- D1.339 - Renal and urinary tract disorders in inborn errors of immunity

Inborn errors of immunity (IEIs) are a diverse group of inherited disorders that affect various components of the immune system. The rapidly increasing number of identified IEIs highlights the indispensable role of a multidisciplinary approach in clinical diagnosis. Renal involvement is a major comorbidity in some patients and plays a decisive role in diagnosis and disease progression. However, renal and urinary tract manifestations remain largely underrecognised and require greater attention from paediatricians, nephrologists and immunologists.

Children diagnosed with inborn errors of immunity and under the care of the Paediatric Allergy and Immunology Division at Cerrahpaşa Faculty of Medicine, who also had renal or urinary tract abnormalities, were included in the study. Diagnoses, clinical features, laboratory findings and treatment approaches were obtained retrospectively from patient medical records.

Among the 389 patients with inborn errors of immunity, the 51 patients included in the study consisted of 31 males (60%) and 20 females (39%).The mean age at the onset of the first immunological symptom was 30.5 months, and the mean age at the onset of the first nephrological symptom was 114 months. Syndromic combined immunodeficiencies were the immunological category most frequently associated with renal findings (35%), followed by complement deficiencies (15%). The most common immunodeficiency syndrome was ataxia-telangiectasia, observed in seven patients (13%). The most frequent nephrological abnormality was structural anomalies of the urinary tract, observed in 16 patients (31%), including simple cortical cysts, urachal cysts, renal lobulation and renal agenesis. The most common initial renal manifestation was proteinuria (25%). The most frequent finding on urinary tract ultrasonography was increased renal parenchymal echogenicity (17%). Eleven patients (21%) had chronic kidney disease (CKD). Renal biopsy was performed on eight patients, with lupus nephritis diagnosed in five and focal segmental glomerulosclerosis (FSGS) in three. Three patients (5.8%) were receiving dialysis and three (5.8%) had undergone kidney transplantation.

Renal involvement in patients with inborn errors of immunity may be overlooked, presenting across a wide spectrum ranging from isolated proteinuria to end-stage kidney disease. Regular screening and early nephrological evaluation are critical for preventing or delaying chronic kidney disease and other complications.