Large Granular Lymphocytosis Following Transplantation: Institutional Experience over a 10-Year Period at City of Hope.

Large Granular lymphocyte (LGL) expansion and LGL leukemia have been described in patients following both ablative and non-myeloablative conditioning regimens for hematopoietic cell transplantation (HCT), and have been associated with viral infection and graft-vs.-host disease (GVHD). We describe here an analysis of 41 cases of clonal LGL expansion identified at our institution over a 10-year period. Of these, 18 occurred in patients post autologous HCT (autoHCT), 23 in patients post allogeneic HCT (alloHCT). In the same time period, an additional 23 diagnoses were made in patients who had never undergone HCT. LGL expansion appeared an average of 485 days (range 30 – 1935 d) from alloHCT. In most patients, this occurred as an isolated finding, while in 5 patients, the clonal expansion was detectable on serial evaluations over a period of months or years (75 – 1662 d). LGL expansion was detected an average of 133 days from auto HCT, and only one patient had detectable clonal expansion over a prolonged period of time (70d). AutoHCT patients ranged from 23 to 72 years, average age 48.5 years. AlloHCT patients ranged from 26 to 62 years, average age 47.8 years. Incidence of reactivation of CMV postHCT was 56.5% in the alloHCT and 11% in the autoHCT. Relapse rates were 39% in the alloHCT and 28% in the autoHCT groups. At a median follow-up of 1372 days, 14 alloHCT patients remain in remission, with 9 relapses, and 5 deaths. At a median follow-up of 887 days, autoHCT patients remain in remission, with 5 relapses, and 3 deaths. Deaths were primarily attributed to relapse of disease and infectious complications, while no deaths were attributable to LGL clonal expansion. No patients with LGL clonal expansion have required treatment specifically for this condition.