Urine protein in patients with type I hypersensitivity is indicative of reversible renal tube injury.

Aims: In our clinical work, some patients with type I hypersensitivity could be detected protein in their urine. This study focused on the early renal injury in patients with type I hypersensitivity.

Main Methods: From 43 type I hypersensitivity patients with proteinuria, 10 patients were randomly selected for mass spectrometry analysis of 24-h urine together with 5 healthy volunteers. Mice were vaccinated with Dermatophagoides farina (Der f) and ovalbumin (OVA) were used as antigen to establish the type I hypersensitivity animal models.

Key Findings: The urine protein of hypersensitivity patients was significantly increased in the alpha-1-microglobulin/ bikunin precursor (Protein AMBP) (t = 3.140, P = 0.008), retinol binding protein 4 (RBP4) (t = 2.426, P = 0.031), kininogen-1 (t = 2.501, P = 0.027), and transferrin appeared only in patients' urine. After immunizing mice with antigens, significant increases of the total serum immunoglobulin E (IgE) were observed in both Der f (86.92 ± 36.01 U/mL, t = 5.231, P = 0.0004) and OVA group (34.65 ± 24.72 U/mL, t = 2.891, P = 0.0161) compared with the negative control group (2.68 ± 0.47 U/mL). Meanwhile, definite eosinophil infiltration around the impaired renal tubules as well as the bronchus in Der f mice were observed, and urine protein appeared. After stopping the allergen stimulation, proteinuria disappeared. Instead, when the mice were treated with the antigen again, proteinuria reappeared.

Significance: Our findings suggest that renal tubular damage in patients with type I hypersensitivity is reversible, and proteinuria disappears with allergy symptoms remission.