[Progression of multiple myeloma during treatment with recombinant G-CSF and absence of G-CSF and IL-6 cell surface receptors on malignant cells].

Recombinant human hematopoietic growth factors are widely used in the treatment of multiple myeloma (MM) especially due to the increasing role of autologous blood stem cell transplantation (ABSCT). We report a patient with MM in whom rapid extramedullary progression of disease was observed during stem cell mobilization with G-CSF. In 56-year-old man with relapsing IgG lambda MM myeloablative therapy with ABSCT was planned 2 years after diagnosis. G-CSF is increasing doses was used for mobilization. Ten days after the start of G-CSF therapy 2 extramedullary (subcutaneous) myeloma infiltrates appeared. For the second mobilization high dose cyclophosphamide and VP-16 with subsequent G-CSF was used. During the time of chemotherapy tumour infiltrates disappeared, however, after one week of G-CSF treatment rapid progression of disease with the formation of multiple extramedullary infiltrates occurred and the patient died in June 1996. Small pieces of subcutaneous tumour infiltrates were removed at autopsy and immediately frozen in liquid nitrogen. Using the panel of specific antibodies the expression of cytokine receptors (IL-1, 2, 3, 6, 7, 8, 10, SCF, gp130, G-CSF, GM-CSF, EPO) and Fas, Pgp and 24-34 kD multidrug resistance-associated protein were examined. However, no expression of cytokine receptors on tumor cells was found. On the contrary, high positivity of surface MDR associated proteins was observed.