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

Abstract

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.

• Authors: Ferah Genel, Anders G Sjöholm, Lillemor Skattum, Lennart Truedsson
• Journal: Scandinavian journal of infectious diseases (Scand J Infect Dis) Vol. 37 Issue 8 Pg. 615-618 ( 2005) ISSN: 0036-5548 [Print] England
• PMID: 16138437 (Publication Type: Case Reports, Journal Article)

Chemical References

• Complement Factor I

Topics

• Adolescent
• Child
• Complement Factor I (deficiency)
• Consanguinity
• Female
• Glomerulonephritis (complications, immunology)
• Humans
• Infections (complications)
• Recurrence
• Turkey
• Vasculitis (complications)