Fig. 4.

Secondary nodules are characterized by IFN-γ-producing CTLs. a The number of CTLs and microglia within a nodule is direct proportional (n (FFPE n(nodules) = 336 from 20 patients) Spearman correlation, r = 0.60, p < 0.0001). b Triple labeling of microglia (Iba1), T cells (CD3) and T-bet as a marker for IFN-γ-producing cells. Triple labeling of microglia (Iba1), T cells (CD3), and pSTAT1, the phosphorylated transcription factor for IFN signaling in c PN, d SN, where pSTAT1 is visible in T cells (white arrow) and microglia (yellow arrow) and e a neuron with T-cell apposition. Double labeling of pSTAT1 and IL-1β in f a small SN with only one IL-1β⁺ cell and g a big SN with many IL-1β⁺ cells. h The number of IL-1β⁺ cells is directly proportional to pSTAT1⁺ cells [n(nodules) = 48 from 8 patients], Spearman correlation, r = 0.63, p < 0.0001). i The number of t-bet⁺ cells correlates positively with the number of microglia within a nodule, (r = 0.7, p < 0.0001, n (single nodules) = 67 from 4 patients). Scale bars in b and d correspond to 25 µm, in c and to 10 µm, and in f and g to 50 µm