Chemotherapy-associated changes in 31P MRS spectra of sera from patients with multiple myeloma.

31P NMR spectra were obtained from sera of 22 healthy volunteers and 20 patients with multiple myeloma at the time of diagnosis and repeated up to five times during therapy. All spectra consisted of a Pi peak (used as a reference peak) and two peaks from phospholipids (PL): one peak due to phosphatidylethanolamine and sphingomyelin (PE + SM) and a second peak due to phosphatidylcholine (PC). Prior to therapy, peak intensities of the phospholipids were low relative to Pi. During therapy leading to remission, the resonance from PL progressively increased to approximate the spectral pattern seen in normal sera. By contrast, in non-responders an opposite trend was noted: the intensities of the phospholipid peaks became progressively reduced or remained unchanged. Long-term follow-up studies showed a good correlation between this 31P MRS evaluation of sera and the response of the disease to the therapy. In addition to the correlation with tumor response, our studies also show significant correlations between area, intensities of peaks of PE + SM, PC, and the concentrations of high-density lipoprotein (HDL) (correlation coefficients 0.46, 0.43, 0.59, respectively; p < 0.001). We found that the concentration of HDL in serum of patients with multiple myeloma was significantly reduced. In individuals responding to therapy HDL levels increased to the point where there were no statistically significant differences between them and healthy volunteers. In patients not responding to therapy, HDL concentration did not increase.(ABSTRACT TRUNCATED AT 250 WORDS)