MS lesions contain increased levels of pro- and secreted IL-16 compared to control tissue. Markedly different relative levels of IL-16 were measured between different types of lesions and control (A) brain and (B) spinal cord tissue, by western blot. Representative blots show levels of pro-IL-16 (80 kD) and secreted IL-16 (22 kD) in: (A) normal control (periventricular white matter of left parietal lobe), and MS brains. Periventricular white matter of MS lesions and adjacent normal-appearing white matter were sampled from: AL (acute lesion – right parietal lobe); NAWM (normal appearing white matter – right temporal lobe); NAGM (normal-appearing grey matter – right temporal lobe); SAL (subacute lesion – right parietal lobe) and CL (chronic lesion – right parietal lobe); and (B) spinal cord: lumbar spinal cord was analyzed from control and MS patients. Representative blots are shown from a total of 7 experiments analyzing 39 MS cases and 19 controls. Relative levels of IL-16/GAPDH were estimated by densitometry. Mean values ± SD are shown in corresponding graphs.