INCREASED LEVELS OF IL-13 MESSENGER-RNA, BUT NOT IL-4 MESSENGER-RNA, ARE FOUND IN-VIVO IN PERIPHERAL-BLOOD MONONUCLEAR-CELLS (PBMC) OF PATIENTS WITH ATOPIC-DERMATITIS (AD)

Previous studies using in vitro systems with various stimuli have show n that PBMC from patients with AD show increased levels of IL-4 but de creased levels of interferon-gamma (IFN-gamma) compared with PBMC from normal controls. However, in vitro conditions do not always mimic the in vivo condition. We therefore believe that it is important to quant ify the expression of these cytokines in freshly isolated PBMC. This s tudy examines the expression of IFN-gamma, IL-4 and IL-13 mRNA in fres hly isolated PBMC from adult patients with AD, from patients with psor iasis vulgaris and from healthy adults, using the semiquantitative rev erse transcriptase-polymerase chain reaction (RT-PCR) method. Levels o f IFN-gamma mRNA were significantly lower in PBMC of patients with AD than in controls. IL-4 mRNA levels did not differ significantly betwee n groups. Conversely, levels of mRNA for IL-13 were significantly grea ter in PBMC of patients with AD than in controls. An increase in IL-13 expression may regulate the in vivo synthesis of IgE in patients with AD.