Further characterization of histamine releasing chemokines present in fractionated supernatants derived from human mononuclear cells

Chronic Spontaneous Urticaria: The Devil's Itch

Chronic urticaria is defined as the presence of urticaria for a period exceeding 6 weeks, assuming symptoms for most days of the week. It is divided into chronic inducible urticarias and chronic spontaneous urticaria, previously termed chronic idiopathic urticaria. The latter designation emphasizes that patients can experience urticaria independent of any exogenous stimulus even if one can define circumstances that may worsen symptoms. A search for such an external "cause" is fruitless because the underlying abnormality is "intrinsic," whether it is autoimmune, or some unknown process. Approximately 40% of patients with chronic spontaneous urticaria report accompanying episodes of angioedema, whereas 10% have angioedema as their primary manifestation. In most cases, it is a self-limiting disorder, persisting for 2 to 5 years in most cases, although 20% of patients suffer for more than 5 years. The treatment that has evolved is largely empiric, based on double-blind, placebo-controlled studies whenever possible, but is not yet targeted to any particular pathogenic mechanism. In this article, we review the current status regarding pathogenesis, discuss the diagnostic workup, and update the approach to treatment including consideration of published guidelines, our own experience, and guideline updates that are being prepared.

A method of computationally enhanced detection of chromatogram regions with apparent high relative agonist activity

An occasional but difficult problem arises in drug discovery during a chromatographic analysis in which high background activity is associated with the presence of most eluting molecular species. This makes the isolation of material of high relative activity difficult. A computational method is shown that clarifies the identification of regions of the chromatogram of interest. The data for bioactivity and absorbance are normalized to percent of maximal response, filtered to raise very small or zero values to a minimal level, and the activity/absorbance ratio is plotted per fraction. The fractions with relatively high activity become evident. This technique is a helpful adjunct to existing graphical methods and provides an objective relationship between the data sets. It is simple to implement with Visual Basic and spreadsheet data, making it widely accessible.

A method for production and determination of histamine releasing activity from human peripheral blood mononuclear cells

Histamine releasing factors, i.e. cytokines capable of inducing histamine release from basophils or mast cells, have been suggested to be involved in the pathogenesis of, for example, allergic late-phase reactions. Here we describe a controlled method for production and determination of histamine releasing activity (HRA) from human peripheral blood mononuclear cells (MNC). MNC were incubated with concanavalin A (Con A) for 2 h and cultured for another 40 h in fresh serum free medium. The culture supernatants were concentrated 19-25 fold by ultrafiltration (molecular weight cut-off: 3000 Da). The preparations of HRA induced dose- and Ca2+-dependent histamine release from leukocytes. Supernatants of parallel cultures of unstimulated MNC did not induce histamine release. The HRA was neither due to exogenous histamine releasing compounds (e.g. Con A) nor to residual histamine in the preparations of HRA. The kinetics of HRA induced histamine release (half-maximal release after > 40 min) were slower and more protracted than those of anti-IgE induced histamine release. However, based on a comparison between HRA induced histamine release from leukocytes and purified (97%) basophils, this did not appear to be due to an indirect effect on the basophils. Finally, neither the production of nor the response to HRA was dependent on the allergic status of the donor.