Surface expression of adenosine deaminase in mitogen-stimulated lymphocytes.

Adenosine deaminase (ADA) expression on the surface of mitogen-stimulated lymphocytes was studied by flow cytometry. The gate for lymphocytes was located by cell size (forward scatter), cytoplasmic complexity (side scatter) and by expression of the markers CD2, CD4, CD8 and CD19. After mitogenic proliferation two populations appeared, one corresponding to non-stimulated cells, and the other consisting of larger cells which showed relatively high expression of adenosine deaminase on their surface. The increase was similar to that observed for CD71 expression, and paralleled the increase in 3H-thymidine incorporation. There was a correlation between ADA and CD71 expression (r = 0.92 for phytohaemagglutinin (PHA) and 0.97 for pokeweed mitogen (PWM)). These results suggest a role for ecto-adenosine deaminase in lymphocyte proliferation and/or triggering.

Histamine and catecholamine values in allergic subjects under specific hyposensitization treatment.

It has been quite some time since a histamine/catecholamine balance was established. This balance was also observed at the moment of anaphylactic shock in dogs previously hypersensitized. Few findings have demonstrated that histamine is released in skin reaction produced by allergen injection. The hypothesis that the histamine release was positive in intradermal and subcutaneous reaction provoked through injecting both routes by allergen used for hyposensitization led us to carry out the present study in a group of allergic patients. We determined the quantity of histamine found in blood plasma prior to and 4 hours after hyposensitization, and observed if there was an increase in the histamine and catecholamine produced, that is to say if a histamine-catecholamine balance was established. However, no such balance was produced. Instead it was evident in this work that no histamine was released in the area of administration. We in part confirm the works of other authors which doubt the existence of such a release and incline towards the idea that what is released are vasoactive kinins.

The role of catecholamines in specific hyposensitization.

With the use of modern techniques for the evaluation of catecholamines, this work studies the behavior of catecholamines in the urine of a group of 33 allergic patients before and after injection of allergens as part of immunotherapy. In 24 of these patients the amount of adrenalin and norepinephrine had increased 24 hours after the injection of the allergens (p less than 0.001). This confirms the noradrenergic role of the allergen, apart from the release of histamine as a result of the immunologic mechanism. Histamine is released as a result of the increase of the norepinephrine and is evidence of a homeostatic mechanism, as had been established in a previous investigation by the authors.

The role of cyclic amp in the process of specific hyposensitization.

The parenteral administration of a specific allergen produces a local edema due to the liberation of histamine. We have investigated the plasmatic cyclic AMPO in this reaction. A group of allergic patients (36 in all) with asthma or rhinitis or both diseases and with a very positive prick skin test was studied. The level of cyclic AMP was investigated before and after injecting the patients with the specific hyposensitizing extract. The average levels of cyclic AMP in our patients before the injection of the specific extract were 2.6 pmol/ml and this corresponded to the normal levels found in the controls in our laboratory (13.8 pmol/ml). After the injection of the allergen these levels increased by an amount that varied between 0.1 pmol/ml and 33.4 pmol/ml in 61.1% of the cases (p > 0.05). The cyclic AMP decreased by an amount that varied between 0.1 pmol/ml and 16.0 pmol/ml in 38.8% of the patients (p > 0.05).