All STAT3 mutated (n = 38) and almost all neutropenic (38 out of 39) patients belonged to CD8+ T-LGL leukemia (n = 68), while among CD4+ T-LGL leukemia (n = 33) only one neutropenic patient (1 out of 33, 3%) was found, this last characterized by mild neutropenia (ANC: 1,470 mm3) over 9 years mean follow up. This evidence concerns the gene STAT3 and neutropenia.