This communication reports the clinical and cellular features of five elderly female patients with persistent moderate to severe neutropenia and concomitant relative expansions of CD3+TCR gamma delta+ (n = 4) or CD3+TCR alpha beta+CD4-CD8- (n = 1) lymphocyte populations. In clinical terms, severe neutropenia was the main contributing factor to patient symptoms although two additionally had long-standing histories of rheumatoid arthritis. The absolute lymphocyte counts did not exceed the normal upper limit in these patients, and morphologically the lymphocytes were not typically of large granular lymphocyte (LGL) type although LGL-associated BLT-esterase staining was consistently increased. Expression of NK-associated (NKa) membrane determinants (CD16, CD56 and CD57) were variable but there was an apparent correlation between weak membrane CD8 and CD16 expression. DNA genotypic studies confirmed that the four CD3+TCR gamma delta+ cases were clonal in nature and add further support to an emerging impression that expansions of these lymphocyte subpopulations may frequently be clinically associated with autoimmune phenomena in general and neutropenia in particular.