IGHE and hereditary spastic paraplegia: The C3 (0.33 ± 0.09 vs. 0.45 ± 0.03 g/L) (P < 0.05) and C4 (0.027 ± 0.01 vs. 0.038 ± 0.006 g/L) (P < 0.05) levels significantly decreased and there was no change in serum IgE levels (0.03 ± 0.009 vs. 0.025 ± 0.003 g/L) in HSP rats compared with controls (Fig. 2C).