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Clinical & Experimental Allergy

Increased interferon-γ- and interleukin-4-synthesizing subsets of circulating T lymphocytes in pregnant asthmatics

Authors


Dr György Losonczy, Department of Pulmonology, Semmelweis University, Diós árok 1/C, 1125 Budapest, Hungary.
E-mail: losonczy@pulm.sote.hu

Summary

Background Pregnancy frequently interferes with the course of bronchial asthma, and asthmatic pregnant women experience less successful pregnancies. T lymphocytes synthesizing IL-4 or IFN-γ are important in allergic mechanisms of the airways as well as in materno-fetal immunity.

Objective We hypothesized that pregnancy (a T helper-2 polarized state) of asthmatics will enhance the number of circulating T2 lymphocytes, but decrease the subset-producing IFN-γ (T1 lymphocytes) and thereby cause a culminating T2 dominance with possible clinical consequences.

Methods IL-4- or IFN-γ-producing T lymphocytes were determined by flow cytometry in healthy (n=8) and asthmatic (n=13) non-pregnant women and healthy (n=18) and asthmatic (n=48) pregnant women of similar chronological and gestational (2nd–3rd trimester) age and asthma severity (Global Initiative for Asthma II–III).

Results In the blood of non-pregnant women – healthy or asthmatic – the numbers of IL-4- and IFN-γ+ T cells were very low (<10/μL blood). In contrast, in asthmatic pregnant women, the cell counts were 182±27 and 39±6 for IFN-γ+ and IL-4+ T cells/μL blood, respectively (both P<0.05 vs. respective control values of non-pregnant asthmatics). Within the asthmatic pregnant group, significant negative correlations were revealed between the numbers of IFN-γ+ or IL-4+ T cells and maternal peak expiratory flow as well as birth weight of newborns (both P<0.05).

Conclusion These data show a previously unknown immunological interference between asthma and pregnancy. The culminating proliferation of IFN-γ+ and IL-4+ T lymphocytes may potentially impair maternal airway symptoms as well as fetal development.

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