Summary. Activated protein C (APC) protects against sepsis in animal models and inhibits the lipopolysacharide (LPS)-induced elaboration of proinflammatory cytokines from monocytes. The molecular mechanism responsible for this property is unknown. We assessed the effect of APC on LPS-induced tumour necrosis factor a (TNF-a) production and on the activation of the central proinflammatory transcription factor nuclear factor-kB (NF-kB) in a THP-1 cell line. Cells were preincubated with varying concentrations of APC (200 mg/ml, 100 mg/ml and 20 mg/ml) before addition of LPS (100 ng/ml and 10 mg/ml). APC inhibited LPS-induced production of TNFa both in the presence and absence of fetal calf serum (FCS), although the effect was less marked with 10% FCS. APC also inhibited LPS-induced activation of NF-kB, with APC (200 mg/ ml) abolishing the effect of LPS (100 ng/ml). The ability of APC to inhibit LPS-induced translocation of NF-kB is likely to be a significant event given the critical role of the latter in the host inflammatory response.

To investigate which subsets of peripheral blood mononuclear cells (PBMCs) are susceptible to infection with hepatitis C virus (HCV) and hepatitis G virus (HGV) or GB virus C (GBV-C), a PCR-based assay using tagged primers in the core region (HCV) and NS3 region (HGV/GBV-C) for the specific detection of negative strand (replicating) viral RNA sequences was developed. In liver biopsy samples both positive and negative strands of HCV RNA were detected, at levels ranging from 3 to 11i10 6 RNA copies per 10 6 cells and 3n7-4n2i10 3 copies per 10 6 cells respectively, while lower frequencies of positive strands of GBV-C/HGV RNA were detected (from 13 biopsies, the highest frequency was 7n3i10 3 per 10 6 cells). In no samples were negative RNA strands detected. To investigate extra-hepatic

Objective. To determine whether functional cytokine gene polymorphisms influence disease susceptibility and phenotype in patients with psoriatic arthritis (PsA).Methods Results. No significant difference in genotype frequencies was observed between the control and the PsA patient populations, and no association with Steinbrocker functional class, disease classification (polyarticular or oligoarticular), presence of spinal involvement, or age at PsA onset was observed. The presence of joint erosions was significantly associated with the TNF␣ ؊308 and TNF␤ ؉252 polymorphisms (P < 0.0001 and P ‫؍‬ 0.0017, respectively). Frequencies of the TNF␣ ؊308 and TNF␤ ؉252 genotypes were also significantly different (P ‫؍‬ 0.0078 and P ‫؍‬ 0.0486, respectively) in a group of progressors (patients with early PsA in whom the number of joint erosions in the hands and feet increased over a median interval of 24 months) compared with a group of nonprogressors. Age at psoriasis onset was significantly associated with the TNF␤ ؉252 and TNF␣ ؊308 polymorphisms (P ‫؍‬ 0.0003 and P ‫؍‬ 0.0081, respectively). The TNFB2B2 and TNF␣ ؊308 AA genotypes were associated with the earliest mean ages at psoriasis onset.Conclusion. The TNF␣ ؊308 and TNF␤ ؉252 polymorphisms were significantly associated with age at psoriasis onset, presence of joint erosions in PsA, and progression of joint erosions in early PsA. TNF gene polymorphisms may be useful prognostic markers in PsA, and these results support the rationale for using anti-TNF treatment in patients with severe, progressive PsA.

Summary. Many sequelae associated with endotoxaemicinduced shock result from excessive production of the cytokine mediators, tumour necrosis factor alpha (TNF-a), interleukin 1 (IL-1) and IL-6 from lipopolysaccharide (LPS)-activated monocytes. Protein C (PC)/activated protein C (APC) has potent cytokine-modifying properties and is protective in animal models and human clinical trials of sepsis. The precise mechanism by which this antiinflammatory response is achieved remains unknown; however, the recently described endothelial protein C receptor (EPCR) appears to be essential for this function. The pivotal role that monocytes play in the pathophysiology of septic shock led us to investigate the possible expression of a protein C receptor on the monocyte membrane. We used similarity algorithms to screen human sequence databases for paralogues of the EPCR but found none. However, using reverse transcription±polymerase chain reaction (RT±PCR), we detected an mRNA transcribed in primary human monocytes and THP1 cells that was identical to human EPCR mRNA. We also used immunocytochemical analysis to demonstrate the expression of a protein C receptor on the surface of monocytes encoded by the same gene as EPCR. These results confirm a new member of the protein C pathway involving primary monocytes. Further characterization will be necessary to compare and contrast its biological properties with those of EPCR.

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