Clinical, Instrumental, Serological and Histological Findings Suggest That Hemophilia B May be Less Severe Than Hemophilia A

Background: Recent evidences suggest that patients with severe hemophilia B (HB) may have a less severe disease compared to severe hemophilia A (HA). Objectives: to investigate clinical, radiological, laboratory and histological differences in the arthropathy of severe HA and HB. Patients/Methods: 70 HA and 35 HB patients with at least one joint bleeding were consecutively enrolled. In all patients were assessed: joint bleedings ( 50), regimen of treatment (prophylaxis/on demand), WFH, Pettersson and ultrasound (US) scores, serum sRANKL and OPG. Expression of RANK, RANKL and OPG was also evaluated in synovial tissue from 18 HA and 4 HB patients. Chi-square test, T-test, Mann-Whitney and Spearman9s rank correlation coefficient were performed. Results: The percentage of patients with either 10-50 or >50 hemarthrosis was greater in HA than in HB (p s RANKL were decreased in HA versus HB (p 50 hemarthrosis. The expression of OPG was markedly reduced in synovial tissue from HA patients. Conclusions: The reduced number of hemarthrosis, the lower WFH and US scores and higher OPG levels in serum and expression in synovial tissue in HB suggest that HB is a less severe disease than HA. OPG reduction seems to play a pivotal role in the progression of arthropathy in HA. Disclosures No relevant conflicts of interest to declare.