Urinary β2-microglobulin and disease activity in patients with tubulointerstitial nephritis and uveitis syndrome

Tubulointerstitial Nephritis and Uveitis Syndrome in the United Arab Emirates

PURPOSE

To report the first series of tubulointerstitial nephritis (TINU) syndrome from the Middle East.

METHODS

We retrospectively included patients with elevated urine beta-2 microglobulin, and a diagnosis of TINU based on anterior uveitis with or without posterior involvement. Multimodal imaging, duration of follow-up, local and systemic treatment used were recorded.

RESULTS

24 eyes of 12 patients (8 male, mean age 20.3 years) met the criteria for TINU. The most common posterior segment clinical finding was optic nerve head edema (41.7%), while on fluorescein angiography 58.3% and 75% of eyes had peripheral vascular and optic disc leakage, respectively. The mean follow-up was 2.5 years and all patients required immunomodulatory treatment.

CONCLUSIONS

Middle Eastern patients with TINU seem to have a male predominance, a bimodal distribution in terms of age, and present with ocular involvement first. Multimodal imaging is paramount in detecting subclinical inflammation and tailoring immunomodulatory treatment.

Ocular manifestations and clinical outcomes in Tubulointerstitial Nephritis and Uveitis Syndrome (TINU)

PURPOSE

To describe the various ocular clinical features and visual outcomes in Tubulointerstitial Nephritis and Uveitis Syndrome (TINU).

METHODS

The medical records of 13 patients (26 eyes) diagnosed with TINU were reviewed.

RESULTS

Twenty-six (26) eyes of 13 patients with TINU were reviewed in this study. The median age at onset of uveitis was 14 (range, 9-45). Eight (61.5%) subjects were female. The median follow-up of patients was 30 months (range, 6-89 months). Posterior segment findings were seen in 18 eyes of 9 patients (69.2%). The most common posterior findings were optic nerve head inflammation (16 eyes, 88.8%) and retinal vasculitis (13 eyes, 72.2%). Other posterior findings included vitritis (8 eyes, 44.4%), macular edema (6 eyes, 33.3%), snowball (4 eyes, 22.2%), and chorioretinal lesions (2 eye, 11.1%). Eight patients had fluorescein angiography (FA) data available and most eyes had retinal capillary leakage (13 eyes, 81.2%) followed by optic disc staining/leakage (12 eyes, 75%). Twelve (12) patients (92.3%) were treated with immunomodulatory treatment (IMT) and/or biologics. Five patients (%38.4) required biologics to control intraocular inflammation.

CONCLUSION

Posterior segment involvement may be common in patients with TINU syndrome. FA provides significant information for detecting posterior segment involvement and disease activity in TINU. The majority of patients required systemic treatment in order to control intraocular inflammation and prevent relapses.

Diagnosis and Characteristics of Presentation of Tubulointerstitial Nephritis and Uveitis Syndrome During the COVID-2019 Pandemic

PURPOSE

To compare the diagnosis and clinical features of tubulointerstitial nephritis and uveitis syndrome (TINU) before and during the COVID-19 pandemic.

METHODS

Retrospective chart review.

RESULTS

Before the COVID-19 pandemic (March 2017 to March 2019), 1/561 (0.18%) new patient was diagnosed with TINU. During the pandemic (March 2020 to March 2022), 15/581 (2.58%) new patients were diagnosed with TINU. We found a significant increase in TINU cases during the pandemic (P=0.0005). Various posterior segment findings were observed in 2/3 (66.7%) patients before the pandemic and 13/15 (86.7%) patients during the pandemic, including disc edema, chorioretinal scars, disc leakage, and peripheral vascular leakage.

CONCLUSION

This is the first study reporting an increased number of TINU during the COVID-19 pandemic. With most of the American population now exposed to COVID-19, a large multi-center epidemiological study would be helpful to investigate any association of COVID-19 disease or vaccination with TINU in recent years.

Diagnostic and Management Strategies of Tubulointerstitial Nephritis and Uveitis Syndrome (TINU): Current Perspectives

Tubulointerstitial nephritis and uveitis (TINU) syndrome is a rare autoimmune disease with unclear pathogenesis but probably related to a combination of genetic predisposition and environmental triggers. Diagnosis is challenging due to the asynchronous onset of renal and ocular symptoms, and it is necessary to exclude other causes of nephritis and uveitis. It affects both sexes, with an overall predominance of females and a median age of onset of 15 years. TINU syndrome is characterized by bilateral, non-granulomatous anterior uveitis and tubulointerstitial nephritis, which can cause acute renal failure in severe cases. Several triggers have been identified including concurrent infections, medications, or endocrine diseases. The diagnosis of TINU is mainly based on clinical and analytical findings, and although urinary β2-microglobulin is a useful parameter no specific diagnostic test is available. Current perspectives intend to facilitate its diagnosis identifying susceptibility HLA genotypes, serologic markers and imaging tools to avoid renal biopsy. Treatment options for TINU syndrome include corticosteroids, immunosuppressive agents, and intravenous immunoglobulins, but relapses are frequent, and management can be challenging. The purpose of this review is to provide an updated summary of the diagnostic and treatment strategies of TINU syndrome, helping clinicians recognize and manage this rare autoimmune disorder.

Clinical Features and Outcomes of Tubulointerstitial Nephritis and Uveitis Syndrome in Spain and Portugal: The IBERTINU Project

PURPOSE

To assess the clinical features, management and prognosis of patients diagnosed with tubulointerstitial nephritis and uveitis (TINU) syndrome in Spain and Portugal.

METHODS

Retrospective multicenter study, which included all patients diagnosed with TINU syndrome managed in 15 uveitis referral centers from Spain and Portugal.

RESULTS

Forty-eight subjects with a mean age at diagnosis of 25.0 [14.8; 49.5] years were included. Both eyes were affected in 43 patients (89.6%). The visual outcome was favorable, but immunosuppressive systemic therapy (IST) was needed in 26 (54.16%) due to relapses. Renal function normalized in 35 patients (72.9%). HLA-DQB1*05 was the most common genetic typing (57.1%). The mean follow-up time was 22.5 [11.0; 48.0] months.

CONCLUSIONS

Both visual and renal outcomes were favorable, although IST was frequently used. TINU is under- diagnosed, so further prospective studies would provide more knowledge about its recognition and management.

EXPERT OPINION

TINU Syndrome is underdiagnosed because ocular and renal disease are asynchronous. Outcomes are favorable so it has to be highly suspected in cases of bilateral anterior uveitis. According to literature and our experience, systemic immunosuppressive therapy is often required because of ocular relapses.This study adds to the previous knowledge that HLA-DQB1*05 could be an important HLA type amongst the TINU Syndrome Iberian population. HLA typing should be assessed in these patients in order to describe its phenotype-genotype relationship better. A considerable number of patients in our series were diagnosed in their sixties, so TINU Syndrome should also be suspected in elderly patients.

Subclinical Choroidal Inflammation Revealed by Indocyanine Green Angiography in Tubulointerstitial Nephritis and Uveitis Syndrome

PURPOSE

To describe subclinical chorioretinal lesions revealed by indocyanine green angiography (ICGA) and their evolution under systemic treatment in tubulointerstitial nephritis and uveitis (TINU) patients.

METHODS

Retrospective case series of three patients with TINU syndrome. Choroidal and retinal involvement were assessed by fluorescein angiography (FA) and ICGA.

RESULTS

Three patients were analyzed. FA demonstrated hot disc, associated in two cases with retinal vascular leakage, and ICGA revealed subclinical chorioretinal dots in all three cases. Given the presence of posterior uveitis and deterioration of kidney function, asystemic treatment by oral methylprednisolone was started. Persistence of retinal and choroidal inflammations under systemic corticosteroids required association with immunosuppressive agent to control the disease activity.

CONCLUSION

Multimodal imaging and more precisely ICGA is useful to assess subclinical choroidal inflammation and monitor treatment response in TINU syndrome. Immunosuppression needs to be revised and adapted when uveitis and/or kidney function are unresponsive to systemic steroids.

ABBREVIATIONS

TINU: tubulointerstitial nephritis and uveitis; TIN: tubulointerstitial nephritis; ACE: angiotensin-converting enzyme; RF: rheumatoid factor; Uβ2M: urinary β-2microglobulin; AMPPE: acute multifocal placoid pigment epitheliopathy; FA: fluorescein angiography; ICGA: indocyanine green angiography; CT: computed tomography.

Renal Prognosis in Children With Tubulointerstitial Nephritis and Uveitis Syndrome

Introduction

Tubulointerstitial nephritis (TIN) and uveitis (TINU) syndrome is a rare disease. The renal prognosis is generally thought to be better in children with TINU syndrome than in adults. However, data are scarce. We aimed to investigate the long-term renal prognosis in a French cohort of children with TINU syndrome.

Methods

We performed a national retrospective study including 23 French pediatric nephrology centers enrolling patients with TINU syndrome diagnosed between January 2000 and December 2018.

Results

A total of 46 patients were included (52% female, median age 13.8 years). At diagnosis of TIN, the median estimated glomerular filtration rate (eGFR) was 30.6 ml/min per 1.73 m² (4.9–62.8). The median time between diagnosis of uveitis and TIN was 0.4 months (−4.1; +17.1). All patients had anterior uveitis, but 12 (29%) were asymptomatic. Nearly all patients (44 of 46) received steroid treatment, and 12 patients (26%) received a second-line therapy. At last follow-up (median 2.8 years), the median eGFR was 87.5 ml/min per 1.73 m² (60.3–152.7) and <90 ml/min per 1.73 m² in 20 patients.

Conclusion

In our study, nearly half of the patients had renal sequelae at last follow-up. Given the possible progression to chronic kidney disease, long-term monitoring of children with TINU syndrome is mandatory. Approximately a quarter of the children had asymptomatic uveitis suggesting all children presenting with TIN should undergo systematic ophthalmologic screening even in the absence of ocular signs.

Immunomodulation and TNF-α inhibition for tubulointerstitial nephritis and uveitis syndrome: a case series

BACKGROUND

Tubulointerstitial nephritis and uveitis (TINU) syndrome combines acute inflammatory nephritis (AIN) and uveitis. Uveitis in TINU often requires systemic immunomodulatory therapy (IMT), including steroid-sparing agents. Although common for other noninfectious uveitides, the use of tumor necrosis factor-α inhibitors (TNFi) in TINU has seldom been described.

METHODS

This retrospective case series included patients <18 years of age with TINU followed at our tertiary care pediatric hospital. Disease characteristics at time of diagnosis and subsequent ophthalmological and rheumatologic evaluations were extracted from the record. AIN was defined as the presence of abnormal renal function and urinalysis or renal biopsy findings consistent with TINU. Uveitis grading, site of inflammation, inactivity, and flare were defined according to Standardization of Uveitis Nomenclature.

RESULTS

A total of 10 patients (median age, 12.3 years; 6 females) were included. AIN preceded uveitis onset in 6 patients. Uveitis was bilateral at onset in 7 patients. Uveitis inactivity was achieved with systemic corticosteroids (CS) in 2 and with mycophenolate mofetil (MMF) in 3 patients. Because of persistent ocular inflammation, despite CS and IMT, 4 patients were treated with TNFi. All rapidly achieved uveitis quiescence and maintained prolonged inactivity under combined treatment with TNFi and MMF.

CONCLUSIONS

Most patients in our study cohort required a steroid-sparing immunomodulator to achieve and maintain uveitis control. In the 50% of the cohort in whom conventional IMTs were inadequate, TNFi were able to maintain quiescence. TNF inhibition might be a useful treatment in IMT-refractory uveitis in TINU patients.

Tubulointerstitial nephritis and uveitis syndrome in an adolescent female: a case report

BACKGROUND

Tubulointerstitial nephritis with uveitis syndrome is a rare disease affecting mainly children and young women. Tubulointerstitial nephritis with uveitis is a diagnosis of exclusion, requiring a high degree of clinical suspicion. Studies report recent infections or certain drugs as precipitating factors of a lymphocytic oculorenal immune response. The prognosis is usually favorable with topical and systemic corticosteroid therapy.

CASE PRESENTATION

We report a literature review and the case of a 14-year-old white girl, who presented to the ophthalmology department with features of one-sided uveitis. Upon transfer of patient to nephrological care, diagnostic work-up revealed renal involvement. Renal biopsy showed a mixed-cell and granulomatous tubulointerstitial nephritis with some noncaseating granulomas, leading to a diagnosis of tubulointerstitial nephritis with uveitis syndrome. With topical ocular and systemic corticosteroid therapy, the patients' condition improved over several weeks.

CONCLUSIONS

Our case highlights the importance of early recognition and treatment of this syndrome, where cross-specialty care typically leads to a favorable outcome.

Behçet's Disease with Extremely High Levels of Urinary β2-Microglobulin after Non-Steroidal Anti-Inflammatory Drug Treatment

Behçet's disease is an inflammatory disease which manifests itself as various symptoms, such as uveitis, oral and genital aphthae, erythema nodosa, gastro-intestinal ulcerations and encephalopathy. Among the manifestations, renal dysfunction is reported in some percentage of the patients with this disorder. We experienced a middle-aged male with Behçet's disease who showed an extremely high level of urinary β2-microglulin, which is one of the markers of renal dysfunction, despite normal serum creatinine levels. The patient was on non-steroidal anti-inflammatory drug (NSAID) therapy for 7 weeks, and this could have affected his renal dysfunction. The present report suggests that renal injury should not be underestimated in patients with Behçet's disease, especially in patients using NSAIDs.

Classification Criteria for Tubulointerstitial Nephritis With Uveitis Syndrome

PURPOSE

To determine classification criteria for tubulointerstitial nephritis with uveitis (TINU).

DESIGN

Machine learning of cases with TINU and 8 other anterior uveitides.

METHODS

Cases of anterior uveitides were collected in an informatics-designed preliminary database, and a final database was constructed of cases achieving supermajority agreement on the diagnosis, using formal consensus techniques. Cases were split into a training set and a validation set. Machine learning using multinomial logistic regression was used on the training set to determine a parsimonious set of criteria that minimized the misclassification rate among the anterior uveitides. The resulting criteria were evaluated on the validation set.

RESULTS

One thousand eighty-three cases of anterior uveitides, including 94 cases of TINU, were evaluated by machine learning. The overall accuracy for anterior uveitides was 97.5% in the training set and 96.7% in the validation set (95% confidence interval 92.4, 98.6). Key criteria for TINU included anterior chamber inflammation and evidence of tubulointerstitial nephritis with either (1) a positive renal biopsy or (2) evidence of nephritis (elevated serum creatinine and/or abnormal urine analysis) and an elevated urine β-2 microglobulin. The misclassification rates for TINU were 1.2% in the training set and 0% in the validation set.

CONCLUSIONS

The criteria for TINU had a low misclassification rate and seemed to perform well enough for use in clinical and translational research.

Tubulointerstitial nephritis and uveitis (TINU) syndrome: a review

Inflammation of renal interstitium and uveal tissue establishes the two components of tubulointerstitial nephritis and uveitis (TINU) syndrome. Although believed to occur more frequently in young females, a broad spectrum of patients can be affected. Both renal and eye disease can be asymptomatic and may not manifest simultaneously, having independent progressions. Renal disease manifests as acute kidney injury and may cause permanent renal impairment. Eye inflammation can manifest in different anatomical forms, most commonly as bilateral anterior uveitis and may progress to a chronic course. TINU syndrome accounts for approximately 1%–2% of uveitis in tertiary referral centres. A literature review covering the clinical features, pathogenesis, diagnosis and treatment is presented.