Diagnostic Sensitivity of Different Applications of Pathergy Test for Behçet's Disease

Risk factors, clinical features and treatment of Behçet's disease uveitis

Behçet's disease is a systemic vasculitis frequently associated with intraocular inflammation. Recent findings identified independent clinical clusters in Behçet's disease, each involving distinct combinations of affected organs. Ocular Behçet's disease, mainly manifested as uveitis, is characterized as an independent cluster with a low likelihood of association with other system involvements, such as intestinal, cardiovascular, or central nervous system. A prevailing theory suggests that the pathogenesis of the disease is multifactorial, where a variety of genetic and infectious agents may interact with each other to cause the disease. Among sporadic cases, the human leukocyte antigen (HLA) genes, including HLA-B51, HLA-A26, HLA-B15, and HLA-B5701, have been found to be a key component conferring genetic susceptibility. Outside the HLA region, a set of susceptibility variants are identified, closely related to interleukin (IL)-23/IL-17 pathway, tumor necrosis factor (TNF) signaling, and pattern recognition receptor systems. Microbial infections, such as Streptococcus sanguinis, Mycobacterium tuberculosis, and Herpes simplex virus (HSV), are linked to play the triggering of disease in immunogenetically predisposed individuals. Clinically, due to the notable relapsing-remitting course of ocular Behçet's disease, the prevention of recurrent attack would be the primary treatment goal. Combination of corticosteroids and immunomodulatory drugs, such as anti-TNF agents, interferon, and conventional immunosuppressants (e.g. cyclosporine, azathioprine), have been the mainstream regimen for the disease. Future research may focus on comparing the effectiveness of immunomodulatory drugs and identifying the most suitable subgroups for a specific drug on the basis of the knowledge of the molecular heterogeneity of the disease.

The diagnostic role of pathergy test in patients with Behçet's disease from the Western Europe

The aim of the study is to evaluate the frequency and features of positive pathergy test (PPT) in Italy, its role in the diagnosis of Behçet's disease (BD), and any association with other BD-related manifestations. 52 BD patients, 52 patients with axial spondyloarthritis (ax-SpA), and 26 healthy controls (HCs) underwent intradermal injection of normal saline and intradermal needle soaked with fresh self-saliva. The results of pathergy tests were statistically analysed in the light of demographic, clinical, and therapeutic features of subjects enrolled. Pathergy test performed with saline resulted always negative in all groups. Skin prick test using self-saliva resulted in the occurrence of a papule in 3 (5.8%) BD patients and in 1 (1.9%) patient with ax-SpA. A ≥ 15 mm erythematous area surrounding the needle prick site was observed in 22 (42.3%) BD patients, 5 (9.6%) patients with ax-SpA, and 2 (7.7%) HCs (p = 0.00002). The frequency of skin erythema was significantly more frequent in patients with BD than those with ax-SpA (p < 0.0001) and HCs (p = 0.003). No statistically significant differences were observed between ax-SpA patients and HCs (p = 1.000). The occurrence of skin erythema at pathergy test was not associated with any BD-related clinical manifestation. Erythema at self-saliva prick test presented a sensitivity of 42.31% (CI 28.73-56.80%) and a specificity of 91.03% (CI 82.38-96.32%). The development of a ≥ 15 mm erythematous area at self-saliva prick test could be sufficient to unveil the hyper-reactivity of the innate immune system in BD patients from Western Europe, where the development of skin erythema shows good sensitivity and specificity toward the diagnosis of BD.

Autophagy-related genes in Egyptian patients with Behçet's disease

Background

Behçet's disease (BD) is a chronic, multi-systemic, recurrent condition that affects the vascular, ocular, mucocutaneous, and central nervous systems. The diagnosis of this disease depends on its clinical features, which are similar to those observed in several diseases, such as Parkinson’s disease, pemphigus vulgaris, systemic lupus erythematosus, Crohn ҆s disease, and Sjӧgren’s syndrome. Lysosome-mediated autophagy is a catabolic, cytoprotective mechanism that maintains cell homeostasis by degrading undesired long-lived proteins and recycling nutrients. The aim of this study was to evaluate the correlations between some autophagy-related genes (ATG5, ATG7, ATG12, LC3b, mTOR) and the pathogenesis and immunopathology of BD. The expression levels of the genes were evaluated by quantitative polymerase chain reaction (qPCR) in 101 individuals that are classified into two groups. Group 1: (n = 71) BD patients, Group 2: (n = 30) healthy controls.

Results

Patients with BD had lower mRNA expression levels of ATG5 and mTOR and higher levels of LC3b mRNA than the controls. No significant differences in the levels of both ATG7 and ATG12 were observed between the two groups. According to the area under the curve analysis, LC3b was considered the best candidate biomarker among the selected markers for the diagnosis of BD. The mRNA expression of ATG5 was significantly correlated with patient age and the presence of oral ulcers. The mRNA expression of ATG7 was significantly associated with age and the presence of erythema nodosum and vascular lesions, whereas that of LC3b was significantly correlated with the presence of pustules.

Conclusion

These findings indicated that elevated levels of LC3b were strongly associated with BD. Likewise, the levels of ATG5 and ATG7 were associated with the complications and outcomes of this disease. Additional assessments of the mRNA expression levels of these autophagy-related genes might prove beneficial in diagnosing this autoimmune disorder.

Histopathological comparison of pathergy positive and negative areas of newly diagnosed Behçet patients

BACKGROUND

Behcet's disease is an inflammatory vasculitis, and pathergy reaction is a compulsory element of the diagnostic criteria. In the literature, there is no study comparing the histopathology of negative pathergy tests and positive pathergy tests in newly diagnosed Behcet's patients. The primary goal was to investigate the frequency of vasculitis, which is an important finding of Behcet's disease, in pathergy histopathology.

METHODS

The histopathology of patients with positive and negative pathergy tests revealed vasculitis or vasculopathy. In histopathology, neutrophils, lymphocytes, eosinophils, and mast cells in the perivascular area were counted and recorded as a percentage.

RESULTS

Of the 88 Behcet's patients who participated in the study, 45 were female and 43 were male. The rate of vasculitis in the histopathology of those who were positive for the pathergy test was not statistically different than those of those with negative pathergy tests (P = .14). In our study, although the relationship between the male gender and uveitis was significant at the border, and the relationship between pathergy positivity and uveitis was not found to be significant, a significant relationship was found between vasculitis in histopathology and uveitis (P = .023).

CONCLUSIONS

Based on the results of our study, we think that a pathergy test of histopathology will contribute to the clinical diagnostic evaluation in cases with suspicious clinical pathergy tests and especially in cases with negative pathergy tests.

Pathergy test with a 23G needle with and without self-saliva in patients with Behçet's disease, recurrent aphthous stomatitis and control group compared to the 20G test

Objectives

The pathergy test (PT) is part of the diagnostic criteria of Behçet’s disease (BD). Factors like needle character and number of punctures can affect the sensitivity of PT. We tried to compare its positivity using a thinner needle with and without self-saliva in active and inactive BD, recurrent aphthous stomatitis (RAS), and healthy people.

Material and methods

Twenty patients with active and 13 with inactive BD, 20 with RAS, and 34 healthy controls underwent 3 types of PT: 1 – the most recommended 20G dry needle PT, 2 – 23G dry needle PT, and 3 – 23G PT with self-saliva. The positivity and diagnostic accuracy of the tests between groups were compared.

Results

All tests were negative in the normal healthy group. In active BD, the positivity of PT with self-saliva (70%) was higher than the 20G PT (20%) (p-value = 0.004), being more correlated to disease activity (p-value = 0.046). In the RAS group, there was no difference in the positivity of all tests (p-value = 0.068). All tests had high diagnostic accuracy in discriminating between patients with active BD and the controls (p < 0.05). The pathergy test with self-saliva showed significant diagnostic accuracy in discriminating BD from non-BD participants (p < 0.001). The results of dry 23G PT were the same as those of 20G PT.

Conclusions

The self-saliva PT test was more positive in patients with active BD, correlated with disease activity, was more sensitive, had equal specificity in detecting BD from the control group, and was more sensitive but less specific in detecting BD, compared to the RAS group. The positivity and accuracy of dry 23G needle PT were the same as the 20G PT.

Pathergy test with self-saliva using a thin (23G) needle is more sensitive has equal specificity in detecting patients with BD compared to the control group and is more sensitive but less specific in detecting the patients with BD compared to the RAS group. The positivity and accuracy of dry 23G needle PT is the same as the most recommended 20G dry PT. Pathergy test by wet 23G needle (with self-saliva) is more positive in patients with active BD compared to PT by dry 20G needle.

Pathergy Phenomenon

Skin pathergy reaction (SPR) is a hyperreactivity response to needle induced trauma which is characterized by a papule or pustule formation, 24-48 h after sterile-needle prick. It is affected by a wide array of factors, including the physical properties of the needles being used, number of pricks and disease related factors such as male gender, active disease. There is a great variation in reactivity among different populations with very low positivity rate in regions of low prevalence like Northern Europe, and higher prevalance mainly in communities living along the historical Silk Road, like Turkey, China and Middle Eastern countries. SPR is not constant during the disease course, has lost its sensitivity over decades and can be positive in various disorders including Sweet's syndrome, pyoderma gangrenosum, Crohn's diesease, A20 haploinsufficiency, deficiency of IL-1-receptor antagonist and few others. Nevertheless, it is a criteria included into many currently used diagnostic or classification criteria for Behçet's disease. Although, not being fully uncovered yet, available data points to the activation of both innate and adaptive immune system with an inflammatory response mediated by polymorphonuclears and T-cells. In addition to its utility in diagnosis of Behçet's Disease, SPR may serve as a model for investigating the inflammatory pathways involved in the etiopathogenesis of this complex disease.