Th17 cells reflect colon submucosal pathologic changes in active eosinophilic granulomatosis with polyangiitis

Intravenous cyclophosphamide and immunoglobulin ameliorated visual field defects in a patient with eosinophilic granulomatosis with polyangiitis

Treating ocular involvement in eosinophilic granulomatosis with polyangiitis (EGPA) can be challenging. We present the case of a 37-year-old woman with EGPA who had severe bilateral visual field defects. Laboratory results showed leukocytosis (17,500 WBC/μL, 25.8 % eosinophils), negative MPO-ANCA titer, and elevated PR3-ANCA level (33.2 IU/mL). Diffusion-weighted MRI revealed bilateral hyperintense occipital lesions, which were more prominent on the left. Her therapy initially included a steroid pulse, followed by daily prednisolone, but her visual field defects remained refractory. The addition of intravenous cyclophosphamide (5 courses) and intravenous immunoglobulin decreased her optic neuropathy and resolved her visual field defects.

Long-term mepolizumab treatment reduces relapse rates in super-responders with eosinophilic granulomatosis with polyangiitis

BACKGROUND

The mainstay of treatment for eosinophilic granulomatosis with polyangiitis (EGPA) is systemic corticosteroid therapy; some patients also receive intravenous immunoglobulins, other immunosuppressive agents, and biologics. Mepolizumab, an anti-interleukin-5 monoclonal antibody, induces remission and decreases the daily corticosteroid dose; however, the clinical efficacy of mepolizumab in EGPA and the prognosis with long-term treatment with this drug are unknown.

METHODS

Seventy-one EGPA patients were treated at Hiratsuka City Hospital, Japan, between April 2018 and March 2022. We administered mepolizumab for a mean of 2.8 ± 1.7 years to 43 patients in whom remission could not be induced by conventional treatment. After excluding 18 patients who had received mepolizumab for less than 3 years, we classified 15 patients into a "super-responder group" (the daily dose of corticosteroids or other immunosuppressant could be decreased, or the interval between IVIG treatments could be prolonged) and 10 patients into a "responder group" (neither of these changes was achievable). Eosinophil numbers, serum IgG levels, daily doses of corticosteroids and other immunosuppressants, Birmingham Vasculitis Activity Score (BVAS), and relapse frequency before and after mepolizumab initiation were determined.

RESULTS

Blood eosinophil count at diagnosis and the lowest serum IgG level before mepolizumab treatment were significantly higher in super-responders than in responders (p < 0.05). In super-responders, the prednisolone dose at last visit on mepolizumab treatment was lower than that before treatment (p < 0.01) and lower than that at last visit in the responders (p < 0.01). In both groups, peripheral blood eosinophil numbers and BVAS were lower after starting mepolizumab than before (p < 0.01). BVAS before mepolizumab (p < 0.05) and at last visit (p < 0.01) were lower in super-responders than in responders. Relapse rates every year after the start of mepolizumab were lower in super-responders than in responder groups (p < 0.01). In super-responders, relapse rates were lower during the 3 years following mepolizumab initiation (p < 0.01) and at last visit (p < 0.01) were significantly lower than after 1 year of treatment.

CONCLUSION

Mepolizumab treatment of super-responders sustainably reduced the relapse rate.

Gut Microbiota and Associated Mucosal Immune Response in Eosinophilic Granulomatosis with Polyangiitis (EGPA)

Eosinophilic granulomatosis with polyangiitis (EGPA) is an anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis. A genome-wide association study showed a correlation between ANCA-negative EGPA and variants of genes encoding proteins with intestinal barrier functions, suggesting that modifications of the mucosal layer and consequent gut dysbiosis might be involved in EGPA pathogenesis. Here, we characterized the gut microbiota (GM) composition and the intestinal immune response in a cohort of EGPA patients. Faeces from 29 patients and 9 unrelated healthy cohabitants were collected, and GM and derived metabolites’ composition were compared. Seven intestinal biopsies from EGPA patients with gastrointestinal manifestations were analysed to assess the T-cell distribution and its correlation with GM and EGPA clinical and laboratory features. No significant differences in GM composition, nor in the total amount of faecal metabolites, emerged between patients and controls. Nevertheless, differences in bacterial taxa abundances and compositional GM-derived metabolites profile were observed. Notably, an enrichment of potential pathobionts (Enterobacteriacee and Streptococcaceae) was found in EGPA, particularly in patients with active disease, while lower levels were found in patients on immunosuppression, compared with non-immunosuppressed ones. Significantly lower amounts of hexanoic acid were found in patients, compared to controls. The analysis of the immune response in the gut mucosa revealed a high frequency of IFN-γ/IL-17-producing T lymphocytes, and a positive correlation between EGPA disease activity and intestinal T-cell levels. Our data suggest that an enrichment in potential intestinal pathobionts might drive an imbalanced inflammatory response in EGPA.

The Th17 Pathway in Vascular Inflammation: Culprit or Consort?

The involvement of IL-17A in autoimmune and inflammatory diseases has prompted the development of therapeutic strategies to block the Th17 pathway. Promising results came from their use in psoriasis and in ankylosing spondylitis. IL-17A acts on various cell types and has both local and systemic effects. Considering the premature mortality observed during chronic inflammatory diseases, IL-17A action on vascular cells was studied. Both in vitro and in vivo results suggest that this cytokine favors inflammation, coagulation and thrombosis and promotes the occurrence of cardiovascular events. These observations led to study the role of IL-17A in diseases characterized by vascular inflammation, namely allograft rejection and vasculitis. Increased circulating levels of IL-17A and histological staining reveal that the Th17 pathway is involved in the pathogenesis of these diseases. Vasculitis treatment faces challenges while the use of steroids has many side effects. Regarding results obtained in giant cell arteritis with IL-6 inhibitors, a cytokine involved in Th17 differentiation, the use of anti-IL-17 is a promising strategy. However, lessons from rheumatoid arthritis and multiple sclerosis must be learnt before targeting IL-17 in vasculitis, which may be culprit, consort or both of them.

Clinical Features of Patients with Active Eosinophilic Granulomatosis with Polyangiitis Successfully Treated with Mepolizumab

BACKGROUND

In some patients with eosinophilic granulomatosis with polyangiitis (EGPA), remission cannot be induced, despite treatment with corticosteroids and immunosuppressants. We evaluated the clinical features of patients with EGPA in whom mepolizumab was effective.

METHODS

There were 59 EGPA patients treated at Hiratsuka City Hospital, Japan, between April 2018 and September 2020, and 30 of them received mepolizumab. Twenty (66.7%) experienced a "marked effect" (the daily dose of corticosteroid or immunosuppressant could be decreased, or the interval between intravenous immunoglobulin (IVIG) treatments could be prolonged) and 10 (33.3%) experienced a "weak effect" (these measures were not achieved). Eosinophil numbers, serum IgG levels, daily doses of corticosteroids and immunosuppressants, and the interval between IVIG treatments at diagnosis and before and after mepolizumab initiation were determined.

RESULTS

Eosinophil numbers at diagnosis were significantly higher in the marked-effect group than in the weak-effect group (p < 0.05) but not before mepolizumab initiation or at the last visit. Birmingham Vasculitis Activity Scores (BVASs) before mepolizumab initiation (p < 0.05) and at last visit (p < 0.01), and frequency of relapse before treatment initiation (p < 0.05) were significantly higher, and the serum IgG level before mepolizumab treatment was significantly lower in the weak-effect group than in the marked-effect group. The weak-effect group received higher doses of corticosteroids, even if the corticosteroid dose could be reduced for a while after mepolizumab initiation.

CONCLUSION

High peripheral blood eosinophil numbers at EGPA diagnosis were suggestive of a positive clinical response to mepolizumab.

Gastrointestinal involvement in patients with vasculitis: IgA vasculitis and eosinophilic granulomatosis with polyangiitis

Background and study aims  Among vasculitides, IgA vasculitis (IgAV) and eosinophilic granulomatosis with polyangiitis (EGPA) frequently damage the gastrointestinal tract. However, only a few studies have investigated the entire gastrointestinal tract in patients with IgAV or EGPA by endoscopy. The aim of this study was to clarify endoscopic characteristics of patients with IgAV and those with EGPA. Patients and methods  Clinicopathological and endoscopic findings were retrospectively compared between 33 patients with IgAV and 19 patients with EGPA. Results  Gastrointestinal involvement was observed in 33 patients with IgAV (100 %) and in 8 patients with EPGA (42 %; P  = 0.0001). Duodenal involvement was more frequent in patients with IgAV (75.8 %) than in those with EGPA (21.1 %, P  = 0.0002). Jejunoileal involvement was frequent in both groups (IgAV 94.4 %; EGPA 77.8 %). Gastric mucosal erythema was more frequent in patients with IgAV (18.2 %) than in those with EGPA (0 %, P  = 0.0481). Duodenal mucosal erythema (IgAV 54.6 %; EGPA 21.1 %, P  = 0.0227), ulcer (IgAV 33.3 %; EGPA 0 %, P  = 0.0041), and hematoma-like protrusion (IgAV 21.1 %; EGPA 0 %, P  = 0.039) were more frequently observed in patients with IgAV than in those with EGPA. Conclusions  Frequent duodenal involvement, gastric mucosal erythema, and duodenal lesions including erythema, ulcer, and hematoma-like protrusion are characteristic of patients with IgAV. Because jejunoileal involvement was frequent in both groups of patients, small-bowel endoscopies should be performed for diagnosis of small-bowel lesions in patients with IgAV and EGPA.

No Differences in Nasal Tissue Inflammatory Cells and Adhesion Molecules (iCAM-1 and vCAM-1) Based on the Comparison of EGPA With Eosinophilic Chronic Sinusitis With Polyposis

Background

An example of aggressive eosinophilic polyposis can be found in eosinophilic granulomatosis with polyangiitis (EGPA). Intercellular adhesion molecule-1 (iCAM-1) and vascular cell adhesion molecule-1 (vCAM-1) play a part in mediating the recruitment and adhesion of leukocytes to the vessel wall, and their blood-to-tissue migration under inflammatory conditions.

Objective

This prospective study compared 3 groups—patients with a definite diagnosis EGPA, non-EGPA patients with phenotypic features suggestive of EGPA, and patients with non-eosinophilic nasal polyposis (controls)—in terms of nasal tissue histology, iCAM-1 and vCAM-1 expression, and blood inflammatory cells.

Methods

A total of 58 adults underwent sinus surgery (13 patients with EGPA, 23 suspected of having EGPA, and 22 controls).

Results

Mean tissue eosinophil counts were significantly higher in EGPA patients and suspected cases of EGPA than in controls. Although iCAM-1 and vCAM-1 were diffusely expressed in sinonasal tissues, they did not differently stain EGPA, eosinophilic-type and non-eosinophilic polyposis. Blood basophil and eosinophil levels were high in both the EGPA and the suspected EGPA groups. Intergroup differences were found for eosinophils but not for basophils.

Conclusions

We do not have yet blood or tissue markers able to differentiate the early phase of EGPA from chronic rhinosinusitis with nasal polyps. Further investigations are mandatory considering EGPA patients at their initial diagnosis and before any treatment, in terms of nasal histology and blood inflammatory cells, to identify markers characterizing sinonasal mucosa inflammation and useful for an early diagnosis of EGPA.

Can colonic inflammatory polyp with numerous immunoglobulin G4-positive plasma cells represent a colonic manifestation of immunoglobulin G4-related disease? A case report

We present an asymptomatic case of a 79-year-old Japanese man who had a 6 mm colonic inflammatory polyp with numerous immunoglobulin G4 (IgG4)-positive plasma cells. No symptoms or abnormal laboratory data, such as changes in serum IgG4 levels, were found at the time of diagnosis or during the 1 year of follow-up thereafter. Additionally, no diffuse/localized swelling or masses were found in organs, except for colonic polyps, by abdominal computed tomography 1 year prior to the polypectomy. Inflammatory myofibroblastic tumor was unlikely from the lack of spindle cell proliferation and ALK immunoreactivity. This is the first case of this colonic polyp in an asymptomatic person. This polyp could be probable for single organ manifestation of IgG4-related disease (IgG4-RD), according to the comprehensive diagnostic criteria for IgG4-RD published in 2012; however, colonic manifestation of IgG4-RD has not been clarified owing to its rarity, and colon-specific criteria for IgG4-RD have not been proposed. Thus, we could not definitively establish the colonic polyp as IgG4-RD. Therefore, careful clinicopathological evaluation is needed to reveal whether this colonic polyp represents a nonspecific inflammatory response or an early manifestation of IgG4-RD.

Innate immune response reflects disease activity in eosinophilic granulomatosis with polyangiitis

BACKGROUND

Eosinophilic granulomatosis with polyangiitis (EGPA) is a disease characterized by allergic granulomatosis, necrotizing vasculitis, and peripheral blood eosinophilia. Interleukin (IL)-33, thymic stromal lymphopoietin (TSLP), and type 2 innate lymphoid cells (ILC2) are involved in the innate and type 2 immune responses in EGPA. However, the relationships among these molecules and the mechanisms underlying the development of EGPA remain unknown.

OBJECTIVE

We investigated the relationships among peripheral blood eosinophil count, serum IL-33 and TSLP concentration, and peripheral blood ILC2 count in patients with EGPA, chronic eosinophilic pneumonia (CEP), or bronchial asthma (BA).

METHODS

We recruited 86 patients with EGPA in three groups (remission, relapse, and onset), 25 patients with CEP at active or inactive stages of disease, and 11 patients with BA. In patients with EGPA, CEP, or BA, serum IL-33, sST2, and TSLP concentrations were determined using ELISA and peripheral blood ILC2 counts (as Lin-1^- CD127⁺ CRTH2⁺ cells) were determined using flow cytometry.

RESULTS

Peripheral blood eosinophil count or ILC2 count, and serum sST2 or TSLP concentration were higher in patients with EGPA at onset than in those with EGPA at relapse or remission, or in those with BA or CEP. Serum IL-33 concentration was higher in patients with EGPA at relapse than in those with EGPA at onset or remission, or in those with BA or CEP. In a logistic regression model, EGPA disease activity was correlated with serum IL-33 concentration and peripheral blood ILC2 count, but not daily systemic and inhaled corticosteroid dose or immunosuppressant use. Eosinophil count was correlated with peripheral blood ILC2 count and serum TSLP concentration, but not serum IL-33 concentration.

CONCLUSIONS

Increased peripheral blood ILC2 count and serum IL-33 concentration were associated with disease activity in EGPA. Increases in serum IL-33 concentration may indicate the presence of active vasculitis rather than peripheral or tissue eosinophilia.

Developmental endothelial locus-1 (Del-1) antagonizes Interleukin-17-mediated allergic asthma

Interleukin (IL)-17 is a major contributor to the pathogenesis of allergic asthma. Developmental endothelial locus-1 (Del-1) is an endothelial cell-secreted protein known to inhibit IL-17 expression. However, little is known about the association between Del-1 and IL-17 in the pathogenesis of allergic asthma. Using bronchoalveolar lavage fluid (BALF) and peripheral blood samples collected from allergic asthmatic patients and controls, we explored the role of Del-1 in relation to IL-17 in allergic asthma. We found that the negative correlation between Del-1 and IL-17 was significant in BALF of allergic asthmatics. Del-1 treatment inhibited the expression of IL-17, the differentiation of IL-17-secreting leukocytes and associated cytokines. Contrarily, IL-17 levels were increased after treatment with anti-Del-1 mAb. Consistent with this, Del-1 treatment led to downregulation of IL-5, CCL5 and IL-4, thus reducing secretion of eosinophil cationic protein. Furthermore, Del-1 significantly downregulated the expression of ICAM-1 and may have the potential to reduce leukocyte transendothelial migration. Our data demonstrate that Del-1 can negatively regulate IL-17 and its proinflammatory function, thereby limiting airway inflammation in allergic asthmatics, and suggest Del-1 as a potential candidate for prevention and treatment of allergic asthma.

Systemic vasculitis and the gut

PURPOSE OF REVIEW

Gastrointestinal system can be involved in primary and secondary vasculitides. The recent data regarding the pathophysiology, clinical findings, diagnosis, management, and outcome of gastrointestinal involvement in different types of vasculitis are reviewed.

RECENT FINDINGS

Diagnosis of gastrointestinal vasculitis may be difficult and relies mostly on imaging, because biopsy samples are hard to obtain and superficial mucosal biopsies have a low yield. There are conflicting reports on the association of antineutrophilic cytoplasmic antibodies (ANCA) type with the frequency of gastrointestinal involvement in ANCA-associated vasculitis. Pancreatitis is a rare but serious complication of ANCA-associated vasculitis. Terminal ileitis may be observed in immunoglobulin A vasculitis and can be hard to distinguish from Crohn's disease. High fecal calprotectin levels can indicate active gastrointestinal involvement in both immunoglobulin A vasculitis and Behçet's syndrome. Refractory gastrointestinal involvement in Behçet's syndrome can be treated with thalidomide and/or TNF-α antagonists. The outcome of mesenteric vasculitis in systemic lupus erythematosus can be improved with high-dose glucocorticoids and cyclophosphamide or rituximab.

SUMMARY

Gastrointestinal system can be commonly involved in immunoglobulin A vasculitis, ANCA-associated vasculitis, polyarteritis nodosa, and Behçet's syndrome and can be an important cause of morbidity and mortality. Treatment depends on the type of vasculitis and is usually with high-dose corticosteroids and immunosuppressives.

Longterm Prognosis of 121 Patients with Eosinophilic Granulomatosis with Polyangiitis in Japan

OBJECTIVE

We investigated the risk factors for relapse or prognosis of eosinophilic granulomatosis with polyangiitis (EGPA) in Japanese patients presenting to our hospital.

METHODS

From June 1999 through March 2015, we retrospectively recruited 121 patients with EGPA according to the American College of Rheumatology criteria. Frequent relapse was defined as disease occurrence at least once every 2 years after a period of initial remission. The study endpoint was the last examination performed. We used multiple logistic regression to analyze risk factors for relapse or survival in EGPA.

RESULTS

Gastrointestinal (GI) involvement with both abnormalities on endoscopy and biopsy (p < 0.01) and symptoms; myocardial involvement with both abnormalities on 1 or more cardiac investigations and symptoms (p < 0.01); and treatment at initial or maintenance with immunosuppressants (p < 0.01) or administration of intravenous immunoglobulin (IVIG; p < 0.01) were associated significantly more often with frequent relapse than with infrequent. Overall 5-, 10-, and 20-year survival rates were 91.1%, 83.7%, and 68.6%, respectively. Survival in EGPA was associated with age of onset < 65 years. Age at onset of EGPA was the only significant predictor of survival (p < 0.01). Myocardial or GI tract involvement did not affect mortality risk.

CONCLUSION

Patients with myocardial or GI tract involvement had frequent relapses, but these conditions were not reflected in increased mortality. Treatment with immunosuppressants or IVIG in addition to corticosteroids might have improved the prognosis in Japanese patients with EGPA.