Paclitaxel is a chemotherapeutic agent used in the treatment of multiple types of malignant tumors which was discovered from the Taxus brevofilia tree. In some patients, anaphylaxis develops during the first exposure to paclitaxel, suggesting that primary sensitization may have occurred through hidden or unidentified allergens that produce cross-reactivity. Skin testing may be useful in identifying sensitization to these allergens. Atopy has also been reported in patients with hypersensitivity reactions (HSR) to paclitaxel.The aim of this study is to evaluate the association between atopy and sensitization to allergens with the development of immediate HSR to paclitaxel.

Skin prick tests (SPT) for environmental and food allergens were applied to 76 patients recently diagnosed with cancer. A SPT to paclitaxel was applied and if negative, an intradermal test was performed. After paclitaxel's infusion, the development of immediate HSR was observed.

Of 76 skin tests, 43% of patients had allergen sensitization and 57% did not. HSR occurred in 12.1% and 11.6% of each group, respectively. Five percent of patients tested positive to paclitaxel and only one had an immediate HSR. Eighty-nine percent of patients who developed an HSR had a family or personal history of atopy.

Sensitization to environmental or food allergens does not appear to be a risk factor for the development of immediate HSR to paclitaxel, suggesting that there are other non-IgE-mediated immunologic mechanisms responsible for their development, however, a personal and family history of atopy increases 8x the risk of developing anaphylaxis.

Pollen is an important cause of allergic respiratory ailments in the Mexico City Metropolitan Area (MCMA). However, very little is known if ambient air temperature correlates with the early blooming of plants observed in other urban areas around the world. A research study was conducted during the dry season of 2012-2013 at three representative sites of the MCMA with different urban characteristics with the aim to understand the relationships between the profusion and diversity of pollen against temperature and other meteorological variables and degree of urbanization. Pollen samples were collected using a Hirst-type trap sampler in the sites: Merced (highly urbanized), Iztapalapa (medium-high urbanized) and Coyoacan (moderately urbanized). Urbanization levels were determined using a composite index based on population density, proportion of surface covered by construction and asphalt, and urban heat island intensity. A set of representative pollen sampling tapes were assayed under a light microscope at magnification of ×1,000 and converted to grains per cubic meter. The most representative pollen types found in the three sites were, regardless of urbanization levels were: Fraxinus, Cupressaceae/Taxodiaceae, Casuarina, Alnus, Myrtaceae, and Pinus. Total pollen concentration was greatest in the moderately urbanized area, although earlier blooming took place at the highly urbanized zone. Total pollen concentration in the medium-high urbanized site has the lowest because the green areas in this zone of MCMA are few. In a diurnal basis, the most abundant pollen types peaked near midday or in the afternoon evening at the three sites. A Spearman test showed a positive correlation among bihourly pollen concentrations, temperature and relative humidity in all sites, but wind speed just correlated in Iztapalapa and Coyoacan. The results obtained suggest that Urban Heat Island Intensity can disturb flowering periods and pollen concentrations, largely in the highly urbanized areas. A principal components analysis established that the concentrations of each pollen type differed across the urbanization gradients. Additionally, it was found that a large number of allergenic pollens are produced by ornamental trees, some only recently introduced by urban planners.