Endothelial specific isoform of type XVIII collagen (COL-18N): A marker of vascular integrity in haemophilic arthropathy

Background Haemophilic arthropathy (HA) is a major complication in haemophilia. Collagens IV, XV and XVIII are responsible for maintaining the integrity of the vessel wall in the joint. Following joint remodelling and damage, the short isoform of collagen type XVIII (COL-18N) is degraded, releasing measurable fragments. Our goal was to quantify the specific isoform COL-18N in haemophilia A patients and to assess its relation to the clinical and radiological data as well as haemophilia joint health score (HJHS), functional independence score for haemophilia (FISH), and haemophilia quality of life (Haemo-Qol). Methods This cross-sectional study included 50 haemophilia A patients recruited from the Paediatric Haematology and Oncology unit, Ain Shams University, Cairo, Egypt. Quantification of COL-18N was done by ELISA. Assessment of joint state clinically using FISH and HJH scores and radiologically by X-rays and ultrasound. Results Haemophilia A patients had significantly higher median COL-18N levels compared to the control group. Inhibitor positive and negative haemophilia A patients as well as those on non-steroidal anti-inflammatory drug and those not had comparable COL-18N levels. Patients with >= 2 target joints had significantly higher COL-18N level compared to those with one or those without target joints. There were significant positive correlations between COL-18N level and the total HJHS, Haemo-Qol, the HEAD-US score and annual bleeding rate. Conclusion Our results demonstrated a high level of COL-18N in haemophilia A patients and argued its benefit as a potential marker for monitoring the development of haemophilic arthropathy and tailoring the optimal treatment to prevent further joint damage.