Anticollagen antibodies predict favorable prognosis in RA
medwireNews: Antifibrillar collagen type II (anti-CII) antibodies are associated with a favorable inflammatory outcome among patients with rheumatoid arthritis (RA), researchers report.
“Analysing these antibodies, in combination with other relevant antibodies, could be used for predicting prognosis and choosing therapy for rheumatoid arthritis patients,” study lead Johan Rönnelid (Uppsala University, Sweden) said in a press release.
Rönnelid and colleagues analyzed data from the Swedish Epidemiological Investigation in Rheumatoid Arthritis study and the Swedish Rheumatology Quality Register, and found that anti-CII antibodies were present in 6.6% of 1476 patients with RA.
The presence of anti-CII antibodies was associated with elevated levels of C-reactive protein, in addition to higher erythrocyte sedimentation rate, swollen joint count, and disease activity scores, at the time of diagnosis and up to 6 months later.
However, the antibodies were associated with improvements in these measures over 5 years of follow-up.
Anti-CII antibodies could thus be linked to “a distinct RA phenotype characterised by acute but transient inflammation around the time of diagnosis,” suggest the researchers in the Annals of the Rheumatic Diseases.
Patients with anti-CII antibodies were also more likely to achieve a moderate or good EULAR response. At the 5-year follow-up, 94.7% of 38 anti-CII-positive patients with available disease activity data attained a EULAR response, compared with 80.6% of 397 anti-CII-negative patients.
“[T]he detection of anti-CII could predict a less aggressive disease course as compared with antibody-negative patients,” say Rönnelid and team.
Conversely, the presence of anti-cyclic citrullinated peptide (CCP)2 antibodies was associated positively with higher disease activity later in the 5-year follow-up period and negatively with EULAR response at the 3- and 5-year timepoints.
Median levels of anti-CCP2 antibodies were higher among ever versus never smokers (159.00 vs 18.71 AU/mL), but smokers had lower levels of anti-CII antibodies (15.2 vs 16.5 AU/mL).
Furthermore, anti-CCP2 was associated with various HLA-DRB1* alleles – associations that no longer remained after shared epitope (SE)-positive individuals were excluded from the analysis – whereas anti-CII expression was positively associated with HLA-DRB1*03 and negatively associated with HLA-DRB1*04. The association between anti-CII and HLA-DRB1*03 remained significant after the exclusion of SE-positive individuals.
Anti-CII-positive RA “in many ways behaves as the opposite to ACPA [anticitrullinated protein peptide autoantibody]-associated RA concerning clinical outcome, HLA-DRB1* association and relation to smoking history,” explain the authors.
And they conclude that “the combined analysis of anti-CII and ACPA/anti-CCP2 may be a new two-dimensional tool for predicting the prognosis and choosing therapy in newly diagnosed patients with RA.”
By Claire Barnard
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