dr <- data.frame(tSNE1 = tsne_out$Y[, 1], tSNE2 = tsne_out$Y[, 2], 
  expr[tsne_inds, lineage_markers])

ggplot(dr,  aes(x = tSNE1, y = tSNE2, color = CD4)) +
  geom_point(size = 0.8) +
  theme_bw() +
  scale_color_gradientn("CD4", 
    colours = colorRampPalette(rev(brewer.pal(n = 11, name = "Spectral")))(50))