IL-16 immunoreactivity is present in occasional infiltrating lymphocytes adjacent to degenerate axonal cytoskeletons, in normal-appearing white matter (NAWM). A) Occasional IL-16-positive CD3+ T cells were observed around small venules in NAWM adjacent to acute lesions in spinal cord (at arrows). B) Note degenerate axonal neurofilaments [NF(M+H)P], which appear rounded, ballooned and irregularly shaped (at arrows). Some IL-16 immunoreactivity was observed in the proximity of axons, either confined to or adjacent to sparse infiltrating mononuclear cells (merged image, arrows). Note that IL-16 does not co-localize with axonal neurofilament. Two color fluorescence × 40.