In 93 newly diagnosed lymphoma patients, tumor necrosis factor alpha (TNF alpha) and its p55 soluble receptor (p55-sR), were prospectively determined in plasma by IRMA and ELISA methods respectively. These 93 patients included 31 patients with low grade lymphoma, 55 with intermediate or high grade lymphoma and 7 with Hodgkin's disease. Median TNF alpha plasma values were 20 pg/mL (range 5-380 pg/mL) in patients versus 7 pg/mL (range 4-9 pg/mL) in healthy control subjects. Presence of TNF alpha level equal or greater than 20 pg/mL was significantly associated with elevated LDH level, serum beta 2-microglobulin level > or = 3 mg/L, hemoglobin < or = 12 g/dL, Ann Arbor stage III or IV disease, and with bulky tumor. High level of TNF alpha was also associated, although less strongly, with B symptoms, poor performance status, and serum albumin < or = 35 g/L, yet it was not associated with change in acute phase protein levels. Levels of p55-sR were also markedly elevated in these lymphoma patients (median of 3.5 ng/mL, range 0.8-18.8 ng/mL) versus 1.45 ng/mL in control subjects (range 1.1-2.3 ng/mL). Level of p55-sR equal or greater than 3.5 ng/mL was significantly associated with poor performance status, B symptoms, beta 2-microglobulin levels > or = 3 mg/L, serum albumin < or = 35 g/L, C-reactive protein > 6 mg/L, hemoglobin < or = 12 g/dL, and bulky tumor. In the whole group of 93 patients, both high TNF alpha and p55-sR levels strongly predicted short freedom from progression and overall survival. This study suggests that elevated TNF alpha and p55-sR plasma levels have a high correlation with other adverse prognostic factors in lymphoma patients and predict their poor outcome.