LYMPHOCYTE PROFILES IN MULTIPLE-MYELOMA AND MONOCLONAL GAMMOPATHY OF UNDETERMINED SIGNIFICANCE - FLOW-CYTOMETRIC CHARACTERIZATION AND ANALYSIS IN A 2-DIMENSIONAL CORRELATION BIPLOT

The distribution of 27 T-, B-, and natural killer-cell subsets in the peripheral blood of 40 patients with multiple myeloma (MM), ten patien ts with monoclonal gammopathy of undetermined significance (MGUS), and 40 healthy donors was investigated by means of classical univariate s tatistics and advanced multivariate data-analytical techniques. The la tter approach was used to describe, represent, and analyze lymphocyte subset distribution in a two-dimensional correlation biplot, allowing comparison of complex lymphocyte profiles (i.e., compound lymphocyte s ubset distributions) of individual subjects rather than isolated subse t values of selected patient and/or donor groups. The correlation bipl ot revealed that, in accordance with the univariate statistics, the MM patients were characterized by marked shifts towards CD8(+). CD57(+) CD62L(-), CD(16 + 56)(+), and HLA-DR+ T cells, suggesting in vivo immu ne activation. The activation profile was most markedly observed in tr eated MM patients in the advanced disease stage category. The lymphocy te profiles of MGUS patients were heterogeneous, with approximately ha lf of them located in the swarm of MM patients and the other half in t he swarm of healthy donors. Although the univariate statistics reveale d significant differences between MGUS patients and healthy donors onl y within the B-cell compartment, the correlation biplot revealed that two MGUS patients clearly had a typical T-cell activation profile simi lar to that of the MM patients. One MGUS patient with a T-cell activat ion profile progressed 13 months later to a stage IA MM and required c hemotherapy. A marked lymphocyte profile shift in one MM patient was a ssociated with terminal and aggressive disease transformation. Our stu dy illustrates further the practical use of correlation biplots for th e detection of aberrant lymphocyte profiles and/or profile shifts in i ndividual patients.