Abstract
Tumor necrosis factor α (TNF‐α) has come into recent focus as a proinflammatory cytokine derived from monocytes/macrophages. We developed a novel system (the SEK‐5001 system) for measurement of ex vivo production of TNF‐α stimulated by lipopolysaccharide (LPS) as a marker of immune function. In the present study, we evaluated the performance of this system as a diagnostic tool. Furthermore, we compared TNF‐α levels with data from other immune function tests, including lymphocyte blast formation test and differential leukocyte counts. Incubation of whole blood with a stimulation of low‐dose LPS (100 EU/mL blood) for 4hr at 37°C gave acceptable results. After incubation, plasma TNF‐α levels were determined by enzyme‐linked immunosorbent assay (ELISA). The specificity, reproducibility, and recovery of the SEK‐5001 system were excellent. No correlation between TNF‐α levels and total leukocyte counts was found. Lymphocyte blast formation test and monocyte counts, however, were correlated with TNF‐α levels in blood from patients with hematological malignancy and aplastic anemia before treatment. This assay system may potentially be clinically applicable to assess in vivo immune function. J. Clin. Lab. Anal. 16:273–278, 2002. © 2002 Wiley‐Liss, Inc.
Keywords: TNF‐α production, low‐dose LPS stimulation, whole‐blood culture, monocyte/macrophage, lymphocyte blast formation test
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