Distribution of natural killer cells and cytotoxic T cells in vitiligo lesional and non-lesional skin.

<p>Skin biopsies taken from 12 vitiligo patients and 6 normal individuals were subjected to immunofluorescence analysis of natural killer (NK) cells. <b><u>A</u>:</b> Micrographs showing natural killer cells (CD3−/NKG2D+) (red) present in vitiligo lesional and non-lesional skin but absent from the normal skin of healthy volunteers. Some NK cells are in close proximity to the basal epidermal layer where melanocytes reside (arrows). In addition, increased numbers of cytotoxic T cells (CD3+/NKG2D+) (yellow: co-localization of red and green) as well as non-cytotoxic T cells (CD3+/NKG2D−) (green) were also found in both vitiligo peri-lesional and lesional skin. <b><u>B</u>:</b> Quantification of cells demonstrates a statistically significant increase in NK cells, cytotoxic T cells and non-cytotoxic T cells in vitiligo non-lesional skin (p = 0.0021, 0.0015, 0.001; mean ± SEM) and lesional skin (p = 0.021, 0.0017, 0.0023; mean ± SEM) as compared with normal skin. Color keys: <b><i>Green</i></b>: CD3 (a pan-T cell marker); <b><i>Red</i></b>: NKG2D (NK cell activation receptor); and <b><i>blue</i></b>: DAPI (nuclear stain). Comparisons between the respective groups are indicated in the figure by lines with an asterisk (*) denoting statistical significance (p<0.05). Abbreviations: NS: normal skin; NLS: non-lesional skin; LS: lesional-skin. Magnification: 400×; scale bar: 20 µm.