Spontaneous expression of mRNA for IL-10, GM-CSF, TGF-β, TNF-α, and IL-6 in peripheral blood mononuclear cells from atopic dermatitis

Background: Monocytes and T helper cells play major roles in the immunologic dysfunction of atopic dermatitis (AD). There have been many studies on the cytokine pattern to evaluate abnormalities of immune cells in AD, but the results were conflicting and most of these previous reports were performed with various mitogen-stimulation. Objective: The purpose was to investigate de novo cytokine pattern in AD peripheral blood mononuclear cells (PBMC). We focused on the expression of cytokines that have effects on monocytes and T cells. Methods: We measured mRNA expression of IL-10, GM-CSF, TGF-beta, TNF-alpha, and IL-6 in freshly isolated PBMC with semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR). The intensity of cytokine cDNA were normalized to that of beta-actin product as a standard marker. Results: Interleukin-10 mRNA expression was significantly enhanced in AD compared with control subjects (P <.05). Spontaneous mRNA expression of TGF-beta and TNF-alpha was significantly lower in AD patients (P <.01). The level of GM-CSF mRNA expression was heterogenous and spontaneous mRNA expression was slightly increased in AD although the difference didn't reach the statistical significance. Interleukin-6 mRNA was not detected in most of AD and controls. Conclusion: Our data could represent in vivo cytokine expression state associated with monocytes and other immune cells. Increased expression of IL-10 and GM-CSF may be associated with monocyte dysfunction in AD although increase in the expression of GM-CSF mRNA was not statistically significant. Inhibitory effect of increased IL-10 was suggested on decreased expression of TNF-alpha mRNA. The role of TGF-beta in AD remains to be seen.