Complement factor h functional assay may help to monitor atypical haemolytic uraemic syndrome : a pilot study
Faculty of Medicine and Health Sciences
Acta clinica Belgica. - Leuven, 1946 - 1997
, p. 9-14
Background: Atypical haemolytic uraemic syndrome (aHUS) results from uncontrolled complement system activation. Complement factor H gene mutations are common causes of aHUS. Plasmatherapy, including plasma infusions and/or plasma exchanges, has been tried in this Setting with various successes. At present, we lack a specific marker to monitor functional factor H deficiency-related aHUS. Methods: We report the use of factor H functional assay in three patients-with atypical haemolytic uraemic syndrome. This assay is based on the requirement of soluble complement regulators that bind sheep red cells to prevent haemolysis. As factor H is highly abundant in the plasma, its defect results in haemolysis. Factor H activity was also measured among plasma donors. Results: One patient suffered from a plasma-dependent form of atypical haemolytic uraemic,syndrome, Plasma exchanges restored higher factor H activity-and were associated With a 15-months-disease-free period. In the two other patient, one With-a failing renal graft and the-other-on chronic dialysis,,a bout of thrombotic micro-angiopathy was preceded by a drop of haemolytic activity below normal values. Plasma from healthy donors (N = 65) showed only minimal variations of Factor H activity (mean activity: 98.3%, SD=4.0). Conclusion: These preliminary data suggest that factor H activity could be of interest in both the diagnosis and the treatment by plasmatherapy of factor H-related aHUS.