Multiple myeloma: the relationship between CALLA (CD10) positive lymphocytes in the peripheral blood and light chain isotype suppression

Abstract

This study describes the presence of small numbers of common acute lymphocytic leukaemia antigen (CALLA, CD10)-positive lymphocytes in the peripheral blood of patients with multiple myeloma. A significant correlation (0.001 < P < 0.01) was found between the lack of light chain isotype suppression (LCIS), which is characteristic of progressive myeloma, and the presence of CALLA-positive lymphocytes. Sixty patients with multiple myeloma, four with benign monoclonal gammopathy (BMG) and seven with solitary plasmacytoma (SP) were monitored in this study. Nineteen of the patients with multiple myeloma demonstrated LCIS, of which only three were found to have CALLA-positive lymphocytes in their blood. Forty-four of the patients with multiple myeloma were also monitored for serum beta-2-microglobulin (SB2M) levels. There was no correlation between the SB2M and either LCIS or CALLA-positivity. Detection of CALLA-positive lymphocytes in the blood of patients with multiple myeloma may be an early marker of the onset of progressive disease. The correlation of CALLA expression on lymphocytes with lack of LCIS provides further evidence for the operation of immunoregulatory systems in these patients.