In vitro diagnosis of drug allergy. Assessment of the chromatin activation test (CAT).

A controlled in vitro study was performed on people suspected to be allergic to one or more drugs by using the chromatin activation test. This test is based on the decrease of the nuclear lymphocyte birefringence induced by stimulation with allergens. A group of 70 patients with suspected drug hypersensitivity and a control group of 37 persons were studied. Fifty-two patients were evaluated by clinical criteria and the cause-effect relationship classified as definitive, probable, possible, improbable and not related. Previously, 18 patients had been considered allergic to penicillin by means of RAST and/or skin tests. The chromatin activation of the peripheral lymphocytes was determined by comparing the nuclear birefringence of cells incubated with different sequential drug concentrations, with that detected in cells incubated without drugs, employing a polarized light microscope. When possible, the oral challenge was carried out in the negative cases. In 123 tests made in the patient group, 45 were positive and distributed as follows: in the cases of definitive imputability (83.3%), probable (60.5%), possible (22.7%), improbable (0%) and not related (0%); in the cases with RAST and/or skin positive tests (33.3%). Thirty-two of 36 oral tests confirmed those results. Among 50 tests performed in the control group, two (4%) were false positive. These results point to the usefulness of this test in the diagnosis of drug allergy.

Immunopharmacological effects of Saccharomyces boulardii in healthy human volunteers.

Investigation of oral administration of Saccharomyces boulardii in healthy volunteers demonstrates several cellular and humoral changes in peripheral blood. Among its effects are the increase of erythrocytes, leucocytes, polymorphs, neutrophils, complement components C3, C5, C3d, serum anticomplementary activity and leucocyte chemokinesis, specially when autologous serum and antigen have been added to the culture medium and decrease of complement haemolytic activity (CH50, classic and alternative pathways). We have also demonstrated that in vitro S. boulardii was able to activate complement directly, to fix C3b to its surface and that its phagocytosis by mononuclear cells was complement-dependent. The overall changes in serum proteins suggested changes of acute phase proteins typical of an inflammatory process. Furthermore S. boulardii had no mitogenic response of lymphocyte populations. Our results demonstrated that S. boulardii activates the reticuloendothelial system and complement system and suggest that S. boulardii merits therapeutic trial in a variety of clinical situations.