Study of lymphocyte subpopulations at different stages of contact dermatitis

Contact dermatitis has traditionally been regarded as a T-lymphocyte-mediated delayed hypersensitivity reaction. This has led authors to focus their studies of this affection on establishing the role played by lymphocytes and the different lymphocyte subpopulations in its pathophysiology. However, as most of the research conducted on contact dermatitis has so far been carried out on experimental animals, we believed it of interest to study the potential alterations to the immune system involved in contact dermatitis in humans. For this purpose, we chose 30 patients suffering from contact dermatitis in whom we studied the blood levels of total lymphocytes, as well as those of CD3, CD4 and CD8, and the CD4/CD8 ratio. These parameters were determined at three clinical stages, namely, the clinical stage (acute phase), a period when the symptoms had subsided (intercrisis phase) and another when the lesions recurred (acute outbreak). The aim of this work was to study the changes in these lymphocyte subpopulations in each of the stages. We also studied a control group consisting of 30 healthy subjects in order to contrast the results obtained. We found no significant differences among the results obtained at the three stages. However, they did differ from those obtained for the control group: the patients had lower CD4 and CD8 levels than their healthy counterparts, the differences only being significant in the acute phase.