Higher LPS-stimulated TNF-α mRNA levels in peripheral blood mononuclear cells from non-Hodgkin's lymphoma patients

Objective. The aim of the present study was to investigate the capacity of normal immune blood cells from non-Hodgkin's lymphoma patients to produce tumor necrosis factor (TNF) after lipopolysaccharide (LPS) stimulation and the influence of the TNF (-308) polymorphism in this production. Materials and methods. A whole peripheral blood cell assay was utilized following LPS stimulation. At selected incubation times, supernatants were harvested for protein dosage, while mRNA was extracted and reverse-transcribed. The amount of TNF mRNA was quantified using real-time quantitative polymerase chain reaction (PCR) and genomic DNA was typed for TNF (-308) polymorphism. Results. Upon LPS stimulation, TNF-secreted protein was slightly but not significantly increased in lymphoma patients when compared to controls. In contrast, the relative TNF mRNA amounts were significantly higher in lymphoma patients at 30 minutes (median 27.75 vs 16.00; Mann-Whitney U-test p < 0.05), at 4 hours (52.00 vs 31.00;p < 0.05), and at 24 hours (19.50 vs 9.00;p < 0.05). In addition, patients carrying the variant TNF2 allele had higher relative TNF mRNA levels than TNF1 homozygotes (p = 0.02). Conclusion. The LPS-induced TNF mRNA levels are higher in peripheral blood cells (PBC) from lymphoma patients than from controls, while TNF protein secretion is not strikingly different. Altered regulation of TNF mRNA translation or TNF protein secretion may contribute to these observations. Taken together, an increased susceptibility for TNF gene transcription after LPS stimulation was observed in PBC (mainly in monocytes) from lymphoma patients, and especially those carrying the TNF2 allele. (C) 2001 International Society for Experimental Hematology. Published by Elsevier Science Inc.