Plasma cell acid phosphatase activity as prognostic factor in multiple myeloma: relationship to the thymidine-labeling index.

Abstract

Plasma cell acid phosphatase (AP) activity and thymidine labeling index (LI%) were evaluated concomitantly in 52 patients with monoclonal gammopathies. AP score, percentage of AP positive plasma cells, and LI% were significantly higher in 26 patients with multiple myeloma (MM) at the time of diagnosis than in 11 monoclonal gammopathy of undetermined significance (MGUS) and eight smoldering myeloma (SM) patients. LI% had the highest statistical correlation with disease status. A 1% cutoff could clearly separate the patients with progressive MM compared to those with stable disease (SM-MGUS) (P less than .001). There was a significant overall correlation between the AP score and LI% (P less than .005). Since LI% is a recognized powerful prognostic factor, this correlation suggests that the AP score can also be a reliable test predicting patient survival duration. In addition, we identified a subgroup of IgG MM patients with very high tumor mass who had a low LI% but a high AP score. This was associated with very poor patient survival and indicated the discrete prognostic importance of AP score in this subgroup with low LI%. Thus, both the LI% and AP score can be recommended as helpful clinical tests in patients with monoclonal gammopathies.

Multiple Myeloma: Beta-2-Microglobulin is not a Useful Follow-Up Parameter

“…However, some authors have argued that serum p2M is not a reliable clinical parameter in indi vidual patients [17], In previous papers, we demon strated the powerful prognostic significance of plas ma cells proliferative activity [21,22]. However, plas ma cells proliferative activity and serum p2M were not correlated and we concluded for an indepen dent utility of both these parameters [23].…”

Lack of Correlation between Plasma Cell Thymidine Labelling Index and Serum Beta-2-Microglobulin in Monoclonal Gammopathies

“…In very high tumor burden, MM SB2M is usually very high, but LI may be low. However, a small increase in tumor burden may be life-threatening for these patients, thus even a low LI in this group may not confer a good prognosis [20]. For evaluation of patient survival du ration, LI alone is not a useful parameter.…”

Allogeneic Bone Marrow Transplantation in Multiple Myeloma

“…Bone marrow aspiration revealed a massive infiltra tion (94% of the nucleated cells) by typical small plasmocytes and some plasmablasts (fig. 1); plasma cell acid phosphatase activity, evaluated by a modification of the method of Goldberg and Barka as described elswhere (4], was very high (score 2.8; normal values in our laboratory 1.29 ± 0.79). An x-ray film of the axial skeleton con-1 Supported by the 'Consiglio Nazionale delle Ricerche' (CNR), Roma, CT 83.00870.96, by the 'Associazione Italiana Ricerca contro il Cancro" (AIRC), Milano, and by the 'Associazione Italiana contro la Leucemia' (AIL), Genova.…”