Gamma/Delta T Cells and Human Skin Reactivity to Heavy Metals

The study investigated the presence of gamma/delta T cells in human skin following exposure to heavy metal salts through patch testing. Gamma/delta T cells were absent in normal skin but were found in all 14 allergic or irritant reactions to gold chloride and in 6 out of 8 reactions to mercuric chloride, making up 16 ± 6% and 15 ± 6% of CD3+ cells in the dermis, respectively. These cells were also present in hair follicle epithelium in response to silver nitrate. The gamma/delta T cells expressed specific gene segments and were identified as 'memory' T cells, suggesting their role in skin defense against reactive heavy metals.