While the exact trigger that facilitates cell lysis is yet to be elucidated, the neutropenia of T-LGL may be the result of elevated soluble Fas-L (sFas-L) levels, a cleaved product of Fas, and thus, increased apoptosis; this could explain the overlap between Felty syndrome and LGL [94]. This evidence concerns the gene FASLG and Decreased total neutrophil count.