Elevated levels of T-bet and phosphorylated Stat-1 suggest substantial infiltration by CD4+ Th1 cell in MS lesions. Expression of T-bet was not detected in control brain (A) or spinal cord (B). In MS lesions, relatively high levels T-bet were measured in acute lesions (AL) and chronic lesions (CL) in brain, and in AL in spinal cord. Compared to AL, markedly lower levels of T-bet were found in subacute lesions (SAL) and NWAM. C) Regulation of Stat-1 was similar to that of T-bet in brain. Phospho-Stat-1 (Tyr701) was not detected in control brain. Conversely, it was abundant in AL and CL in brain. Representative blots are shown from a total of 5 experiments analyzing 39 MS cases and 19 controls. Relative levels of T-bet/GAPDH and Stat-1 (Tyr701)/GAPDH were estimated by densitometry. Mean values ± SD are shown in corresponding graphs.