Diagnosis of complement alternative pathway disorders

Area of Science:

• Nephrology
• Immunology
• Genetics

Background:

• Kidney diseases such as atypical hemolytic uremic syndrome, C3 glomerulonephritis, dense-deposit disease, and atypical postinfectious glomerulonephritis stem from aberrant complement alternative pathway regulation.
• These diverse conditions share a common etiology: impaired complement control due to genetic or acquired defects in the alternative pathway.

Purpose of the Study:

• To outline a unified diagnostic strategy for kidney diseases linked to complement alternative pathway dysregulation.
• To emphasize the importance of comprehensive analysis for identifying specific defects and guiding treatment.

Main Methods:

• Biochemical assessment including functional complement pathway activity, component/regulator analysis, and activation product quantification.
• Genetic analysis to identify causative mutations in complement alternative pathway genes.
• Pathologic examination of kidney biopsies using immunofluorescence and laser microdissection with mass spectrometry.
• ADAMTS-13 activity testing to differentiate from thrombotic thrombocytopenic purpura in thrombotic microangiopathy cases.

Main Results:

• The diagnostic approach involves a multi-faceted analysis of the complement alternative pathway.
• The genetic landscape of these disorders is continually expanding.
• Advanced techniques like laser microdissection with mass spectrometry enhance pathologic analysis.

Conclusions:

• A comprehensive diagnostic workup is essential for identifying the specific defect in the complement alternative pathway.
• Pinpointing the underlying cause enables precise, targeted therapeutic interventions for improved patient outcomes.