Background: IgA nephropathy (IgAN) is prevalent among both children and adults. Illumination of the differences between them is important for clinical doctors.
Methods: We retrospectively compared clinicopathological features in 110 children and 908 adults with IgAN.
Results: The male to female ratio was 1.62:1 in children and 0.85:1 in adults. Most patients lacked triggers, but IgAN was preceded by upper respiratory infection (URI) in 45.5% of children and 20.2% of adults. Gross hematuria was the most common initial symptom in children (53.6%), especially in those associated with URI (82.0%), while other symptoms and abnormal laboratory parameters were more common in adults. Estimated glomerular filtration rate (eGFR) was higher in children than in adults. Co-deposition of IgA and C3 were found in 50.9% of children, while IgA deposit was often accompanied by two or more immune complexes in adults. The frequency of subclass I was significantly higher in children than in adults. Mild histological lesions were more common in pediatric IgAN patients associated with URI than other patients.
Conclusions: Pediatric patients showed relatively mild clinical manifestations and histological lesions compared with adult patients. URI was the most important trigger for IgAN, particularly in children. IgAN associated with URI was relatively mild.