AB0846 HLA-B51 prevalence in patients with spondyloarthritis and impact on disease phenotype: a case-control study

Background

Spondyloarthritis (SpA) is a group of rheumatic diseases with a heritable component associated with Human Leucocyte Antigen B27 (HLA-B27). Although many studies have reported an overlap between the clinical features of SpA and Behcet’s disease (BD), as well as an increased prevalence of HLA-B27 in BD, the prevalence of HLA-B5 (namely B51 and B52, the split antigens of B5) in SpA, have been scarcely examined, particularly in countries with a low HLA-B27 prevalence.

Objectives

To estimate the prevalence of HLA-B51 and HLA-B52 in patients with SpA compared to healthy controls (HC), to identify the alleles found in HLA-B locus in patients with SpA compared to HC, and to evaluate the impact of HLA-B51 on SpA disease phenotype.

Methods

A case-control study included consecutive patients with a diagnosis of SpA (axial SpA (axSpA), peripheral SpA (pSpA), and psoriatic arthritis (PsA)) from three rheumatology clinics. HC were recruited among blood donors and medical students. Demographic data, as well as SpA and BD disease features, were collected through an interview with a trained medical student and file review (low back pain, peripheral joint disease, enthesitis, dactylitis, psoriasis, uveitis, inflammatory bowel disease, family history, oral and genital ulcerations, skin, vascular and neurologic manifestations, CRP, BASDAI, imaging of the spine and sacroiliac joints). The entire B locus was tested using molecular biology technique on Luminex with the possibility of precise B51/B52 differentiation. The prevalence of HLA-B51/B52 was calculated in patients and compared to HC using the Chi-square test. A complete HLA-B mapping was performed for patients and HC. A binary logistic regression identified factors associated with HLA-B51 in patients with axSpA.

Results

Data from 119 HC and 89 patients with SpA were available (66 axSpA, 16 pSpA, and 7 PsA). Mean age of the patients was 44.8 years [SD 13.5], 66.3% were males, disease duration was 12 years [SD 12.7], 72.4% had a history of elevated CRP, 30.3% were positive for HLA-B27, 53.9% had sacroiliitis on MRI, 47.2% had radiographic sacroiliitis, and 23.6% had syndesmophytes. Oral ulcerations were reported in 38.2% of patients, genital ulcerations in 3.4%, uveitis in 5.6%, skin lesions in 18%, and vascular lesions in 3.4%. Patients with SpA fulfilled the classification criteria for BD in 2.9% (International Study Group criteria for BD) and 38.2% (International Criteria for BD). HLA-B51/B52 were found more frequently in patients with SpA (20.2%/ 7.9%) compared to HC (11.8%/4.2%), although the difference was not statistically significant. The difference was mainly driven by ant association between HLA-B51 and axSpA (27.2% versus 11.8%, OR 2.8 [95%CI 1.3-6.1], p=0.008) (Table 1). The most frequent allele in SpA and HC was HLA-B35; complete HLA-B mapping is shown in Figure 1. In patients with axSpA, HLA-B51 was associated with radiographic damage in peripheral joints, while it was negatively associated with sacroiliitis. Uveitis was numerically associated with HLA-B51, but the association did not reach statistical significance.

Table 1.

Prevalence of HLA-B5 genes in patients with spondyloarthritis (SpA) and healthy controls

ControlsSpAAxial SpAPeripheral SpAPsoriatic Arthritisp-value (SpA vs. Controls)p-value (axSpA vs controls)N1198966167HLA-B51+, N (%)14 (11.8)18 (20.2)18 (27.3)0 (0.0)0 (0.0)0.0940.008HLA-B52+, N (%)5 (4.2)7 (7.9)5 (7.6)2 (12.5)0 (0.0)0.2620.331HLA-B51 or HLA-B52+, N (%)19 (16)21 (23.6)19 (28.8)2 (12.5)0 (0.0)0.1670.039Figure 1.

Distribution of the HLA-B alleles in patients with spondyloarthritis and healthy controls (Statistically significant differences between patients and controls indicated with*)

Conclusion

HLA-B51/B52 were more numerically more prevalent in patients with SpA compared to HC. A statistically significant association was found between HLA-B51 and axSpA and correlated with more peripheral and less axial radiographic involvement.

Acknowledgements

The authors would like to thank the Research Council of Saint-Joseph University and NewBridge Pharmaceuticals FZ LLC for an unrestricted research grant to fund the study.

Disclosure of Interests

Nelly Ziade Speakers bureau: Roche, Abbvie, Eli Lilly, Pfizer, Janssen, Novartis, Pierre Fabre, Apotex, Pharmaline, Paid instructor for: Abbvie, Eli Lilly, Sanofi-Aventis, Pfizer, Janssen, Novartis, Grant/research support from: NewBridge Pharmaceutical FZ LLC (current study), Pfizer, Abbvie, Celgene, Rhea Nacouzi: None declared, Kamel Mroue’ Speakers bureau: Roche, Abbvie, Eli Lilly, Pfizer, Janssen, Novartis, Georges Merheb Speakers bureau: Roche, Abbvie, Eli Lilly, Pfizer, Janssen, Novartis, Pierre Ghorra: None declared

Oral manifestations associated with inherited hyperhomocysteinemia: A first case description

Hyperhomocysteinemia is a rare disease caused by nutritional deficiencies or genetic impairment of cysteine metabolism. To date, no oral manifestations of hyperhomocysteinemia have been described in humans. Therefore, to our knowledge, the present case report is the first description of a hyperhomocysteinemic patient showing oral tissue alterations leading to both early tooth loss and failed implant osseointegration. The patient presented with a methylenetetrahydrofolate reductase gene mutation (677T polymorphism) leading to mild hyperhomocysteinemia. The radiologic analysis showed hyperdense lesions scattered in the maxillae. The histologic observations indicated alterations in both collagen and elastic networks in the gingiva and dermis. Interestingly, the presence of ectopic mineralized inclusions was noted in both periodontal ligament and gingiva. Strong osteoclastic activity was associated with abnormal calcification of trabecular spaces. Uneven oral tissue remodeling due to high tissue levels of homocysteine could explain the pathologic manifestations observed in this case.

Added Value of Anti-CD74 Autoantibodies in Axial SpondyloArthritis in a Population With Low HLA-B27 Prevalence

Axial spondyloarthritis (axSpA) is often diagnosed late due to the non-specific nature of its main symptom [chronic back pain (CBP)] and to the paucity of diagnostic markers, particularly in regions with low HLA-B27 prevalence, such as the Middle-East. We tested the performance of IgG4 and IgA anti-CD74 antibodies as an early diagnostic marker for axSpA, compared with the performance of HLA-B27, in Lebanon. Sera of axSpA patients diagnosed by the rheumatologist and also fulfilling the imaging arm of the ASAS criteria (patients) and of blood donors (BD) (controls) were analyzed for HLA-B27, IgG4 and IgA anti-CD74, blinded to clinical characteristics. Receiver Operating Characteristic curves were constructed to identify an optimal cut-off point for anti-CD74 antibodies. Diagnostic properties were calculated (sensitivity, specificity, positive, and positive predictive values (PPV, NPV), Likelihood ratios) for each marker. Forty-nine axSpA patients and 102 BD were included in the final analysis. IgA anti-CD74 correlated poorly with axSpA (Area Under the Curve (AUC) 0.657), whereas IgG4 anti-CD74 had a good discriminative value (AUC 0.837). Respectively, for HLA-B27, IgG4 anti-CD74, and the combination of both, we found a sensitivity of 33-92-33%, specificity of 96-79-98%, PPV 80-68-89%, NPV 75-95-75%, and LR+ 8.2-4.4-16.5. IgG4 anti-CD 74 were positive in 88% of HLA-B27 negative axSpA patients, and correlated with BASDAI. In this first study in a population with low HLA-B27 prevalence, IgG4 anti-CD74 antibodies combined with HLA-B27 showed higher diagnostic value than HLA-B27 alone for early axSpA. IgG4 anti-CD74 should be considered for further evaluation as an early axSpA diagnostic marker in future dedicated research, particularly in patients with CBP.

HLA-B27 prevalence in axial spondyloarthritis patients and in blood donors in a Lebanese population: Results from a nationwide study

AIM

To calculate the prevalence of human leukocyte antigen (HLA)-B27 in axial spondyloarthritis patients (axSpA) compared to blood donors (BD) in Lebanon, to identify the clinical and radiological findings associated with HLA-B27 and to estimate the proportion of patients fulfilling the clinical arm of the Assessment of the Spondyloarthritis International Association (ASAS) criteria.

METHOD

Consecutive Lebanese adult axSpA patients fulfilling the ASAS classification criteria were included from 12 rheumatology clinics across Lebanon. BD served as controls. A binary logistic regression was used to study the association between HLA-B27 and the disease features.

RESULTS

A total of 247 individuals were included (141 axSpA patients and 106 BD). The prevalence of HLA-B27 was 3.8% in BD and 41.1% in axSpA. Overall, 39.7% of the axSpA patients fulfilled the clinical arm of the ASAS classification criteria. Sensitivity of HLA-B27 for axSpA was 41.1%, specificity was 96.2%, positive predictive value was 93.6%, and negative predictive value was 55.13%. Positive likelihood ratio (LR) was 10.9 and negative LR was 1.63. We found a positive association of HLA-B27 with family history of SpA and psoriasis.

CONCLUSION

Our study confirmed a low prevalence of HLA-B27 in axSpA patients and BD in this Lebanese population, However, we found a high specificity and positive LR, as well as the same number of axSpA patients fulfilling the clinical arm of the ASAS criteria as in European studies. HLA-B27 is therefore valuable for identification of axSpA in Lebanese patients despite the overall low prevalence in this population. Our results may guide future evaluations the role of HLA-B27 in planning local referral strategies.

Effects of clopidogrel on soluble CD40 ligand and on high-sensitivity C-reactive protein in patients with stable coronary artery disease

BACKGROUND

Antiplatelet therapy with clopidogrel decreases ischemic complication especially in patients with acute coronary syndromes or after percutaneous coronary interventions. Our study was designed to test the effects of clopidogrel on soluble CD40 ligand (sCD40l) and on high-sensitivity C-reactive protein (hs-CRP) in patients with stable coronary artery disease (CAD).

METHODS

This is a randomized, double-blind, placebo-controlled study. A total of 73 patients with stable CAD for > 6 months were randomized to receive either clopidogrel (loading dose 300 mg followed by 75 mg/d) for 8 weeks or placebo. Soluble CD40 ligand and hs-CRP were measured at baseline and at completion of the study.

RESULTS

All patients were on aspirin therapy, and 74% were on statins. Median and interquartile ranges (IQR) of sCD40l decreased from 64 pg/mL (43-99) at baseline to 53 pg/mL (35-77) at 8 weeks (P = .03) in the clopidogrel group and remained unchanged in the placebo group (59 pg/mL, IQR 35-77 vs 55 pg/mL, IQR 35-78) (P = non significant). Levels of hs-CRP were not affected by therapy and remained unchanged in both groups.

CONCLUSIONS

In patients with stable CAD, clopidogrel inhibits the release of sCD40l by platelets, which may contribute to the clinical benefit provided by this drug. This, however, does not translate in a reduction of subclinical inflammation, as measured by hs-CRP.

Coagulation disorders associated with acute promyelocytic leukemia: corrective effect of all-trans retinoic acid treatment

The bleeding diathesis in patients with acute promyelocytic leukemia (APL) is generally attributed to disseminated intravascular coagulation (DIC), initiated by the release of procoagulant activity from leukemic cells. Primary fibrinogenolysis, mediated by the release of leukocyte proteases, may also contribute to this disorder. We analyzed coagulation parameters in 15 non-septic APL patients. Before treatment, there was evidence of thrombin activation with DIC: increased levels of circulating thrombin-antithrombin III complexes, prothrombin fragments 1 + 2 and D-Dimer complexes. This DIC syndrome was probably limited, since no prothrombin time decrease, no significant factor V consumption, and normal levels of coagulation inhibitors (antithrombin III and protein C) were observed in APL patients when compared to normal controls. In this context, marked hypofibrinogenemia suggested primary fibrinogenolysis as the predominant etiology. Despite normal or high tissue plasminogen activator (tPA) and plasminogen activator inhibitor (PAI-1) antigen levels, the plasma PAI-1 activity and the formation of tPA/PAI-1 complexes were lower in APL patients than in normal controls, suggesting a proteolytic degradation of PAI-1, not able to complex tPA. Two other fibrinolytic inhibitor molecules (alpha-2 plasmin inhibitor antigen and histidine-rich glycoprotein antigen) were also significantly reduced, as well as the two subunits of fibrin stability factor XIII, although only subunit A is known to be susceptible to thrombin action. Evidence of degraded forms of von Willebrand factor in the plasma suggested an extended proteolytic activity. Four patients treated with all-trans-retinoic acid (ATRA) as a single differentiating agent were studied serially. A dissociation between these two syndromes--DIC and fibrinogenolysis/proteolysis--was observed. The rapid correction of the lysis markers contrasted with a more prolonged persistence of the procoagulant activity. We observed persistently high elastase/alpha 1-proteinase inhibitor complex levels during ATRA therapy, despite progressive correction of all lysis markers. Thus, the release of elastase from promyelocytic leukemic cells is probably not the only determinant of the fibrinogenolytic/proteolytic syndrome. In summary, the present findings provide new arguments for the association of DIC and proteolysis syndromes in APL-associated coagulation disorders. Further prospective studies are needed in order to confirm the persistence of thrombin activation in course of ATRA therapy.