Diminution of T cells with gamma delta receptor in the peripheral blood of allergic asthmatic individuals

Abstract

Background: T cells are shown to regulate allergy and asthma. They are heterogeneous by virtue of surface receptor subtypes (alpha beta and gamma delta receptors), however, their pathophysiological roles in asthma are unclear.

Objective and methods: The present study employed flow cytometric analysis to compare the size of T-cell subsets and eosinophils present in the peripheral blood of healthy, allergic and allergic asthmatic individuals.

Results: Current results demonstrated that the percentages of gamma delta T cells declined from 4.1% in healthy to 3.2% in the allergic subjects and to a significantly lower (P = 0.01) 2.4% in allergic asthmatics. The absolute numbers of circulating gamma delta T cells also were diminished in a similar fashion such that healthy individuals had a significantly higher mean cell count (91.8 x 10(3)/mL) than did allergic asthmatics (47.8 x 10(3)/mL) (P = 0.0266). In contrast, alpha beta T cells were comparable in the healthy, allergic, and allergic asthmatic populations (65.3%, 65.8% and 69.4%, respectively); the differences were not statistically significant. On a populational basis, the proportion of individuals having both gamma delta T cells < or = 4.1% and eosinophils > or = 2.1% was the lowest in the healthy population (30.8%), but was elevated in the allergic group (85.7%) as well as in the allergic asthmatic group (86.6%). However, on an individual basis, those who had reduced gamma delta T cells did not have consistently higher eosinophil counts or IgE level.

Conclusion: It was concluded that no significant correlation existed between the levels between gamma delta T cells and eosinophils or between gamma delta T cells and IgE present in the peripheral blood. This report, for the first time, documents that allergic asthmatics have reduced gamma delta T cells with reciprocally elevated eosinophil numbers in their peripheral circulation. However, it does not indicate that the reduction of gamma delta T cells directly correlates with the predominance of eosinophils of IgE levels in the diseased populations. The pathophysiological role of gamma delta T cells in allergic diseases awaits further exploration.