Does tonsillectomy have a role in the treatment of patients with immunoglobulin A nephropathy?

Immunosuppressive therapy for IgA nephropathy in children

BACKGROUND

IgA nephropathy (IgAN) is the most common cause of primary glomerulonephritis. It is a heterogeneous disease with different presentations and high morbidity. Thirty per cent of adults and 20% of children (followed into adulthood) will have a 50% decline in kidney function or develop kidney failure after 10 years.

OBJECTIVES

To determine the benefits and harms of immunosuppressive therapy for the treatment of IgAN in children.

SEARCH METHODS

We contacted the Information Specialist and searched the Cochrane Kidney and Transplant Register of Studies up to 03 October 2023 using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and non-randomised studies of interventions (NRSIs) investigating the treatment of IgAN in children with immunosuppressive therapies compared to placebo, no treatment, supportive care, standard therapy (Japanese protocol), other immunosuppressive therapies or non-immunosuppressive therapies.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed the risk of bias. Random effects meta-analyses were used to summarise estimates of treatment effects. Treatment effects were expressed as risk ratios (RR) and 95% confidence intervals (CI) for dichotomous outcomes, and the mean difference (MD) and 95% CI for continuous outcomes. The risk of bias was assessed using the Cochrane risk of bias tool for RCTs and the ROBIN-I tool for NRSIs. The certainty of the evidence was assessed using Grading of Recommendations, Assessment, Development, and Evaluations (GRADE).

MAIN RESULTS

This review included 13 studies with 686 participants. Ten RCTs included 334 children and 191 adults, and three NRSIs included 151 participants, all children. Most participants had mild kidney disease. The risk of bias was unclear for most of the domains relating to allocation concealment, blinding of participants, personnel, and outcome assessment. In children with IgAN, it is uncertain if corticosteroid (steroid) therapy, compared to placebo reduces proteinuria (1 study, 64 children and young adults: RR 0.47, 95% CI 0.13 to 1.72; low certainty evidence) or the decline in estimated glomerular filtration rate (eGFR) (1 study, 64 children and young adults: RR 0.47, 95% CI 0.09 to 2.39; low certainty evidence). It is uncertain if steroids reduce proteinuria compared to supportive care (2 studies, 61 children: RR 0.04, 95% CI -0.83 to 0.72; low certainty evidence). Adverse events associated with steroid therapy were not assessed due to heterogeneity in steroid protocols, including dose and duration, and lack of systematic assessment for adverse events in the included studies. Azathioprine, mycophenolate mofetil, mizoribine, or cyclophosphamide alone or in combination with steroid therapy had uncertain effects on improving proteinuria or preventing eGFR decline in children with IgAN. Fish oil, vitamin E and tonsillectomy had uncertain effects on improving proteinuria or preventing eGFR decline. Effects of other immunosuppressive therapies, secondary outcomes and adverse events were not assessed due to insufficient data.

AUTHORS' CONCLUSIONS

There is a lack of high-quality evidence to guide the management of IgAN in children. There is no evidence to indicate that steroids, other immunosuppressive therapies, or tonsillectomy, when added to optimal supportive care, prevent a decline in eGFR or proteinuria in children with IgAN. Available studies were few, with small numbers, low-quality evidence, high or uncertain risk of bias, did not systematically assess harms associated with treatment, or report net benefits or harms. Severe cases and atypical presentations of IgAN were not included in the reviewed studies, and our findings cannot be generalised to these situations.

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.

Pregnancy in a woman with recurrent immunoglobulin a nephropathy: A case report

Immunoglobulin A nephropathy (IgAN) is the most common form of primary glomerulonephritis and is increasingly encountered in pregnancy. The obstetric and renal outcomes of pregnancy are controversial, however. Women with IgAN are at higher risk of hypertension, preeclampsia and foetal loss; the prognosis is worse for those who have advanced chronic kidney disease and proteinuria. Here we report the case of a 32-year-old nulliparous woman with chronic hypertension who conceived during an active phase of her IgAN, which had been diagnosed 8 years earlier. Antihypertensive therapies and a low-protein diet were key to her reaching 34 weeks' gestation with acceptable kidney function. Rupture of membranes occurred at 34 weeks 3 days' gestation and a healthy boy was delivered the next day. This report aims to provide clinicians with useful information for the management of patients with IgAN during pregnancy.

Functional networks of aging markers in the glomeruli of IgA nephropathy: a new therapeutic opportunity

IgA nephropathy(IgAN) is the most common primary glomerular disease in China. Primary infections always occur before IgAN. However, the pathology of IgAN is still unclear. Previously we found that LL37, a protein secreted by senescent cells, was specific for the progression of IgAN, and also played a role in the neutrophil function. So we hypothesized that the infiltration of neutrophils, inflammation factors, and aging markers, which were modulated by functional networks, induced the immune response and renal injury. RNA-Sequencing (RNA-seq) can be used to study the whole transcriptome and detect splicing variants that are expressed in a specific cell type or tissue. We separate glomerulus from the renal biopsy tissues. After RNA extraction, the sequences were analyzed with Illumina HiSeq 2000/2500. 381 genes with differential expression between the IgAN patients and the healthy controls were identified. Only PLAU, JUN, and FOS were related to DNA damage, telomere dysfunction-induced aging markers, neutrophil function and IgA nephropathy. The networks showed the possibility of these genes being connected. We conclude that DNA damage and telomere dysfunction could play important roles in IgA nephropathy. In addition, neutrophils are also important factors in this disease. The networks of these markers showed the mechanism pathways that are involved in the duration of the occurrence and progression of IgA nephropathy and might be a new therapeutic opportunity for disease treatment.

The gut-kidney axis in IgA nephropathy: role of microbiota and diet on genetic predisposition

Recent data suggest that gut-associated lymphoid tissue (GALT) plays a major role in the development of immunoglobulin A (IgA) nephropathy (IgAN). A genome-wide association study showed that most loci associated with the risk of IgAN are also associated with immune-mediated inflammatory bowel diseases, maintenance of the intestinal barrier and regulation of response to gut pathogens. Studies involving experimental models have demonstrated a pivotal role of intestinal microbiota in the development of IgAN in mice producing high levels of IgA and in transgenic mice overexpressing BAFF, a B-cell factor crucial for IgA synthesis, indicating the role of genetic background, B-cell activity, GALT intestinal immunity and diet. The effect of diet was suggested by pilot studies carried out 30 years ago which showed that a gluten-rich diet induced IgAN in mice and that some patients benefited from a gluten-free diet. A recent experimental model in mice expressing human IgA1 and Fc alpha receptor CD89 reported clinical and histological improvement after a gluten-free diet. Clinical observations have elicited new interest in GALT hyper-reactivity in IgAN patients. In a pilot study, a reduction in proteinuria was attained using an enteric controlled-release formulation of the corticosteroid budesonide targeted to the Peyer's patches at the ileocecal junction. This formulation was tested in the placebo-controlled NEFIGAN phase 2b trial, with a reduction in proteinuria after 9 months of treatment together with stabilization of renal function in patients with persistent proteinuria. In conclusion, the gut-kidney axis modulated by microbiota and diet is a promising target for focused treatment of IgAN in genetically predisposed patients at risk of progression.

Genome-wide association study identifies variants in HORMAD2 associated with tonsillectomy

BACKGROUND

Inflammation of the tonsils is a normal response to infection, but some individuals experience recurrent, severe tonsillitis and massive hypertrophy of the tonsils in which case surgical removal of the tonsils may be considered.

OBJECTIVE

To identify common genetic variants associated with tonsillectomy.

METHODS

We used tonsillectomy information from Danish health registers and carried out a genome-wide association study comprising 1464 patients and 12 019 controls of Northwestern European ancestry, with replication in an independent sample set of 1575 patients and 1367 controls.

RESULTS

The variant rs2412971, intronic in HORMAD2 at chromosome 22q12.2, was robustly associated with tonsillectomy (OR=1.22; p=1.48×10^-9) and is highly correlated with SNPs previously found to be associated with IgA nephropathy, Crohn's disease (CD) and early onset inflammatory bowel disease (IBD). The risk allele for tonsillectomy corresponded to increased risk of IgA nephropathy and decreased risk of CD and IBD. We further performed lookup analyses of the top SNP for outcomes related to tonsillectomy in the combined discovery and replication sample and found that rs2412971 was associated with acute tonsillitis (OR=1.19; p=7.82×10^-4), chronic disease of the tonsils (OR=1.19; p=2.32×10^-6) and appendectomy (OR=1.18; p=1.13×10^-3).

CONCLUSIONS

We identified and replicated a genetic association at 22q12.2 with tonsillectomy. Further functional investigation is required to illuminate whether the molecular mechanisms underlying the genetic association involve general lymphoid hyper-reaction throughout the mucosa-associated lymphoid tissue system.

The efficacy of tonsillectomy on clinical remission and relapse in patients with IgA nephropathy: a randomized controlled trial

BACKGROUND

The efficacy of tonsillectomy in immunoglobulin A nephropathy (IgAN) remains controversial. The aim of the study was to conduct a randomized controlled trial to evaluate the effect of tonsillectomy in patients with IgAN.

METHODS

We randomly selected 98 patients with biopsy-proven IgA nephropathy and randomly allocated to receive tonsillectomy combined with drug therapy (Group A) or drug therapy alone (Group B). The participating patients were entered into a 4-year single-center study. Remission and relapse rate were calculated for hematuria and proteinuria using the Kaplan-Meier method.

RESULTS

No differences were found between the two groups in their baseline clinical and histological characteristics. Patients with tonsillectomy exhibited considerable improvement in the following aspects compared to those patients who did not undergo tonsillectomy: time to reach first remission (3.1 vs. 24.9 months, p < 0.001) for hematuria and (2.5 vs. 26.1 months, p < 0.001) for proteinuria, cumulative remission rate (91.8% vs. 46.9%, p < 0.001 by log-rank test) for hematuria and (95.9% vs. 51.0%, p < 0.001) for proteinuria, the duration of first remission (26.5 vs. 11.8 months, p = 0.0047) for hematuria and (23.5 vs. 10.5 months, p = 0.0012) for proteinuria, as well as lower relapse rate for hematuria and proteinuria in Group A.

CONCLUSION

Our clinical data demonstrated that tonsillectomy could be beneficial for IgAN patients, particularly by contributing to faster and longer remission, as well as reducing the frequency of possible future relapses.

Tonsillectomy in a European Cohort of 1,147 Patients with IgA Nephropathy

BACKGROUND

Tonsillectomy has been considered a treatment for IgA nephropathy (IgAN). It is aimed at removing a source of pathogens, reducing mucosa-associated lymphoid tissue and decreasing polymeric IgA synthesis. However, its beneficial effect is still controversial. In Asia, favorable outcomes have been claimed mostly in association with corticosteroids. In Europe, small, single-center uncontrolled studies have failed to show benefits.

METHODS

The European validation study of the Oxford classification of IgAN (VALIGA) collected data from 1,147 patients with IgAN over a follow-up of 4.7 years. We investigated the outcome of progression to end-stage renal disease (ESRD) and/or 50% loss of estimated glomerular filtration rate (eGFR) and the annual loss of eGFR in 61 patients who had had tonsillectomy.

RESULTS

Using the propensity score, which is a logistic regression model, we paired 41 patients with tonsillectomy and 41 without tonsillectomy with similar risk of progression (gender, age, race, mean blood pressure, proteinuria, eGFR at renal biopsy, previous treatments and Oxford MEST scores). No significant difference was found in the outcome. Moreover, we performed an additional propensity score pairing 17 patients who underwent tonsillectomy after the diagnosis of IgAN and 51 without tonsillectomy with similar risk of progression at renal biopsy and subsequent treatments. No significant difference was found in changes in proteinuria, or in the renal end point of 50% reduction in GFR and/or ESRD, or in the annual loss of eGFR.

CONCLUSION

In the large VALIGA cohort of European subjects with IgAN, no significant correlation was found between tonsillectomy and renal function decline.

The role of tonsillectomy in IgA nephropathy

The IgA nephropathy (IgAN) is a very common glomerulonephritis and can result in end-stage renal disease. From a clinical point of view, IgAN is characterised by repeated events of macrohaematuria associated with infections of the upper airways. In IgAN, the IgA released by the tonsillar lymphatic tissue into blood circulation are defective in glycosylation. These aberrant IgA can reach the glomeruli and deposit into mesangium causing an inflammation with cellular proliferation. The treatment is not yet well defined: steroids and immunosuppressive drugs are suggested in cases with a progressive disease. Tonsillectomy was proposed to reduce the infective events of upper airways and the lymphatic tissue producing undergalactosylated IgA. The experiences in literature coming from Asia report positive effects of tonsillectomy on IgAN. In patients with tonsillectomy, the renal signs improved (less haematuria and proteinuria) and the renal outcome was better (slower progression of renal damage). These were uncontrolled studies and tonsillectomy was associated with steroid and immunosuppressive treatment, so it is not possible to tell the real effect of tonsillectomy. In contrast, the European studies reported that the tonsillectomy was not associated with a better outcome of IgAN. A critical review of the subject reveals that most of the papers with positive results were uncontrolled retrospective experiences, while in a randomised controlled trial paper the advantages of tonsillectomy disappeared. In conclusion, this review, in agreement with the international guidelines, concludes that tonsillectomy does not play any role in the progression of IgAN.

Impact of tonsillectomy combined with steroid pulse therapy on immunoglobulin A nephropathy depending on histological classification: a multicenter study

BACKGROUND

In addition to corticosteroids and inhibition of the renin-angiotensin-aldosterone system, tonsillectomy with steroid pulse therapy (TSP) may have a beneficial impact on the clinical course of IgA nephropathy (IgAN). However, there is still much uncertainty regarding the indications for therapy, treatment protocol, and therapeutic options for IgAN.

METHODS

In this multicenter retrospective cohort study, we enrolled 284 patients with biopsy-proven IgAN who received TSP or corticosteroid therapy or conservative therapy. The effects of TSP on clinical remission (CR) were evaluated after a median follow-up period of 4.1 years in relation to histological classifications.

RESULTS

Among the 284 participants, 161 patients received TSP. During the observation time, 141 patients (49.6%) achieved CR, with a median time to remission of 397 days. In multivariate Cox regression analyses, TSP had an impact on achieving CR in only the group with histological grade 3 defined as glomerulosclerosis, crescent formation or adhesion to Bowman's capsule in 10-30% of all biopsied glomeruli, or mild cellular infiltration in the interstitium (hazard ratio (HR) 4.29, 95% confidence interval (95%CI) 1.88-11.19, P < 0.001). TSP independently contributed to a higher incidence of CR, particularly in the patient group showing evident mesangial hypercellularity (HR 2.54, 95%CI 1.38-5.08, P = 0.002).

CONCLUSIONS

TSP may have a beneficial effect on the clinical course in IgAN patients with mild to moderate glomerular and interstitial lesions, particularly with distinct mesangial cell proliferation.