Fig. 2

Confocal microscopic images of intercostal muscle from controls (a, b, c) and ALS donors (d, e, f) double-labeled with antibodies against neurofilament (NF-H, Cy3) and antibodies against classical pathway component of the complement system C1q (C1q, FITC). C1q deposition was detected on the nerves as well as near the nerve endings (white asterisks in f) in muscle of ALS donors but not in controls. g Quantification showed C1q-positive staining co-localizing with nerves and in the vicinity of nerve endings (white arrowhead pointing to NF-H and asterisk on C1q in f) in the intercostal muscle of ALS donors but not in controls (P = 0.001 and P = 0.001, respectively). NE staining (dark brown) followed by an immune staining for C1q (blue) showed (i) C1q deposition on the end-plates of ALS donors (white arrow in i and enlargement of the area as insert) (h) by contrast, no C1q deposition was found deposited on the motor end-plates in the intercostal muscle of control donors. Numbers of C1q-positive nerve endings in 20 non-overlapping Z-stacks in 40-μm thick intercostal muscle sections is given on the y-axis. Error bars represent standard deviation of the mean. n.d. not detected