A study of granular lymphoproliferative disorders including a CD3 negative case with a rearrangement of the T-cell receptor locus.

The clinical, and laboratory features of 9 patients presenting with chronic proliferations of large granular lymphocytes (LGL) are described. The median patient age was 61 years (33-80) and median patient follow up was 3.5 years (28 mo-10 years) with all patients surviving. Clinical features and blood and bone marrow findings are documented. Immunophenotypic analysis showed lymphocytes from 4 patients were CD3 negative and 5 were CD3 positive with natural killer associated cell surface antigens expressed in both these groups. Analysis of the T-cell receptor (TCR) loci revealed a clonal rearrangement in 4 samples including one CD3 negative sample. Clonality did not correlate with immunophenotype or clinical or haematological features. We conclude that patients with persistent LGL have a wide diversity of cell surface marker expression and that whilst some patients with CD3 negative LGL proliferations have cells which are most likely of natural killer (NK) cell origin, in others TCR rearrangements can be demonstrated suggesting these cells are possibly of T-cell, not NK cell, origin.