Seasonal Variations of T-Cell Cytokine Pattern in Peripheral Blood from Atopic Subjects

Abstract

Previous studies on the effect of seasonal exposure to the sensitizing antigen on T-cell cytokine pattern from atopic subjects evaluated T-cell cytokine production by titration in the serum or culture supernatants. The purpose of this study was to determine the seasonal variations of T-cell cytokine pattern from atopic subjects at the single-cell level. We examined the interleukin-4 (IL-4) and interferon-gamma expression in peripheral blood CD4 + and CD8 + T cells from 11 subjects with grass-pollen-sensitive allergy before and during the 1999 grass pollen season using a flow cytometric method of intracellular cytokine detection. Eight healthy volunteers served as the control group. Flow cytometric analysis of peripheral blood lymphocytes showed no seasonal variations of IL-4- and interferon-gamma-producing T cells in atopic subjects. However, there was a decreased percentage of IL-4-producing cells among peripheral blood CD4+ and CD8+ T cells from the atopic subjects both during and outside the pollen season in comparison to the controLs. We did not find seasonal variations of T-cell cytokine pattern in peripheral blood from atopic subjects. However, we observed a decreased percentage of IL-4-producing T cells in peripheral blood from these subjects in comparison to healthy controls. These data add to the view of a continuous migration of T helper 2 (TH2) cells from the blood to the tissues of primary allergen exposure.

Lack of allergy to timothy grass pollen is not a passive phenomenon but associated with the allergen‐specific modulation of immune reactivity

“…In the present study, the impact of timothy grass (TG) pollen season on TG‐specific T cell responses was analysed in allergic and non‐allergic individuals. In line with previous studies , responses in allergic subjects were polarized towards a Th2 type, significantly increased during TG pollen season. Strikingly, in non‐allergic donors an opposing pattern with broadly decreased immune reactivity in season was observed.…”

“…The impact of seasonality on immune reactivity has been studied in allergic subjects , but little is known about T cell reactivity in non‐allergic subjects during natural allergen exposure. In the present study, we analysed the impact of grass pollen season on TG‐specific T cell responses in allergic and non‐allergic subjects.…”

Cytokine production in peripheral blood cells during and outside the pollen season in birch‐allergic patients and non‐allergic controls

“…The absolute frequencies of cytokine‐positive cells found in the present study after in vitro PMA/ionomycin stimulation are comparable to the frequencies reported by others using similar experimental protocols i.e. short incubation time and relatively low concentration of PMA [21, 30]. Nevertheless, the frequency of IL‐5 + , IL‐10 + and IL‐13 + lymphocytes after in vitro PMA/ionomycin stimulation was lower than might be expected in response to allergen stimulation.…”

“…Munoz‐Bellido et al [1] reported similar results from polyclonally stimulated PBMNC during natural pollen exposure, while another group observed an increased release of IL‐4 but unchanged IFN‐γ production [20]. In contrast, one investigation utilizing flow cytometry to measure the numbers of IL‐4‐ and IFN‐γ‐producing CD4 + and CD8 + lymphocytes found no seasonal variation [21].…”

“…PB samples from the allergic patients were collected during four test periods established according to the daily pollen count ( Fig. 1); test period 1 -the alder season April), test period 2 -beginning of the birch season (20)(21)(22)(23)(24)(25)(26)(27)(28)(29) April ), test period 3 -peak of the birch season (30 April-15 May) and test period 4 -outside the pollen season (10 October-11 December) ( Fig. 1).…”