[LGL syndrome can imitate Felty's syndrome. The diagnosis can be established by a simple test].

The article consists in a discussion of neutropenia caused by large granular lymphocytes (LGLs), illustrated by a review of the literature and case reports of five patients with LGL syndrome and one patient whose clinical characteristics were more consistent with classic Felty's syndrome. Recent years have witnessed advances in our knowledge of clonal expansions of suppressor-type T-cells and their capacity to induce neutropenia. The phenotypes of such cells are CD3+, CD8+ and CD57+. The syndrome is often seen in patients with rheumatoid arthritis, and if they also manifest splenomegaly it may be confused with Felty's syndrome. Appropriate evaluation and treatment of the condition are also discussed, and an attempt made to clarify the confusing terminology.