Tumor necrosis factor-alpha and interferon-gamma in serum of multiple myeloma patients.

The levels of TNF-alpha and IFN-gamma were examined in serum from 32 patients with multiple myeloma and 33 healthy controls using sensitive enzyme-linked immunosorbent assays (ELISA). The detection limits for TNF-alpha and IFN-gamma were 80 pg/ml and 200 pg/ml, respectively. All samples were obtained at the time of diagnosis, before treatment. In sera from 8 of the myeloma patients the TNF-alpha concentrations were above the detection limit with a maximum value of 1.0 ng/ml. Overall, the TNF-alpha levels of the myeloma patients did not differ from the levels of the control group. Detectable amounts of IFN-gamma were found in 17 of the patient sera with 10.7 ng/ml as the top value. In contrast, the control group showed significantly lower s-IFN-gamma levels without detectable amounts in any of the samples (p less than 0.01). High IFN-alpha levels in 4 patients coincided with intercurrent infections but were not accompanied by a parallel increase of the TNF-alpha levels. The TNF-alpha and IFN-gamma values were compared with the serum levels of beta 2-microglobulin, calcium and creatinine, the M-component, the erythrocyte sedimentation rate, the degree of plasma cell infiltration of the bone marrow, the degree of skeletal destructions and with patients survival. No significant correlations could be observed between TNF-alpha or IFN-gamma and these variables of myeloma activity. We conclude that detection of serum TNF-alpha and IFN-gamma levels in multiple myeloma appears to be without any clinical value.