Outcome of tonsillectomy for recurrent IgA nephropathy after kidney transplantation

Guidance of clinical management for patients with tonsillar focal disease

Tonsillar focal diseases (TFDs) are defined as "diseases caused by organic and/or functional damage in organs distant from tonsil, and the disease outcome is improved by tonsillectomy." Although several reports and reviews have shown the efficacy of tonsillectomy for TFDs, no guidelines for the clinical management of the diagnosis and treatment of TFDs have been reported. Therefore, the Society of Stomato-pharyngology established a committee to guide the clinical management of patients with TFDs, and the original guide was published in May 2023. This article summarizes the English version of the manuscript. We hope that the concept of TFDs will spread worldwide, and that one as many patients with TFDs will benefit from tonsillectomy.

Current Status and Perspectives on Recurrent IgA Nephropathy after Kidney Transplantation

IgA nephropathy (IgAN) is the most common form of glomerulonephritis worldwide. IgAN progresses to end-stage kidney disease in 20-40% of patients within 20 years of diagnosis. Kidney transplantation is the most effective option for patients with end-stage kidney disease caused by IgAN, but recurrence can occur in the transplanted kidney. The IgAN recurrence rate varies from 1% to 10% per year and varies according to the follow-up period, diagnostic modality, and biopsy criteria. Of note, studies based on protocol biopsies have reported a higher incidence of recurrence, which also occurred earlier after transplantation. In addition, recent data show that recurrence of IgAN is a more significant cause of allograft failure than previously believed. Little is known about the pathophysiology of IgAN recurrence, but several potential biomarkers have been investigated. Among them, galactose-deficient IgA1 (Gd-IgA1), IgG anti-Gd-IgA1 antibodies, and soluble CD89 could play a pivotal role in disease activity. This review aims to describe the current status of recurrent IgAN, including the incidence, clinical characteristics, risk factors, and future perspectives, with a focus on the available therapeutic approaches.

Title IgA Nephropathy and Oral Bacterial Species Related to Dental Caries and Periodontitis

A relationship between IgA nephropathy (IgAN) and bacterial infection has been suspected. As IgAN is a chronic disease, bacteria that could cause chronic infection in oral areas might be pathogenetic bacteria candidates. Oral bacterial species related to dental caries and periodontitis should be candidates because these bacteria are well known to be pathogenic in chronic dental disease. Recently, several reports have indicated that collagen-binding protein (cnm)-(+) Streptococcs mutans is relate to the incidence of IgAN and the progression of IgAN. Among periodontal bacteria, Treponema denticola, Porphyromonas gingivalis and Campylobacte rectus were found to be related to the incidence of IgAN. These bacteria can cause IgAN-like histological findings in animal models. While the connection between oral bacterial infection, such as infection with S. mutans and periodontal bacteria, and the incidence of IgAN remains unclear, these bacterial infections might cause aberrantly glycosylated IgA1 in nasopharynx-associated lymphoid tissue, which has been reported to cause IgA deposition in mesangial areas in glomeruli, probably through the alteration of microRNAs related to the expression of glycosylation enzymes. The roles of other factors related to the incidence and progression of IgA, such as genes and cigarette smoking, can also be explained from the perspective of the relationship between these factors and oral bacteria. This review summarizes the relationship between IgAN and oral bacteria, such as cnm-(+) S. mutans and periodontal bacteria.

Association Between Galactose-Deficient IgA1 Derived From the Tonsils and Recurrence of IgA Nephropathy in Patients Who Underwent Kidney Transplantation

Background: Recurrence of IgA nephropathy (IgAN) in the transplanted kidney is associated with graft survival, but no specific treatment is available. Tonsillectomy (TE) reportedly arrests the progression of IgAN in the native kidney. Thus, we conducted a single-center retrospective cohort study to evaluate the effect of TE prior to IgAN recurrence.

Methods: Of the 36 patients with biopsy-proven IgAN who underwent kidney transplantation, 27 were included in this study. Nine patients underwent TE at 1 year after kidney transplantation (group 1), and the remaining 18 did not undergo TE (group 2).

Results: The rate of histological IgAN recurrence was significantly lower in group 1 than in group 2 (11.1 vs. 55.6%, log-rank p = 0.046). In addition, half of the recurrent patients in group 2 exhibited active lesions, compared to none in group 1. Serum Gd-IgA1 levels decreased after TE in group 1, whereas they remained stable or increased slightly in group 2. In the recurrent cases, IgA and Gd-IgA1 were found in the germinal center in addition to the mantle zone of tonsils. Finally, mesangial IgA and Gd-IgA1 immunoreactivity was reduced after TE in some cases.

Conclusion: Our data suggest that TE at 1 year after kidney transplantation might be associated with the reduced rate of histological IgAN recurrence. TE arrested or reduced serum Gd-IgA1 and mesangial Gd-IgA1 immunoreactivity. Therefore, we generated a hypothesis that serum Gd-IgA1 derived from the tonsils may play a pivotal role in the pathogenesis of IgAN. Based on these findings, we need to conduct verification in a prospective randomized controlled trial.

Association Between Tonsillectomy and Outcomes in Patients With Immunoglobulin A Nephropathy

IMPORTANCE

Immunoglobulin A nephropathy is a major cause of end-stage renal disease worldwide; previous methods of medical management, including use of renin-angiotensin system inhibitors and corticosteroids, remain unproven in clinical trials.

OBJECTIVE

To investigate the possible association between tonsillectomy and outcomes in patients with IgA nephropathy.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study included 1065 patients with IgA nephropathy enrolled between 2002 and 2004 and divided into 2 groups, those who underwent tonsillectomy and those who did not. Initial treatments (renin-angiotensin system inhibitors or corticosteroids) within 1 year after renal biopsy were also evaluated. A 1:1 propensity score matching was performed to account for between-group differences and 153 matched pairs were obtained. Follow-up concluded January 31, 2014. Analysis was conducted between September 11, 2017, and July 31, 2018.

EXPOSURE

Tonsillectomy.

MAIN OUTCOMES AND MEASURES

The primary outcome was the first occurrence of a 1.5-fold increase in serum creatinine level from baseline or dialysis initiation. Secondary outcomes included additional therapy with renin-angiotensin system inhibitors or corticosteroids initiated 1 year after renal biopsy and adverse events.

RESULTS

In 1065 patients (49.8% women; median [interquartile range] age, 35 [25-52] years), the mean (SD) estimated glomerular filtration rate was 76.6 (28.9) mL/min/1.73 m2 and the median (interquartile range) proteinuria was 0.68 (0.29-1.30) g per day. In all, 252 patients (23.7%) underwent tonsillectomy within 1 year after renal biopsy and 813 patients (76.3%) did not undergo tonsillectomy. The primary outcome was reached by 129 patients (12.1%) during a median (interquartile range) follow-up of 5.8 (1.9-8.5) years. In matching analysis, tonsillectomy was associated with primary outcome reduction (hazard ratio, 0.34; 95% CI, 0.13-0.77; P = .009). In subgroup analyses, benefit associated with tonsillectomy was not modified by baseline characteristic differences. Those undergoing tonsillectomy required fewer additional therapies 1 year following renal biopsy (adjusted hazard ratio, 0.37; 95% CI, 0.20-0.63; P < .001) without increased risks for adverse events, except transient tonsillectomy-related complications.

CONCLUSIONS AND RELEVANCE

This study found that tonsillectomy was associated with a lower risk of renal outcomes in patients with IgA nephropathy. The potential role of tonsillectomy should be considered for preventing end-stage renal disease in patients with IgA nephropathy.

Effect of steroid pulse therapy on post-transplant immunoglobulin A nephropathy

AIM

Recent studies have suggested that patients with post-transplant immunoglobulin A nephropathy have poor graft survival. There is limited research on the therapeutic effectiveness for post-transplant immunoglobulin A nephropathy, especially steroid pulse therapy. The present study evaluated the efficacy of steroid pulse therapy on post-transplant immunoglobulin A nephropathy.

METHODS

We retrospectively analyzed patients diagnosed with de novo or recurrent immunoglobulin A nephropathy at Kyushu University Hospital between January 2013 and August 2015. Patients with moderate proteinuria (≥0.5 g/g creatinine) and/or cellular or fibrocellular crescents on a graft biopsy were treated with steroid pulse therapy. Steroid pulse therapy was 500 mg/day for 3 days in weeks 1 and 2, followed by 20 mg of oral prednisolone that was tapered after 6 months. Patients were followed for 2 years, and the estimated glomerular filtration rate, urinary findings, and adverse events were recorded.

RESULTS

Seven patients received steroid pulse therapy. The mean duration after kidney transplantation was 6.6 ± 4.7 years. After 2 years of treatment, 85.7% of patients reached complete remission of proteinuria, urinary protein excretion declined (0.82 ± 0.51 to 0.26 ± 0.22 g/g creatinine, P = 0.007), and the estimated glomerular filtration rate was maintained (48.7 ± 12.8 to 47.4 ± 14.0 mL/min per 1.73 m² , P = 0.98). Adverse events were observed in one patient who developed herpes zoster infection.

CONCLUSION

Steroid pulse therapy for post-transplant immunoglobulin A nephropathy effectively reduces proteinuria over 2 years. However, comparison of steroid pulse therapy and other regimens with a high-quality design is required.

[Current insights about recurrence of glomerular diseases after renal transplantation]

Recurrence of glomerular disease after renal transplantation is a frequent cause of graft loss. Incidence, risk factors and outcome of recurrence are widely due to the underlying glomerular disease. Graft biopsy analysis is required to confirm the definitive diagnosis of recurrence and to start an appropriate therapy that, in some cases, remains challenging to prevent graft failure. Increased use of protocol biopsy and recent advances in our understanding of the pathogenesis of some glomerular diseases with the identification of some relevant biomarkers provide a unique opportunity to initiate kidney-protective therapy at early stages of recurrence on the graft. This review summarizes our current knowledge on the management of many recurrent primary and secondary glomerulonephritis after kidney transplantation.

Treatment protocol with pulse and oral steroids for IgA Nephropathy after kidney transplantation

BACKGROUND

No specific treatment for IgA nephropathy (IgAN) after kidney transplantation is currently available.

METHODS

We conducted a retrospective single-center study on 29 patients with biopsy-proven de novo and recurrent IgAN after kidney transplantation, divided into two groups. Group 1 (n = 16) received intravenous methylprednisolone 500 mg per day for three consecutive days at the beginning of months 1, 3 and 5, plus oral prednisone 0.5 mg/kg every other day for 6 months. The control group (n = 13, Group 2) received supportive therapies.

RESULTS

The two groups were comparable for serum creatinine (sCr) and proteinuria at the time of renal biopsy, but differed significantly at the end of follow-up. sCr was 1.8 ± 0.4 mg/dl in Group 1 vs. 2.7 ± 0.9 in Group 2 (p = 0.002), and proteinuria was 0.9 g/day in Group 1 vs. 1.9 in Group 2 (p = 0.04). The composite outcome of death-censored graft loss or doubling of sCr displayed 2 events in Group 1 (12.5 % of the entire group) and 5 events in Group 2 (38.5 % of the entire group), p = 0.19, odds ratio (OR) 4.4 [95 % confidence interval (CI) 0.7-27.8].

CONCLUSIONS

In the absence of therapeutic guidelines for de novo or recurrent IgAN after kidney transplantation, our study reports that therapy with pulse and oral steroids for 6 months is associated with an improved renal function. Nevertheless, further randomized controlled studies in larger patient cohorts are necessary to establish the gold standard treatment.

The value of long-term protocol biopsies after kidney transplantation

Protocol biopsies for the detection and treatment of subclinical rejection in the early period after kidney transplantation are useful for preventing allograft dysfunction. However, little has been reported on the relationship between subclinical rejection and long-term protocol biopsies. In this review, we examine the potential benefits associated with long-term allograft biopsies focusing on the issue of immunological and non-immunological factors. Early detection and treatment of subclinical rejection improves outcome. However, the benefit of long-term allograft biopsies is largely unproved, and the strategy is yet to be widely implemented. The procurement of long-term protocol biopsies for the sole purpose of detecting subclinical rejection may be unwarranted. On the other hand, the early detection of IgA nephropathy using long-term protocol biopsy may improve graft survival. In addition, assessment of long-term protocol biopsies is useful not only for detection of calcineurin inhibitor nephrotoxicity, but also for follow-up after withdrawal of calcineurin inhibitor regimens. Also, identifying normal histology on a protocol biopsy may inform us about the safety of reducing overall immunosuppression. Thus, the potential benefit of long-term protocol biopsy may be of clinical significance for the detection of graft dysfunction as a result of non-immune factors, such as recurrence of glomerulonephritis and calcineurin inhibitor nephrotoxicity, rather than subclinical rejection.