Complement dysregulation, premature death and development of aHUS symptoms in FH W1206R mutant mice. (A) Western blot analysis of plasma FH levels in WT (FH^W/W), heterozygous (FH^W/R), and homozygous (FH^R/R) mutant mice showing that mutant FH was stable and present at a slightly higher level in FH^R/R mice. A polyclonal rabbit anti–mouse FH antibody was used to detect both WT and mutant FH. (B-C) Western blot analysis of plasma C3 (B) and FB (C) levels showing that both intact C3 and FB were lower in FH^R/R mice than in FH^W/W mice. (D) ELISA of plasma intact C5 showing that FH^R/R mice had significantly lower C5 levels than FH^W/W or FH^W/R mice. (E) ELISA of LPS-induced AP complement activity in 10% mouse sera. Data are normalized to the average value of FH^W/W mice (100%). (F) Hemolytic assay using 50% sera from FH^W/W, FH^W/R, and FH^R/R mice and RBCs from DAF^−/−Crry^−/−C3^−/− mice. Hypotonic lysis in pure water was used as reference control (100% lysis). (G) FH^R/R mice had lower body weights than FH^W/W or FH^W/R mice (n = 10 in each group, all male mice). (H) Survival curves of FH^W/W (n = 275), FH^W/R (n = 310), and FH^R/R (n = 147) mice up to 30 weeks of age. (I-J) CBC analysis showing FH^R/R mice had thrombocytopenia (I) and anemia with low blood hemoglobin (Hb) levels (J). (K-L) BUN and serum Cr levels in mice at different ages. Serum samples were collected from the same mice at 4, 12, and 20 weeks of age (FH^W/W n = 20, FH^W/R n = 16, and FH^R/R n = 19). Data shown in panels K-L are mean ± SD of the results. Each lane in panels A-C and each symbol in panels D-F,I-J represent an individual mouse (4-25 weeks old). Horizontal bars through the scatterplots in panels D-F,I-J indicate the average values in each group. *P < .05; **P < .01; ***P < .001; NS, not significant (Mantel-Haenszel log-rank test for panel H; 1-way ANOVA and Student t test for other panels).