ANALYSIS OF NATURAL KILLER-ASSOCIATED ANTIGENS IN PERIPHERAL-BLOOD AND BONE-MARROW OF MULTIPLE-MYELOMA PATIENTS AND PROGNOSTIC IMPLICATIONS

The aim of this study was to analyse the expression of NK-associated a ntigens in both peripheral blood and bone marrow lymphocytes from a la rge series of newly diagnosed multiple myeloma patients. 112 patients with untreated multiple myeloma (MM) were included in the study. 36 se x- and age-matched healthy volunteers were used as controls for periph eral blood (PB) studies and 14 for the bone marrow (BM) studies. Simul taneous stainings with the CD3/CD56, CD2/CD16 and CD8/CD57 monoclonal antibodies were systematically performed in PB and CD3/. CD56 and CD2/ CD16 in BM in order to analyse their relationship with the clinical an d biological characteristics of the disease and survival. The expressi on of NK-associated antigens (CD56, CD16 and CD57) assessed within the lymphoid gate, was significantly increased (P < 0 . 001) in the PB of MM patients both in relative and absolute numbers. In the BM a signif icant increase in the percentage of CD56(+) lymphocytes (P < 0 . 001) was also observed; in contrast, the proportion of CD16(+) cells did no t differ significantly from that of normal BM samples. The number of C D56(+)CD3(-) lymphocytes increased significantly within high-risk pati ents (869 +/- 671) as compared to intermediate (388 +/- 212) and low-r isk patients (274 +/- 199) (P = 0 . 04). Moreover, patients with high values of CD56(+)CD3(-) lymphocytes showed a statistically significant association with several adverse prognostic factors including anaemia , hypoalbuminaemia, renal failure, high beta 2M, DNA diploidy and high S-phase plasma cells. In addition, patients with higher absolute numb ers of PB CD56(+)CD3(-) lymphocytes displayed a poorer prognosis, wher eas patients with higher values of CD57(+)CD8(-) cells had a better ou tcome.