[Modern Perspectives on Peripheral Neuropathology].

Recent advances in genetic and antibody testing have limited pathological examination of peripheral nerve specimens. However, when examining peripheral neuropathological findings from a modern perspective, there is often an opportunity to comprehend previously unnoticed observations upon re-examining the same specimen. For example, electron microscopy studies have suggested that the components that distinguish between nodal regions and internodes play a pivotal role in the behavior of macrophages that initiate myelin phagocytosis in the demyelinating form of Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy (CIDP). Conversely, some patients previously diagnosed with CIDP were found to possess distinctive mechanisms initiated by autoantibodies against paranodal junction proteins such as neurofascin 155 leading to the emergence of the concept of autoimmune nodopathy. In vasculitis, the roles of neutrophils in antineutrophil cytoplasmic antibody-associated vasculitis, eosinophils in eosinophilic granulomatosis with polyangiitis, and complements in nonsystemic vasculitic neuropathy in tissue damage have also been demonstrated when viewed from a modern perspective. Furthermore, mechanisms attributable to predominant small-fiber loss in hereditary transthyretin amyloidosis have been clarified at an ultrastructural level.

Proteinase 3-specific antineutrophil cytoplasmic antibody-associated vasculitis.

Proteinase 3 (PR3)-specific antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis is one of two major ANCA-associated vasculitis variants and is pathogenically linked to granulomatosis with polyangiitis (GPA). GPA is characterised by necrotising granulomatous inflammation that preferentially affects the respiratory tract. The small vessel vasculitis features of GPA are shared with microscopic polyangiitis. Necrotising granulomatous inflammation of GPA can lead to PR3-ANCA and small vessel vasculitis via activation of neutrophils and monocytes. B cells are central to the pathogenesis of PR3-ANCA-associated vasculitis. They are targeted successfully by remission induction and maintenance therapy with rituximab. Relapses of PR3-ANCA-associated vasculitis and toxicities associated with current standard therapy contribute substantially to remaining mortality and damage-associated morbidity. More effective and less toxic treatments are sought to address this unmet need. Advances with cellular and novel antigen-specific immunotherapies hold promise for application in autoimmune disease, including PR3-ANCA-associated vasculitis. This Series paper describes the inter-related histopathological and clinical features, pathophysiology, as well as current and future targeted treatments for PR3-ANCA-associated vasculitis.

Acute paraplegia in a patient with eosinophilic granulomatosis and polyangiitis with 20 years of evolution: case report.

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare and necrotizing vasculitis of small and medium vessels with a heterogeneous presentation, multiorgan involvement, characterized by the presence of chronic rhinosinusitis, asthma, and peripheral eosinophilia. Nervous system involvement is frequent, especially in the peripheral nervous system (PNS), in the form of mononeuritis multiplex. However, subarachnoid and cerebral hemorrhage, cerebral infarction, cranial nerve palsies, and cortical blindness have also been reported in the literature. Initial therapy involves systemic GC, which are not free of complications. We present the case of a patient with EGPA of more than 20 years duration who suddenly developed bilateral paresthesia of the lower limbs and urinary retention. The neurological exam revealed paraplegia with a sensorial level in D4; the MRI showed spinal cord compression in the D2-D7 level, and the patient was emergently submitted to surgical decompression. The histopathology of the surgical specimen demonstrated the presence of epidural adipose tissue with multiple vasculitic lesions. The effects of systemic corticosteroid therapy may contribute to abnormal fat deposition in various body segments, including the neuroaxis, leading to the development of epidural lipomatosis. However, the intra-lesional vasculitic character is a unique manifestation of myelopathy that has shown us to have a more aggressive attitude.

The role of anti-eosinophilic therapies in eosinophilic granulomatosis with polyangiitis: a systematic review.

Eosinophilic granulomatosis with polyangiitis (EGPA) is an antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, mostly affecting small-sized arteries and usually occurring in patients with an allergic background. Eosinophils seem to play a significant role in the pathogenesis of the disease and, therefore, biologics targeting interleukin 5 (IL5), a cytokine tightly linked to eosinophils, have emerged as a promising therapeutic tool. A systematic review of Medline was conducted from 2007 to 2022 to search for data regarding the use of anti-IL5 therapies in patients with EGPA. Ongoing or unpublished trials were also searched in ClinicalTrials.gov and the World Health Organization trials portal. The efficacy and safety of mepolizumab, an anti-IL5 monoclonal antibody (mAb), was confirmed by a randomized controlled trial (RCT), although a significant proportion of patients did not respond to this treatment. Other studies showed that both doses of 100 mg and 300 mg of mepolizumab are almost equally effective in EGPA. Benralizumab, an anti-IL5 receptor mAb has preliminary promising results and an RCT is planned to be conducted. Apart from their clinical efficacy in EGPA, anti-IL5 therapies may have steroid-sparing properties. Anti-IL5 therapies seem to be effective and safe in patients with refractory/relapsing EGPA and can be used as a steroid-sparing treatment. Nevertheless, more research is needed to clarify the pathophysiology of the disease; this may potentially lead to the identification of biomarkers to pinpoint patients most likely to respond to anti-IL5-blockade.

Clinical characteristics of eosinophilic granulomatosis with polyangiitis involving the lung in 13 patients. / 13ä¾‹ç´¯åŠè‚ºéƒ¨çš„å—œé ¸æ€§è‚‰èŠ½è‚¿æ€§å¤šè¡€ç®¡ç‚Žçš„ä¸´åºŠç‰¹å¾.

OBJECTIVES: Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare systemic vasculitis, which often starts with respiratory symptoms such as asthma, and it is difficult to make early clinical diagnosis.This study aims to improve the therapeutic level of EGPA with lung involvement via analyzing the clinical characteristics, diagnosis, and treatment . METHODS: We retrospectively analyzed the clinical data of 13 EGPA patients with lung involvement who were diagnosed from February 1, 2014 to July 31, 2021 in the Second Xiangya Hospital, Central South University. RESULTS: The ratio of male to female in 13 patients was 7꞉6. The patients were diagnosed at median age 52 (46-68) years old and 6 had been diagnosed as "bronchial asthma". Pulmonary clinical manifestations mainly included cough, expectoration, wheezing, and shortness of breath; while extra-pulmonary manifestations mainly included rash and subcutaneous mass, fever, limb numbness, muscle and joint pain, abdominal pain, etc. Peripheral blood tests of all patients showed that 11 patients had eosinophils ≥10%, 10 had elevated inflammatory indicators, and 3 were anti-neutrophil cytoplasmic antibody (ANCA) positive. The major lung imaging features were patches or strips of increased density, multiple nodules, bronchiectasis, bronchial wall thickening, exudation, mediastinal lymph nodes, and so on. Eight patients had sinusitis and 9 with abnormal electromyography. Extravascular eosinophil infiltration was found in 9 patients. Six patients with lung biopsy showed eosinophil, lymphocyte, and plasma cell infiltration, 3 patients were involved in small blood vessels, and 1 had granuloma. Pulmonary function tests were performed in 7 patients, 5 of them showed different degrees of pulmonary ventilation dysfunction, and 4 of them had diffusion dysfunction. Almost all patients respond well to glucocorticoid and immunosuppressant. CONCLUSIONS: EGPA is rare in clinical, often involving multiple systems with great harm and may combine with asthmatic manifestations. Pulmonary involvement is relatively common. However, due to insufficient recognition of this disease and huge heterogeneity of pulmonary imaging manifestations, misdiagnosis and missed diagnosis are easy to occur. Relevant laboratory, imaging, and biopsy examination should be performed as early as possible with comprehensive consideration of extrapulmonary involvement. Early identification has great significance to improve the diagnosis rate and prognosis of diseases.

Regulatory T Cells in Autoimmune Vasculitis.

Blood vessels are indispensable for host survival and are protected from inappropriate inflammation by immune privilege. This protection is lost in patients with autoimmune vasculitides, a heterogeneous group of diseases causing damage to arteries, arterioles, and capillaries. Vasculitis leads to vascular wall destruction and/or luminal occlusion, resulting in hemorrhage and tissue ischemia. Failure in the quantity and quality of immunosuppressive regulatory T cells (Treg) has been implicated in the breakdown of the vascular immune privilege. Emerging data suggest that Treg deficiencies are disease-specific, affecting distinct pathways in distinct vasculitides. Mechanistic studies have identified faulty CD8+ Tregs in Giant Cell Arteritis (GCA), a vasculitis of the aorta and the large aortic branch vessels. Specifically, aberrant signaling through the NOTCH4 receptor expressed on CD8+ Treg cells leads to rerouting of intracellular vesicle trafficking and failure in the release of immunosuppressive exosomes, ultimately boosting inflammatory attack to medium and large arteries. In Kawasaki's disease, a medium vessel vasculitis targeting the coronary arteries, aberrant expression of miR-155 and dysregulated STAT5 signaling have been implicated in undermining CD4+ Treg function. Explorations of mechanisms leading to insufficient immunosuppression and uncontrolled vascular inflammation hold the promise to discover novel therapeutic interventions that could potentially restore the immune privilege of blood vessels and pave the way for urgently needed innovations in vasculitis management.

Updates in ANCA-associated vasculitis.

Antineutrophil cytoplasm antibody (ANCA)-associated vasculitides (AAV) are small-vessel vasculitides that include granulomatosis with polyangiitis (formerly Wegener's granulomatosis), microscopic polyangiitis, and eosinophilic granulomatosis with polyangiitis (Churg - Strauss syndrome). Renal-limited AAV can be considered a fourth entity. Despite their rarity and still unknown cause(s), research into AAV has been very active over the past decades and has allowed for the development of new therapeutic regimens. The pathogenesis is a complex process of immune dysregulations with genetic and environmental influences. Recent genome-wide association studies have identified multiple genetic predisposing variants, especially at the major histocompatibility complex region. The pathogenic role of antimyeloperoxidase ANCA (MPO-ANCA) is well supported by several animal models, but that of antiproteinase 3 ANCA (PR3-ANCA) is not as strongly demonstrated. B cells likely play a major role in the pathogenesis because they produce ANCAs, as do neutrophil abnormalities, imbalances in T-cell subtypes, and/or cytokine - chemokine networks. The role of the alternative complement pathway was established more recently, and studies of the antagonist of human C5a receptor (avacopan) in AAV have just been completed, with promising results. The current standard management of severe AAV still consists of remission induction therapy with glucocorticoids combined with rituximab or, less often now, cyclophosphamide. Several studies showed that reduced-dose regimens of glucocorticoids are noninferior to the previously used heavier regimens, for therefore less cumulative exposure to glucocorticoids. Avacopan use may even lead to new steroid-free therapeutic approaches, at least for some selected patients. Several trials and studies have now shown the superiority of rituximab over azathioprine or methotrexate as maintenance therapy. However, the optimal dosing regimen and duration for maintenance remain to be better defined, at the individual patient level. Many changes have occurred in the standard of care for AAV over the past decades, and more are expected soon, including with use of avacopan, but also, likely, a few other agents under investigation or development.

Comprehensive characterization of central BCL-2 family members in aberrant eosinophils and their impact on therapeutic strategies.

PURPOSE: Hypereosinophilia represents a heterogenous group of severe medical conditions characterized by elevated numbers of eosinophil granulocytes in peripheral blood, bone marrow or tissue. Treatment options for hypereosinophilia remain limited despite recent approaches including IL-5-targeted monoclonal antibodies and tyrosine kinase inhibitors. METHODS: To understand aberrant survival patterns and options for pharmacologic intervention, we characterized BCL-2-regulated apoptosis signaling by testing for BCL-2 family expression levels as well as pharmacologic inhibition using primary patient samples from diverse subtypes of hypereosinophilia (hypereosinophilic syndrome n = 18, chronic eosinophilic leukemia not otherwise specified n = 9, lymphocyte-variant hypereosinophilia n = 2, myeloproliferative neoplasm with eosinophilia n = 2, eosinophilic granulomatosis with polyangiitis n = 11, reactive eosinophilia n = 3). RESULTS: Contrary to published literature, we found no difference in the levels of the lncRNA Morrbid and its target BIM. Yet, we identified a near complete loss of expression of pro-apoptotic PUMA as well as a reduction in anti-apoptotic BCL-2. Accordingly, BCL-2 inhibition using venetoclax failed to achieve cell death induction in eosinophil granulocytes and bone marrow mononuclear cells from patients with hypereosinophilia. In contrast, MCL1 inhibition using S63845 specifically decreased the viability of bone marrow progenitor cells in patients with hypereosinophilia. In patients diagnosed with Chronic Eosinophilic Leukemia (CEL-NOS) or Myeloid and Lymphatic Neoplasia with hypereosinophilia (MLN-Eo) repression of survival was specifically powerful. CONCLUSION: Our study shows that MCL1 inhibition might be a promising therapeutic option for hypereosinophilia patients specifically for CEL-NOS and MLN-Eo.

Massive Transoral Bleeding from the Internal Carotid Artery in a Patient With Granulomatosis With Polyangiitis (Wegener).

BACKGROUND: In the oral and maxillofacial area, granulomatosis with polyangiitis (GPA) can lead to extended tissue destruction. CASE REPORT: This is a case report of a life-threatening local complication resulting from a large osseous defect in the cranial base with consecutive massive bleeding from the right internal carotid artery. Intraoperative examination and diagnostic imaging led to neuroradiological interventional treatment by embolization, and in neurosurgical and further reconstructive surgical treatment by the oral and maxillofacial surgeons. The purpose of this case report was to draw attention to the possibly life-threatening local complications of GPA and to discuss the importance of early intervention. CONCLUSION: As a prevention strategy, regular examinations including three-dimensional radiographic diagnostic imaging are important for the early detection of complications and the possible involvement of important structures.

Tumor-like Lesions in Patients with Granulomatosis with Polyangiitis: A Case Series.

BACKGROUND: Granulomatosis with polyangiitis (GPA) is a rare small vessel vasculitis. It usually involves the respiratory tract and kidney. Rarely, tumor-resembling inflammatory changes ensue. OBJECTIVES: To report three unique cases of GPA presenting with tumor-like lesions in various organs. METHODS: We presented three cases of GPA. Case 1 presented with typical upper respiratory symptoms of GPA and a mediastinal mass. Case 2 presented with low back pain, a large retroperitoneal mass, and nodular skin lesions. Case 3 presented with epigastric pain and a paravertebral inflammatory mass. RESULTS: The patients were treated successfully with rituximab. CONCLUSIONS: Clinicians should be aware of this presentation of granulomatosis with polyangiitis, which is known as Tumefaction Wegener's granulomatosis.

Eosinophilic granulomatosis with polyangiitis: Cutaneous clinical and histopathologic differential diagnosis.

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare, but severe systemic vasculitis that can affect skin and other organ systems. Diagnostic criteria have evolved, and many attempts have been made to classify the vasculitides based on clinical and/or histopathologic features, with an aim to develop standardized criteria. According to the EGPA Consensus Task Force recommendations, EGPA is a syndrome of asthma, eosinophilia, pulmonary infiltrates, and extrapulmonary vasculitis (such as cutaneous involvement with purpura). Histopathologic evidence of vasculitis in EGPA may be associated with eosinophilic infiltration and/or perivascular granulomatous inflammation. We review clinicopathologic criteria of this enigmatic vasculopathy.

Elevated Serum Amyloid a Levels Are not Specific for Sarcoidosis but Associate with a Fibrotic Pulmonary Phenotype.

Elevated Serum Amyloid A (SAA) levels have been found in several inflammatory diseases, including sarcoidosis. SAA is suggested to be involved in sarcoidosis pathogenesis by involvement in granuloma formation and maintenance. We hypothesized that SAA serum levels would be higher in sarcoidosis compared to other non-infectious granulomatous and non-granulomatous diseases. SAA levels were measured in serum from sarcoidosis, Hypersensitivity pneumonitis (HP), and (eosinophilic) granulomatosis with polyangiitis ((E)GPA) patients. Idiopathic pulmonary fibrosis (IPF) patients were included as non-granulomatous disease group. SAA levels of patients with sarcoidosis (31.0 µg/mL), HP (23.4 µg/mL), (E)GPA (36.9 µg/mL), and IPF (22.1 µg/mL) were all higher than SAA levels of healthy controls (10.1 µg/mL). SAA levels did not differ between the diagnostic groups. When SAA serum levels were analyzed in sarcoidosis subgroups, fibrotic sarcoidosis patients showed higher SAA levels than sarcoidosis patients without fibrosis (47.8 µg/mL vs. 29.4 µg/mL, p = 0.005). To conclude, the observation that fibrotic sarcoidosis patients have higher SAA levels, together with our finding that SAA levels were also increased in IPF patients, suggests that SAA may next to granulomatous processes also reflect the process of fibrogenesis. Further studies should clarify the exact role of SAA in fibrosis and the underlying mechanisms involved.

Fibrosis-5 predicts end-stage renal disease in patients with microscopic polyangiitis and granulomatosis with polyangiitis without substantial liver diseases.

We previously reported that fibrosis-4 (FIB-4) was associated with poor outcomes of microscopic polyangiitis (MPA) and granuloma with polyangiitis (GPA). We also investigated the potential of FIB-5, a novel index, in predicting all-cause mortality and end-stage renal disease (ESRD) during follow-up in patients with MPA and GPA without substantial liver diseases. Clinical and laboratory data at diagnosis were collected by reviewing the medical records of 180 patients with MPA and GPA. FIB-5 was obtained by a following equation: FIB-5 = (serum albumin (g/L) × 0.3 + platelet count (109/L) × 0.05) - (alkaline phosphatase (IU/L) × 0.014 + aspartate aminotransferase/alanine aminotransferase ratio × 6 + 14). The median age of the patients at diagnosis was 61.0 years. FIB-5 at diagnosis could not reflect the cross-sectional vasculitis activity. The cutoffs of FIB-5 for poor outcomes was set as 0.82 (the lowest tertile) and -0.42 (the lowest quartile) at diagnosis. In Kaplan-Meier survival analysis, patients with FIB-5 < 0.82 and those with FIB-5 < -0.42 exhibited lower ESRD-free survival rates than those without. However, it could not predict all-cause mortality. In multivariable Cox hazards analysis, both FFS (Hazard ratio (HR) 1.554) and FIB-5 < 0.82 (HR 2.096) as well as both FFS (HR 1.534) and FIB-5 < -0.42 (HR 2.073) at diagnosis independently predicted ESRD during follow-up. In conclusion, FIB-5 < 0.82 and FIB-5 < -0.42 at diagnosis could predict the occurrence of ESRD, but not all-cause mortality, during follow-up in patients with MPA and GPA without substantial liver diseases.

Relapsed granulomatosis with polyangiitis with panhypopituitarism.

A man in his early 60s with a medical history of granulomatosis with polyangiitis (GPA) in remission for two decades without maintenance therapy presented with non-specific complaints of profound fatigue and 40-pound weight loss. He was seronegative for antinuclear antibodies and cytoplasmic antineutrophilic antibodies, but erythrocyte sedimentation rate and C reactive protein levels were elevated. Endocrinological testing revealed adrenal insufficiency, hypogonadism, hypothyroidism and diabetes insipidus. An MRI of the head revealed extensive sinonasal inflammation eroding through the floor of the sella turcica and into the pituitary gland and stalk. Biopsy of the sinonasal tissues was inconclusive. On review of his case, a multidisciplinary team diagnosed him with panhypopituitarism secondary to a recurrence of GPA. He responded well to glucocorticoids and methotrexate with marked reduction of pituitary enhancement on imaging and resolution of diabetes insipidus. He will require lifelong testosterone, levothyroxine and glucocorticoids for hormone replacement therapy.