Proposed Biomarker for Rare Cartilage Disease Fails Scientific Scrutiny

Scientists have long sought a reliable biomarker for relapsing polychondritis (RP), a rare and painful disease characterised by recurrent inflammation of cartilage. Antibodies that target collagen II, a key protein in cartilage, were a promising candidate, but a comprehensive new evaluation has found them wanting.

In a two-part investigation, researchers first measured anti-collagen II antibody levels in a cohort of patients, finding they performed poorly in distinguishing RP from similar inflammatory diseases, with a low sensitivity of just 18%. Their levels also failed to correlate with disease activity.

Alongside this, a systematic review and meta-analysis of over 2,400 articles confirmed the findings on a larger scale. The analysis showed no significant association between the antibodies and RP. Instead, the antibodies were linked to a broad group of inflammatory diseases that involve cartilage. The study's authors conclude that using this antibody test for the diagnosis or monitoring of RP is not advisable.