Current pathological and clinical aspects of Buerger's disease in Japan

Buerger Disease: Pathological Changes in Elderly Patients

Reports of vascular lesion changes in elderly Buerger disease patients are rare. Patients are expected to continue to have typical Buerger disease even after the age of 50. However, after 50, when patients suffer from atherosclerotic risk factors, such as hypertension, diabetes mellitus, or hyperlipidemia, what kind of changes will occur? We will report on 3 cases of hypertension, diabetes mellitus, or hyper lipidemia after or around 50 years of age. As a result, atherosclerosis was present in the iliac or aortic regions in the remaining thromboangiitis lesions below the groin area. (This is secondary publication from the J Jpn Coll Angiol 2021; 61: 107–113.)

Current Trends in Epidemiology and Clinical Features of Thromboangiitis Obliterans in Japan - A Nationwide Survey Using the Medical Support System Database

BACKGROUND

The epidemiology and clinical features of thromboangiitis obliterans (TAO) in Japan have not been updated extensively.Methods and Results:This retrospective study used the Japanese Ministry of Health, Labour and Welfare (JMHLW) medical support system database and associated health insurance data. The number of medical financial support recipients registered as TAO patients and estimated prevalence of TAO decreased from fiscal year (FY) 2000 (10,089 and 7.95 [95% confidence interval, CI: 7.79-8.10] per 100,000 population) to FY 2010 (7,147 and 5.58 [95% Cl: 5.45-5.71] per 100,000) and leveled off until 2014. The prevalence of TAO among patients with peripheral arterial occlusive diseases declined from 7.15% (95% Cl: 7.00-7.31) in FY 2008 to 6.12% (95% Cl: 5.98-6.26) in FY 2014. Clinicodemographic features were obtained from 89 new recipients in FY 2013 and 2014: 12 (13%) women, 36 (40%) aged ≥50 years, 26 (29%) had probable onset age ≥50 years, 7 (8%) were non-smokers, and 12 (13%) had arteriosclerosis-related comorbidities. The symptoms were similar regardless of registration age, smoking history, or sex. Although 40 (45%) had digit ulcers, only 12 (13%) fulfilled Shionoya's criteria. They rarely had infrapopliteal lesions combined with upper extremity involvement or phlebitis.

CONCLUSIONS

The prevalence of TAO has decreased in Japan. In the current diagnosis of TAO, various clinical characteristics including late onset, arteriosclerotic factors, non-smoking, or mild symptoms should be considered.

Associations Between Elevated Plasma Total Homocysteine Level and Risk of Thromboangiitis Obliterans in a Chinese Population: A Matched Case-Control Study

BACKGROUND

Elevated plasma total homocysteine level is a risk factor for various vascular diseases; however, an association with risk of thromboangiitis obliterans (TAO) has not been defined. This study aims to assess whether elevated plasma total homocysteine level is associated with risk of TAO.

METHODS

We performed a matched case-control study including 64 patients with TAO and 256 controls. Multivariate logistic regression models were used to estimate the association between elevated plasma homocysteine level and the risk of TAO. Interaction and stratified analyses were conducted according to age, sex, smoking, alcohol consumption, and histories of chronic diseases.

RESULTS

Patients with TAO versus controls had a higher mean plasma total homocysteine level (21.2 ± 12.8 μmol/L vs. 14.1 ± 4.9 μmol/L; P < 0.01). The risk of TAO was 3.68-fold increased in participants with plasma total homocysteine level >15 μmol/L (95% confidence interval [95% CI], 1.2-11.7). A 1 μmol/L increase in plasma total homocysteine level was associated with 20% higher risk of TAO (odds ratio, 1.2; 95% CI, 1.1-1.3).

CONCLUSIONS

Our findings suggest that the risk of TAO was significantly associated with elevated plasma total homocysteine level independently of other factors analyzed, including smoking. Studies on the use of homocysteine-lowering therapy to prevent TAO would allow testing causality of the latter association.

Three cases of dorsal metatarsal artery bypass in patients with Buerger disease

Buerger disease is a rare peripheral vascular disease that most frequently affects young men and is strongly correlated with tobacco use. Although several options have been suggested, no consensus exists on the management of patients with Buerger disease except for smoking cessation. Revascularization is sometimes required to salvage ischemic limbs; however, it is often not feasible because of a lack of distal target vessels. Herein, we present the cases of three patients with tissue loss and gangrene due to Buerger disease. These patients underwent dorsal metatarsal artery bypass and avoided amputation.

The Incidence and Prevalence of Thromboangiitis Obliterans in Taiwan: A Nationwide, Population-based Analysis of Data Collected from 2002 to 2011

OBJECTIVE

To estimate the incidence and prevalence of thromboangiitis obliterans in Taiwan in the period spanning from 2002 to 2011.

METHODS

We identified all incident and prevalent cases with a diagnosis of thromboangiitis obliterans (International Classification of Diseases, Ninth Revision code 443.1) in the period spanning from 2002 to 2011 using Taiwan's National Health Insurance Research Database. We calculated the age- and sex-specific incidence and prevalence rates of thromboangiitis obliterans during the study period.

RESULTS

From 2002 to 2011, 158 patients were diagnosed with thromboangiitis obliterans; of these, 76% were men. Most (63%) of the patients were <50 years old when they were first diagnosed. After reaching 20 years of age, the incidence rate increased with age and peaked among those aged ≥60 years. The average incidence rate of thromboangiitis obliterans during the 2002-2011 period was 0.068 per 105 years. The incidence of thromboangiitis obliterans decreased with time, from 0.10 per 105 years in 2002 to 0.04 per 105 years in 2011. The prevalence increased from 0.26 × 10-5 in 2002 to 0.65 × 10-5 in 2011.

CONCLUSION

This is the first epidemiologic study of thromboangiitis obliterans using claims data from a general population in Taiwan. This nationwide, population-based study found that the incidence and prevalence of thromboangiitis obliterans in Taiwan in the 2002-2011 period were lower than those in other countries before 2000. This study also revealed a trend of decreasing incidence with simultaneous increasing prevalence of thromboangiitis obliterans in Taiwan from 2002 to 2011.

The Epidemiologic and Clinical Findings of Patients with Buerger Disease

BACKGROUND

Buerger disease is a nonatherosclerotic peripheral arterial disease, which is mostly observed in young male smokers. Buerger disease is characterized by the observation of peripheral arterial occlusion by angiography. The condition may be caused by microembolization in the small-sized arteries of the distal extremities. Buerger disease is diagnosed based on the Shionoya's clinical diagnostic criteria, which include: (1) a history of smoking, (2) onset before the age of 50 years, (3) the presence of infrapopliteal arterial occlusions, (4) either upper limb involvement or phlebitis migrans, and (5) the absence of atherosclerotic risk factors other than smoking. Several studies have reported that oral bacterial infections (periodontitis) could activate the onset of Buerger disease. In this study, we report the epidemiologic and clinical manifestations of patients with Buerger disease.

METHODS

Fifty-eight patients who were surgically treated between July 1989 and June 2014 at Tokyo Medical and Dental University Hospital were enrolled in this study. All of the patients clinically diagnosed with Buerger disease based on Shionoya's clinical diagnostic criteria. Fifty-five male and 3 female patients were treated. The mean age of the patients was 48 years (range, 21-73 years).

RESULTS

All of the patients were either smokers or had a history of smoking. The mean Brinkman index score was 780 (range, 150-1,640). Their mean age at the onset of Buerger disease was 38 years (range, 21-50). The arterial lesions extended to the femoral arteries in 25% of cases, to the iliac arteries in 8% and to the abdominal aorta and/or visceral arteries in 6% of cases. Upper limb involvement, including cyanosis, paleness, and gangrene, was obvious in 84% of patients, and phlebitis migrans was recognized in 34%. The lower extremities symptoms involved intermittent claudication in 23% of the patients, rest pain in 13% of the patients, and ulceration or gangrene in 64% of the patients. Fifteen patients had undergone surgical arterial reconstruction, 4 patients had received endovascular therapy, 33 patients had undergone lumbar sympathectomy and 8 patients had undergone thoracic sympathectomy. Twenty percent of the patients needed minor limb amputations, and 4% required major limb amputations. In the patients who were examined for their oral conditions, periodontitis corresponding to grades B (moderate periodontitis), C (severe periodontitis), and D (edentulous patients) was revealed in 31%, 56%, and 13% of the patients, respectively.

CONCLUSIONS

More than half of the Buerger disease patients in this study were suffering from severe periodontitis. It is possible that not only the cessation of smoking, but also the improvement of periodontal care could improve the clinical symptoms related to Buerger disease.

Endarteritis obliterans in the pathogenesis of Buerger's disease from the pathological and immunohistochemical points of view

Buerger's disease (thromboangiitis obliterans) is considered to be a nonatherosclerotic, inflammatory, and vaso-occlusive disease, although the details of the mechanisms of pathogenesis remain unknown. The occurrence of the disease is strongly related to tobacco abuse and its progression is closely linked to continued smoking. The purpose of this review article is to demonstrate the pathological characteristics of arteries affected with Buerger's disease from a possible immunoreactive point of view. In addition, we present the mechanisms for preserving the architecture of the arterial wall in affected vasculatures. Thereafter, we discuss the possibility that the pathogenesis of Buerger's disease is a type of endarteritis obliterans, deeply connected to the Notch pathway, distinct from arteriosclerosis obliterans and other vasculitides.

Fate of ischemic limbs in patients with Buerger's disease based on our 30-year experience: does smoking have a definitive impact on the late loss of limbs?

PURPOSE

We herein review the long-term results of our series of critical ischemic limbs caused by Buerger's disease.

METHODS

A retrospective review of 103 patients with critical limb ischemia who were diagnosed with Buerger's disease by Shionoya's criteria between 1980 and 2010.

RESULTS

The age of onset was 38.0 ± 9.7 years (mean ± SD). The median follow-up was 97 months. Thirty-three patients had pain at rest, and 65 patients presented with ischemic ulcers in their toes and/or fingers. Gangrene was present in five patients. Sixteen patients achieved remission with medical therapy and smoking cessation. Sixty-six patients underwent sympathectomy. Bypass to the crural arteries was performed in 23 limbs, with assisted primary patency rates of 67.0 and 45.6 % at five and 10 years. Graft failure caused major amputation in two out of 10 smokers, but no limbs were lost among the 12 ex-smokers. Therapeutic angiogenesis using cell transplantation led to improvement in three ex-smokers; however, amputation was unavoidable in the one smoker who was treated. The limb salvage rate at 20 years was 90 % in ex-smokers and 69 % in smokers, which was not significantly different.

CONCLUSIONS

This study demonstrated no significant difference in the limb salvage rate between ex-smokers and smokers. Our results do not support any advantageous effect of smoking cessation on the long-term remission in patients with Buerger's disease.

Critical limb ischemia in a young man: saddle embolism or unusual presentation of thromboangiitis obliterans?

Thromboangiitis obliterans (TAO), also known as Buerger's disease, is a rare cause of peripheral arterial disease in western countries. Tobacco smoking is strongly correlated to the pathogenesis of this inflammatory vascular disease. We report the case of a 32-year-old tobacco and cannabis consumer presenting with right critical limb ischemia. Computerized tomography angiography revealed a bilateral tibioperoneal arterial occlusion and an aortoiliac saddle embolus. The patient was treated with intravenous heparin, transcatheter thrombolysis, and selective Fogarty embolectomy. Instrumental and laboratory examinations revealed that patient's most likely diagnosis was TAO. Arterial embolism is uncommon in Buerger's disease but should be always excluded in these patients.

Current status of patients with buerger disease in Japan

THE PREVALENCE AND CLINICAL CHARACTERISTICS OF JAPANESE PATIENTS WITH BUERGER DISEASE (THROMBOANGIITIS OBLITERANS: TAO) were analyzed based on the Ministry of Health, Labour and Welfare (MHLW) database in 2009. A total of 129 new patients and 3639 patients in follow-up were selected according to the clinical criteria of TAO. The current number of patients with TAO in Japan is estimated at about 4000. The clinical course is relatively favorable, and the rates of limb morbidity and mortality were not completely discouraging.

Possible involvement of Notch signaling in the pathogenesis of Buerger's disease

PURPOSE

Under pathological conditions, the Notch signal pathway is involved in the inflammatory process in arteriosclerosis, atherosclerosis and angiogenesis under ischemic conditions. The purpose of this study was to observe whether or not Buerger's disease is associated with Notch signal activation.

METHODS

All the patients were diagnosed between 1980 and 2009 at Nagoya University Hospital. Twenty-two specimens from 12 patients with Buerger's disease (TAO) and 13 specimens from nine patients with arteriosclerosis obliterans (ASO) were analyzed by immunohistochemistry for Notch1, Jagged-1 (a Notch ligand) and Hes-1 (a Notch 1 target transcription factor).

RESULTS

Notch1 and Jagged-1 were highly expressed in the endothelium in the new vasa vasorum and in the smooth muscle cells in the media of specimens from both groups. These Notch-related proteins were also remarkably expressed in inflammatory cells in the intima of specimens from TAO patients. Fewer inflammatory cells expressed Notch-related proteins in atheromatous plaques (Notch1 (%): 8.4 ± 0.76 versus 1.3 ± 0.43, P < 0.001; Jagged-1(%): 9.3 ± 1.1 versus 5.2 ± 1.1, P = 0.03). Indeed, Hes-1, which is a transcription factor downstream of Notch1, was remarkably expressed in the endothelium of new capillary vessels and inflammatory cells in TAO patients. Notch1-positive mononuclear cells were also seen in the thrombus in samples from the TAO group.

CONCLUSIONS

Our findings are the first demonstration that Notch signal activation in inflammatory cells may be involved in the pathophysiological mechanism underlying Buerger's disease.

Activation of cytokines corroborate with development of inflammation and autoimmunity in thromboangiitis obliterans patients

Thromboangiitis obliterans (TAO) is a segmental inflammatory occlusive disorder that affects the arm and leg arteries of young smokers. The immune system seems to play a critical role in the aetiology of TAO; however, knowledge of the aspects involved in the progression of vascular tissue inflammation and, consequently, the evolution of this disease is still limited. This study was carried out to investigate the cytokine levels of tumour necrosis factor (TNF)-α, interleukin (IL)-1β, IL-4, IL-17 and IL-23 in the plasma of TAO patients presenting with acute clinical manifestations. The study included 20 TAO patients (n = 10 women; n = 10 men) aged 38-59 years under clinical follow-up, classified into two groups: (i) TAO former smokers (n = 11) and (ii) TAO active smokers (n = 9); the control groups included normal volunteer non-smokers (n = 10, active smokers (n = 10) and former smokers (n = 10). Patients' plasma samples were measured using the sandwich enzyme-linked immunosorbent assay. Statistical analyses were performed using the non-parametric Mann-Whitney U-test, with parameters significant at P < 0·05. The activities of all cytokines were different in groups of TAO patients when compared with normal controls, and decreased for control smokers. Increased levels of TNF-α, IL-1β, IL-4, IL-17 and IL-23 were significant in patients with TAO when compared to the controls (P < 0·005, all parameters). The results presented here indicate an increased production of cytokines in TAO, possibly contributing to the inflammatory response observed in the patients' vascular levels. In addition, the increased levels of IL-17 and IL-23 suggest that the disturbance of TAO is involved with mechanisms of autoimmunity. Thus, the discovery of IL-17 and its association with inflammation and autoimmune pathology has reshaped our viewpoint regarding the pathogenesis of TAO, which was based previously on the T helper type 1 (Th1)-Th2 paradigm.

Imbalanced matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 activities in patients with thromboangiitis obliterans

The pathogenic mechanisms of thromboangiitis obliterans (TAO) are not entirely known and the imbalance of matrix metalloproteinases (MMPs) plays a role in vascular diseases. We evaluated the MMP-2 and MMP-9 circulating levels and their endogenous tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2) in TAO patients with clinical manifestations. The study included 20 TAO patients (n = 10 female, n = 10 male) aged 38-59 years under clinical follow-up. The patients were classified into two groups: (1) TAO former smokers (n = 11) and (2) TAO active smokers (n = 9); the control group included normal volunteer non-smokers (n = 10) and active smokers without peripheral artery disease (n = 10). Patient plasma samples were used to analyze MMP-2 and MMP-9 levels using zymography, and TIMP-1 and TIMP-2 concentrations were determined by enzyme-linked immunosorbent assays. The analysis of MMP-2/TIMP-2 and MMP-9/TIMP-1 ratios (which were used as indices of net MMP-2 and MMP-9 activity, respectively) showed significantly higher MMP-9/TIMP-1 ratios in TAO patients (p < 0.05). We found no significant differences in MMP-2/TIMP-2 ratios (p > 0.05). We found higher MMP-9 levels and decreased levels of TIMP-1 in the TAO groups (active smokers and former smokers), especially in active smokers compared with the other groups (all p < 0.05). MMP-2 and TIMP-2 were not significantly different in patients with TAO as compared to the control group (p > 0.05). In conclusion, our results showed increased MMP-9 and reduced TIMP-1 activity in TAO patients, especially in active smokers compared with non-TAO patients. These data suggest that smoke compounds could activate MMP-9 production or inhibit TIMP-1 activity.

The Wound Healing Effects of Iloprost in Patients with Buerger's Disease: Claudication and Prevention of Major Amputations

BACKGROUND

This study analyzes the therapeutic effects of intravenous infusion of iloprost in wound healing, healing of the amputation stump wound, improvement in intermittent claudication and prevention of major amputation in patients with Buerger's disease.

METHODS

In a prospective study, 19 patients with known Buerger's disease, received intravenous iloprost infusion, 6 hours per day for 10 days. Iloprost with a dose of 0.5-2 ng/kg/min according to the patients' tolerance and using cardiac monitoring during the whole infusion period was administered for 6 hours/day using saline solution. Patients with larger wounds underwent simultaneous transmetatarsal or Ray amputation of the involved toe(s). All patients were discharged after 10 days. Patients were followed to detect their healing changes.

RESULTS

Nineteen patients, 19-55 years old received 0.5-2 ng/kg/min iloprost intravenously for 6 hours/day for 10 days. During this period, there was relative improvement in resting pain, but no significant amelioration was noticed in wound healing. In a 2 years follow-up, 14 patients showed a complete healing of the amputation stump and increased distance of walking without any pain. Some previous candidates of major amputation did not need amputation anymore. Five patients (26%) did not respond to therapy.

CONCLUSION

Although Buerger's disease patients who were under iloprost therapy, may not show significant changes in wound healing during treatment and at discharge, late results have proved that iloprost infusion is promising in improving wound healing and claudication and preventing major amputations.

Successful treatment of thromboangiitis obliterans (Buerger's disease) with immunoadsorption: results of a pilot study

BACKGROUND

No established therapy is available for patients with thromboangiitis obliterans (TAO) and critical limb ischemia. Since abnormalities of the immune system appear to be involved in the pathogenesis, we investigated in this pilot study the efficiency of Ig immunoadsorption (IA) therapy.

METHODS

Ten patients with advanced TAO underwent a single IA course over five consecutive days. Before IA angiography was performed. In addition, the following were conducted prior to IA, directly after, as well as 1, 3, and 6 months after IA: clinical examination, pain scale (0-10), treadmill test for evaluation of maximum walking distances, and several angiological methods for evaluation of disease extent: photoplethysmography, ultrasound Doppler, and transcutaneous assessment of partial carbon dioxide (tcPCO(2)) and oxygen (tcPCO(2)) pressure.

RESULTS

Immunoadsorption treatment was tolerated without side effects. Pain intensity decreased rapidly from 7.7 ± 0.8 (mean ± SEM) before treatment to 2.0 ± 1.2 at the second day of IA. One month after IA, all patients were without pain. This functional amelioration persisted over the follow-up period of 6 months. Correspondingly, maximum walking distances significantly increased from 301.7 ± 191.4 to 727.0 ± 192.7 m immediately after IA, and further continuously up to 1,811.0 ± 223.7 at 6 months after IA. Healing of ischemic ulcerations was observed in all patients during follow-up. (tcPCO(2)) and (tcPCO(2)) values as well as photopletysmographic data that were severely compromised before IA reflecting reduced tissue oxygenation and perfusion showed rapid amelioration reaching normal values at 1 month.

CONCLUSION

Anti-Ig IA appears to be an effective therapeutic option for patients with advanced TAO.

Determination of kininogens levels and kallikrein/kininase II activities in patients with thromboangiitis obliterans

Some components of the kinin system such as plasma kallikrein levels, the activities of tissue kallikrein (including saliva) and kininase II and the concentrations of kininogen fractions (low-molecular weight/LKg and high-molecular weight/HKg) were evaluated in the plasma of patients with thromboangiitis obliterans (TAO) presenting clinical symptoms of the condition. Twenty TAO were diagnosed by means of the traditional Shionoya and Olin criteria and later classified into non-smokers (n = 11) and active smokers (n = 9). Fifty-three normal, non-smoking/smoking individuals (control) were also studied. Kininogen levels were determined by ELISA; the activities of kallikreins and kininase II were determined using selective substrates. The levels of enzymes (kallikreins and kininase II) and protein (kininogens) were significantly higher in patients with TAO who were active smokers compared to the control groups (no matter whether control individuals were active smokers or non-smokers, P < 0.001 for all comparisons). Interestingly, regardless of the time of disease onset, a significant increase in the levels of these components of the kinin system was also observed in patients when TAO active smokers were compared with TAO ex-smokers (P < 0.01 for all analysed parameters). Activation of the kinin system in patients with TAO may indicate the involvement of vasodilatation in an attempt to control vascular changes, thereby favouring the deposition of immune complexes at the vascular level because of nicotine stimulation. Moreover, our results corroborate the idea that TAO can be an autoimmune disorder with specific mechanisms.

Colon Ischemia Associated with Buerger's Disease: Case Report and Review of the Literature

Buerger's disease, or thromboangiitis obliterans, is a nonatherosclerotic inflammatory disease affecting the small- and medium-sized arteries and veins of the extremities (arms, hands, legs, and feet). It is most common in the Orient, Southeast Asia, India, and the Middle East, and usually affects men aged between 20 and 40 years, although it is becoming more common in women. It is well established that most such patients smoke heavily and experience an improvement in symptoms following smoking cessation. Mesenteric involvement in Buerger's disease is extremely rare; however, we describe herein two cases of colon ischemia in patients who were previously diagnosed with lower-extremity Buerger's disease. In one case, the patient developed colonic obstruction, and surgical resection was performed. Histopathologic findings were compatible with the chronic stage of Buerger's disease. In the other case, angiography revealed abrupt occlusion of the inferior mesenteric artery with numerous collateral vessels, just like the corkscrew appearance found in the extremities. If patients with established Buerger's disease of the extremities complain of gastrointestinal symptoms, early interventional diagnosis should be performed to prevent intestinal obstruction and gangrene.

Thromboangiitis obliterans in the 21st century--a new face of disease

Thromboangiitis obliterans (TAO) is a relatively rare disease of peripheral blood vessels, affecting small and medium sized arteries and veins. Although the first description of the disease was given by Winiwarter almost 130 years ago, etiology of TAO remains not elucidated. Smoking is considered as a precipitating factor of the disease. We emphasised some particular features of the new face of TAO - significant decrease in incidences, increased disease prevalence among women and coexistence of other than smoking atherosclerotic risk factors (especially disturbances of glucose metabolism). Contemporary methods of treatment were also discussed.

Synergistic contribution of CD14 and HLA loci in the susceptibility to Buerger disease

Buerger disease (BD) is an occulusive vascular disease of unknown etiology. Although cigarette smoking is a well-known risk factor of BD, genetic factors may also play a role in the etiology. Because chronic bacterial infection such as oral periodontitis is suggested to be involved in the pathogenesis of BD, gene polymorphisms involved in the infectious immunity might be associated with BD as the genetic factor(s). We have previously reported that HLA-DRB1*1501 and B54 was associated with BD in Japanese. In this study, polymorphisms in HLA-DPB1, DRB1 and B were analyzed in 131 Japanese BD patients and 227 healthy controls. In addition, we investigated a functional promoter polymorphism, -260 C > T, of CD14 that is a main receptor of bacterial lipopolysaccharide. It was found that the frequencies of CD14 TT genotype [37.4 vs. 24.2%, P = 0.008 OR = 1.87, 95% confidence interval (CI); 1.18, 2.97], DRB1*1501 (34.4 vs. 13.2%, P (c) = 4.4 x 10(-5), OR = 3.44, 95%CI; 2.06, 5.73) and DPB1*0501 (79.4 vs. 55.1%, P (c) = 4.7 x 10(-5), OR = 3.14, 95%CI; 1.93, 5.11) were significantly higher in the patients than in the controls, demonstrating that at least three genetic markers were associated with BD. Stratification analyses of these associated markers suggested synergistic roles of the genetic factors. Odds ratios ranged from 4.72 to 12.57 in individuals carrying any two of these three markers. These findings suggested that the susceptibility to BD was in part controlled by genes involved in the innate and adaptive immunity.