The detection of clonal proliferation in granular lymphocyte-proliferative disorders of natural killer cell lineage

The clonal proliferation of large granular lymphocytes can be detected in patients with T-cell-lineage granular lymphocyte-proliferative disorders (T-GLPD) by Southern blotting T-cell receptor genes. However, this cannot be applied to patients with natural killer-cell-lineage GLPD (NK-GLPD) as it lacks a clonal marker. We therefore investigated the use of two other diagnostic techniques in evaluating clonal proliferation in Japanese patients with NK-GLPD (n = 4) and T-GLPD (n = 3) by chromosomal analysis of peripheral blood mononuclear cells (PBMC) stimulated with either interleukin-2 or phytohaemagglutinin, and Epstein-Barr viral (EBV) genomic DNA analysis. Chromosomal analysis revealed abnormal karyotypes in the PBMC of three of four patients with NK-GLPD, whereas EBV analysis showed a monoclonal terminal configuration in the PBMC in the fourth patient. Southern blots revealed rearrangements of the TCR genes in all three patients with T-GLPD but in none of those with NK-GLPD. It is suggested that these methods may be useful in detecting the abnormal proliferation of large granular lymphocytes in NK-GLPD.