Neopterin, a pteridine derivate, is produced and released by lymphocytes and monocytes/macrophages after stimulation by T-cell derived interferon (IFN) gamma. The urinary excretion of neopterin and plasma IFN-gamma levels were measured in 35 patients with multiple myeloma (MM) and 21 patients with other monoclonal gammapathies (MG). Significantly higher excretion of neopterin was found in patients with MM in the time of diagnosis and/or progressive phase of disease (median 963,7 mumol/mol creatinine, range 183,9-2 376,3) comparing the patients in stable phase of MM (median 407,4, range 184,3-826,4), monoclonal gammapathy of undetermined significance (406,2, 226,9-1 689,3) and other MG (452,5, 240, 4-913,6) (p < 0,05). Elevation of urinary neopterin levels preceded changes of other parameters of disease activity by several months, persistent high urinary excretion was associated with refractory disease respectively. The differences of neopterin levels between patients of various clinical stages of MM was observed in newly diagnosed and progressive disease (III. vs. I and II. clinical stage, p < 0.05), but not in stable phase of MM. The plasma concentration of IFN-gama were insignificantly higher in MM than in health controls, however, the difference between all groups of patients was not found. We conclude, that neopterin is a good marker of disease activity in patients with MM. The plasma levels of its regulatory cytokine, IFN-gama, did not correlate with urine neopterin levels in our study.

Keywords: Adult; Aged; Biopterin /analogs & derivatives/; Humans; Interferon-gamma /blood/; Middle Aged; Multiple Myeloma /metabolism/; Neopterin