Predominance of "memory" T cells (CD4 super(+), CDw29 super(+)) over "naive" T cells (CD4 super(+), CD45R super(+)) in both normal and diseased human skin

Absolute numbers of CD3 super(+) T lymphocytes and their subpopulations were determined and statistically evaluated in the lesional skin of psoriasis, atopic dermatitis, nummular dermatitis, pityriasis rosea, and lichen planus. Skin sections were divided into horizontal layers and the numbers of CD3 super(+) T cells as well as CD4 super(+) inducer and CD8 super(+) suppressor-cytotoxic T-cell subsets were counted. In addition, absolute numbers of the two subpopulations of inducer T cells, i.e., "memory" (4B4 super(+) 2H4 super(-)) and "naive" (4B4 super(-) 2H4 super(+)) were evaluated. The results indicate disease-specific and significantly different infiltration patterns of T-lymphocytes subsets in the chronic inflammatory dermatoses investigated. The predominant presence of the CD4 super(+) 2H4 super(-) "memory" subpopulation of CD4 super(+) T cells in all diseases studied as well as in normal human skin (reported previously) seems to indicate that the skin immune system is rather unidirectional in its increase in this subpopulation of the inducer T-cell subset. This predominance of the "memory" subpopulation thus indicates that most T cells of normal and diseased human skin are already primed, i.e., have already met their specific ligand in a MHC II context.