Increased nuclear factor-kappaB activation in peripheral blood monocytes of patients with rheumatoid arthritis is mediated primarily by tumor necrosis factor-alpha.

OBJECTIVE: Rheumatoid arthritis (RA) is a disease characterized by prolonged production of tumor necrosis factor-alpha (TNF-alpha), which is regulated by the Rel/nuclear factor-kappaB (NF-kappaB) transcription factors. We assessed NF-kappaB activation in peripheral blood mononuclear cells (PBMC), peripheral blood lymphocytes (PBL), and monocytes from patients with RA, patients with ankylosing spondylitis (AS), and healthy subjects. METHODS: NF-kappaB activation was determined by electrophoretic mobility shift assays and by Western blotting in PBMC, monocytes, and PBL isolated from peripheral blood of patients with RA, patients with AS, and healthy subjects and determined after ex vivo pretreatment of PBMC, PBL, and monocytes of patients with RA and healthy subjects with infliximab and with etanercept. RESULTS: Enhanced NF-kappaB activation was observed in monocytes, PBL, and PBMC isolated from patients with RA, but not in PBMC, PBL, and monocytes of patients with AS and healthy subjects. The NF-kappaB complex was composed of p50 and p65 subunits and its activation required inhibitor of NF-kappaBalpha degradation. We observed a positive correlation between the NF-kappaB activation in monocytes, PBL, and PBMC, and TNF-alpha levels in peripheral blood of patients with RA. Ex vivo treatment with infliximab and etanercept decreased NF-kappaB activation in monocytes of patients with RA, but not in PBL and PBMC, and not in healthy subjects. CONCLUSION: Our results indicate a role for NF-kappaB activation and TNF-alpha in the activation of monocytes of patients with RA, and suggest an important role of circulating monocytes in RA pathogenesis.

Mixed cytomegalovirus glycoprotein B genotypes in immunocompromised patients.

On the basis of sequence variation in the UL55 gene that encodes glycoprotein B (gB), human cytomegalovirus (CMV) can be classified into 4 gB genotypes. The goal of the present study was to determine the distribution of CMV gB genotypes and the effect of gB type on clinical outcomes in a cohort of immunocompromised patients, including both transplant recipients and nonrecipients. The distribution of gB genotypes was as follows: gB1, 28.9% of patients; gB2, 19.6%; gB3, 23.7%; gB4, 2.0%; and mixed infection, 25.8%. In contrast to patients infected with a single gB genotype, patients infected with multiple gB genotypes developed progression to CMV disease, had an increased rate of graft rejection, had higher CMV loads, and were significantly more often infected with other herpesviruses. The presence of multiple gB genotypes, rather than the presence of a single gB genotype, could be a critical factor associated with severe clinical manifestations in immunocompromised patients.