Overall, there were few CD4 + lymphocytes but parenchymal CD4+ cells were significantly increased in FTLD-tau overall (P = 0.0109), with increased CD4+ T cells only detected in PiD versus controls in the parenchyma (P = 0.0040) and the perivascular space (P = 0.0158) (Fig. 8). Here, MAPT is linked to pelvic inflammatory disease.