Influence of RANKL and OPG in Hemophilic arthropathy


Yussur Falah Faraj, Fatma Abd Alhamza Obed, Baan Abdulatif Mtashar,

Nidal Karim Al-Rahal, Jaafar Hussien Kareem.

National Center of Hematology, Mustansiriyah University, Baghdad, Iraq.

*Corresponding Author E-mail:



Background: Hemophilia is a bleeding disorder characterized by recurrent bleeding, especially in joints (hemarthrosis), leading to destructive effect to the most of joint components, resulting in synovitis, osteochondral degeneration, and eventually, end-stage hemophilic arthropathy. Objective: Since few published data exist about the influence of OPG (Osteoprotegrin) and RANKL (receptor activator of nuclear factor-kappa B ligand) in haemophilic arthropathy, the present study is conducted to investigate their serum level in hemophilic patients. Methodology: This study has been carried out on Iraqi patients with hemophilia in the National Center of Hematology/Mustansiriyah University. Forty male patients involved in this study with a range of (11-44) years old, Hemophilia A affected 25 of them, while the other 15 were hemophilia B. Along with patient group, 20 healthy subjects with matched age and gender were involved as control group. The presence and severity of arthropathy among patients was determined based activated partial thromboplastin time (aPTT)) in hemophilic patients, while RANKL and OPG were determined in the serum samples of healthy and patient subjects. Result: The serum level of RANKL in Hemophilia A patients was (204.6pg/ml) is significantly (p0.001) higher than in control (164.5pg/ml) and in Hemophilia B patients was (200pg/ml). While the serum level of OPG in Hemophilia A patients was (67.2pg/ml) is significantly (p0.002) higher than in control (30.21pg /ml) and in Hemophilia B patients (48.85pg/ml). Conclusion: It can be concluded that this system RANKL, RANK, and OPG are important for the metabolism of bones.


KEYWORDS: Hemophilia, Hemarthrosis, RANKL, aPTT, OPG.




Hemophilia A and B are X-linked congenital bleeding disorders caused by a lack of or absence in coagulation factor VIII (FVIII) or factor IX (FIX). Joint bleeding is the most prevalent symptom in both adults and children with severe hemophilia.1-2 Hemophilia arthropathy commonly starts with proliferative synovitis, which is comparable to rheumatoid arthritis (RA) and osteoarthritis (OA), but may be more complex in haemophilic patients3-4. Analysis of biomarkers of joint disease can be valuable in observation the effects of joint bleeding and evaluating the therapy of such bleeds.3


In rheumatoid arthritis (RA) or osteoarthritis (OA) patients, a crucial pathway regulating bone biology is the

molecular triad consisting of receptor activator of nuclear factor-kB (RANK), RANK ligand (RANKL), and Osteoprotegerin which tightly controls bone turnover.5


RANKL binds to its receptor RANK expressed on the cell surface of osteoclast precursors, and induces osteoclast differentiation and maturation, leading to bone resorption. In the synovium, RANKL is expressed by fibroblast-like synoviocytes (type B synoviocytes) and by activated T cells, and may induce osteoclastogenesis through a mechanism enhanced by several cytokines, including TNF-α, interleukin 1 (IL-1), and IL-17, that promote both inflammation and bone resorption6-7. The secretion of RANKL by activated T cells and expression of RANKL by synovial cells in inflamed joints contribute in joint destruction in rheumatoid arthritis8. On the other hand, OPG acts as a decoy receptor for RANKL and competes for binding of RANKL to RANK, that inhibits osteoclast differentiation, activity, and survival both in vivo and in vitro.8-9



A control-based study has been carried out on Iraqi patients with hemophilia in the National Center of Hematology/Mustansiriyah University. forty male patients involved in this study with age ranged from (11-44) years, 25 of them were detected as hemophilia A, while 15 were diagnosed as hemophilia B. Along with patient group, 20 healthy subjects with matched age and gender were involved as control group. All patients were subjected to routine examinations (aPPT). From all subjects (healthy and patients), 5ml of peripheral vein blood were aspirated and divided into 2 aliquots; the first aliquot was prepared in citrate to obtain plasma for directly examination of activated partial thromboplastin time (aPTT) by using Coagulometer Stago (France) to check the coagulation process status11. While the second one was left in gel tube to obtain serum for determining serum level of the RANKL and OPG using the R and D, (USA), sandwich ELISAS kit. Data were analyzed by using Vassar Stats Web Site for Statistical Computation 12.



Out of 40 male patients; 25 of them have hemophilia type A (HA), and the rest 15 have hemophilia type B (HB). Table-1 shows non-significant difference in the age of patients (26.03year) comparing with that of control group (27.5 year).


Table-1: Matching of the age between patients and control group

Age (years)

Control (n=20)

Patients (n=40)

P value






Table-2 shows that the serum level of RANKL in patients of HA group (204.6pg/ml) is significantly (p0.001) higher than those in control (164.155pg/ml) and in HB group (200pg/ml).


Table:2 The serum level of RANKL in control and hemophilic patients groups.




P- value













Table-3 shows the serum level of OPG in patients of HA group (67.2pg/ml) is significantly (p0.002) higher than those in control (30.21pg/ml) and in HB group (48.85 pg/ml). However Table-4 shows serum level of RANKL is highly significantly (p=0.001) with joint, knee and ankle. While, table-5 shows that serum level of RANKL doesn’t have significant positively correlation (r = 0.180, p = 0.267) with OPG and not significantly positive correlation (r = 0.14, p = 0.387) with APTT, also that serum level of OPG has no significant positively correlation (r = 0.153, p = 0.345) with APTT


Table-3 shows the serum level of OPG in control and hemophilic patients groups

















Table-4 shows biomarkers of RANKL with clinical sign in hemophilic patients

Clinical sign



















Table-5 shows correlation between biomarkers and APTT







R = 0.180

R = 0.14

P = 0.267

P = 0.387


R= 0.180


R = 0.153





Along with patient groups, 20 healthy subjects with matching age and gender are involved to act as control group as shown in (Table-1) that revealed non-significant difference in the age of patients (26.03.2 year) comparing with that of control group (27.5 year).


From Table-2 and Table-3, all biomarkers RANKL and OPG had abnormal serum levels in hemophiliaA patients compared to healthy people and hemophilia B patients, indicating that these markers have a significant role in the deterioration of joint condition in the patients of HA. Chronic inflation and delayed healing both lead to the activation of RANKL/OPG system which is responsible for extension joint damage deeper to subchondral bone. However, hemophilic arthropathy in HB patients appears less frequent because there is no chronic inflammation (i.e. normal RANKL/OPG ratio like those in healthy people.


In comparison to these findings, there are few published data on biomarker correlations with joint status in patients with haemophilia because haemophilic arthropathy is a systemic disease that affects only a few joints, and the severity and activity of the arthropathy is determined by the frequency and severity of bleeding events in specific joints.13 As a result, analyzing biomarkers of joint illness in haemophilia patients may be more difficult than in people with RA or OA.4


The RANKL and OPG values reported in this study are not consistent with those found in other recent studies. The RANK/RANKL/OPG molecular triad was compared in patients with hemophilia A and B, and it was discovered that patients with hemophilia A had lower OPG expression in synovial tissue than patients with hemophilia B, emphasizing the severity of arthropathy in the hemophilia A group14.


In the second and third decade of life, people who have a case of severe hemophilia, have chronic degenerative changes (hemophilic arthropathy) in one to six major joints (ankles, knees, elbows). Recurrent spontaneous intra-articular hemorrhages are the primary source of these degenerative changes15-17. The Pettersson score is a comprehensive radiologic categorization of hemophilic joints developed by the World Federation of Hemophilia to assess the degree of radiological joint degradation 18.


However, Table-5 shows Correlation of serum level of biomarkers (RANKL and OPG) with clinical manifestations of hemophilic patients like APTT there is non- significant and also positive correlation between RANKL and OPG.



From all these findings, it can be concluded that the serum level of RANKL and OPG are much higher in HA patients than in HB. Changes in the RANK Ligand (RANK-L)/Osteoprotegerin (OPG) pathway are thought to cause bone turnover during hemarthrosis. RANK-L increases bone resorption by binding to its receptor on osteoclasts, but OPG works as a decoy receptor, preventing RANK-L from interacting with its real receptor, thereby protecting bones against excessive resorption.



The authors have no conflicts of interest regarding this investigation.



The authors would like to thank the laboratory staff in hematology and hemophelia department during hematological and all other lab studies.



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Received on 27.09.2021           Modified on 02.12.2021

Accepted on 12.01.2022         © RJPT All right reserved

Research J. Pharm. and Tech. 2022; 15(8):3656-3658.

DOI: 10.52711/0974-360X.2022.00612