The Syndrome of Tubulointerstitial Nephritis With Uveitis (TINU)

Vaccines and the Eye: Current Understanding of the Molecular and Immunological Effects of Vaccination on the Eye

Vaccination is a public health cornerstone that protects against numerous infectious diseases. Despite its benefits, immunization implications on ocular health warrant thorough investigation, particularly in the context of vaccine-induced ocular inflammation. This review aimed to elucidate the complex interplay between vaccination and the eye, focusing on the molecular and immunological pathways implicated in vaccine-associated ocular adverse effects. Through an in-depth analysis of recent advancements and the existing literature, we explored various mechanisms of vaccine-induced ocular inflammation, such as direct infection by live attenuated vaccines, immune complex formation, adjuvant-induced autoimmunity, molecular mimicry, hypersensitivity reactions, PEG-induced allergic reactions, Type 1 IFN activation, free extracellular RNA, and specific components. We further examined the specific ocular conditions associated with vaccination, such as uveitis, optic neuritis, and retinitis, and discussed the potential impact of novel vaccines, including those against SARS-CoV-2. This review sheds light on the intricate relationships between vaccination, the immune system, and ocular tissues, offering insights into informed discussions and future research directions aimed at optimizing vaccine safety and ophthalmological care. Our analysis underscores the importance of vigilance and further research to understand and mitigate the ocular side effects of vaccines, thereby ensuring the continued success of vaccination programs, while preserving ocular health.

TINU: A Multisystemic Inflammatory Disorder-Case Report and Literature Review

Background. The syndrome of tubulointerstitial nephritis and uveitis (TINU) is a rare oculorenal condition, mainly seen in children and women. The underlying cause of this disease is unknown. Case Presentation. We report a 24-year-old male without any past medical history, diagnosed with bilateral uveitis and azotemia. Biopsy revealed tubulointerstitial nephritis, consistent with TINU syndrome. Fluorescein angiogram revealed peripheral retinal vasculitis. Discussion. TINU is a rare disorder that needs to be distinguished from sarcoidosis, Sjogren's disease, and tuberculosis. Treatment is indicated in patients with progressive renal insufficiency, consisting of steroid therapy. Most patients recover kidney function. Its early recognition is important to offer the best chance of organ preservation.

Clinical manifestations and outcomes in tubulointerstitial nephritis and uveitis syndrome: a case report and a systematic review in China

PURPOSE

Tubulointerstitial nephritis and uveitis (TINU) syndrome is an uncommon disease. We present a confirmed case of TINU syndrome, and a systematic review of epidemiological characteristics, clinical manifestations, management, and outcomes in Chinese patients.

METHODS

A systematic search was carried out using defined terms and updated up to September 2022, in PubMed, Web of Science, Wanfang, CNKI, and VIP, to identify reported cases of TINU in China, according to PRISMA guidelines.

RESULTS

An 18-year-old boy presented with elevated serum creatinine and 24-h urine protein level of > 2 g. Inspection result revealed acute tubulointerstitial nephritis, and bilateral uveitis. The patient was diagnosed with TINU syndrome and received treatment with methylprednisolone sodium succinate, which resulted in a significant decrease in creatinine and urinary protein levels. Systematic review identified 35 publications that met the inclusion criteria. A total of 71 cases were included in this article, of which 70 were from publications and 1 was from our hospital. The median age at onset was 42 years and was significantly lower in males than females (P < 0.05). The symptoms of uveitis often occurred after kidney injury (54%) and most uveitis was anterior (55%) and bilateral (75%). Among the 51 patients who were followed up for more than 6 months, 24 had recurrent ocular symptoms or progression to chronic uveitis. Twenty patients experienced chronic or progressive kidney disease.

CONCLUSION

TINU syndrome is prone to misdiagnosis because kidney damage may not occur simultaneously with uveitis. The incidence of kidney sequelae in children is lower than that in adults, and glucocorticoids are the preferred treatment.

INPLASY REGISTRATION NUMBER

INPLASY202350050.

Tubulointerstitial Nephritis and Uveitis: A Case Report

Tubulointerstitial nephritis and uveitis (TINU) is a rare disease of unknown pathogenesis that is characterized by tubulointerstitial nephritis and uveitis. Currently, there are over 250 reported cases of TINU syndrome. TINU syndrome typically presents with mild uveitis and nephritis that is self-limited; however, in this case, the symptoms were severe making it different from previous case reports. We present a case of a 29-year-old female with a history of cytomegalovirus (CMV) with a recent diagnosis of bilateral uveitis who was admitted for worsening systemic symptoms. Laboratory testing revealed acute renal insufficiency along with hematuria and proteinuria. A kidney biopsy revealed tubulointerstitial nephritis, and the patient was initiated on corticosteroids for the diagnosis of TINU. The patient's renal function recovered to baseline after a prolonged three-month course of systemic steroids but had a recurrence of her uveitis with steroid taper requiring initiation of steroid-sparing therapies. TINU syndrome should be considered in patients presenting with uveitis and renal dysfunction. Prompt diagnosis is necessary to preserve renal function with corticosteroids. The prognosis for patients with TINU is variable, with a frequently recurring and relapsing course. More research is needed to determine the optimal 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 Management of Non-Infectious Uveitis in Pediatric Patients

Uveitis in children accounts for 5-10% of all cases. The causes vary considerably. Classically, uveitis is distinguished according to its infectious or inflammatory origin and whether it is part of a systemic disease or represents an isolated ocular disease. It is important to highlight the specificity of certain etiologies among children such as juvenile idiopathic arthritis. The development of visual function can potentially be hindered by amblyopia (children aged < 7 years), in addition to the usual complications (synechiae, macular edema) seen in adult patients. Moreover, the presentation of uveitis in children is often "silent" with few warning signs and few functional complaints from young children, which frequently leads to a substantial diagnostic delay. The diagnostic approach is guided by the presentation of the uveitis, which can be characterized by its location, and corresponds to the initial and main site of intraocular inflammation; its presentation, whether acute or chronic, granulomatous or not; and the response to treatment. Pediatricians have an important role to play and must be aware of the various presentations and etiologies of uveitis in children. Juvenile idiopathic arthritis is the most common etiology of pediatric non-infectious uveitis, but other causes must be recognized. Promptly initiated treatment before complications arise requires early diagnosis, recognition, and treatment. Any dependence on prolonged local corticosteroid therapy justifies discussing the introduction of a corticosteroid-sparing treatment considering the risk to develop corticoid-induced glaucoma and cataracts. Systemic corticosteroid therapy can be required for urgent control of inflammation in the case of severe uveitis. Long-lasting immunosuppressive treatment and biotherapies are most often prescribed at the same time to reinforce treatment efficacy and to prevent relapse and corticosteroid dependency. We review the different causes of uveitis, excluding infection, and the diagnostic and therapeutic management aimed at limiting the risk of irreversible sequelae.

Epidemiology of Pediatric Uveitis

Uveitis is uncommon in children and its diagnosis and treatment are challenging. Little is known of the epidemiology of pediatric uveitis. Indeed, population-based studies in the literature are rare. However, there are many tertiary referral center reports that describe the patterns of uveitis in childhood, although few are from developed countries, and their comparison presents some issues. Anterior uveitis is the most frequent entity worldwide, especially in Western countries, where juvenile idiopathic arthritis is diffuse. Most cases of intermediate uveitis do not show any association with infectious or noninfectious systemic diseases. In low- and middle-income countries, posterior uveitis and panuveitis are prevalent due to the higher rates of infectious etiologies and systemic diseases such as Behçet disease and Vogt-Koyanagi-Harada disease. In recent decades, idiopathic uveitis rate has decreased thanks to diagnostic improvements.

Tubulointerstitial Nephritis and Uveitis Syndrome in Pediatric Patients

Tubulointerstitial nephritis and uveitis (TINU) syndrome is a disorder that was originally described in 1975. The syndrome, although diagnosed in all age ranges, is more frequently reported in pediatric patients. Diagnosis can be difficult, and its clinical spectrum is still being defined. In this article, we review the epidemiology, diagnosis, pathogenesis, clinical findings, prognosis, and treatment of both the ocular and renal disease. We comment on the current difficulties in diagnosis and study of the disease, its expanding clinical spectrum, and treatment strategies in pediatric patients.

Tubulointerstitial Nephritis and Uveitis Syndrome: A Report of 6 Cases with Renal Biopsy and Electron Microscopy Evaluation

Tubulointerstitial nephritis with uveitis syndrome is a rare, immune-mediated entity, characterized by oculo-renal inflammation. Diagnosis requires the exclusion of all other causes of tubulointerstitial nephritis (TIN). We present 6 patients with clinical, laboratory, and renal biopsy findings denotative of tubulointerstitial nephritis with uveitis syndrome. All our patients experienced ocular and renal manifestations, defined by bilateral uveitis and photosensitivity, along with a decline of renal function. In some patients, increased serum creatinine was accompanied by non-nephrotic range proteinuria, glucosuria or "full-blown" Fanconi syndrome. The rest of the laboratory evaluation was normal apart from the presence of elevated erythrocyte sedimentation rate and increased urine β2-microglobulin, as well as normochromic, normocytic anemia in some cases. All patients underwent renal biopsy. Histochemical (PAS, Masson, silver, Congo-red) and immunohistochemical stains for immune cell populations (CD3, CD20, CD4, CD8, PGM1, CD138) and for the assessment of β2-microglobulin were conducted. Electron microscopy examination of the biopsies was also performed. Follow-up, ranging from 18 months to 10 years, was available for 4 patients. Histological evaluation revealed interstitial inflammatory infiltration consisting mainly of lymphocytes, with a T-cell predominance, along with several macrophages. Inflammation severity varied among different patients, with some showing scarce foci of immune cell clusters, while others demonstrated a dense, diffuse interstitial infiltration. Interestingly, in 2 cases, a granulomatous pattern, characterized by non-necrotic, ill-defined granulomas was detected. Tubulitis was also encountered in some patients. A divergence was noted regarding the chronicity index, with different levels of tubular atrophy, interstitial fibrosis, and global glomerulosclerosis among different cases. β2-Microglobulin immunohistochemical evaluation revealed a substantial diminishment of cytoplasmic staining in tubular epithelial cells compared to control kidneys. The most notable finding derived from electron microscopy examination was the presence, in 1 patient, of scattered granular electron-dense deposits along some tubular basement membranes. First-line treatment included steroids, supplemented in some cases by additional immunosuppressive agents. Three patients experienced a partial or complete response, while progressive renal damage was observed in a case with severe chronic lesions and persistence of inflammation-triggering factor. Our cases seem to represent progressive stages within the continuum of disease evolution. Patients with more prominent inflammation might represent a more initial state, while those with a more severe chronicity index, probably depict more advanced stages. While the predominance of T-cells predicates a cell-mediated autoimmune mechanism, as the driving force of the disease occurrence, the presence of immune complexes in more advanced stages might indicate the involvement of humoral immunity as a late event during the disease course.

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.

TUBULOINTERSTITIAL NEPHRITIS WITH UVEITIS (TINU SYNDROME). A CASE REPORT

In this case report, we describe the case of a 50-year-old woman referred by her general practitioner to a pulmonologist in order to investigate persistent fever and elevation of C-reactive protein despite antibiotic treatment following a respiratory infection. The patient was examined extensively, during which rheumatology, gastroenterology, nephrology, ophthalmology, laboratory and imaging tests were performed. Due to a rapid progression of renal insufficiency with active urinary sediment, the patient was referred for a renal biopsy, which confirmed tubulointerstitial nephritis, followed by a diagnosis of bilateral anterior uveitis two months later - genetic testing was also conducted, which confirmed the diagnosis of tubulointerstitial nephritis with uveitis syndrome. Steroid treatment brought about a gradual reduction of proteinuria and a stabilisation of renal function.

Tubulointerstitial nephritis and uveitis syndrome: a systematic review

BACKGROUND

Tubulointerstitial nephritis and uveitis (TINU) syndrome is defined as the occurrence of tubulointerstitial nephritis (TIN) and uveitis in the absence of other systemic diseases. The most comprehensive review on this condition was published in 2001.

METHODS

We conducted a systematic review of the literature for cases of TINU syndrome. MEDLINE and Embase databases were screened. Full-length articles or letters reporting cases with both TIN and uveitis were selected. We investigated differences between males and females and paediatric and adult cases. Multivariate analysis was performed to identify potential risk factors for chronic kidney disease (CKD) development.

RESULTS

A total of 233 articles reporting 592 TINU cases were retained for the analysis. The median age of the included subjects was 17 years (interquartile range 13-46) with a female predominance (65%). Uveitis most frequently (52%) followed renal disease and was mostly anterior (65%) and bilateral (88%). Children tended to have more ocular relapses, while they were slightly less likely than adults to suffer from acute kidney injury and to develop CKD. Adult age as well as posterior or panuveitis were associated with an increased risk of developing CKD.

CONCLUSIONS

TINU affects both children and adults, with some differences between these two categories. Adult age and the presence of a posterior uveitis or panuveitis appear to be associated with the development of CKD.

Pediatric uveitis: Role of the pediatrician

The challenges of childhood uveitis lie in the varied spectrum of its clinical presentation, the often asymptomatic nature of disease, and the evolving nature of the phenotype alongside normal physiological development. These issues can lead to delayed diagnosis which can cause significant morbidity and severe visual impairment. The most common ocular complications include cataracts, band keratopathy, glaucoma, and macular oedema, and the various associated systemic disorders can also result in extra-ophthalmic morbidity. Pediatricians have an important role to play. Their awareness of the various presentations and etiologies of uveitis in children afford the opportunity of prompt diagnosis before complications arise. Juvenile Idiopathic Arthritis (JIA) is one of the most common associated disorders seen in childhood uveitis, but there is a need to recognize other causes. In this review, different causes of uveitis are explored, including infections, autoimmune and autoinflammatory disease. As treatment is often informed by etiology, pediatricians can ensure early ophthalmological referral for children with inflammatory disease at risk of uveitis and can support management decisions for children with uveitis and possible underling multi-system inflammatory disease, thus reducing the risk of the development of irreversible sequelae.

Bilateral Recurrent Uveitis in a Young Patient with Family History of Spondyloarthritis: Spondyloarthritis or Not?

We present the case of a young man with a strong family history of SpA, who was referred to the Rheumatology Clinic due to bilateral uveitis refractory to treatment with corticosteroids. The patient’s renal function gradually deteriorated and a subsequent biopsy was positive for interstitial nephritis. After excluding all other systemic diseases, the diagnosis of TINU syndrome was confirmed. Although rare, TINU syndrome should be considered in the differential diagnosis of non-infective uveitis especially in the presence of urinalysis abnormalities.

Renal replacement therapy-requiring acute kidney injury due to tubulointerstitial nephritis and uveitis syndrome: case report

BACKGROUND

Acute kidney injury is a major challenge for today's healthcare systems around the globe. Renal replacement therapy has been shown to be beneficial in acute kidney injury, but treatment highly depends on the cause of the acute kidney injury. One less common cause is tubulointerstitial nephritis, which comes in different entities. A very rare type of tubulointerstitial nephritis is tubulointerstitial nephritis and uveitis syndrome, in which the patient presents with additional uveitis.

CASE PRESENTATION

A 19-year-old caucasian male presented with mild dyspnea, lack of appetite, weight loss, and moderate itchiness. Lab results showed an acute kidney injury with marked increase of serum creatinine. The patient was started on prednisolone immediately after admission. As the patient in this case showed symptoms of uremia on admission, we decided to establish renal replacement therapy, which is unusual in tubulointerstitial nephritis and uveitis syndrome. During his course of dialysis, the patient developed symptoms of sepsis probably due to a catheter-related infection requiring intensive care and antibiotic treatment, which had to be terminated early as the patient developed a rash. Intensified immunosuppression, combined with antibiotics, significantly resolved excretory kidney dysfunction.

CONCLUSIONS

Since both the primary inflammatory process and the secondary infectious complication significantly impaired excretory kidney function, kidney function of younger individuals with new-onset anterior uveitis should be monitored over time and during follow-up.

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.

Tubulointerstitial nephritis and uveitis syndrome following meningitis and systemic lymphadenopathy with persistent Toxoplasma immunoglobulin M: a case report

Background

Tubulointerstitial nephritis and uveitis syndrome is a rare lymphocyte-related oculorenal inflammatory disease presumed to be associated with drug use and infectious agents. Toxoplasma gondii is one of such pathogens that could exhibit encephalitis, meningitis, and uveitis in immunocompromised or in some immunocompetent individuals. If the immunoglobulin M of Toxoplasma is positive on screening, the interpretation of the result is not simple, especially when immunoglobulin M stays positive persistently.

Case presentation

A 34-year-old Asian male developed fever, headache, and lymphadenopathy with tenderness, which was initially diagnosed as meningitis. Antibiotics were started, and diclofenac sodium was used for the fever. Although his symptoms were alleviated in a week by the treatment, gradual decline in renal function was noted, prompting a renal biopsy that indicated acute granulomatous interstitial nephritis. A week later, tenderness in both eyes with blurred vision appeared and revealed iritis and keratic precipitations in both eyes; hence, the diagnosis of acute tubulointerstitial nephritis and bilateral uveitis syndrome was made. Toxoplasma gondii-specific immunoglobulin G and immunoglobulin M titers were both positive. Although we could not rule out recent infection of Toxoplasma gondii, which may cause uveitis initially, Toxoplasma immunoglobulin G avidity test indicated a distant infection, which allowed us to rule out meningitis and uveitis as responsible for the complication of recent Toxoplasma gondii infection. Drug-induced lymphocyte stimulation test, or lymphocyte transformation test of diclofenac sodium, was solely positive among the tested drugs. Uveitis was alleviated only with ophthalmic steroid, and renal function returned to normal without administration of systemic steroid.

Conclusions

We experienced a case of diclofenac-induced tubulointerstitial nephritis and uveitis syndrome. In ruling out infections, Toxoplasma immunoglobulin M was persistently positive, and Toxoplasma immunoglobulin G avidity test indicated a “distant” infection. From these two results, we ruled out recent infection. However, it should be noted that “distant” infection indicated by commercial immunoglobulin G avidity is still a multiplex profile consisting of reinfection, reactivation, and latent infection. Narrowing down the infection profile of Toxoplasma is challenging in some cases. Therefore, careful diagnosis and extended follow-up of such patients are needed.

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.

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.

Long-term clinical characteristics and renal prognosis of children with tubulointerstitial nephritis and uveitis syndrome

BACKGROUND

Tubulointerstitial nephritis and uveitis (TINU) syndrome is a rare disease, especially in children. Owing to the short-term observational period and the small number of patients analyzed in previous reports, the long-term clinical and laboratory characteristics and renal prognosis of children with TINU syndrome remain unclear.

METHODS

In this retrospective observational study, we enrolled 29 children with TINU syndrome from February 1990 to February 2019.

RESULTS

During the median follow-up duration of 38 months, the kidney function, urinary β2 microglobulin-creatinine ratio (U-β2MG/Cr), and uveitis in the patients had significantly improved at 24, 6, and 36 months after diagnosis. Higher U-β2MG/Cr was associated with longer duration of kidney function normalization. Half of the patients required uveitis treatment for 5 years after the diagnosis.

CONCLUSIONS

Patients with severe low-molecular weight proteinuria at diagnosis needed a longer duration to achieve improvements in kidney function. Uveitis has a much longer treatment period than tubulointerstitial nephritis. This study demonstrates the good prognosis of children with TINU syndrome in terms of their long-term clinical and laboratory characteristics.

Tubulointerstitial nephritis and uveitis in Northern Ireland

Objectives

This paper looks at patients with a diagnosis of tubulointerstitial nephritis and uveitis (TINU) presenting to the Northern Ireland regional adult and paediatric uveitis service in the Belfast Health and Social Care Trust. The demographic distribution, treatment required and the visual and renal outcomes of these patients are documented.

Methods

Data were collected retrospectively on 24 patients with TINU using the Northern Ireland Electronic Care Record, central pathology records alongside the adult and paediatric uveitis databases from 2011 to 2021. Patients were categorised into two groups using the Mandeville classification system. Standard Uveitis Nomenclature (SUN) was used to classify the uveitis.

Results

The population prevalence is at least 12.6 cases per million based on a population of 1.9 million. Nineteen of 24 cases were definite TINU and five of 24 probable. Seventeen out of 24 had biopsy-positive TIN, all of which met all of the Mandeville clinical diagnostic features required for a definite diagnosis. All but one presented with acute bilateral anterior uveitis. The paediatric cases ranged from age 12 to 18 at age of onset with a mean age of 14. Of the 18 adult onset cases, the age ranged from 20 to 76 years. The mean age of onset for the adult cases was 53 years. Of these patients 71% were female; 42% required second-line immunosuppression for ocular disease. Visual acuity was maintained. Follow-up time ranged from 3 months to 16 years. No patient developed long-term renal impairment.

Conclusions

TINU is a cause of uveitis in both the paediatric and adult populations. In Northern Ireland average age with TINU was older than much of the published literature. Long-term immunosuppression for uveitis may be required as ongoing ocular, rather than renal inflammation seemed to require treatment.

Sarcoidosis: A Clinical Overview from Symptoms to Diagnosis

Sarcoidosis is a multi-system disease of unknown etiology characterized by the formation of granulomas in various organs. It affects people of all ethnic backgrounds and occurs at any time of life but is more frequent in African Americans and Scandinavians and in adults between 30 and 50 years of age. Sarcoidosis can affect any organ with a frequency varying according to ethnicity, sex and age. Intrathoracic involvement occurs in 90% of patients with symmetrical bilateral hilar adenopathy and/or diffuse lung micronodules, mainly along the lymphatic structures which are the most affected system. Among extrapulmonary manifestations, skin lesions, uveitis, liver or splenic involvement, peripheral and abdominal lymphadenopathy and peripheral arthritis are the most frequent with a prevalence of 25-50%. Finally, cardiac and neurological manifestations which can be the initial manifestation of sarcoidosis, as can be bilateral parotitis, nasosinusal or laryngeal signs, hypercalcemia and renal dysfunction, affect less than 10% of patients. The diagnosis is not standardized but is based on three major criteria: a compatible clinical and/or radiological presentation, the histological evidence of non-necrotizing granulomatous inflammation in one or more tissues and the exclusion of alternative causes of granulomatous disease. Certain clinical features are considered to be highly specific of the disease (e.g., Löfgren's syndrome, lupus pernio, Heerfordt's syndrome) and do not require histological confirmation. New diagnostic guidelines were recently published. Specific clinical criteria have been developed for the diagnosis of cardiac, neurological and ocular sarcoidosis. This article focuses on the clinical presentation and the common differentials that need to be considered when appropriate.

Novel Evidence of Acute Kidney Injury in COVID-19

The coronavirus 2019 (COVID-19) pandemic has caused a huge impact on health and economic issues. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes cellular damage by entry mediated by the angiotensin-converting enzyme 2 of the host cells and its conjugation with spike proteins of SARS-CoV-2. Beyond airway infection and acute respiratory distress syndrome, acute kidney injury is common in SARS-CoV-2-associated infection, and acute kidney injury (AKI) is predictive to multiorgan dysfunction in SARS-CoV-2 infection. Beyond the cytokine storm and hemodynamic instability, SARS-CoV-2 might directly induce kidney injury and cause histopathologic characteristics, including acute tubular necrosis, podocytopathy and microangiopathy. The expression of apparatus mediating SARS-CoV-2 entry, including angiotensin-converting enzyme 2, transmembrane protease serine 2 (TMPRSS2) and a disintegrin and metalloprotease 17 (ADAM17), within the renal tubular cells is highly associated with acute kidney injury mediated by SARS-CoV-2. Both entry from the luminal and basolateral sides of the renal tubular cells are the possible routes for COVID-19, and the microthrombi associated with severe sepsis and the dysregulated renin-angiotensin-aldosterone system worsen further renal injury in SARS-CoV-2-associated AKI. In the podocytes of the glomerulus, injured podocyte expressed CD147, which mediated the entry of SARS-CoV-2 and worsen further foot process effacement, which would worsen proteinuria, and the chronic hazard induced by SARS-CoV-2-mediated kidney injury is still unknown. Therefore, the aim of the review is to summarize current evidence on SARS-CoV-2-associated AKI and the possible pathogenesis directly by SARS-CoV-2.

Acute Kidney Injury Relevant to Tubulointerstitial Nephritis with Late-Onset Uveitis Superimposed by Thrombotic Microangiopathy: A Case Report and Review of the Literature

Background

The syndrome of tubulointerstitial nephritis and uveitis (TINU) is an uncommon and multisystemic autoimmune disorder. This review reports a rare case of TINU being superimposed on thrombotic microangiopathy (TMA) and, by comparing with the available literature, also summarizes the clinical features, associated conditions, treatment, and outcome of patients with TINU.

Summary

Herein, we report the case of a 37-year-old male patient with acute kidney injury (AKI) clinicopathologically identified as malignant hypertension-induced TMA superimposed by acute tubulointerstitial nephritis, which was suspected to be related to drug hypersensitivity. After treatment with oral prednisone combined with a renin-angiotensin system inhibitor, the patient achieved partial renal recovery and was withdrawn from hemodialysis. Recurrent AKI concomitant with new-onset asymptomatic uveitis was detected during routine clinical follow-up after cessation of prednisone. TINU was then diagnosed, and prednisone followed by cyclophosphamide was prescribed. The patient achieved better renal recovery than in the first round of treatment and maintained stable renal function afterward. By reviewing the literature, 36 cases were reported as TINU superimposed on other conditions, including thyroiditis, osteoarthropathy, and sarcoid-like noncaseating granulomas.

Key messages

TINU could be complicated by many other conditions, among which TMA is very rare. When presented as AKI, kidney biopsy is important for differential diagnosis. The case also shows that recurrent AKI with concomitant uveitis after prednisone withdrawal strongly suggested the need for long-term follow-up and elongated prednisone therapy for TINU syndrome.

Tubulointerstitial nephritis and uveitis (TINU) syndrome and recent Streptococcus infection in a 9-year-old girl

A 9-year-old girl presented to hospital with a 6-week history of non-specific constitutional symptoms and weight loss. She initially underwent extensive medical investigation without diagnosis being achieved. Although raised inflammatory markers and impaired renal function were noted during her initial admission to hospital, it was her subsequent presentation 2 weeks later with sudden-onset bilateral anterior uveitis that prompted a renal biopsy that indicated acute tubulointerstitial nephritis. A diagnosis of tubulointerstitial nephritis and uveitis (TINU) syndrome was made and systemic glucocorticoid treatment initiated to prevent visual loss and preserve renal function. She has subsequently been reviewed in multidisciplinary outpatient clinics and treated with a tapering regimen of immunosuppressive therapy. Her treatment has been complicated by the side effects of glucocorticoids and by persistent relapses in ocular disease and abnormalities on urinalysis. Recent clinical investigations indicate that her uveitis is controlled and that renal function remains well preserved.

Case Report: Exome Sequencing Reveals LRBA Deficiency in a Patient With End-Stage Renal Disease

Background: Lipopolysaccharide-responsive and beige-like anchor protein (LRBA) deficiency is characterized by autoimmunity, chronic diarrhea, and immunodeficiency. Minor renal manifestations have been found in a few patients, but kidney disease has not been systematically studied and may remain underdiagnosed in this highly variable entity. Results: Our patient initially presented with pancytopenia, enteropathy, hypogammaglobulinemia, and failure to thrive at the age of 15 months. Chronic kidney disease was diagnosed at 6 years. A renal biopsy taken at 11 years of age showed interstitial nephritis. The patient progressed rapidly to end-stage renal disease (ESRD) and underwent kidney transplantation at the age of 12 years. Bronchiolitis obliterans, post-transplant lymphoproliferative disease (PTLD), and chronic rejection complicated the post-transplant management. Graft loss required reinstitution of hemodialysis within 3 years. After negative results of different targeted sequencing strategies, exome sequencing identified a homozygous nonsense mutation (p.Q1010^*) in the LRBA gene more than 21 years after the patient's initial presentation. Conclusions: We report here the development of ESRD and long-term follow-up in a patient with LRBA deficiency. A molecular diagnosis in rare (kidney) disease like LRBA deficiency bears many advantages over a descriptive diagnosis. A precise diagnosis may result in improved (symptomatic) treatment and allows differentiating treatment- and procedure-related complications from manifestations of the primary disease.

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.

Update on the management of uveitis in children: an overview for the clinician

INTRODUCTION

Pediatric uveitis comprises a range of ocular inflammatory diseases that may lead to vision impairment, often due to ocular complications from the disease itself or side effects of therapies. The impact on vision, visual functioning, and vision-related quality-of-life over the lifetime horizon can be substantial, underscoring the importance of appropriate ophthalmic evaluation, diagnostic testing and treatment. This review focuses on the anatomic classification, laboratory diagnosis, associated systemic diseases, and management of pediatric uveitis.

AREAS COVERED

A review of the literature was performed to synthesize our current understanding of the anatomic classification of pediatric uveitis, disease epidemiology, associated systemic diseases, and management principles. We also review important corticosteroid-sparing strategies including non-biologic and biologic agents such as the anti-tumor necrosis factor (TNF)-alpha family of medications, given their key role in the treatment of pediatric uveitis, particularly juvenile idiopathic arthritis (JIA). Recent advances in the assessment of vision-related quality-of-life using the Effects of Youngsters' Eyesight on Quality of Life (EYE-Q) instrument are discussed.

EXPERT OPINION

Pediatric uveitis can lead to long-term vision impairment if not appropriately screened and treated. JIA is the most common systemic disease associated with uveitis, is typically asymptomatic, and thus requires rigorous screening to detect uveitis and avoid secondary ocular complications. While topical and systemic corticosteroids are useful for the acute treatment of uveitis, the disease chronicity of many pediatric uveitis syndromes including JIA, often warrants early escalation of therapy to immunosuppressive medications including methotrexate (MTX) and anti-TNF-alpha inhibitors. Future directions include an improved understanding of risk factors for uveitis and better metrics to evaluate the impact of disease on vision-related quality-of-life of pediatric uveitis patients.

IL-10 polymorphisms +434T/C, +504G/T, and -2849C/T may predispose to tubulointersititial nephritis and uveitis in pediatric population

BACKGROUND

Tubulointerstitial nephritis (TIN) and uveitis syndrome (TINU) are likely to be autoimmune diseases. Based on previous studies, adults with isolated idiopathic uveitis have polymorphisms in interleukin 10 (IL-10) and tumor necrosis factor α (TNF-α) genes. We aimed to evaluate the presence of IL-10 and TNF-α polymorphisms in a nationwide cohort of pediatric TIN/TINU patients.

METHODS

Single nucleotide polymorphisms in IL-10 (+434T/C, +504G/T, -1082G/A, -2849C/T) and in TNFα (-308G/A, -238G/A, -857C/T) genes were genotyped in 30 well-defined pediatric patients with idiopathic TIN/TINU syndrome. Control group frequencies for these SNPs were obtained from 393 independent Finnish subjects.

RESULTS

The homozygous minor allele in IL-10 +434T (rs2222202) and IL-10+504G (rs3024490) was found in all patients with TIN or TINU syndrome while the frequency of these minor alleles in the control population was 44% and 23%, respectively (p <0.001). In IL-10 SNP -2849 (rs6703630) a significant difference was found with genotype TT in all patients (p = 0.004) and in subgroups with TINU syndrome (p = 0.017) and TINU syndrome with chronic uveitis (p = 0.01) compared to reference population. There were no statistical differences in any of the studied TNF-α genotypes between TIN/TINU patients and control population.

CONCLUSIONS

A significant difference in the frequency of IL-10+434T and +504G alleles was found between TIN/TINU patients and control population. Genotype -2849TT was more frequently present in patients with TINU syndrome than in the reference subjects. Genetic variation in the inflammatory mediators may predispose to autoimmune nephritis and uveitis.

Tubulointerstitial nephritis and uveitis syndrome in a female adult

Tubulointerstitial nephritis and uveitis (TINU) syndrome is a rare disease characterised by the association of acutetubulointerstitial nephritis and uveitis. It affects mainly children and young women. Drugs and infections may be precipitating factors. It is a diagnosis of exclusion. The mainstays of treatment are topical and systemic corticosteroids. Prognosis is usually favourable. We report a case of TINU which occurred in our unit. A 37-year-old woman presented with an influenza-like illness, bilateral ocular pain and blurred vision. Ophthalmological evaluation revealed bilateral anterior uveitis and later renal involvement was seen as acute tubulointerstitial nephritis. A diagnosis of TINU was assumed after exclusion of other systemic diseases. She was treated with topical corticosteroids for the uveitis and evolved favourably, with resolution of ocular symptoms and normalisation of serum creatinine and proteinuria. This case highlights the importance of a high degree of clinical suspicion to make the diagnosis of TINU syndrome.

Eosinophilia and Kidney Disease: More than Just an Incidental Finding?

Peripheral blood eosinophilia (PBE), defined as 500 eosinophils or above per microliter (µL) blood, is a condition that is not uncommon but often neglected in the management of patients with chronic kidney disease (CKD), acute kidney injury (AKI), or patients on renal replacement therapy (RRT). The nature of PBE in the context of kidney diseases is predominantly secondary or reactive and has to be distinguished from primary eosinophilic disorders. Nonetheless, the finding of persistent PBE can be a useful clue for the differential diagnosis of underdiagnosed entities and overlapping syndromes, such as eosinophilic granulomatosis with polyangiitis (EGPA), IgG4-related disease (IgG4-RD), acute interstitial nephritis (AIN), or the hypereosinophilic syndrome (HES). For patients on RRT, PBE may be an indicator for bio-incompatibility of the dialysis material, acute allograft rejection, or Strongyloides hyperinfection. In a subset of patients with EGPA, eosinophils might even be the driving force in disease pathogenesis. This improved understanding is already being used to facilitate novel therapeutic options. Mepolizumab has been licensed for the management of EGPA and is applied with the aim to abrogate the underlying immunologic process by blocking interleukin-5. The current article provides an overview of different renal pathologies that are associated with PBE. Further scientific effort is required to understand the exact role and function of eosinophils in these disorders which may pave the way to improved interdisciplinary management of such patients.

TINU-associated Fanconi syndrome: a case report and review of literature

Background

Tubulo-interstitial Nephritis and Uveitis (TINU) syndrome is a rare oculo-renal inflammatory disease. Renal tubular defects are usually found, but full proximal tubular abnormalities have rarely been described.

Case presentation

We report the case of a 55-year old woman, native from Morocco, presenting with bilateral, non-granulomatous, anterior uveitis, mild renal insufficiency, leucocyturia and glycosuria. Further work-up showed hypophosphatemia and hyperphosphaturia, hypouricemia and hyperuricosuria, and hyper aminoaciduria, consistent with Fanconi syndrome. A kidney biopsy was obtained and showed diffuse interstitial infiltrates with tubular necrosis. The patient improved after the initiation of a corticosteroid therapy, with tapering dose.

Conclusions

We reviewed the literature and found nine similar cases. This association mostly occurs in adult woman, without current evidence for an ethnic predilection, unlike previously reported. The renal prognosis seems favorable after corticosteroid therapy, even in case of severe renal injury. Nonetheless mild tubular defects may persist after treatment or spontaneous remission.