Complement factor I deficiency associated with recurrent infections, vasculitis and immune complex glomerulonephritis

Summary, in English

Here we report complement factor I deficiency in an 11-y-old girl from a consanguineous Turkish family, who presented with recurrent pyogenic infections, vasculitic eruptions and immune complex glomerulonephritis. A moderately low C3 level together with the clinical picture suggested a deficiency affecting regulation of complement activation. Analysis of haemolytic activity revealed absence of alternative pathway activity and subsequent analysis showed no detectable factor I (<2%) together with a low level of factor B and a moderately low level of factor H, indicating consumption secondary to the factor I deficiency. Factor I inhibits complement activation beyond C3 by cleavage of C3b in the presence of cofactors. Complement factor I deficiency is frequently associated with recurrent pyogenic infections mainly affecting the upper and lower respiratory tract, or presenting as meningitis or septicaemia, while rheumatic disorders have not been a prominent feature. The patient's sister also suffered from recurrent pyogenic infections and had a low C3 level clearly suggesting the same deficiency.

• Author: F Genel; Anders Sjöholm; Lillemor Melander Skattum; Lennart Truedsson
• Department/s: Division of Microbiology, Immunology and Glycobiology - MIG
• Publishing year: 2005
• Language: English
• Pages: 615-618
• Publication/Series: Scandinavian Journal of Infectious Diseases
• Volume: 37
• Issue: 8
• Links: http://dx.doi.org/10.1080/00365540510034536
• Document type: Journal article
• Publisher: Informa Healthcare
• Topic: Infectious Medicine
• Status: Published
• ISBN/ISSN/Other: ISSN: 1651-1980