Hematologic and cytofluorographic analysis of patients with Felty's syndrome. A hypothesis that a discrete event leads to large granular lymphocyte expansions in this condition.

OBJECTIVE: To compare hematologic and cytofluorographic features in Felty's syndrome (FS) patients with and without the large granular lymphocyte (LGL) syndrome.
METHODS: Peripheral blood cells from FS patients and from 2 control groups (rheumatoid arthritis [RA] patients and subjects without symptoms of a rheumatic disease) were analyzed by hematologic and cytofluorographic techniques. A separate assessment of disease activity was performed.
RESULTS: FS patients had reduced lymphocyte and platelet counts, with a parallel reduction in lymphocyte subsets examined. CD4 counts were reduced in all FS patients, including those with the LGL syndrome. Disease activity was lower in FS patients than in RA control patients. Treatment was similar in all patient groups. No direct association was seen between LGL numbers and duration of RA or neutrophil counts in RA groups.
CONCLUSION: Hematologic abnormalities in FS extend beyond neutropenia. Although similarities were seen between FS patients and FS patients with the LGL syndrome (e.g., CD4 lymphopenia), evidence for a gradation from FS to the LGL syndrome was not seen, thus favoring the hypothesis that a "transforming event" is required.