Kinetics of regulatory T cells in the ovalbumin asthma model in the rat.

Abstract

BACKGROUND: The kinetics of regulatory T cells (T(Reg)) in allergic diseases such as asthma are only partly known. METHODS: The asthma model in the Fischer rat with ovalbumin (OVA) sensitization and aerosol challenge was used. The relative and absolute numbers of leukocytes, lymphocytes and T(Reg) subsets were determined by flow cytometry in the lung interstitium and draining bronchial lymph nodes at different time points after two challenges, and lung function was tested in parallel. RESULTS: The progressive number of challenges resulted in increased relative and absolute numbers of lymphocytes and in particular of T(Reg). The T(Reg) number was augmented with each aerosol challenge and was already significantly increased 6 h after the second challenge. The relative (%) and absolute numbers of CD4+ and CD8+ T(Reg) and dendritic cells showed different kinetics after two challenges. The leukocyte numbers in the lung did not correlate with lung function. CONCLUSION: T(Reg) increased surprisingly early after challenge in the lung tissue. Relative and absolute numbers of leukocyte subsets should always be calculated. The kinetics of different leukocyte subsets can only be determined when several time points are studied.