Neutrophil F-actin dynamics in Familial Mediterranean Fever: the unequal effect of colchicine on activated neutrophils.

In the innate immune system, cellular adaptation regulates neutrophil activation and chemotaxis, which have a pivotal role in Familial Mediterranean Fever (FMF) pathogenesis. We investigated neutrophil F-actin, phagocytosis and macropinocytosis dynamics during neutrophil chemoattractant-dependent activation in FMF patients carrying mutations in the MEFV locus. We found that while a non-stimulated neutrophil shows an increased overall F-actin content in patients with FMF, the activation-dependent F-actin dynamics in the presence of chemoattractant peptide is significantly reduced.

The 1F7 idiotype is selectively expressed on CD5+ B cells and elevated in chronic hepatitis C virus infection.

Antibodies against different chronic viruses, including hepatitis C virus (HCV), express a public cross-reactive idiotype (Id) designated as 1F7. The prominence of this Id may reflect selective engagement of B1 B cells by chronic pathogens. We investigated this by comparing 1F7 Id expression on CD5(+) and CD5(-) B cells, total IgG, total IgM and anti-HCV core antibodies in different HCV exposure settings.

Heightened endotoxin susceptibility of monocytes and neutrophils during familial Mediterranean fever.

Familial Mediterranean fever (FMF) is a relapsing autoinflammatory disorder, caused by various mutations in the MEFV gene, which encodes a protein called pyrin, expressed in neutrophils and activated monocytes. Induction of monocyte endotoxin tolerance is observed in FMF patients during attack, whereas monocytes from patients in the attack-free period failed to induce lipopolysaccharide tolerance and exhibited heightened sensitivity to bacterial endotoxin. In this study, we demonstrated that impaired lipopolysaccharide tolerance induction in attack-free FMF patients correlates with both increased lipopolysaccharide-induced proinflammatory cytokine synthesis polarization and a different time-course pattern of lipopolysaccharide-induced changes on monocytic surface expression of CD14 and CD11b coreceptors.