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Pathway differences may hold clues to steroid-resistant asthma

Differences in the pathways of CD8+ cells may have a crucial role in asthma and represent an important target in the treatment of patients with steroid-resistant asthma, according to researchers.

Eun Hee Chung, MD, PhD, of the division of cell biology in the department of pediatrics at National Jewish Health in Denver, and colleagues isolated CD4+ and CD8+ T cells from peripheral blood of healthy patients and those with steroid-sensitive and steroid-resistant asthma for their analysis.

They found that the number of BLT1-expressing cells was greater in patients with asthma compared with controls and larger on activated CD8+ vs. CD4+ T cells, according to data.

The addition of LTB4 to activated CD8+ T cells resulted in increased intracellular Ca2+ concentrations, the researchers wrote.

Significant reductions were observed in activated CD4+ T cells, unlike in CD8+ T cells, due to the presence of corticosteroids, according to researchers. There were less BLT1-expressing CD8+ T cells, however, in the presence of corticosteroid in patients with steroid-sensitive asthma vs. those with steroid-resistant asthma.

Moreover, interleukin-13 (IL-13) levels appeared greater in cultured CD8+ T cells, while levels of IL-10 were higher in CD4+ T cells from controls and patients with steroid-sensitive asthma. Interferon-gamma levels were lowest in patients with steroid-resistant asthma, they added.

Disclosure: Researcher Richard J. Martin, MD, reports consultancy with Teva, Merck, Novartis, and Genentech; grants from MedImmune; and royalties from UpToDate.