Immunopathogenesis of chronic pyelonephritis

Area of Science:

• Nephrology
• Immunology
• Urology

Background:

• Chronic pyelonephritis is a serious kidney condition.
• The role of Tamm-Horsfall protein (THP) in kidney disease pathogenesis is not fully understood.
• Autoimmune responses may contribute to kidney damage.

Purpose of the Study:

• To investigate immunopathologic responses to THP in the development of chronic pyelonephritis.
• To explore the potential role of autoimmune reactions to THP in various kidney conditions.
• To identify mechanisms linking THP exposure to kidney disease.

Main Methods:

• Rabbit model: Intravenous injection of urine or THP to induce nephritis.
• Porcine model: Assessment of anti-THP antibodies and cell-mediated immunity in pigs with reflux nephropathy.
• Human studies: Analysis of anti-THP antibodies and cell-mediated immunity in patients with recurrent nephrolithiasis.
• Bacterial analysis: Detection of THP-binding inhibitors in uropathic coliforms.

Main Results:

• Rabbits injected with THP developed tubulointerstitial nephritis and showed increased cytotoxic lymphocytes and IgG antibodies against THP.
• Pigs with reflux nephropathy exhibited elevated anti-THP antibody titers and cytotoxic lymphocytes.
• Human patients with recurrent nephrolithiasis showed abnormal anti-THP immune responses, independent of obstruction or bacteriuria.
• Uropathic coliforms produced inhibitors that interfered with THP-antibody binding, with cross-reactivity to THP.

Conclusions:

• Autoimmune responses to Tamm-Horsfall protein can be triggered by intravenous exposure, urinary reflux, and recurrent nephrolithiasis.
• These autoimmune responses may be a key pathogenetic mechanism in chronic pyelonephritis.
• THP-related autoimmunity offers a potential explanation for kidney damage in conditions like recurrent nephrolithiasis, even without overt infection.