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Related Experiment Video

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Ferric Chloride-induced Murine Thrombosis Models

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Published on: September 5, 2016

Complement activation in diseases presenting with thrombotic microangiopathy.

¹Department of Bacteriology and Immunology, Haartman Institute, PO Box 21, FI-00014 University of Helsinki, Helsinki, Finland. seppo.meri@helsinki.fi

European Journal of Internal Medicine

|June 8, 2013

Summary

Atypical hemolytic uremic syndrome (aHUS) involves complement system dysregulation, causing blood cell damage and organ injury. Genetic defects in complement regulation are key drivers of this thrombotic microangiopathy.

Keywords:

ADAMTS13 AP CCP CD46 Complement factor H Complement regulation DDD DGKE FH Hemolytic uremic syndrome Microangiopathy PNH STEC Shiga-toxin producing E. coli TMA TTP Thrombosis a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 aHUS alternative pathway atypical hemolytic syndrome complement control protein domain dense deposit disease diacylglycerol kinase ε factor H paroxysmal nocturnal hemoglobinuria thrombotic microangiopathy thrombotic thrombocytopenic purpura

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Area of Science:

Immunology
Nephrology
Hematology

Background:

Atypical hemolytic uremic syndrome (aHUS) is a severe thrombotic microangiopathy (TMA) involving endothelial and blood cell damage.
It is characterized by thrombotic vascular occlusions affecting kidneys and other organs.
A key feature is a complement system attack on endothelial and blood cells, leading to platelet activation, hemolysis, and inflammation.

Purpose of the Study:

To elucidate the role of the complement system in the pathophysiology of aHUS.
To differentiate complement-mediated aHUS from other forms of HUS and TMAs.
To identify genetic factors predisposing individuals to aHUS.

Main Methods:

Review of complement system biology and aHUS pathogenesis.
Comparison of aHUS with Shiga-toxin induced HUS, TTP, and DGKE-associated TMA.
Analysis of genetic mutations in complement regulatory proteins (Factor H, I, MCP/CD46, thrombomodulin) and pathway components (C3, Factor B).

Main Results:

The fundamental defect in aHUS is excessive complement activation against cellular surfaces.
This can result from impaired complement regulation, hyperactive C3 convertases, or pro-thrombotic cell surface changes.
Mutations in Factor H are the most common genetic cause, impairing self-surface recognition.

Conclusions:

Complement system dysregulation is central to aHUS pathogenesis.
Understanding the genetic basis of complement dysregulation is crucial for diagnosing and managing aHUS.
Most TMAs involve misdirected complement activation impacting endothelial cells and platelets.