Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of systemic diseases caused by a combination of many factors, including genetics, environment, and immunity. AAV is characterized by predominantly small-vessel involvement and has a variety of clinical manifestations. Small-vessel lesions of the kidneys and lungs are common, and lesions of medium-sized arteries may also present, but the involvement of large arteries and their primary branches is very rare. This report delineates two instances of AAV with large arterial involvement, one case presenting with lesions of the aortic valve and the other with lesions of the pulmonary artery. The first case involved a 57-year-old man with no underlying diseases. Transthoracic echocardiography showed thickening of the left and right coronary valves of the aortic valve with enhanced echogenicity, moderate echogenic masses were seen on both valve leaflets, and the leaflets had restricted opening and poor closure. Blood tests showed positive perinuclear anti-neutrophil cytoplasmic antibodies (p-ANCA) and anti-myeloperoxidase (MPO) antibodies. The patient\'s aortic valve thickening virtually disappeared after treatment with hormones combined with immunosuppressive agents. The second case involved a 60-year-old woman whose transthoracic echocardiography and CT (computed tomography) angiography of the pulmonary arteries showed wall thickening of the main pulmonary artery and the proximal left and right pulmonary arteries, leading to luminal stenosis. Blood tests showed positive cytoplasmic anti-neutrophil cytoplasmic antibodies (c-ANCA) and anti-proteinase 3 (PR 3) antibodies. The patient\'s pulmonary artery wall thickening reduced after receiving hormones in combination with immunosuppression but she died of heart failure during subsequent treatment. The patient had been diagnosed with tuberculosis six months earlier and had been poorly treated with anti-tuberculosis therapy. The involvement of large arteries in AAV is a rare and critical condition with rapid progression and a high mortality rate. Early recognition of this type of AAV and aggressive immunosuppressive therapy may facilitate the reversal of the vascular lesion and a reduction in the risk of patient death.

BACKGROUND: Granulomatosis with polyangiitis (GPA) is one of the most prevalent forms of the antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. GPA is characterized histologically by necrotizing granulomatous inflammation in addition to vasculitis. The diagnosis of GPA depends on clinical presentation, serological evidence of a positive ANCA, and/or histological evidence of necrotizing vasculitis or granulomatous destructive parenchymal inflammation. Cytoplasmic ANCA (c-ANCA) is positive in 65%-75% of GPA patients, accompanied by proteinase 3 (PR3), the main target antigen of c-ANCA, another 5% of GPA patients had negative ANCA.
METHODS: The patient, a 52-year-old male, presented with unexplained nasal congestion, tinnitus, and hearing loss. After a duration of 4 months experiencing these symptoms, the patient subsequently developed fever and headache. The imaging examination revealed the presence of bilateral auricular mastoiditis and partial paranasal sinusitis, and the ANCA results were negative. The anti-infective therapy proved to be ineffective, but the patient\'s symptoms and fever were quickly relieved after 1 wk of treatment with methylprednisolone 40 mg once a day. However, after continuous use of methylprednisolone tablets for 3 months, the patient experienced a recurrence of fever accompanied by right-sided migraine, positive c-ANCA and PR3, and increased total protein in cerebrospinal fluid. The patient was diagnosed with GPA. After receiving a treatment regimen of intravenous methylprednisolone 40 mg/d and cyclophosphamide 0.8 g monthly, the patient experienced alleviation of fever and headache. Additionally, the ANCA levels became negative and there has been no recurrence.
CONCLUSIONS: For GPA patients with negative ANCA, there is a potential for early missed diagnosis. The integration of histopathological results and multidisciplinary communication plays a crucial role in facilitating ANCA-negative GPA.

Anti-neutrophil cytoplasmic antibodies (ANCA)-associated systemic vasculitis (AASV) is a rare systemic immunological condition that predominantly impacts small arteries, veins, and capillaries, often leading to kidney damage and pulmonary injury. It is important to note that individuals primarily presenting with peripheral neuropathy (PN) are uncommon in AASV, which can result in significant misdiagnosis or undiagnosed cases. The severity and location of PN can vary among patients. In this article, we present a case of an AASV patient initially showing signs of PN. This case highlights the significance of considering AASV as a potential cause of unexplained neurological symptoms. Timely identification and proper treatment are essential for improving the survival rate and functional prognosis of AASV patients.

Nephrotic range proteinuria in the setting of dual-positive anti-glomerular basement membrane (AGBM) and anti-neutrophil cytoplasmic antibodies (ANCAs) is rare. Furthermore, using rituximab as a primary immunosuppressant along with steroids and plasmapheresis has not been widely studied. We present a case of dual AGBM and ANCA with nephrotic range proteinuria in a young female, where rituximab was used as a primary immunosuppressant with partial recovery.

Chronic primary systemic vasculitis (PSV) comprises a group of heterogeneous diseases that are broadly classified by affected blood vessel size, clinical traits and the presence (or absence) of anti-neutrophil cytoplasmic antibodies (ANCA) against proteinase 3 (PR3) and myeloperoxidase (MPO). In small vessel vasculitis (SVV), ANCA are not present in all patients, and they are rarely detected in patients with vasculitis involving medium (MVV) and large (LVV) blood vessels. Some studies have demonstrated that lysosome-associated membrane protein-2 (LAMP-2/CD107b) is a target of ANCA in SVV, but its presence and prognostic value in childhood MVV and LVV is not known. This study utilized retrospective sera and clinical data obtained from 90 children and adolescents with chronic PSV affecting small (SVV, n = 53), medium (MVV, n = 16), and large (LVV, n = 21) blood vessels. LAMP-2-ANCA were measured in time-of-diagnosis sera using a custom electrochemiluminescence assay. The threshold for seropositivity was established in a comparator cohort of patients with systemic autoinflammatory disease. The proportion of LAMP-2-ANCA-seropositive individuals and sera concentrations of LAMP-2-ANCA were assessed for associations with overall and organ-specific disease activity at diagnosis and one-year follow up. This study demonstrated a greater time-of-diagnosis prevalence and sera concentration of LAMP-2-ANCA in MVV (52.9% seropositive) and LVV (76.2%) compared to SVV (45.3%). Further, LAMP-2-ANCA-seropositive individuals had significantly lower overall, but not organ-specific, disease activity at diagnosis. This did not, however, result in a greater reduction in disease activity or the likelihood of achieving inactive disease one-year after diagnosis. The results of this study demonstrate particularly high prevalence and concentration of LAMP-2-ANCA in chronic PSV that affects large blood vessels and is seronegative for traditional ANCA. Our findings invite reconsideration of roles for autoantigens other than MPO and PR3 in pediatric vasculitis, particularly in medium- and large-sized blood vessels.

To investigate the clinical features and long-term outcomes of Chinese anti-neutrophil cytoplasmic antibodies (ANCAs)-associated vasculitis (AAV) patients with different ANCA serotypes.
Two hundred and twenty-four AAV patients from January 2010 to June 2021 were divided into myeloperoxidase (MPO)-ANCA and proteinase 3 (PR3)-ANCA groups. Clinical and long-term outcomes were compared.
In this study, the average follow-up was 46.4 months (range 0.3-188.4 months). One hundred and seventy-seven (79.0%) patients were MPO-ANCA-positive and 47 were PR3-ANCA-positive; the mean age of MPO-ANCA positive patients at diagnosis was elder than that of PR3-ANCA positive patients (67.0 vs. 60.0 years, p = .004). Among PR3-ANCA-positive patients, ear, nose and throat symptoms were more common (p = .014). Between two ANCA serotypes, there were no differences in complement 3 (C3), Birmingham vasculitis activity score (BVAS), five-factor score (FFS) or other organ involvements. For all AAV patients, the overall survival rates at one, three and five years were 80.0%, 67.0% and 56.4%, respectively. The cumulative relapse-free rates of one, three and five years were 89.5%, 76.4% and 68.4%, respectively. The survival of AAV patients was unaffected by the ANCA serotype (p = .23). The ANCA serotype also had no effect on either disease relapse (p = .20) or remission rates (p = .10). In our study, PR3-ANCA patients showed a better long-term survival, as the 5-year survival rate and the 5-year relapse-free survival rate of PR3-ANCA patients were 60.7% and 76.9%, while that of MPO-ANCA patients were 55.2% and 65.8%, respectively. Rather than ANCA serotype, younger patients with milder kidney involvement and lower disease assessment scores (BVAS and FFS) might be more relevant to better prognosis.
The likelihood of induced remission, patient survival or disease recurrence is all unaffected by ANCA serotypes. A better prognosis is seen in younger patients with milder kidney involvement and lower BVAS/FFS scores.

UNASSIGNED: Anti-glomerular basement membrane (anti-GBM) disease is a rare organ-specific autoimmune disease. The overall and renal outcomes of patients have mostly been reported in small-sized cohorts. We aimed to study the clinical profile, overall survival, and renal survival of anti-glomerular basement membrane disease patients at our center.
UNASSIGNED: We conducted a retrospective analysis of the data regarding the clinical profile and renal survival of patients diagnosed with anti-GBM disease from October 2019 to March 2022, having a minimum follow-up of 12 months.
UNASSIGNED: There were 15 patients in the study, with the mean age of presentation being 51.6 ± 13.7 years. The median duration of symptoms onset to the nephrologist opinion was 15 (10-23) days. The extrarenal manifestations were seen in the respiratory, otorhinolaryngological, and neurological systems. The mean serum anti-GBM titers were 154.5 (14.9-263.5) U/mL. Serum anti-GBM titers were present in 13/15 (86.6%) patients, and 12/13 (92.3%) patients had above the reference range. Anti-neutrophil cytoplasm antibody (ANCA) levels were assessed in 12/15 (80%) patients, and 9/12 (75%) had higher levels. Renal biopsy was available in 14 patients with more than 50% crescents. Along with crescents, necrotizing lesions, rupture of the Bowman\'s capsule, and granulomatous lesions were also seen. Among the initial therapies, the steroid pulse was given to 13 (86.6%) patients, whereas membrane plasmapheresis was given to 8 (53.3%) patients. Inj. cyclophosphamide and inj. rituximab were given to 8 (53.3%) and 4 (26.6%) patients, respectively. No difference was seen in clinical characteristics, renal biopsy features, treatment received, and outcomes with ANCA positivity except for age, where patients who were ANCA positive were older compared to patients who were ANCA negative. One-year renal and patient survival was seen in 4 (26.6%) and 6 (40%) patients, respectively.
UNASSIGNED: Most patients of anti-GBM disease have active sediments, raised creatinine, and non-specific symptomatology. There is poor renal and patient outcome as most patients present with advanced renal failure.

Anti-neutrophil cytoplasmic antibodies (ANCA) are mainly associated with medium and small vessel vasculitis. Two main methodologies currently available for detection of these antibodies are indirect immunofluorescence (IIF) and monospecific proteinase 3 (PR3) and myeloperoxidase (MPO) based immunoassays. However, well-defined guidelines regarding mode of testing for ANCA in laboratories still don\'t exist, leading to problems in diagnosis and further patient management. Anti-neutrophil cytoplasmic antibodies testing by IIF and enzyme linked immunosorbent assay (ELISA) often pose a significant challenge in diseases other than vasculitis and in overlapping autoimmune conditions. Anti-neutrophil cytoplasmic antibodies reporting by IIF can be challenging in certain circumstances. This case series aims to discuss four cases with probable interference of anti-nuclear antibodies (ANA) during ANCA testing by IIF resulting in ANCA false positivity. All four cases on subsequent reflex testing by line immunoassay (LIA) for PR3, MPO and glomerular basement membrane (GBM) antigens proved otherwise. While analysing for the presence of ANCA by IIF, the possible interference of ANA leading to a false positive ANCA result should be kept in mind and alternative methods of testing like ELISA, extended granulocyte based IIF assays with MPO and PR3 coated beads, etc., should also be advised. Probability of atypical ANCA in diseases other than vasculitis should also be considered in case of ambiguous results.

Purpose: To investigate the clinical characteristics, pathological features, and outcomes of patients with antineutrophil cytoplasmic antibody (ANCA)-positive systemic lupus erythematosus (SLE) in northwest China.Methods: This retrospective study included 491 patients with SLE tested for ANCA antibodies and 171 patients with ANCA-associated vasculitis (AAV) as controls. Subgroup analysis limited to those with renal involvement, and by ANCA antibody subtype (PR3 vs MPO). To compare the proteinuria remission rates between ANCA-positive and ANCA-negative lupus nephritis (LN) groups, a logistic regression model was used for propensity score matching based on age, hemoglobin, and baseline estimated glomerular filtration rate (eGFR).Results: Compared to ANCA-negative SLE (n = 442), ANCA-positive SLE (n = 46) occur in older patients; however, these patients were younger than those with AAV (n = 167). The eGFR of patients with ANCA-positive LN (n = 25) was higher than that of patients having AAV with renal involvement (n = 56) but lower than that of patients with ANCA-negative LN (n = 163). Patients with SLE who had MPO-ANCA (n = 16) had higher levels of serum creatinine compared to those with PR3-ANCA (n = 30) (156.5 µmol/L vs. 45.5 µmol/L, p = 0.005). During the follow-up period, the remission rate of proteinuria in patients with ANCA-positive LN was lower than that of patients with ANCA-negative LN (50% vs. 75%, p = 0.008).Conclusion: Patients with ANCA-positive LN may have worse baseline renal function and lower protein remission rates compared to patients with ANCA-negative LN. ANCA titers should be regularly monitored throughout the follow-up period in patients with SLE, especially in cases of renal involvement.

Chronic pulmonary infection is a hallmark of cystic fibrosis (CF) and requires continuous antibiotic treatment. In this context, Pseudomonas aeruginosa (Pa) is of special concern since colonizing strains frequently acquire multiple drug resistance (MDR). Bactericidal/permeability-increasing protein (BPI) is a neutrophil-derived, endogenous protein with high bactericidal potency against Gram-negative bacteria. However, a significant range of people with CF (PwCF) produce anti-neutrophil cytoplasmic antibodies against BPI (BPI-ANCA), thereby neutralizing its bactericidal function. In accordance with literature, we describe that 51.0% of a total of 39 PwCF expressed BPI-ANCA. Importantly, an orthologous protein to human BPI (huBPI) derived from the scorpionfish Sebastes schlegelii (scoBPI) completely escaped recognition by these autoantibodies. Moreover, scoBPI exhibited high anti-inflammatory potency towards Pa LPS and was bactericidal against MDR Pa derived from PwCF at nanomolar concentrations. In conclusion, our results highlight the potential of highly active orthologous proteins of huBPI in treatment of MDR Pa infections, especially in the presence of BPI-ANCA.
Cystic fibrosis is a genetic disorder that makes people produce unusually thick and sticky mucus that clogs their lungs and airways. This inevitably leads to recurring bacterial infections, particularly those caused by the Gram-negative bacterium Pseudomonas aeruginosa. Antibiotics are needed to treat these infections. However, over time most bacteria build modes of resistance to these drugs and, once multiple drug-resistant bacteria colonize the lung, very limited treatment options are left. Therefore, new therapeutic approaches are desperately needed. Notably, humans themselves express a highly potent antimicrobial protein called BPI (short for Bactericidal/permeability‐increasing protein) that attacks Gram-negative bacteria, including multiple drug-resistant strains of P. aeruginosa. Unfortunately, many people with cystic fibrosis also generate antibodies that bind to BPI and interfere with its antimicrobial function. Faced with this conundrum, Holzinger et al. set out to find BPIs made by other animals which might not be recognized by human antibodies and also display a high potential to attack Gram-negative bacteria. Based on specific selection criteria, Holzinger et al. focused their attention on BPI made by scorpionfish, a type of venomous fish that live near coral reefs. Compared to other BPI proteins they investigated, the one produced by scorpionfish appeared to be the most capable of binding to P. aeruginosa via a prominent surface molecule exclusively found on Gram-negative bacteria. Furthermore, when Holzinger et al. tested whether the antibodies present in people with cystic fibrosis could recognize scorpionfish BPI, they found that the BPI completely evaded detection. The scorpionfish BPI was also able to pre-eminently attack P. aeruginosa. In fact, it was even able to potently kill drug-resistant strains of the bacteria that had been isolated from people with cystic fibrosis. This study suggests that scorpionfish BPI could serve as an alternative to antibiotics in people with cystic fibrosis that have otherwise untreatable bacterial infections. Drug-resistant bacteria which cause life threatening conditions are on the rise across the globe, and scorpionfish BPI could be a potential candidate to treat affected patients. In the future, animal experiments will be needed to explore how highly potent non-human BPIs function in whole living organisms.