guided by disease type, severity, and organ involvement, using a step-up approach from NSAIDs to DMARDs and biologics.
  • Australian PBS restrictions apply to many biologic DMARDs (e.g., adalimumab, rituximab), requiring Authority approval.
  • Aboriginal and Torres Strait Islander peoples experience higher prevalence, later diagnosis, and poorer outcomes for many autoimmune conditions.
  • Multidisciplinary care involving GPs, rheumatologists, endocrinologists, and allied health is essential for optimal management.
  • Key safety alerts include infection risk with immunosuppression and the need for pre-biologic screening (TB, hepatitis B/C).
Autoimmune Disorders clinical infographic — pathophysiology, clinical clues, diagnosis, imaging, and management
Tap or click image to enlarge — Autoimmune Disorders: pathophysiology, clinical clues, diagnosis, imaging, and management.
Autoimmune Disorders infographic, full size

Introduction & Australian Epidemiology

Autoimmune disorders encompass a diverse group of more than 80 chronic illnesses characterised by a breakdown of immune self-tolerance, leading to inappropriate immune responses against the body's own tissues. In Australia, these conditions represent a significant and growing burden on the healthcare system, affecting approximately 5-8% of the population, with a higher prevalence in women.

The spectrum of disease ranges from isolated organ-specific conditions, such as autoimmune thyroiditis affecting over 1 million Australians, to complex multi-system disorders like systemic lupus erythematosus (SLE). Epidemiological data from the Australian Institute of Health and Welfare (AIHW) indicates that autoimmune diseases are among the leading causes of morbidity in younger and middle-aged adults, particularly impacting workforce participation and quality of life.

While the aetiology is multifactorial, involving genetic susceptibility (e.g., HLA associations), environmental triggers (e.g., infections, smoking), and hormonal factors, the underlying pathogenesis consistently involves dysregulated adaptive immunity. Understanding this classification and pathophysiology is fundamental to guiding rational investigation and targeted therapy in the Australian clinical setting.

Organ-Specific vs Systemic Autoimmune Disorders

A primary clinical classification divides autoimmune disorders based on the pattern of tissue involvement, which directly guides investigation and specialist referral pathways.

Feature Organ-Specific Systemic
Definition Immune response targets antigens within a single organ or gland. Immune response targets antigens widespread in many tissues; inflammation is diffuse.
Pathology Localised destruction or dysfunction of the specific organ. Widespread inflammation, vasculitis, fibrosis, and immune complex deposition.
Australian Examples • Type 1 Diabetes Mellitus (pancreatic β-cells)
• Hashimoto's Thyroiditis & Graves' Disease
• Autoimmune Hepatitis
• Multiple Sclerosis (CNS myelin)		 • Systemic Lupus Erythematosus (SLE)
• Rheumatoid Arthritis (RA)
• Sjögren's Syndrome
• Systemic Sclerosis (Scleroderma)
Typical Antibodies Organ-specific (e.g., anti-TPO, GAD65, anti-smooth muscle). Non-organ specific (e.g., ANA, RF, anti-dsDNA, anti-CCP).
Primary Specialist Relevant organ specialist (Endocrinologist, Gastroenterologist, Neurologist). Rheumatologist (often with other organ specialists).
⚠️
Clinical Overlap: Some disorders like autoimmune hepatitis and primary biliary cholangitis are organ-specific but can have systemic features and are associated with other autoimmune conditions (e.g., thyroid disease).

Immunological Mechanisms

The tissue damage in autoimmune diseases is mediated by four classical hypersensitivity reaction pathways, often operating concurrently.

🔬
Type II: Antibody-Mediated
Cytotoxic hypersensitivity
Mechanism Autoantibodies bind to cell-surface antigens, leading to complement activation, opsonisation, or direct functional disruption.
Example Graves' disease (anti-TSH receptor stimulatory antibodies), Pemphigus vulgaris (anti-desmoglein).
🔬
Type III: Immune Complex-Mediated
Complex deposition hypersensitivity
Mechanism Circulating antigen-antibody complexes deposit in vessel walls and tissues, triggering complement activation and neutrophilic inflammation.
Example Systemic Lupus Erythematosus (SLE) - glomerulonephritis, vasculitis. Rheumatoid arthritis (local immune complexes in synovium).
🔬
Type IV: T-Cell Mediated
Delayed-type hypersensitivity
Mechanism Autoreactive CD4+ Th1/Th17 cells activate macrophages, or CD8+ cytotoxic T-cells directly kill target cells.
Example Type 1 Diabetes (T-cell mediated destruction of pancreatic β-cells), Multiple Sclerosis (demyelination).

Understanding the dominant mechanism helps predict response to therapy. For example, B-cell depleting therapies (e.g., rituximab) are more effective in antibody-driven diseases like RA and ANCA-associated vasculitis.

Investigations

A tiered, clinical-suspicion-driven approach is essential. The following are key investigations available in Australia, with MBS item numbers where commonly billed.

Essential
Full Blood Count (FBC) & Inflammatory Markers
MBS Item 65070. Assesses for anaemia of chronic disease, leucopenia (SLE), thrombocytosis (RA). ESR and CRP are non-specific but useful for monitoring activity.
Available
Autoantibody Panels
  • Antinuclear Antibody (ANA): High sensitivity for SLE (>95%), but low specificity. Positive in many conditions and ~15% of healthy population.
  • Extractable Nuclear Antigen (ENA) Panel: Follow-up for positive ANA. Includes anti-Ro (Sjögren's, neonatal lupus), anti-La, anti-Sm (specific for SLE), anti-RNP (mixed connective tissue disease).
  • Rheumatoid Factor (RF) & Anti-CCP: Anti-CCP is highly specific (>95%) for Rheumatoid Arthritis.
  • Anti-dsDNA: Specific for SLE; titres correlate with disease activity, especially renal involvement.
  • ANCA (Anti-neutrophil Cytoplasmic Antibodies): c-ANCA/PR3 for Granulomatosis with polyangiitis (GPA); p-ANCA/MPO for Microscopic polyangiitis (MPA).
Specialist
Complement Levels (C3, C4)
Low in active SLE (consumed in immune complex formation). Helps distinguish from hereditary complement deficiencies.
Referral
Biopsy (Renal, Skin, Salivary Gland)
Histopathology remains the gold standard for definitive diagnosis of many conditions (e.g., lupus nephritis, vasculitis, Sjögren's).
⚠️
ANA Interpretation: An isolated positive ANA at low titre (e.g., 1:160) in a well patient is often not clinically significant. Testing should be guided by a strong clinical suspicion of a systemic rheumatic disease. Unnecessary testing leads to patient anxiety and inappropriate referrals.

Treatment Principles

Management follows a stepwise, treat-to-target approach aiming for remission or low disease activity. Therapy must be individualised based on disease type, severity, comorbidities, and patient preference.

Pharmacological Therapy Pyramid

1
Symptomatic & Bridging Therapy
NSAIDs for pain/inflammation (e.g., naproxen). Short-term corticosteroids (prednisone ≤7.5 mg/day for maintenance) for acute flares or bridging until DMARDs take effect.
2
Conventional Synthetic DMARDs (csDMARDs)
Cornerstone of therapy for RA, SLE, etc. Methotrexate is first-line for RA. Others: hydroxychloroquine (SLE), sulfasalazine, leflunomide. Require regular blood monitoring (FBC, LFTs).
3
Biologic & Targeted Synthetic DMARDs (b/tsDMARDs)
For disease refractory to csDMARDs. Target specific cytokines (TNF, IL-6) or cells (B-cells, T-cells). Require PBS Authority approval in Australia after failure of at least one csDMARD.

Key Drug Classes & Australian Considerations

💊
Methotrexate
First-line csDMARD for RA
Adult Dose Start 7.5–10 mg SC/PO once weekly; titrate to 15–25 mg weekly.
Paediatric Dose JIA: 10–15 mg/m² SC/PO once weekly (max 25 mg).
Critical Note Teratogenic. Contraception mandatory. Co-prescribe folic acid 5 mg weekly (not on same day).
PBS Status ✔ PBS General Benefit
💊
Adalimumab
Humira® · TNF inhibitor
Adult Dose RA: 40 mg SC every 2 weeks.
Critical Note Screen for latent TB (IGRA) and Hepatitis B before initiation. Avoid in severe heart failure (NYHA III/IV).
PBS Status Authority Required (RPBS)
💊
Hydroxychloroquine
Plaquenil® · Antimalarial
Adult Dose SLE: 200–400 mg daily (≤5 mg/kg actual body weight).
Critical Note Baseline and annual ophthalmology review (after 5 years) for retinal toxicity screening.
PBS Status ✔ PBS General Benefit

Special Populations

🤰

Pregnancy

Teratogens: Methotrexate, Mycophenolate, Cyclophosphamide
Must be ceased ≥3 months pre-conception. Discuss with specialist.
Safest options: Hydroxychloroquine, Sulfasalazine, Azathioprine
Often continued in pregnancy for disease control. Low-dose prednisone is also used.
Anti-Ro/La antibodies (Sjögren's, SLE)
Risk of neonatal lupus and congenital heart block. Requires fetal cardiac monitoring from 16 weeks gestation.
👶

Paediatrics

Juvenile Idiopathic Arthritis (JIA)
First-line: intra-articular corticosteroids, NSAIDs. Methotrexate is first-line csDMARD. Biologics (etanercept) are PBS-listed for severe polyarticular JIA.
Autoimmune Encephalitis
Increasingly recognised. Requires urgent referral to paediatric neurology. First-line immunotherapy: IVIG or corticosteroids.
🇦🇺

ATSI Health Considerations

Aboriginal and Torres Strait Islander Health
Epidemiology
Higher prevalence and severity of Rheumatoid Arthritis (RA) and SLE reported, with earlier onset and more aggressive articular and extra-articular manifestations.
Access to Care
Geographic isolation, cultural barriers, and socioeconomic factors contribute to delayed diagnosis and lower rates of specialist follow-up and DMARD use.
Key Actions for Clinicians
  • Maintain a lower threshold for investigating inflammatory arthritis.
  • Utilise Aboriginal Health Workers and Liaison Officers to facilitate culturally safe communication and care coordination.
  • Ensure understanding of and access to PBS Authority processes for biologics.
  • Address broader health needs (e.g., cardiovascular risk, diabetes) concurrently.

📚 References

  1. 1. Australian Institute of Health and Welfare (AIHW). Arthritis and other musculoskeletal conditions in Australia. AIHW; 2023.
  2. 2. Royal Australasian College of Physicians (RACP). Autoimmune Diseases: A National Strategic Plan. 2022.
  3. 3. Gordon C, et al. The British Society for Rheumatology guideline for the management of systemic lupus erythematosus in adults. Rheumatology. 2018;57(1):e1-e45.
  4. 4. Smolen JS, et al. EULAR recommendations for the management of rheumatoid arthritis with synthetic and biological disease-modifying antirheumatic drugs: 2022 update. Ann Rheum Dis. 2023;82(1):3-18.
  5. 5. Australian Technical Advisory Group on Immunisation (ATAGI). Australian Immunisation Handbook. Australian Government Department of Health; 2024. (Viewed March 2024).
  6. 6. Pharmaceutical Benefits Scheme (PBS). PBS Schedule. Australian Government Department of Health. Available at: pbs.gov.au. (Accessed 15 March 2024).
  7. 7. Byron JK, et al. The Australian Lupus Registry and Biobank: ten years of advancing lupus care. Intern Med J. 2021;51(12):2009-2016.
  8. 8. Eades LE, et al. High prevalence and early onset of chronic comorbidities in Aboriginal and Torres Strait Islander people with systemic lupus erythematosus. Lupus. 2022;31(10):1269-1277.
  9. 9. Ledingham J, et al. BSR guideline for anti-TNF therapy in rheumatoid arthritis. Rheumatology. 2019;58(6):e3-e42.
  10. 10. National Health and Medical Research Council (NHMRC). National Statement on Ethical Conduct in Human Research. 2023 Update. Canberra: NHMRC.
for PBS-listed medicines at participating pharmacies.
Cultural safety
Engagement with Aboriginal Community Controlled Health Organisations (ACCHOs) is essential. Cultural safety training for non-Indigenous clinicians, use of Aboriginal Health Workers and Liaison Officers, and incorporation of traditional healing practices alongside Western medicine improve treatment adherence and outcomes. Avoidance of eye contact, respect for gender-sensitive examination practices, and understanding of sorry business protocols are critical elements of culturally safe care.
Medication adherence
Complex DMARD regimens with frequent monitoring requirements present adherence challenges. Long-acting depot injections (e.g., methotrexate SC) may improve adherence compared to oral regimens. Community pharmacy partnerships through the Indigenous Pharmacy Programmes improve medication management.
Specific conditions
Rheumatic heart disease (RHD) requires secondary prophylaxis with benzathine penicillin G (BPG) 1.2 MU IM every 3–4 weeks for a minimum of 10 years or until age 21 (whichever is longer). RHD registers (e.g., NT RHD Register) facilitate recall and follow-up. The Australian RHD Endgame Strategy targets elimination by 2031.
Referral pathways
Referral through ACCHOs and Aboriginal Hospital Liaison Officers (AHLOs) improves engagement. The Specialist Outreach Assistance Programme provides funded specialist visits to remote communities. NT, WA, and QLD have specific rheumatology outreach programmes targeting Indigenous communities.

📚 References

  1. 1. Australian Institute of Health and Welfare (AIHW). Autoimmune disease in Australia. Cat. no. PHE 312. Canberra: AIHW; 2023.
  2. 2. Fraenkel L, Bathon JM, England BR, et al. 2021 American College of Rheumatology guideline for the treatment of rheumatoid arthritis. Arthritis Care Res. 2021;73(7):924–939.
  3. 3. Fanouriakis A, Kostopoulou M, Alber K, et al. 2019 update of the EULAR recommendations for the management of systemic lupus erythematosus. Ann Rheum Dis. 2019;78(6):736–745.
  4. 4. Chung SA, Langford CA, Maz M, et al. 2021 American College of Rheumatology/Vasculitis Foundation guideline for the management of antineutrophil cytoplasmic antibody-associated vasculitis. Arthritis Care Res. 2021;73(11):1583–1599.
  5. 5. Smolen JS, Landewé RBM, Bijlsma JWJ, et al. EULAR recommendations for the management of rheumatoid arthritis with synthetic and biological disease-modifying antirheumatic drugs: 2022 update. Ann Rheum Dis. 2023;82(1):3–18.
  6. 6. Australian Technical Advisory Group on Immunisation (ATAGI). Australian Immunisation Handbook. Australian Government Department of Health; 2024. Available from: immunisationhandbook.health.gov.au.
  7. 7. Rheumatic Heart Disease Australia (RHDAustralia). The 2020 Australian guideline for prevention, diagnosis, and management of acute rheumatic fever and rheumatic heart disease. 3rd ed. Darwin: Menzies School of Health Research; 2020.
  8. 8. Pharmaceutical Benefits Scheme (PBS). PBS Schedule. Australian Government Department of Health. Available from: pbs.gov.au. Accessed 2024.
  9. 9. Agarwal S, Cunnington J, Nossent J. Autoimmune disease in Indigenous Australians: a systematic review. Int J Rheum Dis. 2021;24(12):1487–1498.
  10. 10. Pisetsky DS. Antinuclear antibody testing — misunderstood or misused? Clin Immunol. 2023;255:109717.
  11. 11. Bertsias GK, Tektonidou M, Amoura Z, et al. Joint European League Against Rheumatism and European Renal Association–European Dialysis and Transplant Association (EULAR/ERA-EDTA) recommendations for the management of adult and paediatric lupus nephritis. Ann Rheum Dis. 2012;71(11):1771–1782.
  12. 12. Ledingham J, Deighton C; British Society for Rheumatology Standards, Audit and Guidelines Working Group. Update on the British Society for Rheumatology guidelines for prescribing TNFα blockers in adults with rheumatoid arthritis. Rheumatology. 2005;44(2):155–158.
  13. 13. National Health and Medical Research Council (NHMRC). National statement on ethical conduct in human research. Canberra: NHMRC; 2023 (updated).
for PBS-listed medicines at participating pharmacies.
Cultural safety
Engagement with Aboriginal Community Controlled Health Organisations (ACCHOs) is essential. Cultural safety training for non-Indigenous clinicians, use of Aboriginal Health Workers and Liaison Officers, and incorporation of traditional healing practices alongside Western medicine improve treatment adherence and outcomes. Avoidance of eye contact, respect for gender-sensitive examination practices, and understanding of sorry business protocols are critical elements of culturally safe care.
Medication adherence
Complex DMARD regimens with frequent monitoring requirements present adherence challenges. Long-acting depot injections (e.g., methotrexate SC) may improve adherence compared to oral regimens. Community pharmacy partnerships through the Indigenous Pharmacy Programmes improve medication management.
Specific conditions
Rheumatic heart disease (RHD) requires secondary prophylaxis with benzathine penicillin G (BPG) 1.2 MU IM every 3–4 weeks for a minimum of 10 years or until age 21 (whichever is longer). RHD registers (e.g., NT RHD Register) facilitate recall and follow-up. The Australian RHD Endgame Strategy targets elimination by 2031.
Referral pathways
Referral through ACCHOs and Aboriginal Hospital Liaison Officers (AHLOs) improves engagement. The Specialist Outreach Assistance Programme provides funded specialist visits to remote communities. NT, WA, and QLD have specific rheumatology outreach programmes targeting Indigenous communities.

📚 References

  1. 1. Australian Institute of Health and Welfare (AIHW). Autoimmune disease in Australia. Cat. no. PHE 312. Canberra: AIHW; 2023.
  2. 2. Fraenkel L, Bathon JM, England BR, et al. 2021 American College of Rheumatology guideline for the treatment of rheumatoid arthritis. Arthritis Care Res. 2021;73(7):924–939.
  3. 3. Fanouriakis A, Kostopoulou M, Alber K, et al. 2019 update of the EULAR recommendations for the management of systemic lupus erythematosus. Ann Rheum Dis. 2019;78(6):736–745.
  4. 4. Chung SA, Langford CA, Maz M, et al. 2021 American College of Rheumatology/Vasculitis Foundation guideline for the management of antineutrophil cytoplasmic antibody-associated vasculitis. Arthritis Care Res. 2021;73(11):1583–1599.
  5. 5. Smolen JS, Landewé RBM, Bijlsma JWJ, et al. EULAR recommendations for the management of rheumatoid arthritis with synthetic and biological disease-modifying antirheumatic drugs: 2022 update. Ann Rheum Dis. 2023;82(1):3–18.
  6. 6. Australian Technical Advisory Group on Immunisation (ATAGI). Australian Immunisation Handbook. Australian Government Department of Health; 2024. Available from: immunisationhandbook.health.gov.au.
  7. 7. Rheumatic Heart Disease Australia (RHDAustralia). The 2020 Australian guideline for prevention, diagnosis, and management of acute rheumatic fever and rheumatic heart disease. 3rd ed. Darwin: Menzies School of Health Research; 2020.
  8. 8. Pharmaceutical Benefits Scheme (PBS). PBS Schedule. Australian Government Department of Health. Available from: pbs.gov.au. Accessed 2024.
  9. 9. Agarwal S, Cunnington J, Nossent J. Autoimmune disease in Indigenous Australians: a systematic review. Int J Rheum Dis. 2021;24(12):1487–1498.
  10. 10. Pisetsky DS. Antinuclear antibody testing — misunderstood or misused? Clin Immunol. 2023;255:109717.
  11. 11. Bertsias GK, Tektonidou M, Amoura Z, et al. Joint European League Against Rheumatism and European Renal Association–European Dialysis and Transplant Association (EULAR/ERA-EDTA) recommendations for the management of adult and paediatric lupus nephritis. Ann Rheum Dis. 2012;71(11):1771–1782.
  12. 12. Ledingham J, Deighton C; British Society for Rheumatology Standards, Audit and Guidelines Working Group. Update on the British Society for Rheumatology guidelines for prescribing TNFα blockers in adults with rheumatoid arthritis. Rheumatology. 2005;44(2):155–158.
  13. 13. National Health and Medical Research Council (NHMRC). National statement on ethical conduct in human research. Canberra: NHMRC; 2023 (updated).