Background/Purpose: Tubulointerstitial nephritis and uveitis (TINU) syndrome is an uncommon condition that is likely under-recognized. The ideal treatment of both renal and ophthalmologic disease activity in TINU is not known. We sought to characterize a large pediatric cohort of TINU patients followed at a tertiary care children’s hospital and describe their disease course and treatment over time.

Methods: We used ICD9 and ICD10 codes to identify patients treated for TINU at Boston Children’s Hospital between 2011 and 2019. Retrospective chart review was used to collect data on demographic factors, presenting symptoms, medications, ocular complications, renal pathology, and long term disease activity. Linear and logistic regression models, as well as F-test statistics, were used to analyze possible predictive factors associated with achieving renal and/or ocular remission. All statistical analyses were conducted using SPSS version 24. 

Results: We analyzed data from 16 patients with TINU, after excluding 3 patients for whom TINU diagnosis could not be confirmed on further chart review. Mean uveitis follow up period was 1.8 years (SD 1.9; range 0.1-6.6). In this cohort, 10 patients (63%) had both ocular and renal manifestations concurrently, while in 6 patients the organ involvement did not overlap. Most patients presented with ocular manifestations first. Nine patients (56%) underwent kidney biopsy, with results confirming interstitial inflammation. Medications used included oral steroids, topical steroid drops, mycophenolate mofetil, methotrexate and tumor necrosis factor inhibitors (TNFi). Average total duration of systemic immunosuppressive therapy was 11.7 months (SD 11.6; range 1-40). Five patients were treated with a TNFi for chronic active uveitis, two with infliximab and three with adalimumab. One patient still had active renal disease when starting TNFi; both uveitis activity and proteinuria resolved rapidly with initiation of adalimumab.  At the time of this analysis, all five patients receiving TNFi had achieved and maintained control of their uveitis activity. Renal remission was achieved in 12 (75%) patients during the follow up period. No patient progressed to end-stage renal disease and none required renal replacement therapy during the study period. Ocular remission was achieved in 14 (88%) patients, with only one patient developing a long term structural complication. No demographic, disease, or treatment-related factors were significantly associated with achieving either renal or ocular remission.

Conclusion: We describe a large single center pediatric cohort of TINU with longitudinal followup. Overall, patients achieved remission with little or no long term morbidity, although significant and prolonged immunosuppression was required for some patients. We also describe five patients treated successfully with a TNFi. The improvement in proteinuria seen in one patient treated with TNFi suggests that TNF may play a common role in mediating both ocular and renal inflammation in TINU.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/tubulointerstitial-nephritis-and-uveitis-tinu-a-pediatric-case-series-with-longitudinal-followup/