Haemophilus parainfluenzae antigen and antibody in children with IgA nephropathy and Henoch-Schönlein nephritis

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.

An Investigation of the Relationship between Henoch-Schönlein Purpura and Viral Infection in Korea Using the Health Insurance Database

(1) Background: This study investigated the epidemiology and viral connections of Henoch-Schönlein purpura (HSP) using information from the Korea Disease Control and Prevention Agency and the Health Insurance Review and Assessment database. (2) Method: Between 2016 and 2019, a total of 25,443 patients with HSP were identified, with 51.3% of patients under the age of 20 years and the highest incidence in March. (3) Results: The autoregressive integrated moving average model and Granger causality test were used to analyze the association between the virus positivity detection rate and HSP incidence. (4) Conclusions: The incidence of HSP was associated with rotavirus, bocavirus, parainfluenza virus, and respiratory syncytial virus in individuals under 20 years of age, whereas adenovirus, respiratory syncytial virus, and norovirus were associated with individuals above that age.

The mucosal immune system and IgA nephropathy

The precise pathogenesis of immunoglobulin A nephropathy (IgAN) is still not clearly established but emerging evidence confirms a pivotal role for mucosal immunity. This review focuses on the key role of mucosa-associated lymphoid tissue (MALT) in promoting the onset of the disease, underlying the relationship among microbiota, genetic factors, food antigen, infections, and mucosal immune response. Finally, we evaluate potential therapies targeting microbes and mucosa hyperresponsiveness in IgAN patients.

The Influence and Role of Microbial Factors in Autoimmune Kidney Diseases: A Systematic Review

A better understanding of the pathophysiology of autoimmune disorders is desired to allow tailored interventions. Despite increased scientific interest a direct pathogenic factor in autoimmune renal disease has been described only in a minority like membranous nephropathy or ANCA-associated vasculitis. Nonetheless the initial step leading to the formation of these antibodies is still obscure. In this review we will focus on the possible role of microbial factors in this context. Staphylococcus aureus may be a direct pathogenetic factor in granulomatosis with polyangiitis (GPA). Chronic bacterial colonization or chronic infections of the upper respiratory tract have been proposed as trigger of IgA vasculitis and IgA nephropathy. Interventions to remove major lymphoid organs, such as tonsillectomy, have shown conflicting results but may be an option in IgA vasculitis. Interestingly no clear clinical benefit despite similar local colonization with bacterial strains has been detected in patients with IgA nephropathy. In systemic lupus erythematosus injection of bacterial lipopolysaccharide induced progressive lupus nephritis in mouse models. The aim of this review is to discuss and summarize the knowledge of microbial antigens in autoimmune renal disease. Novel methods may provide insight into the involvement of microbial antigens in the onset, progression, and prognosis of autoimmune kidney disorders.

Advances in our understanding of the pathogenesis of Henoch-Schönlein purpura and the implications for improving its diagnosis

Henoch-Schönlein purpura (HSP) is a leukocytoclastic vasculitis classically characterized by palpable purpura, arthritis, abdominal pain and renal disease. In this article, we summarize our current understanding of the pathogenesis of HSP and the implications for improving its diagnosis. Although the pathogenesis of HSP is not fully understood yet, exciting new information has emerged in recent years, leading to a better understanding of its pathogenesis. Here, we discuss genetic predisposition, immunoglobulins with a particular emphasis on IgA1, activated complements, cytokines and chemokines, abnormal coagulation and autoantibodies in the underlying pathogenic mechanisms. Finally, diagnostic criteria for HSP developed by institutions such as the American College of Rheumatology and the European League against Rheumatism/Paediatric Rheumatology European Society were proposed to improve early detection and diagnosis.

Periodontal disease bacteria specific to tonsil in IgA nephropathy patients predicts the remission by the treatment

Background

Immunoglobulin (Ig)A nephropathy (IgAN) is the most common form of primary glomerulonephritis in the world. Some bacteria were reported to be the candidate of the antigen or the pathogenesis of IgAN, but systematic analysis of bacterial flora in tonsil with IgAN has not been reported. Moreover, these bacteria specific to IgAN might be candidate for the indicator which can predict the remission of IgAN treated by the combination of tonsillectomy and steroid pulse.

Methods and Findings

We made a comprehensive analysis of tonsil flora in 68 IgAN patients and 28 control patients using Denaturing gradient gel electrophoresis methods. We also analyzed the relationship between several bacteria specific to the IgAN and the prognosis of the IgAN. Treponema sp. were identified in 24% IgAN patients, while in 7% control patients (P = 0.062). Haemophilus segnis were detected in 53% IgAN patients, while in 25% control patients (P = 0.012). Campylobacter rectus were identified in 49% IgAN patients, while in 14% control patients (P = 0.002). Multiple Cox proportional-hazards model revealed that Treponema sp. or Campylobactor rectus are significant for the remission of proteinuria (Hazard ratio 2.35, p = 0.019). There was significant difference in remission rates between IgAN patients with Treponema sp. and those without the bacterium (p = 0.046), and in remission rates between IgAN patients with Campylobacter rectus and those without the bacterium (p = 0.037) by Kaplan-Meier analysis. Those bacteria are well known to be related with the periodontal disease. Periodontal bacteria has known to cause immune reaction and many diseases, and also might cause IgA nephropathy.

Conclusion

This insight into IgAN might be useful for diagnosis of the IgAN patients and the decision of treatment of IgAN.

The pathogenesis of IgA nephropathy

PURPOSE OF REVIEW

This review will analyze contemporary information concerning the possible pathogenetic mechanisms involved in IgA nephropathy, emphasizing studies in humans rather than experimental animals.

RECENT FINDINGS

Deposition of IgA in the glomeruli, the hallmark of IgA nephropathy, may be a quite common phenomenon. Aberrant O-linked galactosylation of IgA subclass (IgA1) appears to play a central role and 'auto-immunity' to a conformational epitope related to glycans at the hinge region of IgA1 is apparently required. Both a circulating immune complex and an in-situ immune complex mechanism have been advanced. Mediator systems, such as complement activation and engagement of innate immune system, also play prominent roles in determining the clinical onset and severity of disease. Genetic influences are evident but the fine details of genetic predisposition and its impact on outcomes still need to be further elucidated.

SUMMARY

Progress in understanding the details of the pathogenesis of IgA nephropathy will lead to a better means of diagnosis (including noninvasive tests for diagnosis), more accurate individualized prognosis and personalized treatment regimens for this globally distributed and very common primary glomerular disease.

Henoch-Schönlein purpura: a long-term prospective study in Greek children

OBJECTIVE

Henoch-Schönlein purpura is a common vasculitis of childhood. The present study, comprising 74 children enrolled during a 9-year period, aimed to delineate the clinical spectrum and the long term follow-up of the disease.

METHODS

Patients were diagnosed strictly on the criteria established by the American College of Rheumatology. The diagnosis was further strengthened by a skin biopsy performed in more than half of cases (42/74), which revealed leukocytoclastic vasculitis in all patients, whereas IgA deposits were found in 37/42 children.

RESULTS

There was a predominance of boys (41 males), and the mean age of study population was 5.2 +/- 2.54 years. Palpable purpura was identified in 73/74 children, whereas transient arthritis manifested in 68/74 children. Gastrointestinal blood loss was elicited in 30 children, 11 of whom had also renal involvement. The latter was seen in 19/74 (25.7%) children, and in the long term follow-up (extended to 2004, from 4-12 years, mean duration 7.3 years), 2 children remained with persistent occult hematuria. Relapses occurred in 49 children (66%), and half of them experienced more than 1 recurrence. Arthritis was less common in the relapsed episodes, and this difference was statistically significant (P < 0.001). Relapses tended to be more common in children with renal involvement and colicky abdominal pain without however reaching statistical significance.

CONCLUSION

Despite common relapses, this disease is benign in the long term even if severe renal involvement can occur during its active period. Recurrences often differ to some extent from the initial episode with arthritis being less common with relapses.

Efficacy of early dental and ENT therapy in preventing nephropathy in pediatric Henoch-Schönlein purpura

In a previous study, we demonstrated the benefit of tonsillectomy for early recovery from Henoch-Schönlein purpura (HSP) nephritis (HSPN), suggesting the pathological role of tonsils in HSP (Inoue et al., Clin Nephrol 67:298-305, 2007). In this study, we evaluated the efficacy of extensive eradication of infectious foci directly connected to the tonsils, including those involved in oral as well as ear, nose, and throat (ENT) diseases, in reducing the nephropathy in HSP. For this purpose, we examined the focal points of infection in 40 newly diagnosed HSP patients. After these focal points of infection had been identified, they were extensively eradicated; when the clinical course was intractable, we also considered tonsillectomy. After administering such therapy to HSP patients, we prospectively followed them up for 0.6 to 8 years. The identified focal infections included dental caries in 28 (70%), apical periodontitis in 21 (53%), rhinosinusitis in 19 (48%), tonsillitis in five (13%), and otitis media in four (10%) of the 40 patients. Seventeen patients (43%) had more than two simultaneous infectious foci, whereas, in five (13%), no infectious focus was found. In 32 patients, antimicrobial treatment with concurrent dental and/or ENT therapy resulted in a complete cure without development of HSPN or recurrent attacks. In eight patients, we performed tonsillectomy-adenotonsillectomy to treat their clinical symptoms, including aggravated purpura and recurrent attacks of HSP or HSPN. All patients were completely cured. The overall incidence of HSPN was only three out of the 40 patients (8%). Oral and ENT diseases were found with high percentages in HSP patients. Early and extensive treatment for these lesions and tonsillectomy-adenotonsillectomy for intractable cases may prevent the complication of HSPN, contributing to the early curing of HSP.

[Nephropathy in Schönlein-Henoch purpura: a retrospective study of the last 25 years]

Schönlein-Henoch purpura is a systemic vasculitis due to IgA-mediated hypersensitivity, almost exclusively affecting the pediatric age group. Long-term prognosis is mainly conditioned by renal involvement, which can appear at onset or during the course of the disease. To evaluate renal involvement, 764 patients with Schönlein-Henoch purpura were retrospectively reviewed. Of these, 153 (20 %) had renal involvement, the most frequent form of presentation being non-nephrotic hematuria/proteinuria (67 patients) followed by isolated hematuria (41 patients). Renal biopsy was performed in 39 patients, and the most frequent pathological findings were diffuse mesangial proliferation with IgA deposits and less than 50 % of crescentic glomeruli. Treatment was not curative. Three patients (2 %) progressed to end-stage renal failure and required renal transplantation. One patient died. Notably, two of the patients who underwent renal transplantation had disease recurrence. We stress that nephropathy is usually benign and that it requires long-term follow-up.

Vasculitis and systemic infections

PURPOSE OF REVIEW

In recent years, many investigators have focused on potential associations between infections and vascular inflammation. We review the principal pathogenic mechanisms that have been implicated for possible roles in the vascular inflammation initiated by infectious agents. We also summarize the most important literature related to this topic.

RECENT FINDINGS

A novel theory known as autoantigen complementarity suggests that an infectious agent could trigger antineutrophil cytoplasmic antibody-associated vasculitis. Several recent studies investigating the presence of parvovirus B19 and herpesviruses in temporal arteries with giant cell arteritis have yielded contradictory results. A recent study has identified higher frequency of a novel human virus, the 'New Haven coronavirus', in respiratory secretions of children with Kawasaki disease. Many case reports have suggested potential relationships between human pathogens and vasculitis.

SUMMARY

There remains considerable interest in the possibilities of primary vasculitic syndromes caused in some fashion by infection. With the exception of a few well sustained associations - for example hepatitis B or C with known vasculitic syndromes - most of the purported links between microbial agents and primary vasculitides remain speculative.

Successful treatment of progressive Henoch-Schönlein purpura nephritis with tonsillectomy and steroid pulse therapy

Henoch-Schönlein purpura (HSP) is a systemic disorder characterized by a leukocytoclastic vasculitis involving small vessels with the deposition of IgA immune complexes. The renal involvement is the major cause of morbidity and mortality in patients with HSP. We report here an adult patient with HSP nephritis (HSPN) accompanied by persistent proteinuria and progressive renal dysfunction despite conventional therapy. The patient was successfully treated with tonsillectomy followed by intravenous pulse methylprednisolone and oral prednisone. The combination therapy resulted in a significant decrease in proteinuria, improvement of renal function and the disappearance of microhematuria. The patient finally reached a stage of clinical remission.

Race/ethnicity and disease severity in IgA nephropathy

BACKGROUND

Relatively few U.S.-based studies in chronic kidney disease have focused on Asian/Pacific Islanders. Clinical reports suggest that Asian/Pacific Islanders are more likely to be affected by IgA nephropathy (IgAN), and that the severity of disease is increased in these populations.

METHODS

To explore whether these observations are borne out in a multi-ethnic, tertiary care renal pathology practice, we examined clinical and pathologic data on 298 patients with primary glomerular lesions (IgAN, focal segmental glomerulosclerosis, membranous nephropathy and minimal change disease) at the University of California San Francisco Medical Center from November 1994 through May 2001. Pathologic assessment of native kidney biopsies with IgAN was conducted using Haas' classification system.

RESULTS

Among individuals with IgAN (N = 149), 89 (60%) were male, 57 (38%) white, 53 (36%) Asian/Pacific Islander, 29 (19%) Hispanic, 4 (3%) African American and 6 (4%) were of other or unknown ethnicity. The mean age was 37 +/- 14 years and median serum creatinine 1.7 mg/dL. Sixty-six patients (44%) exhibited nephrotic range proteinuria at the time of kidney biopsy. The distributions of age, gender, mean serum creatinine, and presence or absence of nephrotic proteinuria and/or hypertension at the time of kidney biopsy were not significantly different among white, Hispanic, and Asian/Pacific Islander groups. Of the 124 native kidney biopsies with IgAN, 10 (8%) cases were classified into Haas subclass I, 12 (10%) subclass II, 23 (18%) subclass III, 30 (25%) subclass IV, and 49 (40%) subclass V. The distribution of Haas subclass did not differ significantly by race/ethnicity. In comparison, among the random sample of patients with non-IgAN glomerular lesions (N = 149), 77 (52%) patients were male, 51 (34%) white, 42 (28%) Asian/Pacific Islander, 25 (17%) Hispanic, and 30 (20%) were African American.

CONCLUSIONS

With the caveats of referral and biopsy biases, the race/ethnicity distribution of IgAN differs significantly from that of other major glomerulonephridities. However, among individuals undergoing native kidney biopsy, we see no evidence of a race/ethnicity association with severity of disease in IgAN by clinical and IgAN-specific histopathologic criteria. Further studies are needed to identify populations at higher risk for progressive disease in IgAN.

Update on childhood vasculitides

PURPOSE OF REVIEW

The purpose of this review is to provide an update on the new developments in pediatric vasculitis.

RECENT FINDINGS

Because most childhood vasculitides are rare, few large systematic studies have been done. Studies of Henoch-Schönlein purpura have focused on pathogenesis and outcome. Genetic associations and molecular changes occurring during Henoch-Schönlein purpura, including cytokines, and endothelial and nitric oxide metabolism are discussed. Risk factors for renal involvement and poor renal outcome are described. Uncontrolled series of treatment protocols for severe Henoch-Schönlein purpura nephritis are mentioned. Several studies have focused on the pathogenesis of other primary vasculitides, especially polyarteritis nodosa. Series describing the clinical manifestations of childhood vasculitis and case reports of uncommon manifestations of vasculitis in children are presented. The efficacy of new therapies, including the use of thalidomide and biologic modifiers, has been shown in individual childhood cases; however, there are no controlled studies of these agents.

SUMMARY

Besides studies of Henoch-Schönlein purpura, advances in pediatric vasculitis are few as a result of the rarity of most vasculitides in childhood. Multicenter collaboration is necessary to substantially increase the scientific base of investigating and treating childhood vasculitis.