Inherited complete factor I deficiency associated with systemic lupus erythematosus, higher susceptibility to infection and low levels of factor H.
Here we describe two new cases of complete deficiency of factor I (fI) in two sisters from a consanguineous Brazilian family. The eldest sibling (20-year-old) developed systemic lupus erythematosus (SLE) early during childhood while the youngest had been committed on several occasions owing to repeated infections although she was asymptomatic for auto-immune diseases. We also detected lower concentrations of C3 and factor B in both sisters. Biological functions dependent on complement activation such as the production of opsonins and killing of phagocytozed micro-organisms, chemotactic factors and haemolytic activity were all significantly reduced in both probands. Consistent with the absence of fI and low levels of fH, a deregulated production of C3b was observed by bidimensional electrophoresis in sera of both the probands.
Amadei
N
N
Departamento de Imunologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Brazil.
Baracho
G V
GV
Nudelman
V
V
Bastos
W
W
Florido
M P
MP
Isaac
L
L
D000328:Adult; D001424:Bacterial Infections / Q000150:complications*; D002464:Cell Migration Inhibition; D002478:Cells, Cultured; D002675:Child, Preschool; D020147:Coagulation Protein Disorders / Q000150:complications / Q000235:genetics* / Q000276:immunology*; D003167:Complement Activation; D003176:Complement C3 / Q000378:metabolism; D003179:Complement C3b / Q000378:metabolism; D017242:Complement Factor H / Q000378:metabolism*; D005192:Family Health; D005260:Female; D005340:Fibrinogen / Q000235:genetics* / Q000378:metabolism; D020022:Genetic Predisposition to Disease; D006801:Humans; D007123:Immunoelectrophoresis, Two-Dimensional; D008180:Lupus Erythematosus, Systemic / Q000150:complications*; D010587:Phagocytosis
C493495:CFH protein, human; D003176:Complement C3; D003179:Complement C3b; D017242:Complement Factor H; D005340:Fibrinogen