
 rheumatoid arthritis ( ra ) is one of the most prevailing inflammatory arthropathies that affects primarily able - to - work persons what attributes a high social significance to the disease .
the development of ra is associated with the formation of a wide spectrum of autoantibodies , including rheumatoid factors ( rfs ) and anti - citrullinated protein antibodies ( acpas ) ( antiperinuclear factor , antikeratin antibodies , antibodies to cyclic citrullinated peptide ( anti - ccp ) , modified citrullinated vimentin , anti - mcv , citrullinated fibrinogen , etc . )
, the presence of which contributes substantially to the course and prognosis of disease [ 2 , 3 ] . at present
, acpa - positive and acpa - negative ra subtypes are identified , which differ in molecular mechanisms of pathogenesis , severity course and approaches to the treatment administered [ 46 ] .
acpa - positive ra is characterized by accelerated radiologic progression , a severe course of the disease with higher total mortality [ 6 , 7 ] .
hyperproduction of proinflammatory cytokines ( interleukins ( il)-1 , 6 , 17 , tumor necrosis factor  tnf- ) and growth factors in ra promotes the liberation of proteolytic enzymes ( matrix metalloproteinases  mmps ) by synovial cells causing the destruction of connective tissue of the joint   and stimulates an increased production of receptor activator of nuclear factor nf-b ligand ( rankl ) [ 9 , 10 ] .
mmps present a group composing over 20 proteolytic enzymes responsible for the cleavage of protein components of extracellular matrix .
the family of mmps includes collagenases ( mmp-1 , 8 , and 13 ) , which induce the degradation of collagen i , ii , and iii type , and stromelysins ( mmp-3 , 10 , and 11 ) , ensuring the proteolysis of noncollagen proteins ( fibronectin , elastin ) . at present , mmp-3 is considered as one of key mediators of articular destruction in ra [ 12 , 13 ] .
rankl   presents a soluble rank ligand that occupies a central place in molecular regulation of bone tissue remodeling .
when binding with a rank specific receptor located on osteoclasts precursors , rankl stimulates osteoclastogenesis and bone resorption [ 14 , 15 ] .
an important factor in the formation of osteoclasts and acceleration of bone resorption in ra is presented by anti - mcv .
the studies in vitro and in vivo have demonstrated the ability of anti - mcv to specifically interact with cv ( citrullinated vimentin ) expressing upon the membrane of osteoclast precursors [ 1618 ] .
the process induces the production of tnf- and mediated by this cytokine expression of macrophage colony stimulating factor ( mcsf ) and rankl , thus increasing osteoclast precursor sensitivity for differentiation into mature osteoclasts .
one of the markers of cartilage tissue destruction is the cartilage oligomeric matrix protein ( comp ) .
comp is a noncollagen glycoprotein of the thrombospondin family that is present in extracellular matrix of articular cartilage , synovium , and tendons .
the serum level of comp [ 20 , 21 ] correlates with radiologic changes in the joints , the concentration of c - reactive protein ( crp ) and mmp-3 in blood and is a prognostic factor of severe destructive lesion to the joints in ra . the objective of the study was to evaluate the relationships between the level of autoantibodies ( igm rf , anti - ccp , and anti - mcv ) in blood serum , radiologic changes , and laboratory markers of bone and cartilage destruction in ra patients .
a total of 114 patients , with definite diagnosis of ra , who were followed up at nasonova research institute of rheumatology , moscow , within the period from 2009 till 2012 , were examined .
candidate patients fulfilled the following criteria : ( 1 ) they were available for first posteroanterior radiographs of hands and anteroposterior radiographs of feet , ( 2 ) they had been treated with nonbiological dmards for more than 3 months before entry , and ( 3 ) they were not treated with biological dmards throughout the study .
the control group included healthy donors matched for sex , age at the time of blood sampling , and area of residence .
all participating sites received approval from their governing institutional review board ( or equivalent ) and all patients provided written informed consent .
we determined the das28 , the simplified disease activity index ( sdai ) score , and the clinical disease activity index ( cdai ) score , using the following equations : das28 = 0.56  ( tjc28 ) + 0.28  ( sjc28 ) + 0.70  ln(esr ) + 0.014  gh ; sdai score = sjc28 + tjc28 + pga + ega + crp ; and cdai score = sjc28 + tjc28 + pga + ega , whereby the tender joint count ( tjc ) and the swollen joint count ( sjc ) were evaluated using 28 joints , global health ( gh ) was customarily replaced by the patient 's global assessment ( pga ) of disease activity ( in millimeters on a visual analog scale [ vas ] ) , scores for the pga and the evaluator 's global assessment ( ega ) were measured in centimeters on a 0100  mm vas , the erythrocyte sedimentation rate ( esr ) was measured as mm / hour , and the crp level was measured as mg / dl . for all 3 composite measures , cut points for the disease activity states of remission ( rem ) , low disease activity ( lda ) , moderate disease activity ( mda ) , and high disease activity ( hda ) were determined .
these established cut points are as follows : for the das28 , rem < 2.6  lda  3.2 < mda < 5.1 < hda ; for the sdai , rem  3.3 < lda  11 < mda  26 < hda ; and for the cdai , rem  2.8 < lda  10 < mda  22 < hda .
esr was determined by the westergren method ( normal value  30  mm / h ) .
the normal level of crp in blood serum was 5.0  mg / l . according to the manufacturer 's instructions ,
the upper limit of normal ( uln ) for igm rf was 15.0  iu / ml .
high - positive ( > 3  uln ; > 45.0  iu / ml ) , low - positive ( 13  uln ; 15.045.0  iu / ml ) , and negative ( uln ; 15.0  iu / ml ) levels of igm rf were identified .
the quantitative estimation of anti - ccp was made by an electrochemiluminescent technique ( uln 17.0  u / ml ) and enzyme - linked immunosorbent assay ( elisa ) ( uln 5.0  u / ml ) .
high - positive ( > 3  uln ; > 50.0  u / ml  by an electrochemiluminescent technique , and > 15  u / ml  by elisa ) , low - positive ( 13  uln ; 17.050.0  u / ml and 5.015.0  u / ml , resp . ) , and negative ( uln ; 17.0  u / ml and 5  u / ml , resp . ) levels of anti - ccp were identified .
the concentration of anti - mcv in blood serum was measured using elisa kit . according to the manufacturer 's instructions ,
high - positive ( > 3  uln ; > 60.0  u / ml ) , low - positive ( 13  uln ; 20.060.0  u / ml ) , and negative ( uln ; 20.0  u / ml ) levels of anti - mcv were identified .
comp concentration in blood serum was measured in 34 ra patients by elisa ( uln < 1185  ng / ml , in the serum of 30 healthy donors ) .
the concentration of mmp-3 in blood serum was measured in 52 ra patients by elisa with the use of commercial kits of reagents provided by  invitrogen 
( uln < 19.4  ng / ml , in the serum of 30 healthy donors ) and  bender medsystems  in 28 ra patients ( uln < 9.3  ng / ml , in the serum of 24 healthy donors ) .
joint space narrowing and erosions were scored by the sharp - van der heijde ( svh ) method .
the results were statistically processed with the use of software package  statistica 8.0  (  statsoft ,  usa ) , including commonly used methods of parametric and nonparametric analysis . for the parameters with distribution differing from normal , when two groups were compared , the mann - whitney u test was applied , whose results were presented as median ( me ) with an interquartile range ( iqr , from 25th to 75th percentile ) .
as demonstrated by table 1 , the majority of patients were women of middle age with a prolonged course of disease , positive for igm rf ( 82.5% ) , anti - ccp ( 83.3% ) , and anti - mcv ( 86.9% ) , and they had a high clinical ( das 28 > 5.1 ) and laboratory ( esr > 35  mm / h , crp > 20 
mg / l ) disease activity , x - ray phase ii ( 43.9% ) .
the patients received disease - modifying antirheumatic drugs ; the main of which were methotrexate and glucocorticoides ( gc ) ( 61.4% ) . among ra patients ,
das 28 : 5.9 ( 5.26.7 ) , sdai : 34.4 ( 23.545.5 ) , and cdai : 30.5 ( 20.941 ) corresponded to a high disease activity
. an increased level of crp and esr values was recorded in 100 ( 87.7% ) and 70 ( 61.4% ) patients , respectively . a positive correlation of the level of igm rf with das 28 ( r = 0.3 ;
p = 0.02 ) , sdai ( r = 0.3 ; p = 0.02 ) , and esr ( r = 0.3 ; p = 0.003 ) and the concentration of anti - mcv with sdai ( r = 0.25 ,  p = 0.02 ) and cdai ( r = 0.3 ,  p = 0.02 ) were identified .
no significant correlation relationships of the anti - ccp level with indicators of disease activity have been identified .
the median of total modified sharp score ( mtss ) , erosion score , and joint space narrowing score ( jsn ) amounted to 89 ( 57117 ) , 9 ( 327 ) , and 76 ( 5199 ) , respectively .
radiographic changes were analyzed in groups of patients depending on the level of igm rf , anti - ccp , and anti - mcv .
no differences in radiologic signs of articular destruction in groups of ra patients high - positive and negative/ low positive for igm rf and anti - ccp have been identified ( p > 0,05 ) ( data not shown ) . among patients with high - positive level for anti - mcv , the higher values of mtss and jsn were observed as compared with these indicators in anti - mcv negative / low positive ra patients ( p < 0.05 ) ( table 2 ) .
the level of comp in ra patients did not differ from that in healthy donors : 472.5 ( 375.0600.0 )  ng / ml n = 34 and 550.0 ( 435.0740.0 )  ng / ml , respectively , p > 0.05 .
alongside with that , a positive correlation between comp concentration and anti - ccp levels ( r = 0.4 ,  p = 0.02 ) , anti - mcv ( r = 0.5 ,  p = 0.002 ) , x - ray phase ( r = 0.4 , p = 0.02 ) have been identified . in the group of patients with radiologic stages
i and ii , the level of comp was lower than that in patients with ra stages iii and iv , p < 0.05 ( 435.0 ; 367.5472.5 and 550.0 ; 375.0780.0 , resp . ) .
the level of mmp-3 among ra patients was higher ( 35.0 ; 12.566.5  ng / ml , n = 52 ) in comparison with the group of healthy donors ( 7.7 ; 5.511.8  ng / ml , p < 0.05 ) . a positive correlation of the level of mmp-3 with esr ( r = 0.4 , p = 0.01 ) and cpr concentration ( r = 0.4 , p = 0.001 ) in blood was observed .
depending on the positivity level for igm rf , anti - ccp , and anti - mcv , all patients were divided into groups : high - positive ( n = 84 ) and negative / low positive ( n = 30 ) for igm rf ; positive ( n = 94 ) and negative ( n = 20 ) for igm rf ; high - positive ( n = 89 ) and negative / low positive ( n = 25 ) for anti - ccp ; and positive ( n = 95 ) and negative ( n = 19 ) for anti - ccp .
groups of patients , divided according to the level of autoantibodies , are shown in figures 1 and 2 .
no differences in demographic indicators , administration of dmards and glucocorticoides , disease activity , and the level of laboratory biomarkers in groups of ra patients positive for igm rf and anti - ccp have been identified ( p > 0.05 ) ( data not shown ) . among high - positive anti - mcv patients ( n = 79 ) , the higher values of mtss and jsn and the increased levels of comp , esr , igm rf and anti -
ccp were observed as compared with these indicators in anti - mcv negative / low - positive ( n = 27 ) ra patients ( p < 0.05 ) ( table 2 ) .
besides , an increased concentration of mmp-3 was recorded more frequently in the group of high - positive anti - mcv patients ( n = 64 ) as compared with that in patients with negative / low - positive anti - mcv titres ( n = 16 ) ( in 56.0% and 31.0% of cases , respectively , p = 0.038 ) .
patients who are acpa positive are especially prone to rapid radiographic progression , [ 2226 ] and early aggressive treatment will particularly slow progression in those patients . less is known about the importance of the subtypes of acpa related to prognosis .
our results also confirm that there are relationships between hyperproduction of acpa ( primarily anti - mcv ) , radiologic signs of erosive lesion to joints , and an increased level of markers of bone and cartilage destruction in ra .
our study shows that the presence of antibodies towards citrullinated vimentin is a stronger predictor of radiographic progression , compared with anti - ccp and rf .
patients who are anti - mcv positive are especially prone to rapid radiographic progression and need early aggressive treatment .
similar evidence on higher contribution of anti - mcv into development of destructive changes in the joints was obtained by syversen et al . , while evaluating the prognostic value of anti - ccp and anti - mcv in 238 ra patients .
the 10-year follow - up of anti - mcv - positive patients has demonstrated a higher incidence rate of radiologic progression ( by total modified sharp score ) as compared with anti - ccp - positive patients ( 7.3 and 5.7 respectively , p < 0.01 ) .
radiologic progression depended on the level of anti - mcv and reached maximum values in patients with concentration of this indicator higher than 254  u / ml . on a large group of ra patients ( n = 273 ) , mathsson et al .  
have also demonstrated a high rate of progression of destructive changes in the joints ( by the change in larsen score ) in anti - mcv - positive patients . according to our data , high - positive levels of anti - mcv
are associated with higher concentrations of markers of bone and cartilage destruction in blood serum ( comp , mmp-3 ) , as well as with more pronounced destructive changes in the joints confirmed by radiography .
when analyzing the groups of patients who were high - positive and negative / low - positive for anti - ccp , no significant differences have been obtained in comp concentration and mmp-3 ( p > 0.05 ) . among high - positive anti - mcv patients , higher levels of igm rf and anti - ccp were recorded significantly more frequently , what may provide an additional impact on the rate and intensity of destruction of the joints in this group of patients .
the association between acpa status and radiographic progression is well established , [ 2226 ] but the mechanisms behind this association are not known .
acpas have been shown to contribute to disease progression by amplifying inflammation and damage in an animal disease model .
alternative explanations for a more aggressive disease course in patients with high levels are that high acpa levels could reflect either a more evolved immunological response or , as reported from a genome wide association study , a different genetic background . according to our data ,
anti - mcv affects bone and cartilage destruction in a higher degree as compared with anti - ccp .
vimentin presents a natural citrullinated protein that is synthesized and modified in macrophages of a synovial sheath affected by proinflammatory cytokines .
the evidence of pathogenetic relationships between anti - mcv and activity of osteoclasts in ra patients has also been obtained .
harre et al . [ 16 , 17 ] have demonstrated a decreased level of pad4 with a parallel increase in expression of pad2 and cv in the process of differentiation of osteoclast precursors into mature cells .
the laser scanning microscopy technique has revealed a direct binding of serum anti - mcv with cv on the surface of osteoclast precursors inducing a dose - related stimulation of bone resorption and osteoclastogenesis .
an adaptive transfer of human affine - purified anti - mcv induced in mice rag 1 an increased number of osteoclasts in metaphyses of bones , an increased serum concentration of tnf- and ctx1 with the unchanged level of osteocalcin in blood , and an increased number of cd11bcd14 osteoclast precursors of the spleen with hyperexpression of membrane receptors for mcsf and rankl .
the level of comp in our ra patients did not differ from that in healthy donors .
recently , serum comp was evaluated in patients with ra and was found to be preferentially elevated not in late - stage ra but in early - stage ra . we have found a positive correlation between comp concentration , anti - ccp levels ( r = 0.4 , p = 0.02 ) , anti - mcv ( r = 0.5 ,  p = 0.002 ) , and radiologic stage of disease ( r = 0.4 ,  p = 0.02 ) and higher levels of comp in patients with iii and iv x - ray phases .
n = 98 ) , comp values were statistically high in subjects positive for bone erosions on mri ( 12.0  u / l ) compared with the subjects who were negative for bone erosions ( 10.16  u / l , p = 0.017 ) . also several authors have found a positive correlation between comp level and delta larsen score [ 20 , 21 ] . besides , a number of authors have demonstrated correlations between the level of anti - mcv and disease activity [ 33 , 34 ] . also hyperproduction of anti - mcv is associated with higher clinic - laboratory activity of disease ( das 28 , esr , crp ) and an increased rate of exacerbations per year .
anti - ccp is less dependent on the clinical and laboratory disease activity [ 5 , 36 ] .
our study has revealed a positive correlation of the anti - mcv level with indicators of disease activity , sdai and cdai , and an increase in esr values in patients who are high - positive for anti - mcv .
this is not a longitudinal study ; data and blood samples were only collected and analyzed at one time point .
it may be assumed that the detection of anti - mcv could be a consequence of destructive events , rather than a cause .
however , given the data of other authors ( that have looked at anti - mcv as a predictive marker of erosions ) , this alternative hypothesis could likely be discarded .
thus , the results of our study have suggested that there is relationship between the level of autoantibodies in blood serum and the development of destructive changes in the joints .
anti - mcv affects bone and cartilage destruction in a higher degree as compared with anti - ccp and igm rf .
patients who are anti - mcv positive are especially prone to rapid radiographic progression and need early aggressive treatment .
 
 objective . to make individualised decisions regarding treatment is one of the most important challenges in clinical practise , and identification of sensitive and specific markers of prognosis is an important research question . 
 the main objective of this study was to evaluate relationships between the level of autoantibodies , radiographic changes and laboratory markers of bone , and cartilage destruction . 
 methods . a total of 114 ra patients were examined . 
 the serum concentration of igm rf , antibodies to cyclic citrullinated peptide ( anti - ccp ) , modified citrullinated vimentin ( anti - mcv ) , matrix metalloproteinase 3 ( mmp-3 ) , and cartilage oligomeric matrix protein ( comp , ng / ml ) were measured . 
 the van der heijde - modified sharp score was used to quantify the radiologic changes . results . among the patients who were high - positive for anti - mcv , the value of total modified sharp score ( mtss ) ( 96.5 ; 66120 ) was higher as well as the joint space narrowing ( 82 ; 60.5105.5 ) , and a higher level of mmp-3 
 was recorded more frequently ( 56% ) in comparison with negative / low - positive patients ( 57 ; 3188 , 50 ; 2982 , 31% resp . 
 , p < 0.05 ) . 
 the level of comp was also higher among patients high - positive for anti - mcv ( 9.7 ; 8.113.1 and 6.8 ; 5.410.7 , resp . 
 , p = 0.02 ) . conclusion 
 . a high positive level of anti - mcv as contrasted with anti - ccp and igm rf is associated with more pronounced destructive changes in the joints . 
1. Introduction
2. Materials and Methods
3. Results 
4. Discussion
5. Conclusions