Docosahexaenoic acid exerts anti-inflammatory action on human eosinophils through peroxisome proliferator-activated receptor-independent mechanisms.

Background: Despite the fact that previous studies have indicated the significant roles of polyunsaturated fatty acids (PUFAs) in the immune system through peroxisome proliferator-activated receptor alpha (PPARα) and PPARγ, the biological functions and the mechanisms of action in eosinophils are poorly understood.

Methods: We investigated the functional effects of docosahexaenoic acid (DHA, n-3 PUFA) on human peripheral blood eosinophils, using in vitro systems to test the hypothesis that DHA negatively regulates eosinophil mechanisms through PPARα and PPARγ.

Results: Eosinophil apoptosis that spontaneously occurs under normal culture conditions was accelerated in the presence of DHA.

The opposing role of two prostaglandin D2 receptors, DP and CRTH2, in human eosinophil migration.

Background: Prostaglandin D2 (PGD2) regulates various immunological responses via two distinct PGD2 receptors, prostaglandin D receptor (DP), and chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2). Recent studies have demonstrated that PGD2 induces the migration of eosinophils through CRTH2. Although human eosinophils express both DP and CRTH2, it is unclear whether the function of DP is involved in eosinophil migration.

Leptin has a priming effect on eotaxin-induced human eosinophil chemotaxis.

Background: Tissue eosinophilia is one of the hallmarks of allergic diseases and Th2-type immune responses including asthma. Systemic inflammation caused by adipose tissue in obesity via production of adipokines such as leptin has been attracting attention recently as a contributor to exacerbation of allergic immune reactions. In this study, we examined whether leptin might affect eosinophil chemotactic responses.

Acute leukemia of ambiguous lineage, biphenotype, without CD34, TdT or TCR-rearrangement.

Biphenotypic acute leukemia (BAL) is a rare entity that comprises 0.5-3% of all acute leukemias and probably arises from multipotent progenitor cells. The optimal approach for BAL therapy is unknown.

Regulation of peroxisome proliferator-activated receptor-gamma expression in human eosinophils by estradiol.

Background: Peroxisome proliferator-activated receptor-gamma (PPARgamma) is a nuclear receptor that regulates not only adipogenesis but also immune reaction. We previously demonstrated that human eosinophils expressed functional PPARgamma, although the modulator of PPARgamma expression is less well understood. Because clinical studies have shown that the efficacy of PPARgamma agonists as insulin sensitizers is stronger in women than in men, we investigated whether sex hormones caused any changes in eosinophil PPARgamma expression levels.