In Vitro Basophil Responsiveness to Allergen Challenge After Gamma-tocopherol Supplementation in Allergic Asthmatics

Oxidant stress plays an important role in mucosal inflammation such as seen with asthma.
Previous studies have also shown that asthmatic individuals tend to have lower endogenous
levels of antioxidant such as vitamins E and C, and that supplementing antioxidants can
decrease exacerbations associated with ozone exposure in children. We are interested in
future studies to examine the benefits of gamma-tocopherol supplementation for people with
allergic asthma. This current study will determine if gamma tocopherol supplementation
reduces allergic responses in vitro, providing us information that will allow us to design
future masked placebo-controlled studies of this potentially important antioxidant on in
vivo allergic responses.

The purpose of this study is to address the question if in vivo gamma-tocopherol
supplementation at 1200 mg daily blunts allergen-specific inflammatory responses in vitro.
Members of our group have previously shown that administration of 100 mg/kg of gamma
tocopherol daily for four days prior to Ova challenge in sensitized allergic brown Norway
rats prevented eosinophil infiltration into the airways1. In addition, this dose of gamma
tocopherol blunted production of IL-4, IL-5, IL-13, IFN-gamma in the nasal airway; and PGE2,
LTB4 and cysteinyl leukotrienes by the pulmonary airway. Mucous cell metaplasia was
decreased as well in the gamma Tocopherol treatment group 1. In an in vivo study of gamma
tocopherol performed at our center (IRB# 05-CEMALB-1407), we found that daily administration
of 2 capsules of a gamma tocopherol rich preparation (each capsule containing 623 mg of
gamma tocopherol, 61.1 mg of d-alpha-tocopherol, and 11.1 mg of d-beta tocopherol), was able
to increase serum levels of gamma tocopherol to 18.6 + 2.6 uM after 8 days of daily
administration; serum levels of alpha tocopherol were 25.2 + 2.4 uM, and delta-tocopherol
were 5.1 + 1.1 uM2 . Using the data from the in vivo study, we performed basophil
activation tests on dust mite allergic subjects, pretreating blood obtained from
venipuncture with pharmacologic doses attained in the vivo study with gT, aT, gCEHC, and
aCEHC. We found that gT, gCEHC, and aCEHC blunted basophil activation induced by the
allergen D. farinae, as measured by upregulation of CD63 on the cell surface of basophils.
As secondary aims, we will also examine the effect of gamma tocopherol supplementation on
non-allergic stimuli that have been shown to activate basophils, such as IgG anti-IgE and
N-formyl-methionyl-leucyl-phenylalanine (f-met-leu-phe), as well as in vivo
allergen-specific responsiveness through epicutaneous skin testing before and after
supplementation. Exploratory analyses will include assessing the effect of gamma tocopherol
supplementation on monocyte and basophil responsiveness to in vitro endotoxin and
lipoteichoic acid challenge.