[Anticitrulline antibodies and wrist joint MRI parameters in patients with early arthritis].
OBJECTIVE
To examine correlations between immunological markers, clinical parameters and MRI data in patients with early rheumatoid arthritis (RA) and undifferentiated arthritis (UDA).


METHODS
The study was made of 211 patients with early RA (43 males, 168 females) and 47 patients with early UDA (mean age 48.6 +/- 13.4 years), duration of the symptoms 5.5 +/- 4.5 months). RF-positive were 136 (64.5%) patients. X-ray erosions were detected in 45 (21.3%) patients. RA activity was estimated by the integral DAS28 index (by 3 parameters), function--by HAO questionnaire (Russian version). The immunonephelometric analyzer (BN-100, Dade Behring, Germany) determined concentration of C-reactive protein (CRP), IgM. Anticitrulline antibodies (ACAB) were estimated by enzyme immunoassay, the upper limit of the norm was 5.0 U/ml. MR imaging (MRI) of both the wrists in RA patients was made on the 0.2 T Artoscan unit, the assessment was made with the reference atlas OMERACT-RAMRIS.


RESULTS
IgM and ACAB levels were much higher in RA than in UDA. Among the patients positive by both tests (RF+ACAB) 95.2% had a typical clinical picture and RA diagnosis while 60% patients negative by RF and ACAB had UDA (p < 0.001); among patients positive by one of the tests the ratio UDA to RA was 1:2 (32.6 and 67.4%). In RA patients with very high ACAB (> 100 U/ml) CRP reached 38.10 +/- 48.29 mg/l while in negative ACAB--17.07 +/- 19.34 mg/l (p = 0.016). Wrist MRI detected synovitis and bone erosions in 93 and 66% cases, respectively. High ACAB level (> 100 U/ml) and CRP levels were associated with high DAS28, RF IgM and MRI erosions number.


CONCLUSIONS
RF and ACAB patients are characterized by a typical RA picture in the disease onset (specificity 93.6%). MRI detects synovitis in the wrist joints in 93 and erosions in 66% early RA patients. Combination of high ACAB and CRP levels is associated with high RA activity, RF IgM and great number of erosions according to MRI and may serve a marker of a severe disease course.
Karateev
D E
DE
Aleksandrova
E N
EN
Demidova
N V
NV
Luchikhina
E L
EL
Novikov
A A
AA
Pogozheva
E Iu
EIu
Rapoport
I E
IE
Smirnov
A V
AV
Nasonov
E L
EL
D000906:Antibodies / Q000276:immunology*; D001168:Arthritis / Q000276:immunology* / Q000473:pathology*; D002097:C-Reactive Protein / Q000276:immunology; D002956:Citrulline / Q000276:immunology*; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology; D008279:Magnetic Resonance Imaging; D008297:Male; D014955:Wrist Joint / Q000473:pathology*
D000906:Antibodies; D007075:Immunoglobulin M; D002956:Citrulline; D002097:C-Reactive Protein