Case report: Propylthiouracil-induced serious side effect: Perinuclear antineutrophil cytoplasmic antibody-associated vasculitis or IgA vasculitis?

INTRODUCTION: Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a rare disease characterized by the inflammation and destruction of small blood vessels and circulating ANCAs. Drugs such as antithyroid drugs (ATDs), especially propylthiouracil (PTU), have been used for the production of ANCAs and cause the development of drug-induced AAV. The pathogenesis of this disease is unclear but could be related to the physiological processes affecting the degradation of neutrophil extracellular traps (NETs). At present, PTU is widely used in patients with Graves' disease (GD) who are preparing for pregnancy and whose condition has not been controlled. Once drug-induced AAV has occurred with important organ damage, considering NETs have a significant role in the immune system, whether the cessation of drugs could stop the progression of organ damage is unclear, and a consensus regarding standard treatment has not been established. PATIENT CONCERNS: In this case report, a female patient who planned pregnancy was hospitalized with multiple joint pain, impaired renal function, and hematuria. Immunofluorescence of the renal biopsy demonstrated spherical and diffuse mesangial distribution of IgA (3+). Autoimmune serology demonstrated positivity for autoantibodies against p-ANCA and an anti-MPO titer 74.72 RU/mL. DIAGNOSIS: She was diagnosed with PTU-induced p-ANCA-associated and IgA-associated vasculitis (IgAV). INTERVENTIONS: The patient accepted low doses of glucocorticoid, immunosuppressive therapy and RAI treatment. OUTCOMES: Both her kidney function and thyroid function remained were on the mend. CONCLUSION: The authors believe that this type of patient needs to fully consider their pregnancy preparation needs, suspend pregnancy when a small chance of GD remission is indicated, and avoid the use of drugs with reproductive toxicity and other serious adverse events. The multidisciplinary combination therapy of low-dose glucocorticoids and immunosuppressants combined with iodine radiotherapy is one reasonable scheme. At the same time, it is necessary to eliminate the organ damage caused by other reasons. This report provides a clinical treatment basis for patients with drug-induced vasculitis manifestations who cannot receive an accurate diagnosis.

Immunoglobulin A vasculitis: The clinical features and pathophysiology.

Palpable purpura, gastrointestinal symptoms, joint involvement, and renal disease characterize immunoglobulin A vasculitis (IgAV). Renal involvement ranging from mild proteinuria to severe nephritic or nephrotic syndrome highlights the importance of monitoring kidney function in patients with IgAV. Recognizing these key features is crucial for early diagnosis and appropriate management to prevent long-term complications related to kidney disease. However, the pathogenesis of IgAV remains unclear. Disease mechanisms involve various factors, including the interplay of aberrantly glycosylated IgA, anti-endothelial cell antibodies, and neutrophils following infection triggers, which are the main pathogenic mechanisms of IgAV. Insights from cases of IgAV related to Coronavirus disease 2019 have offered additional understanding of the connection between infection and IgAV pathogenesis. This review provides a valuable resource for healthcare professionals and rheumatology researchers seeking a better understanding of the clinical features and pathophysiology of IgAV.

IgA vasculitis after COVID-19: a case-based review.

IgA-associated vasculitis (IgAV) known as Henoch - Schönlein purpura (HSP) disease is an inflammatory disorder of small blood vessels. It's the most common type of systemic vasculitis in children which can be associated with the inflammatory process following infections. IgA vasculitis is a rare and poorly understood systemic vasculitis in adults. Coronavirus disease 2019 (COVID-19) has been associated with HSP in both adults and children. A 58-year-old woman was diagnosed with HSP, fulfilling the clinical criteria: palpable purpura, arthritis, hematuria. The disclosure of the HSP disease was preceded by a infection of the respiratory tract. COVID-19 infection was confirmed via the presence of IgM and IgG antibodies. This case indicates the possible role of SARS-CoV-2 in the development of HSP. The clinical course of IgAV in adults appears to be different from pediatric IgAV, especially due to higher risk of renal complications. Symptoms of the disease quickly resolved with low-dose of steroids.

Extracellular CIRP co-stimulated T cells through IL6R/STAT3 in pediatric IgA vasculitis.

Immunoglobulin A vasculitis (IgAV) is the most common vasculitis of childhood. Disordered immune responses play important roles in its pathogenesis, but the comprehensive immune profile of the disease and the underlying mechanisms are still largely unknown. Here we found a potential disease biomarker cold inducible RNA binding protein (CIRP) in our pediatric IgAV cohort. Serum CIRP level in these patients were elevated and positively correlated with the increased early memory (CD45RA+CD62L+CD95+) T cells revealed using multicolor flow cytometry. Immune phenotyping of the patients showed they had more activated T cells with higher IL6Ra expression. T cell culture experiment showed CIRP further activated both human CD4+ and CD8+ T cells as indicated by increased perforin secretion and phosphorylation of STAT3. Blockade of IL6Rα attenuated CIRP-induced T cell toxicity in vitro. RNA-sequencing data further supported CIRP stimulation promoted human T cell activation and migration, fueled inflammation through the JAK-STAT signaling pathway. Therefore, IL6Ra-mediated T cell activation by extracellular CIRP may contribute to pathogenesis of IgAV in children, both CIRP and IL6Ra could be new therapeutic targets for IgAV.

Lectin and alternative complement pathway activation in cutaneous manifestations of IgA-vasculitis: A new target for therapy?

IgA-vasculitis is a systemic small-vessel leucocytoclastic vasculitis and is associated with a high morbidity. The disease can progress to IgA-vasculitis with nephritis (IgAVN) which can result in chronic renal failure. Complement activation is involved in the pathogenesis of IgA-vasculitis. A recent study has shown that cutaneous C3c deposition in IgA-vasculitis is associated with a higher risk to develop IgAVN. In the current study we investigated the different complement pathways that are activated in cutaneous IgA-vasculitis in order to reveal potential targets for intervention. In addition, we analyzed the association of complement factors with IgAVN and the clinical course of the disease. In this retrospective study, the clinicopathological features of 17 patients with IgA-vasculitis were compared with 25 non-IgA-vasculitis cases. Deposition of immunoglobulins and complement was analyzed by direct immunofluorescence for IgA, IgG, IgM, C1q, C4d, properdin, mannan-binding lectin (MBL), ficolin-2 (FCN2), MBL-associated serine protease 1/3 (MASP1/3), MASP2 and C3c. The vascular intensity and positive area was scored on a nominal scale and cumulative score was calculated by multiplying the intensity x area. Properdin was positive in 82% of IgA-vasculitis cases, reflecting alternative pathway activation. C4d was positive in 88% of IgA-vasculitis cases reflecting classical and/or lectin pathway activation, although only 12% of cases were positive for C1q. Lectin pathway activation was demonstrated by deposition of MBL (47%), MASP1/3 (53%) and MASP2 (6%) while FCN2 was found negative. Significantly more deposition of MASP1/3 was found in IgA-vasculitis versus non-IgA-vasculitis. This study demonstrates for the first time activation of lectin and alternative pathways in cutaneous manifestations of IgA-vasculitis. Hence, drugs that intervene in these complement pathways may be an interesting more targeted alternative to the current drugs, in reducing local cutaneous symptoms of the disease, with potentially less side-effects. No association was found between complement activation and IgAVN and/or response to therapy. Therefore, it is unlikely that intervention in complement activation will lead to a better clinical course of the disease.

Pathogenesis of IgA Vasculitis: An Up-To-Date Review.

Immunoglobin A (IgA) vasculitis (IgAV), formerly called the Henoch-Schönlein purpura (HSP), is a small vessel vasculitis, characterized by IgA1-dominant immune deposition at diseased vessel walls. IgAV is the most common form of vasculitis in children; typical symptoms include palpable purpura, arthritis or arthralgia, abdominal pain, and hematuria or proteinuria. Galactose-deficient IgA1 is detected in the tissues of the kidney and skin in patients with IgAV; it forms immune complexes leading to subsequent immune reactions and injuries. This report provides the recent advances in the understanding of environmental factors, genetics, abnormal innate and acquired immunity, and the role of galactose-deficient IgA1 immunocomplexes in the pathogenesis of IgAV.

The Involvement of Neutrophil Extracellular Traps in Disease Activity Associated With IgA Vasculitis.

Objectives: This aim of this study was to determine whether neutrophil extracellular traps (NETs) are involved in the pathogenesis of IgA vasculitis (IgAV) and investigate whether the circulating NETs levels are associated with disease activity in children. Methods: We performed a case-control study and collected blood samples from 193 children with different stages of IgAV (61 were at the onset stage, 64 at the remission stage, 43 at the active stage, and 25 were undergoing drug withdrawal). A total of 192 healthy children were recruited as controls. Circulating cell free DNA (cf-DNA) was obtained from the plasma and quantified by using the Quant-iT PicoGreen DNA quantification kit. NETs-associated myeloperoxidase-DNA (MPO-DNA), citrullinated-histone H3 (cit-H3), neutrophil elastase (NE), and the deoxyribonuclease I (DNase I) concentrations were measured using enzyme-linked immunosorbent assays. The presence of NETs in the kidney and gastrointestinal tissues of onset and active IgAV patients was determined by multiple immunofluorescence staining in 15 IgAV nephritis patients and 9 IgAV patients without IgAV nephritis, respectively. NETs degradation potency of collected sera samples from IgAV patients were checked in vitro. Relationships between circulating levels of cf-DNA with MPO-DNA, NE, and DNase I and the patients were analyzed. Results: Circulating levels of cf-DNA in onset and active IgAV patients were significantly higher than those in remission and drug withdrawal patients as well as healthy controls. The results were similar for MPO-DNA and NE. The levels of circulating cf-DNA correlated significantly with MPO-DNA, NE and DNase I. A significantly decreased degradation of NETs from the onset and active IgAV patients was observed, but was normal in healthy controls. Furthermore, presence of NETs was also confirmed in all renal and gastrointestinal tissues obtained from the onset and active IgAV patients but not control samples. Conclusions: Our data showed that NETs were released into the circulation of IgAV patients and are involved in the disease activity. The circulating levels of NETs maybe used to assess disease severity in children with IgAV.

Role of the IL33 and IL1RL1 pathway in the pathogenesis of Immunoglobulin A vasculitis.

Cytokines signalling pathway genes are crucial factors of the genetic network underlying the pathogenesis of Immunoglobulin-A vasculitis (IgAV), an inflammatory vascular condition. An influence of the interleukin (IL)33- IL1 receptor like (IL1RL)1 signalling pathway on the increased risk of several immune-mediated diseases has been described. Accordingly, we assessed whether the IL33-IL1RL1 pathway represents a novel genetic risk factor for IgAV. Three tag polymorphisms within IL33 (rs3939286, rs7025417 and rs7044343) and three within IL1RL1 (rs2310173, rs13015714 and rs2058660), that also were previously associated with several inflammatory diseases, were genotyped in 380 Caucasian IgAV patients and 845 matched healthy controls. No genotypes or alleles differences were observed between IgAV patients and controls when IL33 and IL1RL1 variants were analysed independently. Likewise, no statistically significant differences were found in IL33 or IL1RL1 genotype and allele frequencies when IgAV patients were stratified according to the age at disease onset or to the presence/absence of gastrointestinal (GI) or renal manifestations. Similar results were disclosed when IL33 and IL1RL1 haplotypes were compared between IgAV patients and controls and between IgAV patients stratified according to the clinical characteristics mentioned above. Our results suggest that the IL33-IL1RL1 signalling pathway does not contribute to the genetic network underlying IgAV.

Characteristics of immune function in the acute phase of Henoch-Schönlein purpura.

BACKGROUND: Henoch-Schönlein purpura (HSP) is still diagnosed using symptoms and signs together with some histopathological findings. The purpose of this study was to summarize the characteristics and roles of cellular and humoral immunity in children with Henoch-Schönlein purpura (HSP). METHODS: A total of 502 cases of patients with acute HSP were diagnosed and observed. The levels of T lymphocyte subsets, natural killer cells (NK cells), and B cells were analyzed by flow cytometry. The serum immunoglobulin G (IgG), immunoglobulin M (IgM), immunoglobulin A (IgA), and complement C3 (C3) and complement C4 (C4) levels were detected by velocity scatter turbidimetry. RESULTS: Compared with the healthy groups, the levels of cluster of differentiation 3 (CD3), cluster of differentiation 4 (CD4), B cells, and NK cells and ratio of CD4/CD8 in patients with HSP were decreased (P < 0.05). The levels of IgG, IgA, IgM, and C3 were increased (P < 0.05). Compared with the Kawasaki disease (KD) group, the levels of CD3, CD4, CD8, B cells, NK cells, and IgA in patients with HSP were increased (P < 0.05), and the ratio of CD4/CD8 and levels of IgM, C3, and C4 was decreased (P < 0.05). Compared with the pneumonia group, the levels of CD3, CD4, B cells, and IgA in patients with HSP were increased (P < 0.05), and the ratio of CD4/CD8 and levels of IgM and C4 was decreased (P < 0.05). CONCLUSIONS: Cellular immunity and humoral immunity were all involved in the pathogenesis of HSP. The decline of NK cells, B lymphocyte cells, CD3, CD4 the increased secretion of immunoglobulin, and the abnormal appearance of IgA and C3 may exist during the progression. It may indicate a worse prognosis and increasing the risk of dedifferentiation. Cellular immunity was lower, which lead to increased production of inflammatory mediators and increased secretion of immunoglobulin, which then mediated systemic small-vessel vasculitis. Key Points • The pathogenesis of Henoch-Schönlein purpura (HSP) was not completely illuminated. • There was a lack of disease-specific laboratory abnormalities that can be used in the clinical diagnosis of HSP. • We compared the laboratory abnormalities in the immune system of HSP with KD and pneumonia. • Cellular immunity and humoral immunity were all involved in the pathogenesis of HSP. Cellular immunity was lower, which lead to the following pathological changes.

Meta-analysis of the neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios in Henoch-Schonlein purpura and its complications.

OBJECTIVE: The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are associated with the severity of Henoch-Schonlein purpura (HSP). Therefore, we conducted a meta-analysis to evaluate the clinical significance of NLR and PLR in HSP and its complications. METHODS: A comprehensive literature search was conducted by searching the PubMed, EMBASE, Web of Science, Cochrane Library, China National Knowledge Infrastructure, Wanfang, VIP, and SinoMed databases from their inception to September 31, 2020. We used the standard mean difference (SMD) with a 95% confidence interval (CI) to estimate the pooled effect and used subgroup analysis to investigate heterogeneity. RESULTS: A total of 1,691 HSP patients and 563 healthy controls (HCs) from 15 studies were included in the analysis. The NLR value was significantly higher in 431 HSP patients with gastrointestinal complications (HSP-GCs) than that in 833 HSP patients without GCs (SMD = 1.09, 95% CI: 0.62-1.57, P < 0.001); in 83 HSP adult patients with renal involvement (HSP-RI) than that in 131 adult HSP patients without RI (SMD = 0.33, 95% CI: 0.05-0.60, P = 0.021); and in 831 HSP patients than that in 563 HCs (SMD = 0.70, 95% CI: 0.51-0.89, P < 0.001). The PLR was significantly higher in 417 HSP patients than that in 264 HCs (SMD = 0.39, 95% CI: 0.06-0.71, P = 0.02). CONCLUSIONS: NLR could serve as a useful biomarker to predict GCs and RI in patients with HSP. However, further well-designed and large cohort studies are warranted to confirm these findings.

[Effects of IL-27 on Th17 Cells in Patients with Henoch-Schönlein Purpura].

OBJECTIVE: To investigate the effect of IL-27 on Th17 cells in patients with henoch-schönlein purpura（HSP） in order to further elucidate the pathogenesis. METHODS: Fifty patients with HSP treated in our hospital from April 2019 to July 2019 were selected as HSP group, and 30 volunteers underwent physical examination at the same time were selected as control group. The proportion of Th17 cells in peripheral blood of HSP group and healthy control group was determined by flow cytometry (FCM). A total of 27 HSP patients were selected, and candidate peripheral blood mononuclear lymphocytes (PBMC) were co-cultured with exogenous rhIL-27, and the ratio of Th17 cells was detected by flow cytometry. RESULTS: The proportion of Th17 cells in the peripheral blood of HSP patients with acute phase was (1.57±0.54)%, which was significantly higher than that of the control group (0.86±0.40)% (t=-6.298, P<0.001), and the proportion of Th17 cells was decreased significantly after rhIL-27 co-culture (1.39%±0.52% vs 0.98%±0.44%)(P<0.05). CONCLUSION: IL-27 can reduce the level of Th17 cells in patients with HSP, which may be involved in the pathogenic process of HSP and play a protective role in the development of the disease.

Decreased glycolysis induced dysfunction of NK cells in Henoch-Schonlein purpura patients.

BACKGROUND: Henoch-Schonlein purpura (HSP) is the most common systemic vasculitis of the childhood. However, its mechanisms and pathogenesis still need more exploration. Natural killer (NK) cells are innate lymphocytes, and there is a growing appreciation that cellular metabolism is important in determining the immune responsiveness of lymphocytes. Thus, we aimed to analyze the NK cells phenotype and explore the association between glucose metabolism and NK cells function in HSP patients. RESULTS: A total number of 64 HSP patients and 34 healthy children were included. The HSP patients were divided into two groups according to whether accompanied with nephritis or not. NK cells in HSP patients without nephritis showed a reduced frequency in peripheral blood, a down-regulated expression of activating receptors both NKp30 and NKp46, and an attenuated cytotoxic function against tumor cells. In addition, the function impairment of NK cells was shown to exacerbate in HSPN. Our data further revealed an aberrant metabolic reprogramming of NK cells in HSP patients. Upon stimulation with cytokines (IL-15, IL-12 and IL-2), NK cells from healthy controls switched to an elevated glycolysis rate to support their effector function. By contrast, the glycolysis rate of activated NK cells in HSP group was not significantly up-regulated from the resting level possibly owing to the inhibition of mTORC1. CONCLUSIONS: Our study found that HSP patients were accompanied with dysfunction of NK cells. We concluded that the dysfunction of NK cells in HSP patients was induced with a decreased glycolysis rate and suggested that metabolic reprogramming of NK cells might be a player in the pathogenesis of HSP.

Analysis of the association between kidney injury biomarkers concentration and nephritis in immunoglobulin A vasculitis: A pediatric cohort study.

OBJECTIVE: The aim of this study was to investigate the clinical course, selected biochemical parameters and concentrations of renal injury biomarkers such as neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1) and liver-fatty acid binding protein (L-FABP) in patients with immunoglobulin A vasculitis (IgAV) to identify the markers associated with nephritis in the course of the disease (IgAVN). METHODS: The study involved 29 children with IgAV and 34 healthy controls. Eleven (38%) patients had renal involvement (IgAV-N) and 18 (62%) did not exhibit nephritis (IgAV-noN). Initial laboratory tests, determining the concentrations of NGAL, KIM-1 and L-FABP in serum and urine, were conducted on children from the study group in an acute phase of IgAV as well as after an average of 6 months, during a follow-up visit. The interconnection between renal involvement, anthropometric measurements, epidemiological data, laboratory parameters and levels of examined biomarkers have been thoroughly evaluated. RESULTS: The serum and urine levels of NGAL, KIM-1 and L-FABP were significantly higher in children with an acute phase of IgAV as compared to the control group (P < .001) and markedly lower during follow-up retesting in comparison with the values obtained at inclusion (P < .001). However, the concentration of none of the evaluated biomarkers correlated with nephrological indices. Among all examined parameters, only male subjects were associated with nephritis (P = .017). CONCLUSIONS: We have established no evident association between the concentrations of NGAL, KIM-1 and L-FABP and nephritis in the course of IgAV in children. Additionally, we confirmed a significant male predominance in patients with nephritis.

Clinical relevance of membrane attack complex deposition in children with IgA nephropathy and Henoch-Schönlein purpura.

BACKGROUND: IgA nephropathy (IgAN) and Henoch-Schönlein purpura are common glomerular disorders in children sharing the same histopathologic pattern of IgA deposits within the mesangium, even if their physiopathology may be different. Repeated exposure to pathogens induces the production of abnormal IgA1. The immune complex deposition in the renal mesangium in IgAN or potentially in small vessels in Henoch-Schönlein purpura induces complement activation via the alternative and lectin pathways. Recent studies suggest that levels of membrane attack complex (MAC) in the urine might be a useful indicator of renal injury. Because of the emerging availability of therapies that selectively block complement activation, the aim of the present study is to investigate whether MAC immunostaining might be a useful marker of IgA-mediated renal injury. METHODS: We conducted immunohistochemistry analysis of the MAC on renal biopsies from 67 pediatric patients with IgAN and Henoch-Schönlein purpura. We classified their renal biopsies according to the Oxford classification, retrieved symptoms, biological parameters, treatment, and follow-up. RESULTS: We found MAC expression was significantly related to impaired renal function and patients whose clinical course required therapy. MAC deposits tend to be more abundant in patients with decreased glomerular filtration rate (p = 0.02), patients with proteinuria > 0.750 g/day/1.73 m2, and with nephrotic syndrome. No correlation with histological alterations was observed. CONCLUSIONS: We conclude that MAC deposition could be a useful additional indicator of renal injury in patients with IgAN and Henoch-Schönlein purpura, independent of other indicators.

Immune deposits in skin vessels of patients with acute hemorrhagic edema of young children: A systematic literature review.

BACKGROUND: Acute hemorrhagic edema of young children is a benign skin-limited vasculitis mainly affecting children 2 to 24 months of age, which is often considered the infantile variant of immunoglobulin A vasculitis (Henoch-Schönlein purpura). In most cases, the diagnosis is made on a clinical basis without a skin biopsy. METHODS: A systematic review of the literature was performed to examine the reported prevalence of vascular immune deposits in skin biopsies of patients with acute hemorrhagic edema of young children. RESULTS: Testing for vascular immune deposits was performed in 75 cases (64 boys and 11 girls aged from 3.5 to 72, median 11 months) published between 1970 and 2018. Vessel wall deposition of complement C3 was seen in 40 cases. Immunoglobulin M (N = 24), immunoglobulin A (N = 21), immunoglobulin G (N = 13), and immunoglobulin E (N = 3) were less frequently detected. Gender, age, clinical features, and disease duration were not statistically different in cases with and without vessel wall deposition of immunoglobulin A. CONCLUSION: Immune deposits in skin vessels, most frequently complement C3, are common in subjects with acute hemorrhagic edema of young children, providing furhter evidence that acute hemorrhagic edema, immunoglobulin A vasculitis, and pauci-immune vasculitides are different entities.

Risk factors associated with IgA vasculitis with nephritis (Henoch-Schönlein purpura nephritis) progressing to unfavorable outcomes: A meta-analysis.

OBJECTIVE: To identify risk factors associated with unfavorable outcomes in children with IgA vasculitis with nephritis (Henoch-Schonlein purpura nephritis)(IgA-VN). METHODS: PubMed, Embase, and Web of Science databases were searched for studies, published in English through February 2019. The data were extracted to perform pooled analysis, heterogeneity testing, subgroup analysis, sensitivity analysis, and publication bias analysis. RESULTS: This meta-analysis showed that, older age at onset (WMD 1.77, 95% CI 0.35-3.18, p = 0.014), lower glomerular filtration rate (GFR; WMD -23.93, 95% CI -33.78- -14.09, p<0.0001), initial renal manifestations with nephrotic syndrome (OR 1.74, 95% CI 1.12-2.70, p = 0.013), with nephritic-nephrotic syndrome (OR 4.55, 95% CI 2.89-7.15, p<0.0001) and renal biopsy with crescentic nephritis (International Study of Kidney Disease in Children [ISKDC] grades III-V) (OR 3.85, 95% CI 2.37-6.28, p<0.0001) were significant risk factors associated with poor outcomes in IgA-VN, whereas initial clinical features with hematuria (OR 0.33, 95% CI 0.16-0.69, p = 0.003) and mild proteinuria±hematuria (OR 0.46, 95% CI 0.28-0.75, p<0.0001) were associated with progression to good outcomes. By contrast, gender, hypertension and initial renal manifestations of acute nephritic syndrome were not significantly associated with poor outcomes in IgA-VN. CONCLUSION: This meta-analysis showed that older age at onset, lower GFR, initial renal features of nephrotic syndrome and nephritic-nephrotic syndrome and renal biopsy with crescentic nephritis (ISKDC grades III-V) were predictive of poor prognosis in children with IgA-VN.

A clinicopathological comparison between IgA nephropathy and Henoch-Schönlein purpura nephritis in children: use of the Oxford classification.

BACKGROUND: There is controversy over whether IgA nephropathy (IgAN) and Henoch-Schönlein purpura nephritis (HSPN) are the same diseases. This study focuses on the clinicopathological comparison between HSPN and IgAN in children. METHODS: Children with IgAN and HSPN who had a diagnostic renal biopsy were enrolled. This study collected the clinical data of patients at biopsy, re-evaluated the pathological lesions of patients according to the Oxford Classification (MEST-C), and made a retrospective comparison between IgAN and HSPN on different stratifications of the course (Tc) and proteinuria. RESULTS: A total of 142 children with IgAN and 57 children with HSPN were enrolled. Various stratification showed the same result, which suggested that IgAN showed more mesangial proliferation (M). HSPN showed more segmental glomerulosclerosis in the Tc > 12 m group than IgAN (S 60.0% vs. 9.10%, P = 0.008). In the non-nephrotic-range and nephrotic-range proteinuria group, there were no significant differences in MEST-C scores between IgAN and HSPN. CONCLUSION: M is more common in IgAN. HSPN had more S than IgAN over the course of more than 12 months. These results indicate the differences in the pathogenesis in IgAN and HSPN. We propose early biopsy and active treatment of HSPN within 12 months to delay the development of chronic lesions.

Clinical significance of ANCA positivity in patients with IgA vasculitis: a retrospective monocentric study.

We assessed the detection rate of antineutrophil cytoplasmic antibody (ANCA) and investigated the clinical significance of ANCA positivity at diagnosis in patients with IgA vasculitis (Henoch-Schönlein purpura). We retrospectively reviewed their medical records of 86 IgA vasculitis patients. We divided IgA vasculitis patients based on ANCA positivity and compared variables at diagnosis and poor outcomes and medication during follow-up between the two groups. All-cause mortality, relapse, chronic kidney disease (CKD) (stage 3-5) and end-stage renal disease (ESRD) were defined as poor outcomes. We assessed the renal histological features based on the International Study of Kidney Disease in Children (ISKDC) classification and Oxford classification. Comparison of cumulative survivals was analysed by the Kaplan-Meier survival analysis. Five of 86 IgA vasculitis patients (5.8%) had ANCA and all ANCA-positive patients had myeloperoxidase (MPO)-ANCA. IgA vasculitis patients with ANCA exhibited pulmonary and nervous involvement of IgA vasculitis more frequently than those without. There was no significant difference in renal involvement between the two groups. There were no significant differences in renal histological features and poor outcomes related to renal function between IgA vasculitis patients with and without ANCA. In addition, 5 IgA vasculitis patients did not meet the classification criteria for ANCA-associated vasculitis (AAV). Particularly, there were no significant differences in CKD and ESRD-free survival rates between IgA vasculitis patients with and without ANCA. 5.8% of IgA vasculitis patients had MPO-ANCA and poor outcomes of IgA vasculitis were not affected by the presence of ANCA.