[A study of helper T cell (Th)1/Th2 immune response pattern of gammadeltaT cells in asthma].

Objective: To explore the mode of immune responses of gammadeltaT cells in asthma and the role of gammadeltaT cell subsets in the pathogenesis of asthma.

Methods: Wistar rats were sensitized and challenged with ovalbumin to establish an asthmatic model (n = 10, for each group). "Attack-panning" method was used to culture selective gammadeltaT cells. The percentage of gammadelta T cells among cultured cells was determined by flow cytometry. The levels of interleukin (IL)-4 and interferon-gamma (IFN-gamma) were measured by ELISA. The expression of IL-4 mRNA and IFN-gamma mRNA was determined by in situ hybridization.

Results: In the asthmatic group, IL-4 and IFN-gamma were detectable at the same time in cultured supernatant of gammadeltaT cells in peripheral blood mononuclear cells (PBMC) or broncho-alveolar fluid (BALF), and the level of IL-4 [PBMC: (40.5 +/- 3.7) ng/L, BALF: (49.6 +/- 3.1) ng/L] increased as compared with the control group [PBMC: (26.1 +/- 2.1) ng/L, BALF: (23.6 +/- 1.7) ng/L; all P < 0.01], while the level of IFN-gamma [PBMC: (17.6 +/- 2.5) ng/L, BALF: (28.5 +/- 3.6) ng/L] decreased as compared with the control group [PBMC: (24.3 +/- 1.7) ng/L, BALF: (38.4 +/- 2.8) ng/L; all P < 0.01]. In the asthmatic group, the percentage of IL-4 mRNA positive-staining cells [PBMC: (76.2 +/- 7.2)%, BALF: (85.7 +/- 8.4)%] among the gammadeltaT cells significantly increased as compared with the control group [PBMC: (20.6 +/- 5.3)%, BALF: (25.0 +/- 6.8)%; all P < 0.01], while the percentage of IFN-gammamRNA positive-staining cells [PBMC: (30.9 +/- 6.7)%, BALF: (41.5 +/- 3.6)%] among the gammadeltaT cells significantly decrease as compared with the control group [PBMC: (60.1 +/- 4.2)%, BALF: (53.8 +/- 5.1)%; all P < 0.01].

Conclusions: gammadeltaT cells can secrete both IL-4 and IFN-gamma at the same time, or there are two subsets of gammadeltaT cells which can secrete either IL-4 or IFN-gamma in PBMC or BALF in asthma. Th1/Th2 immune response mode is present in gammadeltaT cells of asthma and Th2-cytokine profile predominates. gammadeltaT cells is involved in the pathogenesis of asthma.