1 / 20

AUTOANTIBODIES IN RHEUMATOLOGY

AUTOANTIBODIES IN RHEUMATOLOGY. G. Cooke VTS Trainee. AIMS & OBJECTIVES. Nothing radical Just to enhance consideration of the role of autoantibody titres when… Considering rheumatological diagnosis Assessing for exacerbation / treatment response Interpreting results / letters.

claudia-fitzpatrick
Télécharger la présentation

AUTOANTIBODIES IN RHEUMATOLOGY

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. AUTOANTIBODIES IN RHEUMATOLOGY G. Cooke VTS Trainee

  2. AIMS & OBJECTIVES • Nothing radical • Just to enhance consideration of the role of autoantibody titres when… • Considering rheumatological diagnosis • Assessing for exacerbation / treatment response • Interpreting results / letters

  3. Introduction (1): Autoantibodies?? - Immunoglobulins - Detectable in people with a variety of clinical presentations & in healthy individuals

  4. Introduction (2): - No autoantibody confirms a diagnosis or determines treatment – adjunctive role predominantly - Ask – Will knowing the value of x, y or z alter my management of this patient?

  5. RHEUMATOID FACTOR (1): - IgM which reacts with the fc component of abnormal, antigenic IgG to produce immune complexes  complement activation…inflammatory cascade - Present in 1% of healthy individuals - Present in 70-90% of RA patients - Levels increase with age

  6. RHEUMATOID FACTOR (2): - Blood titres >1:80 considered +ve and suggestive of RA - Titres between “unidentifiable” and 1:80 – consider: SLE, Sjogrens (or healthy) - “unidentifiable” titres don’t exclude RA (10-30% RA patients seronegative)

  7. RHEUMATOID FACTOR (3): - High titres  severe articular / extra-articular disease in RA - Levels don’t alter significantly with Rx - 80% sensitivity (therefore –ve doesn’t exclude diagnosis) - PPV 50%

  8. RHEUMATOID FACTOR (4): - RF +ve patients? Also consider… - SLE / Sjogrens - Chronic viruses - SBE - TB - Dermatomyositis - Scleroderma - EBV - Leukaemia - Cirrhosis - Syphilis - Renal disease

  9. ANTI-NUCLEAR ANTIBODIES (1): - Strongly associated with SLE (but also other rheumatological conditions, bizarre syndromes and healthy people) - MULTIPLE subtypes of Anti-Nuclear Antibodies (ANA, ds-DNA, ss-DNA, anti-DNP, SS-A, SS-B, Scl-70, RNP, RANA, RAP, Antimicrosomal, Antithyroglobulin, ASMA)

  10. - 95% SLE have +ve ANA (good sens – -ve test good for exclusion of SLE) - Specificity for ANA in SLE low (57% - +ve ANA not great at confirming SLE) [false +ve with MULTIPLE medications] - If lupus personified walks in – check ANA, if a bit grey, probably not worth it - Doesn’t reflect disease activityin SLE (use clinical features / ESR / C3 / C4 / dsDNA) ANTI-NUCLEAR ANTIBODIES (2):

  11. ANTI-NUCLEAR ANTIBODIES (3): - More confusion… Different patterns when studies under UV microscopy and ANA subgrouped accordingly (often referred to in clinic letters / ICE results): Homogenous: SLE / Mixed CTD Peripheral: SLE Speckled: SLE / Sjogrens / Scleroderma Polymyositis / RA / Mixed CTD Nucleolar: Scleroderma / Polymyositis

  12. ANTI-NUCLEAR ANTIBODIES (4):

  13. ANTI-NUCLEAR ANTIBODIES (5): - +ve ANA also a/w… - Chronic Hepatitis - PAN - EBV - Leukaemia - Myaesthenia Gravis - Cirrhosis - Order an ANA when… - Support diagnosis of CTD when suspected clinically (FU with specific tests) - To exclude SLE with 1-2 features and no clear alternative

  14. ANTI-ds-DNA ANTIBODIES: - Less sensitive but more specific for SLE compared to ANA - Very low false +ve rate - Do relate to disease activity – esp. renal involvement (e.g. monitoring lupus nephritis)

  15. ANTI-Sm ANTIBODIES: - AKA Anti-Smith (notsmoothmuscle) - V. SLE specific – but present in 30% cases so not particularly sensitive for SLE - Associated with severity and extent of renal involvement - False +ve a/w EBV – molecular mimicry

  16. ANTI-RNP (ribonuclear protein) ANTIBODIES: - Poor sensitivity and specificity for SLE - Present in 40% SLE patients - High levels diagnostic of Mixed CTD - A/W milder renal disease & Raynaud’s

  17. ANTI-SCLERODERMA ANTIBODIES: - Scl-70 / Scleroderma Abs - Present in 45% with scleroderma (PSS) - Scl-70 titre relates to both likelihood of diagnosis, and disease activity - Absence doesn’t exclude scleroderma - Also a/w: Mixed CTD SLE Sjogren’s RA Polymyositis

  18. Anti-Ro / Anti-La / Anti-SS-C (1): - Confusingly, Anti-Ro = Anti-SS-A Anti La = Anti-SS-B - SS-A / SS-B – used to diagnose Sjogren’s (Prim / Sec) - SS-A in 60-70% Primary Sjogren’s; SS-B in 50% (SS-A + SS-B +ve = confirms diagnosis) - Can differentiate between 1° & 2° Sjogren’s – SS-B found only in 1° disease

  19. Anti-Ro / Anti-La / Anti-SS-C (2): - SS-A found in 25% SLE cases (present in the majority of ANA-ve SLE patients) / SS-B never found in SLE - SS-C +ve in 75% RA patients / RA + 2° Sjogren’s - High Anti-SS levels…  Sjogren’s more likely  Disease more active - Anti-SS levels fall with treatent

  20. CONCLUSION: - Think before you request - Clinical impression hugely valuable in guiding Ix choice - Sensitive tests first… specific later to confirm diagnoses

More Related