#1494 Immunotactoid glomerulopathy: a comprehensive analysis of three cases
Authors: Desvignes Ross-Michael , Parnian Jake , Ghalli Farid 
Published: May 2024

Abstract

Background
Immunotactoid glomerulopathy (ITG) is an uncommon cause of glomerular disease encountered in approximately 0.06% of native kidney biopsies. This fibrillary disease is strongly associated with haematologic disorders, including lymphoma (mainly chronic lymphocytic leukaemia/small lymphocytic lymphoma), monoclonal gammopathy, and multiple myeloma. It is usually managed with oral steroids and/or treatment of an underlying lymphoproliferative disorder. Here, we report three cases of ITG, all female patients with varying severity of the disease, timing of malignancy and required treatment.
Case Scenarios:
Case 1: A 76-year-old lady with no significant medical background presented in May 2020 with confusion and progressive peripheral oedema. She had AKI (serum creatinine 210 µmol/L from baseline 68 µmol/L) and a sodium of 104 mmol/l. Urine PCR was 1182 mg/mmol. She was admitted to the ITU, where hyponatraemia was managed with a good clinical response. Blood screening showed negative immune, myeloma and virology screens. Complement was low. A renal biopsy showed a diagnosis of ITG. She had an extensive malignancy screen, but no malignancy was detected. She was started on prednisolone 60 mg once daily and eventually weaned off the drug by March 2021, as she maintained remission of her disease. Two years after her initial presentation, she was seen by the ophthalmologist for a right lacrimal gland mass. This was excised, and a biopsy revealed a MALT Lymphoma.
Case 2: A 50-year-old lady with splenomegaly being investigated under the haematology service was referred to our renal clinic for proteinuria in June 2019. Her serum creatinine was within normal limits, and her UPCR was 302 mg/mmol. She had no paraprotein in her blood, low serum immunoglobulins, low C3 and a negative viral screen. Perindopril, initiated by her GP, was up-titrated. Renal biopsy revealed features in keeping with Immunotactoid Glomerulopathy, and completed haematological investigations revealed Chronic Lymphocytic Leukaemia. Her UPCR peaked at 842 mg/mmol before reducing to 190 mg/mmol within a year after treatment with Veneclotax and Rituximab after not tolerating FCR (Fludarabine, Cyclophosphamide, Rituximab) Chemotherapy.
Case 3: A 69-year-old lady presented to the renal clinic with proteinuria in September 2018. She had a background of breast cancer diagnosed in 2007 (She had surgical resection followed by radiotherapy). Her 24-hour urine protein was 2g, and UPCR was 155 mg/mmol. Serum creatinine was 81 µmol/l and eGFR 66 ml/min. P- ANCA was positive, while PR3 and ANA were negative. She had bilateral leg oedema due to long-standing lymphedema. The biopsy report showed immunotactoid glomerulopathy. Regular surveillance of previous breast cancer with mammography and CT-CAP has shown no evidence of malignancy recurrence, hepatitis virology and paraprotein were negative, and C3/C4 were within normal limits. She had improved UPCR and maintained normal kidney function on full-dose Losartan.

Conclusion
Immunotactoid Glomerulopathy is a rare form of glomerular disease with a strong association with lymphoproliferative malignancies, which may precede, occur concomitantly or present years after the initial diagnosis. This common association highlights the need for diligence in screening for malignancy in each case, and it is a reason for careful follow-up of these patients. Treatment of underlying disorders is associated with positive renal outcomes, and in some cases, there is a good response to steroids.