Three men with Felty's syndrome were treated with long-term testosterone therapy. Two had a full, and one a partial, correction of the neutropenia and a concomitant abatement of tendency to infection. For the two patients with complete correction of the neutropenia, full recovery of neutrophils took 20 and 24 months, respectively, correlating with diminution in splenomegaly. Testosterone may increase stem cell commitment to granulopoiesis, at the same time diminishing lymphopoiesis. It may also exert a weak lympholytic effect.
Wimer BM, Sloan MM. Remission of Felty's Syndrome With Long-Term Testosterone Therapy. JAMA. 1973;223(6):671–673. doi:10.1001/jama.1973.03220060045011