SIMILARITIES BETWEEN IGG-BEARING LYMPHOCYTES AND HAIRY-CELLS - CYTOLOGIC AND CYTOCHEMICAL STUDIES

  • 1 January 1984
    • journal article
    • research article
    • Vol. 64  (1) , 166-172
Abstract
Six patients with hairy cell leukemia (HCL) were studied for surface Ig (sIg). In all 5 sIg-positive cases, the H chain isotype was IgG. Cytologic and cytochemical studies of sIgG+ lymphocytes were performed in normal peripheral blood and compared them with hairy cells. Normal sIgM+ lymphocytes were also examined. sIgG+ and sIgM+ lymphocytes made up 0.9% and 6.1% of normal peripheral blood lymphocytes, respectively. Under a phase-contrast microscope, 76% of sIgG+ lymphocytes showed cytoplasmic processes similar to those found on hairy cells, whereas most sIgM+ lymphocytes had smooth surfaces. Tartrate-resistant acid phosphatase (TRAP) staining revealed that TRAP-positive cells accounted for 65% of sIgG+ lymphocytes and 19% of sIgM+ lymphocytes. Some (8.3%) of the sIgM+ lymphocytes expressed sIgG concomitantly. When sIgM+, sIgG+ lymphocytes were excluded, the percentages of cells with surface processes and of TRAP-positive cells in the remaining sIgM+, sIgG- lymphocytes were 10% and 12%, respectively. A very small proportion (0.2%) of sIgM-, sIgG- lymphocytes had cytoplasmic processes. Normal sIgG+ lymphocytes are cytologically and cytochemically different from most sIgM+ lymphocytes and the phase-contrast microscopic appearances and TRAP activity of sIgG+ lymphocytes are similar to those of HCL tumor cells.