Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.


Characteristics of Anti-Cyclic Citrullinated Peptide Antibody and/or Rheumatoid Factor Positive Juvenile Idiopathic Arthritis in the Childhood Arthritis and Rheumatology Alliance Registry.

Prahalad1,  Sampath, Angeles-Han1,  Sheila, Ponder1,  Lori, Kennedy1,  Christine W., Vogler1,  Larry B., Investigators2,  CARRANet

Emory Children's Center, Atlanta, GA
Stanford

Background/Purpose:

JIA is a common chronic arthropathy with a prevalence of ~1/1000 in children under 16 years of age. The ILAR classification criteria categorize JIA into seven subtypes. Of these, rheumatoid factor (RF) positive polyarthritis resembles adults with seropositive RA. It is now recognized that anti-cyclic citrullinated protein antibodies (CCP) are highly specific for RA. Prior reports of CCP in children with JIA have been in modest sized cohorts from single institutions. Our objective is to characterize children with RF/CCP positive-JIA enrolled in the CARRANet Registry.

Methods:

Children with JIA from pediatric rheumatology clinics in the US were enrolled in the CARRAnet Registry from May 2010 until June 2011. Demographic and disease-related data were collected from time of diagnosis to enrollment. Children who were positive only for CCP (RF negative) were compared with children who were positive for two out of three tests for biomarkers of RA: RF initial (RFI), RF confirmatory (RFC), and CCP. Nominal variables were compared using Chi-square or Fisher's exact tests. Continuous variables were compared using Student's T test.

Results:

In all, of 2725 children with JIA in the database, 535 were reported as not having been tested for either RF/CCP. Children who were not tested for RF/CCP had an earlier onset age than children who were tested (5.2 vs. 6.7 years, p <0.0001). In those tested for RF and/or CCP, the prevalence of CCP was 11.4% (number positive/number tested = 112/978), RFI was 10.9% (234/2141), and RFC was 12.7 % (124/971). Of 937 children tested for both RFI and CCP, 82 % were negative for both, 10.4% positive for both, 1.8% positive for CCP only and 6.4% positive for RF only. Characteristics of children positive for CCP only compared to those who had at least two out of three positive tests are shown in Table 1. Except for subtype distribution, there were no differences. By contrast, the 35 children who were positive only for RFI were significantly younger compared to those who had at least 2 out of 3 positive tests, 6.5 vs. 10.9 years, p <0.0001. 32 individuals were positive for RFI, but were negative for RFC. 18 of these also had a negative CCP when tested. There were 12 children who had 2 positive RFs, but had a physician assigned diagnosis of a JIA subtype other than RF positive polyarticular or undifferentiated JIA (Systemic 2, RF negative poly 1, persistent oligoarthritis 6, psoriatic 2, ERA 1).

Table 1. Characteristics of CCP and RF positive children with JIA*

 CCP only2 out of RFI, RFC and CCPp
Total Number16153 
Age at symptom onset (mean ±SD)9.3 (5.2)10.9 (3.8)ns
Demographic features...
Female gender13133ns
Hispanic ethnicity442ns
African ancestry424ns
Family history of autoimmunity233ns
Family history of RA012ns
Physician assigned JIA subtype...
ERA02ns
Oligoarticular extended21<0.001
Oligoarticular persistent38ns
Polyarticular RF-61<0.0001
Polyaticular RF+3131<0.0001
Psoriatic12ns
Systemic-onset12ns
Undifferentiated05ns
Measures of disease...
CHAQ (mean)0.430.46ns
MD Global (mean)2.62.4ns
Imaging evidence of damage462ns
Current joint count (mean)5.73.4ns
Treatment...
Use of systemic steroids13119ns
Use of DMARD ever15144ns
Use of biologic ever10109ns
* All values are N, except as indicated. CCP: anti cyclic citrullinated protein antibody. RFI: Rheumatoid factor, initial. RFC: rheumatoid factor, confirmatory. ns: not significant.

Conclusion:

This is the largest described cohort of RF/CCP positive children with JIA. Although ILAR criteria require testing of all children for RF, 21% of children with JIA in the CARRANet registry did not have reports of being tested for RF, possibly underestimating the number of children with RF positive JIA. The prevalence of RFI and CCP are comparable. A number of children with RFI were negative when retested for RF. Inclusion of CCP positivity in future revisions of the JIA criteria will improve the specificity of diagnosing childhood onset RA.

To cite this abstract, please use the following information:
Prahalad, Sampath, Angeles-Han, Sheila, Ponder, Lori, Kennedy, Christine W., Vogler, Larry B., Investigators, CARRANet; Characteristics of Anti-Cyclic Citrullinated Peptide Antibody and/or Rheumatoid Factor Positive Juvenile Idiopathic Arthritis in the Childhood Arthritis and Rheumatology Alliance Registry. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :289
DOI:

Abstract Supplement

Meeting Menu

2011 ACR/ARHP