Infection-induced myeloperoxidase specific antineutrophil cytoplasmic antibody (MPO-ANCA) associated vasculitis: A systematic review

Clinical and pathological features of cerebrospinal meningitis caused by Pantoea agglomerans : a case report

BACKGROUND

Pantoea agglomerans (P. agglomerans) is a gram-negative bacterium that is commonly isolated from plant surfaces, seeds, and the environment. As an opportunistic pathogen, it can cause blood, urinary and soft tissue infections in immunocompromised patients. In central nervous system, P. agglomerans infection has been report in children and immune-compromised patients, however, infection by such bacterium in nontraumatized immune competent adults has not been reported. Here, we report a case of P. agglomerans cerebrospinal meningitis accompanied by positive anti-myeloperoxidase (MPO) antibody in a 49-year-old female who has a history of black fungus planting.

CASE PRESENTATION

The patient manifested with repeated fever, headache, generalized muscle pain, and neurological defects. Cerebrospinal fluid (CSF) tests revealed a moderately elevated number of polymorphonuclear leukocytes (50-193 × 106/L), low glucose levels (0.54-2.44 mmo1/L), and extremely high protein content (2.42-25.42 g/L). Blood tests showed positive anti-myeloperoxidase antibodies lasting for 1.5 year before turning negative. Spine MRI showed thickening and enhancement of the whole spinal meninges. CSF metagenomic next-generation sequencing (mNGS) revealed 75,189 specific DNA reads of P. agglomerans. The patient underwent spinal laminectomy due to meningeal adhesions. Pathological results revealed fibrous tissue proliferation, inflammatory infiltration with focal necrosis and calcification in the dura mater. The patient was successfully treated with sufficient antibiotics at 1-year follow-up.

CONCLUSIONS

People should be alert to CNS infections caused by P. agglomerans which presented with relatively mild clinical symptoms at onset, especially for those who contucts relevant agricultural and forestry work. The CSF characterization of P. agglomerans meningitis is elevated multiple nuclei white blood cells, significantly reduced glucose content, and markedly increased protein level which may be related to the secondary spinal membrane adhesions.

Autoimmune Diseases Following Environmental Disasters: A Narrative Review of the Literature

Environmental disasters are extreme environmental processes such as earthquakes, volcanic eruptions, landslides, tsunamis, floods, cyclones, storms, wildfires and droughts that are the consequences of the climate crisis due to human intervention in the environment. Their effects on human health have alarmed the global scientific community. Among them, autoimmune diseases, a heterogeneous group of disorders, have increased dramatically in many parts of the world, likely as a result of changes in our exposure to environmental factors. However, only a limited number of studies have attempted to discover and analyze the complex association between environmental disasters and autoimmune diseases. This narrative review has therefore tried to fill this gap. First of all, the activation pathways of autoimmunity after environmental disasters have been analyzed. It has also been shown that wildfires, earthquakes, desert dust storms and volcanic eruptions may damage human health and induce autoimmune responses to inhaled PM2.5, mainly through oxidative stress pathways, increased pro-inflammatory cytokines and epithelial barrier damage. In addition, it has been shown that heat stress, in addition to increasing pro-inflammatory cytokines, may also disrupt the intestinal barrier, thereby increasing its permeability to toxins and pathogens or inducing epigenetic changes. In addition, toxic volcanic elements may accelerate the progressive destruction of myelin, which may potentially trigger multiple sclerosis. The complex and diverse mechanisms by which vector-borne, water-, food-, and rodent-borne diseases that often follow environmental diseases may also trigger autoimmune responses have also been described. In addition, the association between post-disaster stress and the onset or worsening of autoimmune disease has been demonstrated. Given all of the above, the rapid restoration of post-disaster health services to mitigate the flare-up of autoimmune conditions is critical.

The COVID-19 thrombus: distinguishing pathological, mechanistic, and phenotypic features and management

A heightened risk for thrombosis is a hallmark of COVID-19. Expansive clinical experience and medical literature have characterized small (micro) and large (macro) vessel involvement of the venous and arterial circulatory systems. Most events occur in patients with serious or critical illness in the hyperacute (first 1-2 weeks) or acute phases (2-4 weeks) of SARS-CoV-2 infection. However, thrombosis involving the venous, arterial, and microcirculatory systems has been reported in the subacute (4-8 weeks), convalescent (> 8-12 weeks) and chronic phases (> 12 weeks) among patients with mild-to-moderate illness. The purpose of the current focused review is to highlight the distinguishing clinical features, pathological components, and potential mechanisms of venous, arterial, and microvascular thrombosis in patients with COVID-19. The overarching objective is to better understand the proclivity for thrombosis, laying a solid foundation for screening and surveillance modalities, preventive strategies, and optimal patient management.

Antineutrophil cytoplasmic antibody is an independent risk factor in rheumatoid arthritis-associated interstitial lung disease

OBJECTIVES

This study aimed to investigate the clinical relevance of antineutrophil cytoplasmic antibody (ANCA) in patients with rheumatoid arthritis-associated interstitial lung disease (RA-ILD).

METHODS

Detailed clinical records of rheumatoid arthritis (RA) patients who underwent ANCA screening tests were collected. ANCA measurements were determined by indirect immunofluorescence assay (IIF) and enzyme-linked immunosorbent assay (ELISA). Clinical characteristics were compared between ANCA-positive and ANCA-negative groups, and multivariable logistic models were used to evaluate the independent association of ANCA with ILD in RA patients.

RESULTS

The prevalence of ANCA by IIF was significantly higher in RA-ILD patients compared to those with RA without ILD (31.7 % vs. 19.5 %, p < 0.001). RA-ILD patients positive for ANCA exhibited elevated levels of inflammatory markers and greater disease activity, and showed more severe impairment of lung function compared to ANCA-negative RA-ILD patients. Multivariable logistic regression analysis revealed an independent association of ANCA, especially pANCA, with RA-ILD. ANCA specificities for BPI, elastase, and cathepsin-G were found in 15.6 % of RA-ILD patients; the specificities for most others remain unknown.

CONCLUSIONS

The findings suggest a potential role for ANCA/pANCA in stratifying the risk of RA and provide supplementary information to the existing clinically available assays. This additional information may be valuable in identifying RA patients who require further investigations for RA-ILD, such as high-resolution computed tomography (HRCT). These results emphasize the potential clinical relevance of ANCA in the context of RA-ILD.

Infection-Associated Glomerulonephritis

The nephritic syndrome has been associated with a wide variety of infections, spanning many organisms and myriad clinical presentations. Infection-associated glomerulonephritis is challenging to diagnose given the many confounding factors linking kidney injury to infection; however, urine microscopy can assist in identifying abnormal cellular elements suggestive of glomerulonephritis. Kidney biopsy remains the gold standard for diagnosing the underlying pathologic lesion. Treatment of infection-associated glomerulonephritis centers around aggressive and complete treatment of the underlying infectious driver. It is often hard to know exactly when immunosuppression may be required in addition to treating the infection.

Rat bite fever mimicking ANCA-associated vasculitis

Rat bite fever (RBF) is a rare infectious zoonotic disease caused by two bacterial species: the Gram-negative rod Streptobacillus moniliformis and the Gram-negative coiled rod Spirillum minus. The association between RBF and skin vasculitis and arthritis has been observed. The aim of this paper was to present a case of rat-bite fever with symptoms of skin vasculitis and arthritis, associated with high titers of ANCA antibodies and anti-endothelial cell antibodies suggestive of primary vasculitis. The patient was successfully treated with antibiotics and non-steroidal anti-inflammatory drugs, leading to significant improvement. Based on the presented case, we discuss the differential diagnosis of the signs and the role of infection in the induction of ANCA antibodies. We reviewed the English language literature for cases of RBF presenting with symptoms of vasculitis and/or antibody presence. A literature review was performed in PubMed and Google using the keywords "rat bite fever" AND "vasculitis", "systemic vasculitis", "ANCA", "antiendothelial antibodies". No cases of rat-bite fever with the presence of ANCA antibodies or AECA antibodies in its course have been described thus far. Rat bite fever is a rare disease with nonspecific symptoms. In its course, general weakness, intermittent fever, leukocytoclastic vasculitis, and arthritis are reported. To our knowledge, this is the first reported case of ANCA positivity associated with RBF.

Antineutrophil cytoplasmic antibody-associated vasculitis predominantly manifesting tubulointerstitial nephritis: A case report

The common histopathology of antineutrophil cytoplasmic antibody-associated vasculitis comprises pauci-immune crescentic glomerulonephritis with concomitant tubulointerstitial nephritis. Tubulointerstitial nephritis in the absence of glomerular involvement in patients with antineutrophil cytoplasmic antibody-associated vasculitis is uncommon. We report a case of antineutrophil cytoplasmic antibody-associated vasculitis-associated acute kidney injury manifesting as tubulointerstitial nephritis without glomerulonephritis. A 75-year-old woman with fever, cough, and myalgia developed kidney dysfunction with inflammatory reactions and tubular-type proteinuria, without glomerular hematuria. A kidney biopsy revealed tubulointerstitial nephritis with arteritis. We ruled out important underlying etiologies of tubulointerstitial nephritis, including infection, drug reactions, and autoimmune diseases. Since chest high-resolution computed tomography demonstrated mild interstitial pneumonia in bilateral lower lung fields, myeloperoxidase antineutrophil cytoplasmic antibody was measured and found to be positive. Therefore, we diagnosed the patient with antineutrophil cytoplasmic antibody-associated vasculitis-associated tubulointerstitial nephritis but not glomerulonephritis, and interstitial pneumonia. The patient's kidney function and symptoms markedly improved with prednisolone treatment. Clinicians should maintain high-level vigilance for antineutrophil cytoplasmic antibody-associated vasculitis as a possible underlying component of tubulointerstitial nephritis, particularly when kidney function deteriorates with tubulointerstitial injuries without glomerular features.

Antineutrophil cytoplasmic antibody‑associated vasculitis complicated with oral and maxillofacial space infection in a young woman: A case report

Antibody-associated vasculitis (AAV) is a systemic autoimmune disease, with hormones and immunosuppressants as its main treatment measures. However, during the treatment process, various infections such as lung infections and urinary tract infections are prone to occur, and patients with OMSI are relatively rare. The present case report describes the case of a young woman who received long-term oral glucocorticoids and immunosuppressive agents for the treatment of antineutrophil cytoplasmic (AAV). At hospital admission, the patient with a high fever and painful swelling of the left side of the mouth. The patient was diagnosed with an oral and maxillofacial space infection (OMSI). Therefore, the local incision, drainage and irrigation of abscesses were subsequently performed. Additionally, the immunosuppressive agents were discontinued, the glucocorticoid dose was reduced and intravenous antibiotic therapy was provided. The patient was discharged 1 week later in good condition. Notably, the incidence of AAV is extremely low. Although OMSI is not uncommon, the simultaneous occurrence of AAV in combination with OMSI has not been reported previously. To the best of our knowledge, this is the first reported case of AAV combined with OMSI.

COVID-19 and glomerular diseases

COVID (Coronavirus disease)-19 is a systemic disease and the kidney is one of the target organs of infection. Kidney injury is common and can occur in up to 40% of patients. Several glomerular diseases have been reported in association with COVID-19. Some are likely related to COVID-19 whereas many are likely coincidental. Glomerular diseases that are frequently reported in COVID-19 and have a plausible mechanistic explanation, are likely to be related to COVID-19. On the other hand, glomerular diseases that are seldom reported and have no known plausible mechanism, are likely to be unrelated. Collapsing glomerulopathy (CG) is by far the most prevalent. Its association with COVID-19, resembling human immunodeficiency virus (HIV) and CG, led to the newly proposed term “COVID-19 associated nephropathy” or “COVAN”. High-risk APOL1 genotypes are the major risk factor in COVAN patients. Podocytopathy, membranous nephropathy, pauci-immune crescentic glomerulonephritis, and thrombotic microangiopathy are also reported. In kidney allografts, CG remains the most common glomerular pathology. Patients typically present with acute kidney injury (AKI) or abnormal urinary findings at the time of or shortly after COVID-19 diagnosis. Treatment of glomerular disease in COVID-19 patients is challenging. Providers should cautiously consider balancing risks and benefit of immunosuppression, particularly in patients with active diseases. Short-term outcomes vary but generally remain poor with high morbidity and mortality. Future study of long-term outcomes is needed to improve our understanding of glomerular disease associated with COVID-19.

Utility of the neutrophil-to-lymphocyte ratio in the prediction of anti-neutrophil cytoplasmic antibody-associated vasculitis with infection

OBJECTIVE

This study aimed to evaluate the predictive value of the neutrophil-to-lymphocyte ratio (NLR) for infection in patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).

METHODS

Newly onset patients with AAV in China were included, and their laboratory tests and disease activity were analyzed. Based on infection, patients were divided into the infection group (A-I) and the non-infection group (A-NI). Univariable and multivariable logistic regression analyses were used to investigate variables that are independently associated with infection.

RESULTS

In total, 418 patients were enrolled. Significantly higher white blood cell count (WBC, p < 0.001), neutrophils (p < 0.001), NLR (p < 0.001), platelet-to-lymphocyte ratio (p < 0.001), monocyte-to-lymphocyte ratio (MLR, p < 0.001), erythrocyte sedimentation rate (ESR, p = 0.032), C-reactive protein (CRP, p < 0.001), procalcitonin (PCT, p < 0.001), and Birmingham vasculitis activity score (BVAS, p = 0.005) were observed in the A-I group than in the A-NI group. It was detected that NLR (ρ = 0.273, p < 0.001), MLR (ρ = 0.153, p = 0.011), ESR (ρ = 0.143, p = 0.020), and PCT (ρ = 0.391, p < 0.001) were positively correlated with BVAS. Furthermore, NLR was not only an independent predictor of infection (adjusted OR: 1.144, 95% CI: 1.059-1.236, p = 0.001), but with the largest area under ROC curve, of which value was 0.750. Notably, the optimal cut-off value of NLR for infection was 6.01, with sensitivity of 70.07% and specificity of 71.68%.

CONCLUSION

Our study demonstrated that in addition to WBC, CRP, ESR, and PCT, NLR should also be used as a beneficial inflammatory indicator to differentiate infection in newly diagnosed AAV. Key Points • NLR was a helpful inflammatory marker in differentiating infection in newly diagnosed AAV.

Antimicrobial therapy for nontuberculous mycobacterial pulmonary disease improved hearing loss and normalized myeloperoxidase-anti-neutrophil cytoplasmic antibody level: A case report

Several case reports have indicated that nontuberculous mycobacterial pulmonary disease is associated with anti-neutrophil cytoplasmic antibody-associated vasculitides. However, the effect of the treatment for nontuberculous mycobacterial pulmonary disease on anti-neutrophil cytoplasmic antibody-associated vasculitides remains unclear. An asymptomatic 80-year-old woman presented with nodular bronchiectasis. After 1 year, she developed a productive cough. Mycobacterial culture of the respiratory specimen revealed Mycobacterium avium. She was diagnosed with nontuberculous mycobacterial pulmonary disease based on the criteria proposed by the American Thoracic Society. Concurrently, she had hearing loss, tinnitus, and weight loss. A blood test showed an elevated level of myeloperoxidase-anti-neutrophil cytoplasmic antibody (107 IU/mL, normal level: <3.5 IU/mL). Bilateral otitis media with anti-neutrophil cytoplasmic antibody-associated vasculitis was diagnosed based on the diagnostic criteria proposed by the Japan Otological Society. After starting antimicrobial agents for the nontuberculous mycobacterial pulmonary disease, her pulmonary symptoms and hearing loss improved, and the level of myeloperoxidase-anti-neutrophil cytoplasmic antibody normalized. No immunosuppressive treatment was administered. The present case suggests that nontuberculous mycobacterial pulmonary disease can cause otitis media with anti-neutrophil cytoplasmic antibody-associated vasculitides, and antimicrobial treatment for the nontuberculous mycobacterial pulmonary disease may resolve otitis media with anti-neutrophil cytoplasmic antibody-associated vasculitides.

Relevance of Complement C4 Deposits Localized to Distinct Vascular Compartments in ANCA-Associated Renal Vasculitis

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a small-vessel vasculitis affecting multiple organ systems, including the kidney. Small vessels in the kidney include small-sized arteries, capillaries, and venules. Intrarenal C4 deposits are now increasingly recognized as a potential marker and pathogenic mechanism of autoantibody-mediated tissue damage in ANCA-associated renal vasculitis. We here describe the relevance of complement C4 deposits localized to distinct vascular compartments in a cohort of biopsy-proven ANCA-associated renal vasculitis. A cohort of 43 biopsy-proven cases of ANCA-associated renal vasculitis with myeloperoxidase (MPO) or proteinase 3 (PR3) seropositivity were retrospectively enrolled in a single-center observational study. Univariate and multivariate regression analysis was performed to identify parameters associated with intrarenal C4 deposits in ANCA-associated renal vasculitis. We here show that C4 deposits localize to distinct vascular compartments in ANCA-associated renal vasculitis, and provide evidence for an association with better short-term survival (p = 0.008), implicating that this subgroup had a superior response to remission induction therapy. Second, C4 deposits in interlobular arteries were associated with eosinophilic infiltrates in renal vasculitis with MPO-ANCA seropositivity (p = 0.021). In renal vasculitis positive for MPO-ANCA, the absence of C4 deposits in the glomerular tuft was associated with sclerotic class ANCA-associated renal vasculitis (p < 0.001), and tubular RBC casts (p = 0.024). Fourth, complement C4 in interlobular arteries is associated with tubular atrophy specifically in renal vasculitis with PR3-ANCA seropositivity (p = 0.006). Finally, complement C4 deposits in peritubular capillaries associated specifically with hyaline casts in cases positive for PR3-ANCA (p = 0.025), implicating a role in tubular injury. Interestingly, C4 deposits were localized to distinct vascular compartments independent of the systemic activation of the complement system, reflected by the consumption of respective serum complement molecules in ANCA-associated renal vasculitis. In summary, we here show that C4 deposits localize to distinct vascular compartments in ANCA-associated renal vasculitis, and provide evidence for an association with survival and distinct histopathological lesions. Considering recent advances in AAV therapy with the emergence of new therapeutics that inhibit complement activation, we here provide novel insights into complement C4 as a potential marker to identify patients who may benefit most from these drugs. Thus, our results may contribute to a more personalized treatment approach of AAV depending on the relevance of distinct intrarenal complement deposits.

Infection is associated with increased risk of MPO- but not PR3-ANCA-associated vasculitis

OBJECTIVES

To determine whether development of ANCA-associated vasculitis (AAV) shows a relationship with a prior infection and if prior infection affects disease characteristics and outcome.

METHODS

All incident cases of AAV diagnosed in a defined region of Sweden from 2000 through 2016 were identified. For each case, 10 individuals from the general population, matched for age, sex and area of residence, were selected. Infections occurring in AAV patients and controls prior to the date of AAV diagnosis (index date for respective controls) were identified using an administrative database. Conditional logistic regression models were used to calculate odds ratios (OR) of developing AAV. Occurrence, clinical characteristics and outcome of AAV were analysed with respect to prior infection.

RESULTS

Two-hundred and seventy patients with AAV (48% female) and 2687 controls were included. Prior to diagnosis/index date, 146 (54%) AAV patients had been diagnosed with infection vs 1282 (48%) controls, with OR for AAV 1.57 (95% CI 1.18, 2.19) in those with infections of the upper respiratory tract and 1.68 (1.02, 2.77) in those with pneumonia. Difference from controls was significant in patients with MPO-ANCA 1.99 (95% CI 1.25, 3.1) but not in those with PR3-ANCA 1.0 (0.61, 1.52). Patients with prior infection showed higher disease activity at AAV diagnosis. No differences in disease characteristics, comorbidities or outcome in those with and without prior infections were observed.

CONCLUSIONS

Respiratory tract infections are positively associated with development of MPO- but not PR3-ANCA vasculitis. Prior infection is associated with higher disease activity at AAV diagnosis.

Identification of differentially expressed genes and pathways in kidney of ANCA-associated vasculitis by integrated bioinformatics analysis

The antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a systematic of relatively rare autoimmune diseases with unknown cause. Kidney involvement is one of the most common clinical manifestations, and the degree of renal damage is closely associated with the development and prognosis of AAV. In this study, we utilized the Robust Rank Aggreg (RRA) method in R to integrate GSE104948, GSE104954, GSE108109, GSE108112, and GSE108113 profile datasets loaded from Gene Expression Omnibus (GEO) database and identified a set of differentially expressed genes (DEGs) in kidney between AAV patients and living donors. Then, the results of gene ontology (GO) functional annotation showed that immunity and metabolism involved process of AAV both in glomerulus and tubulointerstitial. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that following pathways, such as complement and coagulation cascades pathway; Staphylococcus aureus infection; disease-COVID-19; and systemic lupus erythematosus (SLE) pathway play a crucial role in AAV. Next, the results analyzed by protein–protein interaction (PPI) network and Cytoscape software exhibited the hub genes ALB, TYROBP, and CYBB existed in both glomerular and tubulointerstitial compartments datasets. Finally, KEGG analysis using genes of two most important modules also further validated complement and coagulation cascades pathway and S. aureus infection existed both in glomerulus and tubulointerstitial compartments datasets. In conclusion, this study identified key genes and pathways involved in kidney of AAV, which was benefit to further uncover the mechanisms underlying the development and progress of AAV, biomarkers, and potential therapeutic targets as well.

ANCA-Associated Vasculitis in Latin America: A Systematic Literature Review: About Their Epidemiology and Their Clinical Features

ABSTRACT

Most of the existing literature, including epidemiological studies and clinical trials, on antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) include North American (mainly United States and Canada), European, and Asian populations. Few studies have focused on multiethnic populations such as the one from Latin America. Racial and ethnic differences in the incidence of AAV could partially explain the comparatively low number of AAV studies originating in Latin America. However, given the racial/ethnic diversity as well as socioeconomic differences existing in this region, better reporting of AAV presentations and outcomes in Latin America could highlight valuable gaps on the understanding and treatment of these patients. Recently, larger case series and studies have provided better clinical information regarding AAV patients in Latin American countries; however, further information is needed to address gaps such as risk factors, genetic profiles, clinical features, and predictors of clinical outcomes. For these reasons, we have performed a systematic literature review to enhance our understanding of AAV patients in Latin America. We have included 11 articles focused on the epidemiological and clinical features of AAV in Latin America; some similarities and differences with AAV in other regions are shown in these articles. We have identified differences in their prevalence across Latin American countries, which may reflect reporting bias or true ethnic differences among the countries. Our findings should encourage further investigation into AAV in Latin America; such studies will hopefully lead to the optimal management of these patients.

Association of COVID-19 antigenicity with the development of antineutrophilic cytoplasmic antibody vasculitis

Inflammatory processes, such as an infection or drug reaction, can cause antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis (AAV). Although quite rare, AAV may occur with SARS-coronavirus disease 2019 (COVID-19) antigenic exposure, either from infection or immunization. We present two cases of AAV: one that developed after COVID-19 infection presenting as diffuse alveolar haemorrhage and another that developed shortly after vaccination, presenting as granulomatous pulmonary nodules. Both patients improved with supportive care and immunosuppressive therapies. This adverse event appears to be a very rare complication of COVID-19 infection or vaccination. Early diagnosis of AAV is important because immunosuppressive therapy may improve patient outcomes.

Epstein-Barr virus reactivation induced myeloperoxidase-specific antineutrophil cytoplasmic antibody (MPO-ANCA)-associated vasculitis

We present a patient with systemic symptoms including 4 months of dyspnoea worsened with exertion, fatigue, rhinorrhoea, intermittent facial swelling, generalised lymphadenopathy and weight loss. Laboratory studies demonstrated proteinuria and eosinophilia. His serology was consistent with Epstein-Barr Virus (EBV) reactivation. A lymph node biopsy was consistent with EBV-associated reactive lymphoid hyperplasia. He was told to continue symptomatic treatment for EBV infection. After several admissions, vasculitis workup and myeloperoxidase-antineutrophil cytoplasmic autoantibody (ANCA) studies were positive. Evolution of clinical symptoms, laboratory parameters and our literature review suggested the diagnosis of EBV-associated ANCA vasculitis. Steroids were started after the patient continued to deteriorate; the viral load started increasing, so we added valganciclovir with favourable clinical response and no relapse during the follow-up for 6 months. This suggests that with evidence of viraemia (primary or reactivation), antiviral treatment likely has clinical benefit while immunosuppression is being considered.

Myeloperoxidase and associated lung disease: Review of the latest developments

Myeloperoxidase (MPO) anti-neutrophil cytoplasmic antibodies (ANCA) are often detected in association with a variety of lung pathologies, the most common being interstitial lung disease (ILD). A growing cohort of patients are being diagnosed with MPO-ANCA in the context of ILD without ANCA-associated vasculitis. Clinically and radiologically, there is little to differentiate this cohort from MPO-ANCA-negative ILD patients; however, the pathophysiology is likely different and different treatments are likely required. We present here a brief summary of the proposed pathophysiology of MPO-ANCA-positive ILD, and a more detailed review of the latest evidence on management, including monitoring for development of ANCA-associated vasculitis, immunosuppression, anti-fibrotics, and novel agents that have yet to be trialled in human experiments.

Viral-induced inflammatory coagulation disorders: Preparing for another epidemic

A number of viral infectious diseases have emerged or reemerged from wildlife vectors that have generated serious threats to global health. Increased international traveling and commerce increase the risk of transmission of viral or other infectious diseases. In addition, recent climate changes accelerate the potential spread of domestic disease. The Coronavirus disease 2019 (COVID-19) pandemic is an important example of the worldwide spread, and the current epidemic will unlikely be the last. Viral hemorrhagic fevers, such as Dengue and Lassa fevers, may also have the potential to spread worldwide with a significant impact on public health with unpredictable timing. Based on the important lessons learned from COVID-19, it would be prudent to prepare for future pandemics of life-threatening viral diseases. Among the various threats, this review focuses on the coagulopathy of acute viral infections since hypercoagulability has been a major challenge in COVID-19, but represents a different presentation compared to viral hemorrhagic fever. However, both thrombosis and hemorrhage are understood as the result of thromboinflammation due to viral infections, and the role of anticoagulation is important to consider.