Infection and vasculitis

Diagnostic delays in systemic vasculitides

Systemic vasculitides are among the less common disorders encountered in routine rheumatology practice. The low incidence and heterogeneous presentation at onset can potentially lead to delayed diagnosis. Not recognizing these in the early phase may prove detrimental, as some vasculitis may progress to a catastrophic course with major morbidity or mortality. The causes of diagnostic delay may vary among different types of vasculitis and may also be disease-, patient-, or physician-related. Disease-related factors include the myriad presentations with diverse and non-specific symptoms, mimicking other conditions like infections. In addition, some forms have prolonged prodromal phases before evident organ damage. Limited awareness among healthcare professionals, particularly outside rheumatology, and a lack of readily available diagnostic tools contribute to missed diagnoses. Delays in seeking care due to non-specific symptoms or lack of access to specialist care can worsen outcomes. The economic burden also increases with delayed diagnosis and damage accrual when the disease remains unrecognized or untreated for prolonged periods. Although the causes of vasculitis are numerous, including secondary causes, in this review, we focus on diagnostic delays in primary vasculitides and suggest potential steps to identify and treat these diseases early. These include educating both healthcare professionals and the public about the signs and symptoms of vasculitis; expanding the rheumatology workforce and facilitating timely referrals; implementing readily available and reliable tests for early detection; and streamlining care and diagnostic pathways. Such measures have the potential to improve the overall outcomes of the disease, with prolonged remission, minimal damage accrual, and improved quality of life.

Vasculitis and infectious risk in a patient with type 2 diabetes mellitus: A case report

The connection between vasculitis and infection is complex. The present study described a typical situation for a patient with unbalanced type 2 diabetes and chronic complications, in which a lack of adherence to the protection and care measures ultimately led to the appearance of some of the worst consequences of the condition, namely, ulceration, gangrene and amputation. In the context of an unstable condition with significant metabolic imbalance there was an impaired response to infections in the present patient, and the amputation resulted in wound persistence and ulcer development, followed by superinfection with methicillin-resistant Staphylococcus aureus according to the antibiogram performed. In this case, an episode of vasculitis was triggered without evidence of bacteraemia. The present case report highlighted the importance of proper hygiene and good metabolic control in patients with diabetes that suffer from amputations and conditions that expose them to certain complications, including vasculitis.

Cardiovascular pathology in vasculitis

Vasculitides are diseases that can affect any vessel. When cardiac or aortic involvement is present, the prognosis can worsen significantly. Pathological assessment often plays a key role in reaching a definite diagnosis of cardiac or aortic vasculitis, particularly when the clinical evidence of a systemic inflammatory disease is missing. The following review will focus on the main histopathological findings of cardiac and aortic vasculitides.

The "Viral" Form of Polyarteritis Nodosa (PAN)-A Distinct Entity: A Case Based Review

Classic polyarteritis nodosa (PAN) is a vasculitis with systemic manifestations that is characterized by inflammatory and necrotizing lesions affecting medium and small muscular arteries, most frequently at the bifurcation of the vessels. These lesions lead to the formation of microaneurysms, hemorrhaging ruptured aneurysms, thrombosis, and, consequently, ischemia or organ infarction. Background and Objectives: We present a complex clinical case of a patient with a late diagnosis of polyarteritis nodosa with multiorgan involvement. Materials and Methods: The 44-year-old patient, in an urban environment, presented on her own in the emergency room for acute ischemia phenomena and forearm and right-hand compartment syndrome, requiring surgical decompression in the Plastic Surgery Clinic. Results: Significant inflammatory syndrome is noted, alongside severe normocytic hypochromic iron deficiency anemia, nitrogen retention syndrome, hyperkalemia, hepatic syndrome, and immunological disturbances: absence of cANCA, pANCA, anti Scl 70 Ac, antinuclear Ac, and anti dDNA Ac, as well as a low C3 fraction of the plasmatic complement system. The morphological aspect described in the right-hand skin biopsy correlated with the clinical data supports the diagnosis of PAN. Conclusions: The viral form of PAN seems to be individualized as a distinct entity, requiring early, aggressive medication.

The Spectrum of Pediatric Infection-Associated Intracranial Arteriopathies and Acute Ischemic Stroke at 2 Eastern Indian Tertiary Care Centres

INTRODUCTION

Major and minor pediatric infections may cause intracranial arteriopathies, the long-term outcome of which we investigated and identified the factors influencing the progression/resolution of arteriopathies.

METHODS

We collected the clinical and radiological data of children aged 1 month-15 years who had ischemic stroke with definite arteriopathy following a recent febrile infection. Repeated neuroimaging was done over the next year to ascertain recurrent strokes and the progression and resolution of arteriopathies.

RESULTS

The anterior circulation was more frequently affected (83.33%), predominantly involving the middle cerebral artery (41.67%), resolving in 20.84% of cases and progressing in 33.33% of cases. Lesions were commonly unilateral (54.17%) and stenotic (75%), resulting predominantly in cortical infarcts (45.83%), with hemiparesis being the most common neurodeficiency. Apart from tubercular meningitis patients, others had a good functional outcome.

CONCLUSION

Lower age, minor infections, and unilateral arteriopathies had a significantly higher chance of resolution. Postviral arteriopathies had a significantly lower chance of progression compared with those following bacterial infections. Progressive and bilateral arteriopathies were significantly associated with worse outcomes and recurrent strokes.

Cutaneous small vessel vasculitis

This review discusses the clinical manifestations of cutaneous small vessel vasculitis. The etiologies and work up will be explored as well as the treatment considerations. This entity is multifactorial and usually involves multiple specialties. The presentation can range from self-limited to life threatening, multi-organ failure. It is essential to be able to diagnose vasculitis and proceed with the appropriate laboratory studies and work-up. Finally, investigation of associated etiologies such as infection and drugs will guide additional diagnostic studies.

An insight in Salmonella typhi associated autoimmunity candidates' prediction by molecular mimicry

Autoimmune diseases develop when the immune system targets healthy cells and tissues of an individual. In developing countries, S. typhi (a gram-negative pathogenic bacteria) remains a major public health issue. This study aimed to employ bioinformatics analyses to determine the 3D structural-based molecular mimicry and sequence of S. typhi and human host proteins. In addition, to classify possible antigenic microbial peptides homologous to human peptides and comprehend the molecular basis of S. typhi-related autoimmune disorders. Protein sequences were obtained from the NCBI database, and redundancy was removed using the CD-HIT tool. The BLASTp comparative sequence analysis was followed for molecular mimicry identification of human and S. typhi protein sequences. The PathDIP database was utilized to simulate essential physical relationships between proteins and curated pathways for metabolic processes. Subsequently, the IEDB database was used to find cross-reactive MHC class-II binding epitopes that could trigger an autoimmune reaction. SPARKS-X computational biology resource was also used to determine the structural homology between human and S. typhi peptides. The BLASTp study showed that S. typhi and the human host have several proteins holding considerable sequence similarities based on a set threshold of e ≤ 10-6 and bit score ≥100. The PathDIP putatively identified that these proteins enriched in a total of 68 metabolic pathways by a significant P-value (P < 0.005). The PSORTb analysis predicted that 26 out of these proteins are cytosolic, 1 predicted to be periplasmic protein, and 1 predicted to be localized in the cytoplasmic membrane. IEDB data analysis predicted many S.typhi and human homologs epitopes as a good binder of human HLA, i.e. DRB1*01:01, DPA1*03:01/DPB1*04:02, and DQA1*01:02/DQB1*06:02 with IC₅₀ < 50 nM. Finally, the docking data demonstrated that homolog lead epitopes promisingly interact with HLA and immune TLR4 receptors by exhibiting the best docking scores and molecular interactions. The analyses ultimately identified several potential candidate proteins and peptides that could cause S.typhi infection-mediated autoimmune diseases in humans.

COVID-19 Vasculitis and vasculopathy-Distinct immunopathology emerging from the close juxtaposition of Type II Pneumocytes and Pulmonary Endothelial Cells

The SARS-CoV-2 virus ACE-2 receptor utilization for cellular entry and the defined ACE-2 receptor role in cardiovascular medicine hinted at dysregulated endothelial function or even direct viral endotheliitis as the key driver of severe COVID-19 vascular immunopathology including reports of vasculitis. In this article, we critically review COVID-19 immunopathology from the vasculitis perspective and highlight the non-infectious nature of vascular endothelial involvement in severe COVID-19. Whilst COVID-19 lung disease pathological changes included juxta-capillary and vascular macrophage and lymphocytic infiltration typical of vasculitis, we review the evidence reflecting that such “vasculitis” reflects an extension of pneumonic inflammatory pathology to encompass these thin-walled vessels. Definitive, extrapulmonary clinically discernible vasculitis including cutaneous and cardiac vasculitis also emerged- namely a dysregulated interferon expression or “COVID toes” and an ill-defined systemic Kawasaki-like disease. These two latter genuine vasculitis pathologies were not associated with severe COVID-19 pneumonia. This was distinct from cutaneous vasculitis in severe COVID-19 that demonstrated pauci-immune infiltrates and prominent immunothrombosis that appears to represent a novel immunothrombotic vasculitis mimic contributed to by RNAaemia or potentially diffuse pulmonary venous tree thrombosis with systemic embolization with small arteriolar territory occlusion, although the latter remains unproven. Herein, we also performed a systematic literature review of COVID-19 vasculitis and reports of post-SARS-CoV-2 vaccination related vasculitis with respect to the commonly classified pre-COVID vasculitis groupings. Across the vasculitis spectrum, we noted that Goodpasture’s syndrome was rarely linked to natural SARS-CoV-2 infection but not vaccines. Both the genuine vasculitis in the COVID-19 era and the proposed vasculitis mimic should advance the understanding of both pulmonary and systemic vascular immunopathology.

Prevalence of ANCA-associated vasculitis amid natural gas drilling sites in West Virginia

BACKGROUND

The epidemiology of ANCA-associated vasculitis (AAV) varies by ethnicity and region. Environmental exposure has been implicated in the pathophysiology of MPO-AAV. The aim of this study was to evaluate the epidemiology of AAV and explore a potential relationship with environmental factors in north central West Virginia.

METHODS

This is a retrospective cohort study of 212 patients diagnosed with AAV at West Virginia University and its affiliated hospitals from January 1, 1990 to December 31, 2019. We assessed prevalence of AAV over time according to patient's zip codes and counties. Silica exposure through natural gas extraction was considered as a possible environmental factor.

RESULTS

The proportion of patients with MPO-ANCA increased after 2010 (37.5% before 2010 vs 61% after 2010, p = 0.008). At the same time, the prevalence of AAV in Monongalia and surrounding counties has increased significantly after 2010 from 64.8 to 141.9 cases per million (p = 0.001). The increase in prevalence of AAV was primarily due to an increase in MPO-AAV (43 vs 101.7 cases per million before and after 2010, respectively, p = 0.028). During this time, the production of natural gas through fracking increased, rising more than tenfold after 2010 (p-value < 0.001). Heat mapping reveals that the increase in cases of AAV occurred in areas of increased fracking activity.

CONCLUSIONS

There was an increase in the prevalence of patients who were newly diagnosed with AAV over time in north central West Virginia. Further studies are required to ascertain the potential role of environmental exposure in the pathophysiology of AAV.

ANCA-associated renal vasculitis is associated with rurality but not seasonality or deprivation in a complete national cohort study

Background

Small studies suggest an association between ANCA-associated vasculitis (AAV) incidence and rurality, seasonality and socioeconomic deprivation. We examined the incidence of kidney biopsy-proven AAV and its relationship with these factors in the adult Scottish population.

Methods

Using the Scottish Renal Biopsy Registry, all adult native kidney biopsies performed between 2014 and 2018 with a diagnosis of granulomatosis with polyangiitis (GPA) or microscopic polyangiitis (MPA) were identified. The Scottish Government Urban Rural Classification was used for rurality analysis. Seasons were defined as autumn (September–November), winter (December–February), spring (March–May) and summer (June–August). Patients were separated into quintiles of socioeconomic deprivation using the validated Scottish Index of Multiple Deprivation and incidence standardised to age. Estimated glomerular filtration rate and urine protein:creatinine ratio at time of biopsy were used to assess disease severity.

Results

339 cases of renal AAV were identified, of which 62% had MPA and 38% had GPA diagnosis. AAV incidence was 15.1 per million population per year (pmp/year). Mean age was 66 years and 54% were female. Incidence of GPA (but not MPA) was positively associated with rurality (5.2, 8.4 and 9.1 pmp/year in ‘urban’, ‘accessible remote’ and ‘rural remote’ areas, respectively; p=0.04). The age-standardised incidence ratio was similar across all quintiles of deprivation (p=ns).

Conclusions

Seasonality and disease severity did not vary across AAV study groups. In this complete national cohort study, we observed a positive association between kidney biopsy-proven GPA and rurality.

Virology and Etiopathogenesis of COVID-19 with Special Reference to Cutaneous Implications

Severe Acute Respiratory Virus Corona Virus 2 (SARS-CoV-2) has got its name Corona from Latin meaning “crown.” It has crown-like spikes present on the surface, which encloses the RNA, genetic material of this deadly virus. The virus attacks pneumocytes after binding with the angiotensin-converting enzyme 2 (ACE2) of the cell surface, which ultimately leads to chemotaxis followed by leukocyte infiltration, increased permeability of blood vessels and alveolar walls, and decreased surfactant in the lung leading to various symptoms. Skin provides a window to the internal changes of the body and also to mechanisms that are not readily visible. Commonly observed skin manifestations include vesicular lesions, maculopapular exanthema, urticarial eruptions, livedo or necrosis, and other forms of vasculitis, chilblain-like lesions. The skin lesions are attributed to either the virus directly affecting the skin or interferon dysregulation due to viral RNA or vascular involvement associated with alteration in coagulation or drug-induced skin manifestations. Observation of skin involvement and the vasculature due to SARS-CoV-2 illustrates the need for a precise stratification and differential diagnostic valuation so that the mechanisms of this novel virus are clearer for better management of the condition in the future. Vascular skin lesions are not seen in all the patients of COVID, but certain lesions should definitely alarm us to evaluate for coagulation abnormalities, complement levels, and skin biopsy, especially in critically ill patients. This review attempts to outline the pathogen briefly and the pathomechanism behind the development of various cutaneous manifestations.

Acute Myelopathy: Vascular and Infectious Diseases

Vascular and infectious causes are rare but important causes of spinal cord injury. High suspicion for these processes is necessary, as symptoms may progress over hours to days, resulting in delayed presentation and diagnosis and worse outcomes. History and clinical examination findings can assist with localization of the affected vascular territory and spinal level, which will assist with focusing spinal imaging. Open and/or endovascular surgical management depends on the associated vascular abnormality. Infectious myelopathy treatment consists of targeted antimicrobial therapy when possible, infectious source control, and again, close monitoring for systemic complications.

Leukocytoclastic Vasculitis as a Rare Manifestation of Staphylococcal Osteomyelitis

Leukocytoclastic vasculitis (LCV), also known as small-vessel cutaneous vasculitis, is rarely seen in the setting of staphylococcal infection without bacteremia. Here, we present a case of LCV in a 61-year-old male with chronic staphylococcal osteomyelitis without any evidence of bacteremia. The rash resolved with the treatment of osteomyelitis. As seen in this case, local infection should be considered in the differential diagnosis of LCV even when there is no evidence of bacteremia.

Non-Typhoidal Salmonella and the Risk of Kawasaki Disease: A Nationwide Population-Based Cohort Study

Objective

The aim of this study was to investigate the relationship between non-typhoidal Salmonella (NTS) infection and the risk of Kawasaki disease (KD) by using a nationwide population-based data set in Taiwan.

Methods

In this retrospective cohort study, we enrolled 69,116 patients under 18 years of age, with NTS from January 1^st, 2000, to December 31^st, 2013, using the population-based National Health Insurance Research Database of Taiwan. A comparison group without NTS was matched (at a 1:4 ratio) by propensity score. The two cohorts were followed from the initial diagnosis of NTS until the date of KD development or December 31^st, 2013. Cox proportional hazard regression analysis was conducted to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) after adjusting for covariates. Also, we conducted sensitivity analyses to examine our findings.

Results

After adjusting for covariates, the risk of KD for the children with NTS was significantly higher than that of the comparison group (hazard ratio = 1.31; 95% confidence interval = 1.03-1.66; p < 0.01). Stratified analysis showed that the associated risk of the investigated outcome was significant in children aged ≤2 years (aHR= 1.31, 95% C.I. 1.02-1.69), in female patients (aHR= 1.46, 95% C.I. 1.03-2.08), and in those without allergic diseases.

Conclusions

NTS is associated with an increased risk of KD in Taiwanese children.

Diagnosis and management of leukocytoclastic vasculitis

Leukocytoclastic vasculitis (LCV) is a histopathologic description of a common form of small vessel vasculitis (SVV), that can be found in various types of vasculitis affecting the skin and internal organs. The leading clinical presentation of LCV is palpable purpura and the diagnosis relies on histopathological examination, in which the inflammatory infiltrate is composed of neutrophils with fibrinoid necrosis and disintegration of nuclei into fragments ("leukocytoclasia"). Several medications can cause LCV, as well as infections, or malignancy. Among systemic diseases, the most frequently associated with LCV are ANCA-associated vasculitides, connective tissue diseases, cryoglobulinemic vasculitis, IgA vasculitis (formerly known as Henoch-Schonlein purpura) and hypocomplementemic urticarial vasculitis (HUV). When LCV is suspected, an extensive workout is usually necessary to determine whether the process is skin-limited, or expression of a systemic vasculitis or disease. A comprehensive history and detailed physical examination must be performed; platelet count, renal function and urinalysis, serological tests for hepatitis B and C viruses, autoantibodies (anti-nuclear antibodies and anti-neutrophil cytoplasmic antibodies), complement fractions and IgA staining in biopsy specimens are part of the usual workout of LCV. The treatment is mainly focused on symptom management, based on rest (avoiding standing or walking), low dose corticosteroids, colchicine or different unproven therapies, if skin-limited. When a medication is the cause, the prognosis is favorable and the discontinuation of the culprit drug is usually resolutive. Conversely, when a systemic vasculitis is the cause of LCV, higher doses of corticosteroids or immunosuppressive agents are required, according to the severity of organ involvement and the underlying associated disease.

Image-guided placement of totally implanted vascular access device: retrospective analysis of the clinical outcomes and associated risk factors

OBJECTIVES

To determine risk factors for catheter survival and complications after image-guided implantation of a totally implanted vascular access device (TIVAD).

METHODS

A total of 2883 TIVADs (2735 patients, 63.5±13 years old, 1060 men, 1675 women) implanted under guidance by ultrasound and fluoroscopy in our institution from January 2010 to December 2019 were evaluated retrospectively. We used the log rank test and logistic regression to analyse risk factors associated with catheter survival and complications.

RESULTS

Female patients (n=1778; 61.7%; mean catheter survival days: 780.6 days) and those with a haematological malignancy (n=277; 10.1%; mean catheter survival days: 1019 days) had significantly better catheter survival than male patients (n=1105; 38.3%; mean catheter survival days: 645.9 days) and those with a solid organ malignancy (n=2447; 89.5%; mean catheter survival days: 701 days) (p<0.001 and p=0.003). Patients with haematological malignancies and benign vascular inflammatory disease (n=11; 0.4%) were vulnerable to infection (n=96; 3.3%) (p<0.001 and p=0.004). Thrombotic malfunction (n=38; 1.3%) was significantly more common in females than males (p=0.005). Non-thrombotic malfunction (n=16; 0.6%) showed a significant association with left positioning of the TIVAD (n=410; 14.2%) (p=0.043). Wound dehiscence (n=3; 0.1%) was significantly more frequent in punctured veins other (n=23; 0.8%) than the internal jugular vein (p<0.001).

CONCLUSIONS

Increased attention should be paid to patients with an underlying haematological malignancy, underlying vascular inflammatory disease, female patients, older patients, those accessed via a vein other than the IJV, those with left positioning of the TIVAD system or those with a prolonged TIVAD maintenance.

Granulocyte Colony-stimulating Factor-induced Aortitis with Lung Injury, Splenomegaly, and a Rash During Treatment for Recurrent Extraosseous Mucinous Chondrosarcoma

We herein report a case of aortitis induced by granulocyte colony-stimulating factor (G-CSF) that coincided with lung injury, splenomegaly, and cutaneous manifestations during treatment for recurrent extraosseous mucinous chondrosarcoma. Computed tomography revealed large-vessel vasculitis, splenomegaly, and pulmonary interstitial changes. Treatment with prednisolone was successful. Because sarcoma is a rare disease, this case is valuable for showing clinicians that G-CSF preparations could cause aortitis regardless of the patient's underlying diseases or therapeutic pharmacological backgrounds.

SARS-CoV-2, COVID-19, skin and immunology - What do we know so far?

The pandemic condition coronavirus disease (COVID-19), caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), can take asymptomatic, mild, moderate, and severe courses. COVID-19 affects primarily the respiratory airways leading to dry cough, fever, myalgia, headache, fatigue, and diarrhea and can end up in interstitial pneumonia and severe respiratory failure. Reports about the manifestation of various skin lesions and lesions of the vascular system in some subgroups of SARS-CoV-2-positive patients as such features outside the respiratory sphere, are rapidly emerging. Vesicular, urticarial, and maculopapular eruptions and livedo, necrosis, and other vasculitis forms have been reported most frequently in association with SARS-CoV-2 infection. In order to update information gained, we provide a systematic overview of the skin lesions described in COVID-19 patients, discuss potential causative factors, and describe differential diagnostic evaluations. Moreover, we summarize current knowledge about immunologic, clinical, and histologic features of virus- and drug-induced lesions of the skin and changes to the vascular system in order to transfer this knowledge to potential mechanisms induced by SARS-CoV-2.

Multiple Pulmonary Nodules in Leptospirosis

A 21-year-old man presented with the chief complaints of fever and sore throat after visiting Cambodia and Thailand. Computed tomography revealed multiple pulmonary nodules. After performing antibiotic therapy, the pulmonary nodules without bacteremia disappeared completely. Paired microscopic agglutination tests revealed seroconversion against Leptospira serogroup Autumnalis. Thus, he was diagnosed with multiple pulmonary nodules caused by leptospirosis. Leptospirosis is a common zoonosis that occurs in tropical and subtropical areas. Its various clinical features include unspecified fever and Weil's disease. Although diffuse alveolar hemorrhaging is known to occur in severe leptospirosis, multiple pulmonary nodules resembling septic emboli or vasculitis are a rare complication.

Post-fever retinitis - Newer concepts

Post-fever retinitis (PFR) is an infectious or para-infectious uveitic entity caused by bacterial or viral agents and seen mainly in tropical countries. Systemic symptoms such as joint pain, skin rash are common during the febrile stage. On the basis of only clinical presentation, it is difficult to pin-point the exact etiology for PFR. Serological investigations, polymerase chain reaction, and knowledge of concurrent epidemics in the community may help to identify the etiological organism. Bacterial causes of PFR such as rickettsia and typhoid are treated with systemic antibiotics, with or without systemic steroid therapy, whereas PFR of viral causes such as chikungunya, dengue, West Nile virus, and Zika virus have no specific treatment and are managed with steroids. Nevertheless, many authors have advocated mere observation and the uveitis resolved with its natural course of the disease. In this article, we have discussed the clinical features, pathogenesis, investigations, and management of PFR.

A Mycotic Common Iliac Artery Pseudoaneurysm of Indeterminate Etiology

We present the unusual case of a mycotic right common iliac artery pseudoaneurysm caused by the methicillin-susceptible Staphylococcus aureus (MSSA) of indeterminate etiology in a healthy 57-year-old man with no risk factors for infection, trauma, or malignancy. The patient initially presented with worsening subacute right lower quadrant pain and was found to have a pseudoaneurysm of the right common iliac artery. Given concern for rupture on a computed tomography angiogram (CTA), he underwent exclusion of the pseudoaneurysm with a covered stent. At the time of presentation, he had no signs or symptoms of infection. However, the patient developed fever, chills, and worsening right lower quadrant pain 13 days after the index operation and was found to have a leukocytosis, blood cultures positive for MSSA, and progressive soft-tissue changes involving the right common iliac artery on CTA consistent with infection. He was definitively treated with stent explantation, aggressive debridement and replacement with an in situ cryopreserved bypass, and short-term suppressive antibiotic therapy.

Elevated antistreptolysin O titer is closely related to cardiac mitral insufficiency in untreated patients with Takayasu arteritis

Background

The etiology of Takayasu arteritis (TA) is unknown; however, a possible relationship between streptococcal infection and TA has been proposed. This study aimed to identify the clinical features and cardiac valvular involvement in untreated TA patients with an elevated antistreptolysin O (ASO) titer.

Methods

In this retrospective study, the clinical characteristics and features of valvular involvement were compared in TA patients with or without an elevated ASO titer.

Results

Of the 74 untreated TA patients, 13 patients were found have elevated ASO titers (17.6%). Mitral insufficiency was the most common in patients with elevated ASO (69.2%, 9/13), followed by aortic valve insufficiency (46.2%, 5/13) and tricuspid insufficiency (46.2%, 5/13), which were no significantly different than that in normal ASO group. The proportions of moderate to severe mitral (30.8% vs 1.6%, p = 0.000) and tricuspid valve (15.4% vs 1.64%, p = 0.023) insufficiency in the ASO positive group were significantly higher than those in the ASO negative group. The odds of mitral regurgitation in patients with elevated ASO titers were 3.9 times higher than those in the group with normal ASO titers (p = 0.053, OR = 3.929, 95% confidence interval [CI]: 0.983–15.694). Furthermore, the risk of moderate to severe mitral insufficiency in patients with elevated ASO titers was 41.6 times higher than that in patients with normal ASO titers (p = 0.002, OR = 41.600, 95% CI: 3.867–447.559).

Conclusions

An increase in ASO titer is related to valvular involvement in TA and is closely linked to mitral insufficiency.

A rare case of polyarteritis nodosa associated with nontuberculous mycobacterial infection

Clinicians should be aware that cutaneous PAN can present with significant extracutaneous and constitutional symptoms which make it hard to differentiate from systemic PAN. The condition can also rarely be associated with NTM infections.

Microbiomes of Inflammatory Thoracic Aortic Aneurysms Due to Giant Cell Arteritis and Clinically Isolated Aortitis Differ From Those of Non-Inflammatory Aneurysms

OBJECTIVE

We sought to characterize microbiomes of thoracic aortas from patients with non-infectious aortitis due to giant cell arteritis (GCA) and clinically isolated aortitis (CIA) and to compare them to non-inflammatory aorta aneurysm controls. We also compared microbiomes from concurrently processed and separately reported temporal arteries (TA) and aortas.

METHODS

From 220 prospectively enrolled patients undergoing surgery for thoracic aorta aneurysm, 49 were selected. Inflammatory and non-inflammatory cases were selected based on ability to match for age (+/-10 years), gender, and race. Biopsies were collected under aseptic conditions and snap-frozen. Taxonomic classification of bacterial sequences was performed to the genus level and relative abundances were calculated. Microbiome differential abundances were analyzed by principal coordinates analysis.

RESULTS

Forty-nine patients with thoracic aortic aneurysms (12 CIA, 14 GCA, 23 non-inflammatory aneurysms) were enrolled. Alpha (P=0.018) and beta (P=0.024) diversity differed between specimens from aortitis cases and controls. There were no significant differences between CIA and GCA (P>0.7). The largest differential abundances between non-infectious aortitis and non-inflammatory control samples included Enterobacteriaceae, Phascolarctobacterium, Acinetobactor, Klebsiella, and Prevotella. Functional metagenomic predictions with PICRUSt revealed enrichment of oxidative phosphorylation and porphyrin metabolism pathways and downregulation of transcription factor pathways in aortitis compared to controls. Microbiomes of aortic samples differed significantly from temporal artery samples from a companion study, in both control and GCA groups (P=0.0002).

CONCLUSION

Thoracic aorta aneurysms, far from being sterile, contain unique microbiomes that differ from those found in temporal arteries. The aorta microbiomes are most similar between aneurysms that were associated with inflammation, GCA, and CIA, but differed from those associated with non-inflammatory etiologies. These findings are promising in that they indicate that microbes may play a role in the pathogenesis of aortitis-associated aneurysms or non-inflammatory aneurysms by promoting or protecting against inflammation. However, we cannot rule out that these changes are related to alterations in tissue substrate that favor secondary changes in microbial communities.

Imaging of Childhood Inflammatory Brain Diseases

Brain has been considered as an immune-privileged site for centuries owing to the presence of blood-brain barrier, absent lymphatic drainage, and antigen-presenting cells. However, the present prevailing concept is of immune surveillance where brain is continuously surveyed by immune cells. However, the presence of immune cells in central nervous system (CNS) brings the risk of inflammation and autoimmunity involving both T and B cell mediated pathways. These mechanisms form the underlying pathology in a wide spectrum of pediatric CNS diseases manifesting as acquired neurological deficits. Overlapping, heterogenous, and ambiguous clinical features often delays the diagnosis. Although not always pathognomonic, magnetic resonance imaging can be an important biomarker leading to early diagnosis, prognostication, and systematic follow-up pf these diseases. This review describes the spectrum of different pediatric inflammatory disorders and their pertinent imaging features illustrated with clinical examples.

Imaging of cerebrovascular complications of infection

Cerebrovascular complications may occur in infectious diseases in the setting of infective endocarditis, central nervous system (CNS) infections, systemic bacteremia and sepsis. Cerebrovascular complications of infections include vasculitis, mycotic aneurysms, and thrombophlebitis. Infectious vasculitis of the CNS may cause cerebral hemorrhage, infarction or ischemia. Ruptured aneurysms may endanger the patient's life. Infectious thrombophlebitis may cause intracranial pressure to increase and lead to cerebral hemorrhage. These cerebrovascular complications are associated with a poor prognosis and often cause irreversible neurological deficits. Cerebrovascular events secondary to infection are not easily distinguishable from the more common cerebral infarct and non-infectious vasculitis. In addition, the clinical manifestations of cerebrovascular complications of infections are non-specific and highly variable. Therefore, early imaging, antibiotics, and anticoagulation may be lifesaving the patient's life and prevent disability. The main focus of this article is to review imaging analysis of the cerebrovascular complications of infections and imaging features that help differentiate them from non-infectious vascular diseases.

New Insights on the Pathogenesis of Takayasu Arteritis: Revisiting the Microbial Theory

Takayasu arteritis (TAK) is a chronic vasculitis that mainly affects the aorta, its major branches, and the pulmonary arteries. Since the description of the first case by Mikito Takayasu in 1908, several aspects of this rare disease, including the epidemiology, diagnosis, and the appropriate clinical assessment, have been substantially defined. Nevertheless, while it is well-known that TAK is associated with a profound inflammatory process, possibly rooted to an autoimmune disorder, its precise etiology has remained largely unknown. Efforts to identify the antigen(s) that trigger autoimmunity in this disease have been unsuccessful, however, it is likely that viruses or bacteria, by a molecular mimicry mechanism, initiate or propagate the auto-immune process in this disease. In this article, we summarize recent advances in the understanding of TAK, with emphasis on new insights related to the pathogenesis of this entity that may contribute to the design of novel therapeutic approaches.

Inter-Pathogen Peptide Sharing and the Original Antigenic Sin: Solving a Paradox

Aims:

To analyse the peptide commonality among viral, bacterial, and protozoan pathogens, and the immunopathologic consequences in the human host.

Methods:

HPV16, HCMV,C. diphtheriae, B. pertussis, C. tetani, T. gondii,andT. cruziwere analysed for common amino acid sequences that are additionally shared with the human host. The pentapeptide, a minimal immune determinant in humoral and cellular immune recognition, was used as a measurement unit of the peptide similarity level. Molecular modeling was applied to compare the amino acid contexts containing common minimal determinants.

Results:

Twenty-nine pentapeptides were found to occur, even hundreds of times, throughout the analyzed pathogen proteomes as well as in the human proteome. Such vast peptide commonalities together with molecular modeling data support the possibility that a pre-existing immune response to a first pathogen can be boosted by a successive exposure to a second different pathogen,i.e., the primary response to a pathogen can be transformed into a secondary response to a previously encountered different pathogen. Two possible consequences emerge. Firstly, no responses might be elicited against the pathogen lastly encountered either by infection or active immunization, but reactions could occur only with the early sensitizing pathogen, which is no more present in the organism. Secondly, the immune response boosted by the pathogen lastly encountered will find a way out by cross-reacting with human proteins.

Conclusion:

This study might explain the “original antigenic sin” phenomenon described seven decades ago [Francis T. Jr. Ann Intern Med 1953;39:203], thus providing explanations for vaccine failures and offering possible clues for designing successful vaccines.

Bartonella Infectious Endocarditis Associated With Cryoglobulinemia and Multifocal Proliferative Glomerulonephritis

Bartonella sp. are a common cause of culture-negative infective endocarditis. Glomerulonephritis is a well-documented consequence of the immune activation associated with infective endocarditis. However, Cryoglobulinemia has not previously been reported in association with Bartonella infective endocarditis. Below we report a case of a 48-year-old male with Bartonella henselae infective endocarditis complicated by cryoglobulinemia and multifocal proliferative glomerulonephritis, highlighting a possible link between Bartonella sp. infection and type III cryoglobulinemia.

Chronic hepatitis C viral infection among SLE patients: the significance of coexistence

The association between viral infection and autoimmune diseases is an established phenomenon in medicine. Hepatitis C viral infection is known to have such an association; however, its association with systemic lupus erythematosus has not been studied in a real life study driven from a large national database. The objective of this study was to investigate the association between SLE and chronic hepatitis C viral infection. Patients with SLE were compared with age- and sex-matched controls regarding the proportion chronic HCV infection. Chi-square and t tests were used for univariate analysis, and a logistic regression model was used for multivariate analysis. The study was performed utilizing the medical database of Clalit Health Services in Israel. There was a significant higher proportion of hepatitis C viral infection in SLE patients as compared to controls (1.06 and 0.39%, respectively; p < 0.001). A significant association was also observed among patients of higher socioeconomic status. In a multivariate logistic regression analysis, SLE was significantly associated with hepatitis C viral infection (OR = 2.07, 95% CI = 1.46-2.90). To conclude, Patients with SLE have a greater proportion of chronic HCV infection than matched controls.

ANCA Vasculitis and Hemophagocytic Lymphohistiocytosis following a Fecal Microbiota Transplant

A 69-year-old female with antisynthetase syndrome, a history of multiple recurrent infections, and documented previous negative titres for anti-neutrophil cystoplasmic antibody (ANCA) suddenly developed a de novo MPO-ANCA-associated glomerulonephritis three weeks after a fecal microbiota transplantation (FMT) for recurrent Clostridium difficile infections. Six months following her FMT and less than two weeks following treatment for urosepsis, she developed severe cholestasis, a markedly elevated ferritin and hypertriglyceridemia. An initial liver biopsy was suggestive of drug-induced liver injury and thus she was treated with supportive care. After she failed to improve, a second liver biopsy supported the diagnosis of hemophagocytic lymphohistiocytosis (HLH). This case highlights difficulties surrounding the early diagnosis of HLH and also questions the role of FMT and/or recurrent infections as a trigger for ANCA-associated vasculitis.

Position paper: Revised 2017 international consensus on testing of ANCAs in granulomatosis with polyangiitis and microscopic polyangiitis

Anti-neutrophil cytoplasmic antibodies (ANCAs) are valuable laboratory markers used for the diagnosis of well-defined types of small-vessel vasculitis, including granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA). According to the 1999 international consensus on ANCA testing, indirect immunofluorescence (IIF) should be used to screen for ANCAs, and samples containing ANCAs should then be tested by immunoassays for proteinase 3 (PR3)-ANCAs and myeloperoxidase (MPO)-ANCAs. The distinction between PR3-ANCAs and MPO-ANCAs has important clinical and pathogenic implications. As dependable immunoassays for PR3-ANCAs and MPO-ANCAs have become broadly available, there is increasing international agreement that high-quality immunoassays are the preferred screening method for the diagnosis of ANCA-associated vasculitis. The present Consensus Statement proposes that high-quality immunoassays can be used as the primary screening method for patients suspected of having the ANCA-associated vaculitides GPA and MPA without the categorical need for IIF, and presents and discusses evidence to support this recommendation.

The NLRP3 inflammasome in kidney disease and autoimmunity

The NLRP3 inflammasome is an intracellular platform that converts the pro-inflammatory cytokines interleukin (IL)-1β and IL-18 to their active forms in response to 'danger' signals, which can be either host or pathogen derived, and mediates a form of inflammatory cell death called pyroptosis. This component of the innate immune system was initially discovered because of its role in rare autoinflammatory syndromes called cryopyrinopathies, but it has since been shown to mediate injurious inflammation in a broad range of diseases. Inflammasome activation occurs in both immune cells, primarily macrophages and dendritic cells, and in some intrinsic kidney cells such as the renal tubular epithelium. The NLRP3 inflammasome has been implicated in the pathogenesis of a number of renal conditions, including acute kidney injury, chronic kidney disease, diabetic nephropathy and crystal-related nephropathy. The inflammasome also plays a role in autoimmune kidney disease, as IL-1β and IL-18 influence adaptive immunity through modulation of T helper cell subsets, skewing development in favour of Th17 and Th1 cells that are important in the development of autoimmunity. Both IL-1 blockade and two recently identified specific NLRP3 inflammasome blockers, MCC950 and β-hydroxybutyrate, have shown promise in the treatment of inflammasome-mediated conditions. These targeted therapies have the potential to be of benefit in the growing number of kidney diseases in which the NLRP3 inflammasome has been implicated.

Behcet’s disease: from heat shock proteins to infections

Background: Behcet’s disease (BD) is a chronic, inflammatory multisystemic condition of unknown etiology. Although the cause of BD is not clear, it is believed to be the result of an autoimmune process triggered by an infectious or environmental agent (possibly local to a geographic region) in a genetically predisposed individual.

Objective: To detail current knowledge of the role of microorganisms in the pathogenesis of BD and review the infectious etiology of this disease.

Methods: The review based on publication in SCOPUS, Science direct, and PubMed.

Results: A microbial infection has been implicated in the development of the disease to explain the strong inflammatory reactions observed, the activation of monocytes and macrophages, and the induction of proinflammatory cytokines and chemokines detected. Common factors linking some of the possible pathogenetic agents are extrinsically induced tissue stress or heat shock proteins, which react with host tissues and elicit significant T-helper type 1 cell responses.

Conclusion: Based on collected data, we conclude that the microorganisms discussed seem to participate and, at least in part, act as triggers during the course of BD. By clarifying the microbial associations of BD and finding its etiology, particularly the causative antigens leading to BD, it would be easier to suggest more effective treatment and preventive strategies for this disease.

Imaging in Pediatric Demyelinating and Inflammatory Diseases of Brain- Part 2

Imaging plays an important role in diagnosis, management, prognostication and follow up of pediatric demyelinating and inflammatory diseases of brain and forms an integral part of the diagnostic criteria. This article reviews the spectrum of aquaporinopathies with an in-depth discussion on present criteria and differentiation from other demyelinating diseases with clinical vignettes for illustration; the latter part of article deals with the spectrum of CNS vasculitis.

Vasculitides and the Complement System: a Comprehensive Review

Systemic vasculitides are a group of rare diseases characterized by inflammation of the arterial or venous vessel wall, causing stenosis or thrombosis. Clinical symptoms may be limited to skin or to other organs or may include multiple manifestations as systemic conditions. The pathogenesis is related to the presence of leukocytes in the vessels and to the IC deposition, which implies the activation of the complement system (CS) and then the swelling and damage of vessel mural structures. The complement system (CS) is involved in the pathogenesis of several autoimmune diseases, including systemic vasculitides. This enzymatic system is a part of the innate immune system, and its function is linked to the modulation of the adaptive immunity and in bridging innate and adaptive responses. Its activation is also critical for the development of natural antibodies and T cell response and for the regulation of autoreactive B cells. Complement triggering contributes to inflammation-driven tissue injury, which occurs during the ischemia/reperfusion processes, vasculitides, nephritis, arthritis, and many others diseases. In systemic vasculitides, a group of uncommon diseases characterized by blood vessel inflammation, the contribution of CS in the development of inflammatory damage has been demonstrated. Treatment is mainly based on clinical manifestations and severity of organ involvement. Evidences on the efficacy of traditional immunosuppressive therapies have been collected as well as data from clinical trials that involve the modulation of the CS. In particular in small-medium-vessel vasculitides, the CS represents an attractive target. Herein, we reviewed the pathogenetic role of CS in these systemic vasculitides as urticarial vasculitis, ANCA-associated vasculitides, anti-glomerular basement membrane disease, cryoglobulinaemic vasculitides, Henoch-Schönlein purpura/IgA nephropathy, and Kawasaki disease and therefore its potential therapeutic use in this context.

Arterial ischemic stroke in HIV: Defining and classifying etiology for research studies

HIV infection, and potentially its treatment, increases the risk of an arterial ischemic stroke. Multiple etiologies and lack of clear case definitions inhibit progress in this field. Several etiologies, many treatable, are relevant to HIV-related stroke. To fully understand the mechanisms and the terminology used, a robust classification algorithm to help ascribe the various etiologies is needed. This consensus paper considers the strengths and limitations of current case definitions in the context of HIV infection. The case definitions for the major etiologies in HIV-related strokes were refined (e.g., varicella zoster vasculopathy and antiphospholipid syndrome) and in some instances new case definitions were described (e.g., HIV-associated vasculopathy). These case definitions provided a framework for an algorithm to help assign a final diagnosis, and help classify the subtypes of HIV etiology in ischemic stroke.

Granulomatous Vasculitis

Vasculitides are uncommon disorders, characterized by inflammation of the blood vessels resulting either in ischemia or hemorrhage. They are commonly classified as small-, medium-, or large-vessel vasculitides. Antineutrophil cytoplasmic antibody-associated vasculitis is an important group of small-vessel vasculitis. This group includes granulomatous vasculitides, namely, granulomatosis with polyangiitis (GPA), eosinophilic granulomatosis with polyangiitis (EGPA), and nongranulomatous vasculitis, namely, microscopic polyangiitis (MPA). Classic polyarteritis nodosa (PAN) is a granulomatous medium-vessel vasculitis. This review discusses the classification, etiopathogenesis, clinical features, and management of GPA, MPA, EGPA and PAN.