Diagnostic and prognostic serological analyses in RA

Transcription

1 9/9/ Diagnostic and prognostic serological analyses in RA Johan Rönnelid Clinical Immunology and Transfusion medicine Akademiska sjukhuset, Uppsala Department of Immunology, Genetics and Pathology Uppsala university Rheumatoid arthritis (RA) A chronic articular and systemic inflammatory disease.5-.7% prevalence Highest insidence at age -5 Mostly females 3:

2 9/9/ Neovius et al, Ann Rheum Dis Two main autoantibody groups (and one coming?). Rheumatoid factor. Antibodies against citrullinated proteins/peptides (ACPA/anti-CCP) 3. (anti-type II collagen)

3 9/9/ 987 ACR classification criteria for RA Morning stiffness Arthritis in 3 joint areas Arthritis in hand joints Symmetric arthritis Rheumatoid nodules Serum rheumatoid factor (spec 95%) Radiographic changes /7 criteria: serology 5% Arnett et al. Arthritis Rheum 988 3

4 9/9/ The RA classification criteria (RA if points): Joint involvement: medium/large joint () - medium/large joints () -3 small joints () - small joints (3) small joints (5) Serology: No RF/ACPA () Low RF/ACPA () High RF/ACPA (3) Duration of synovitis: < weeks () weeks () Acute phase reactants Normal CRP/ESR () Abnormal CRP/ESR () 3/ points: serology 5% Aletaha D et al. Arthritis Rheum RF history 9: Erik Waaler (Norway): RF in RA 98: Rose (USA): RF in RA ACR 987 classification criteria: any method used with a specificity of >95% as compared to a healthy control population

5 9/9/!!Antibodies against the Fc-part of IgG.!RF can however be both IgG/IgM/IgA.!" 75% of RA patients are RF positive (987 criteria) Techniques for measuring RF.! Agglutination (mostly IgM).! Nephelometry (mostly IgM) 3. ELISA (truly isotype specific). Addressable Laser Bead Immunoassay (ALBIA)/Bead array/ Luminex The international RF calibrator help standardize RF levels between laboratories ( IU/mL) 5!

6 9/9/ RF positive RA associate with more severe disease in the future CRP mg/dl RF + RF - ESR 3 Pain VAS mo yr yrs 3 yrs 5 yrs Time after inclusion,5 3 mo yr yrs 3 yrs 5 yrs,5 3 mo yr yrs 3 yrs 5 yrs Global VAS Swollen joint count mo yr yrs 3 yrs 5 yrs 3 mo yr yrs 3 yrs 5 yrs HAQ,75,5,5 Tender joint count 8 3 mo yr yrs 3 yrs 5 yrs 3 mo yr yrs 3 yrs 5 yrs Physicians' assessment DAS8,5, mo yr yrs 3 yrs 5 yrs 3 mo yr yrs 3 yrs 5 yrs Three RF isotypes (IgM, IgA, IgG) Europe: IgM RF Germany: IgM:.% IgA: 5,8% IgG: 3,7% (Vallbracht et al, ) Africa: IgA RF Cameroon: IgM:77% IgA:8% IgG:? (Singwe-Ngandeu et al, 9) Sweden: IgM:79% IgA:78% IgG:8% (Lindqvist et al, 5) Sudan: IgM: 5% IgA: 5% IgG: 5% (Elshafie et al, submitted )

7 9/9/ IgA RF associated with erosions and extraarticular RA? (Icelandic experiences) Association between IgA RF, but not IgG RF or IgM RF and the occurrence of erosions (Arnason JA. Ann Rheum Dis 987;:38) Among IgA RF positive patients 8% had extraarticular RA. IgG/M RF positive: % (Jonsson T. Scand J Rheumatol. 995;:37) RF is increased also in other (non-ra) rheumatological conditions: Arthritides: Rheumatoid arthritis 8% Juvenile chronic arthritis 5% Psoriatic arthritis <5% Reactive arthritis <5% Connective tissue diseases: Primary Sjögren syndrome 7% Systemic lupus erythematosus 3% Mixed connective tissue disease 5% Polymyositis/dermatomyositis % Progressive scleroderma % 7

8 9/9/! RF in infectious diseases: Bacterial Subacute bacterial endocarditis % Tuberculosis 5% Syphilis (primary-tertiary) 8 37% Viral Infectious hepatitis (A, B, C) 5% EBV and CMV infections % Coxsackie B 5% Herpes virus infections 5% HIV infection % Åhlin et al, Scand J Immunol 5! Antibodies against citrullinated proteins/peptides (ACPA) 9: anti-perinuclear factor (APNF) 979 anti-keratin antibodies, highly RA specific 998: AKA and APNF reagerar med citrullinerade (förändrade) proteiner. 8!

9 9/9/! Citrullination: a post-translational modification of arginine by deimination. NH NH + C NH CH CH PAD NH O C NH CH CH Different! protein folding!! More sensitive to! degradation! CH CH CO CH NH CO CH NH Argininrest i protein/peptid (positivt laddad) Citrullinrest i protein/peptid (elektriskt neutral) (PAD= peptidyl arginine deiminase)! : Anti-cyclic citrullinated peptide (anti-ccp) (Schellekens GA et al. Arthritis Rheum ;3:55)!!An ELISA for measurement of antibodies against a cyclic citrullinated peptide (anti-ccp)!different RA patients - but only RA patients - react with different citrullinecontaining peptides Anti-CCP -> anti-ccp! 9!

10 9/9/! Anti-CCP has higher specificity than RF, when compared to disease controls:!! Rheumatic diseases:! Anti-CCP %! RF %!! Infectious diseases:! Anti-CCP %! RF 3%! Positive predictive value (PPV) The use of sensitivity and specificity do not take into consideration how commonly patients with a specific diagnosis appear in the investigated population. PPV= True positives. (true positives + false positives) High PPV: high chance that a positive test result imply disease.!!

11 9/9/ RF: sensitivity 7% RF: specificity: 9% Anti-CCP: sensitivity 7% Anti-CCP: specificity: 98% Assumption: / investigated patients actually have rheumatoid arthritis PPV= True positives. (true positives + false positives) PPV for RF: x.7 (x.7) + (9x.) PPV for anti-ccp: x.7 (x.7) + (9x.) =.9 =.8 PPV= 7% PPV=5%

12 9/9/ 8.5/5.=5. Ann Rheum Dis Anti-CCP represent a stable phenotype Karolinska experiences: qualitative changes in anti-ccp antibody status with time were rare. Only 3.9% (/79) of the patients had an altered status during follow-up. Most qualitative changes concerned marginally positive samples.

13 9/9/! Diagnostic and prognostic value of RF is dependent on the cutoff RF level:! Increasing differences between anti-ccp+/- during five years follow-up CRP mg/dl anti-ccp+ anti-ccp- ESR 3 Pain VAS mo yr yrs 3 yrs 5 yrs Time after inclusion,5 3 mo yr yrs 3 yrs 5 yrs,5 3 mo yr yrs 3 yrs 5 yrs Global VAS 3 8 Swollen joint count 3 mo yr yrs 3 yrs 5 yrs 3 mo yr yrs 3 yrs 5 yrs HAQ,75,5,5 Tender joint count 8 3 mo yr yrs 3 yrs 5 yrs 3 mo yr yrs 3 yrs 5 yrs Physicians' assessment DAS8,5, mo yr yrs 3 yrs 5 yrs 3 mo yr yrs 3 yrs 5 yrs Rönnelid et al. Ann Rheum Dis 5! 3!

14 9/9/ Radiological progression Larsen score 8 8 Anti-CCP negative Anti-CCP positive Baseline Year Year RF Anti-CCP Larsen baseline NS NS Larsen year NS NS Larsen years NS NS Δ Larsen ( ) NS NS Δ Larsen (-).9.8 Δ Larsen (-). <. Rönnelid et al. Ann Rheum Dis 5;:7 RF and anti-ccp associate RF positive RF negative anti-cp positive (53%) (%) 58(57%) anti-cp negative 9(%) 9(3%) 9(3%) 75(3%) (37%) 77() RF Anti-CCP CRP mg/dl RF + 3 RF - ESR 3 mo yr yrs 3 yrs 5 yrs 3 mo yr yrs 3 yrs 5 yrs Time after inclusion,5 Pain VAS mo yr yrs 3 yrs 5 yrs,5 CRP mg/dl anti-ccp+ anti-ccp- ESR 3 mo yr yrs 3 yrs 5 yrs 3 mo yr yrs 3 yrs 5 yrs Time after inclusion,5 Pain VAS mo yr yrs 3 yrs 5 yrs,5 Global VAS 3 HAQ,75,5,5 Physicians' assessment,5,5 Global VAS 3 HAQ,75,5,5 Physicians' assessment,5,5 Swollen joint count 3 mo yr yrs 3 yrs 5 yrs 3 mo yr yrs 3 yrs 5 yrs 8 8 Tender joint count DAS8 3 mo yr yrs 3 yrs 5 yrs 5 3 Swollen joint count 8 3 mo yr yrs 3 yrs 5 yrs Tender joint count 8 3 mo yr yrs 3 yrs 5 yrs DAS8 3 mo yr yrs 3 yrs 5 yrs mo yr yrs 3 yrs 5 yrs 3 mo yr yrs 3 yrs 5 yrs 3 mo yr yrs 3 yrs 5 yrs 3 mo yr yrs 3 yrs 5 yrs 3 mo yr yrs 3 yrs 5 yrs 3 mo yr yrs 3 yrs 5 yrs

15 9/9/ Meta-analyses show ACPA being prognostically more important than RF RF and anti-ccp - which is most important for the prognosis? Investigation of 379 early RA patients in the BARFOT cohort. Stepwise logistic regression showed the significant predictors for radiological damage after two years to be:. Baseline Larsen score. Anti-CCP 3. ESR (Forslind K et al. Ann Rheum Dis ;3:9) 5

16 9/9/! Anti-CCP predict RA development in undifferentiated arthritis! Anti-CCP in SLE: patients with more RA-like disease!!

17 9/9/ Values of ACPA levels for prognosis? Ann Rheum Dis 8 Values of ACPA levels for diagnosis? Clinica Chimica Acta 7

18 9/9/! Anti-CCP and IgA RF predict RA development! 8!

19 9/9/ Rheumatoid arthritis One single disease or a group of (at least two) diseases? The Shared Epitope - a group of HLA molecules with similar structure in an important part of the molecule 9

20 9/9/ ACPA-positive RA - a distinct disease phenotype assoc. with HLA/smoking: Anti-CCP positive RA Anti-CCP negative RA

21 9/9/ Commercial ACPA tests: (Anti-CCP) Anti-CCP ( anti-ccp ) Anti-CCP3 Anti-CCP3. Anti-MCV (mutated citrullinated vimentin) Anti-Sa Anti-VCP Different anti-ccp suppliers with different measures! An international ACPA standard available but not yet used. Scientific ACPA targets: citrullinated fibrinogen (citrullinated filaggrin) citrullinated vimentin citrullinated alpha-enolase citrullinated type II collagen Including corresponding peptides

22 9/9/! Mean.8 Mean 3.33 Mean.93 Mean. Hansson et al. Arhritis Res Ther!

23 9/9/!!"## $"# %"# a. Eno 5- (CEP-) b. Fil 37-3 (CCP-) c. Vim Fluorescense intensity (AU) 3 p<. Fluorescense intensity (AU) 3 p<. Fluorescense intensity (AU) 3 p=ns (.) Anti-CCP+ RA Anti-CCP- RA Healthy controls Anti-CCP+ RA Anti-CCP- RA Healthy controls Anti-CCP+ RA Anti-CCP- RA Healthy controls!"#$%%&'()+,#-.(!"#$%%&'("./#-.( "(3.("#$%%&'$"./#-.(/5)("789( :!%(!%&!()+,#-.( :!%(!%&!("./#-.( 3!

24 9/9/! Appearance of different ACPA specificities at different time points the years preceding RA diagnosis 8! 7! CCPc%! a-enolas%! Fib3-5c%!! CCP%! Vim-75c%! 5! Fib7c%! Fib7c%!! Fib-a3-5%! Fibß-7%! 3! Fib-a5-3%! Fib59c%!! CIIC%! Fib573%!! Vim-7%!! -8!-7!-!-3!-!-!-9!-8!-7!-!-5!-!-3!-! -! -! -9! -8! -7! -! -5! -! -3! -! -! -.5!.! Brink et al, Arthritis Rheum 3! Anti-collagen II! Antibodies associated with early inflammation in RA!!

25 9/9/! Antibodies against cartilage collagen type II in RA Mullazehi et al. Ann Rheum Dis 7 Temporal changes in anti-cii IC-induced cytokine production associate with changes in CRP and ESR 3 Anti-CII, U/mL TNF-!, pg/ml CRP, mg/l 9 B 3 mo yr yrs 3 yrs 5 yrs B 3 mo yr yrs 3 yrs 5 yrs B 3 mo yr yrs 3 yrs 5 yrs Mullazehi et al. Ann Rheum Dis 7 5!

26 9/9/ Anti-CCP, late inflammation (Rönnelid et al.ann Rheum Dis 5) Anti-CII, early inflammation (Mullazehi et al,ann Rheum Dis 7) DAS8. EIRA linked to SRQ (Saedis Saevarsdottir, Helga Westerlind) Anti-collagen II Anti-CCP Unpublished