NGF and myeloid sarcoma: Based on the previous data, we can hypothesize that the expression or not of NGF, TrkA, and p75NTR in the T lymphocytes may be related to various factors such as the phylogenetic differences of the studied organism (human or rodent), the disease (MS, passive or active EAE), and the T lymphocytes’ differentiation stage (naïve or activated), as well as the nature of the activating stimulus/antigen.