Figure 2.

High frequencies of metal-specific T cells in blood interfere with diagnostic blood-based in vitro testing. Following adaptive immune responses, blood frequencies of protein-specific memory T cells are usually higher compared to those in the naïve T cell pool, even decades after antigen exposure (blue line). However, Ni-specific T cells are abundant in non-allergic individuals (red line), due to interactions with certain elements of the TCR repertoire (see Section 5.2) [115]. Therefore, only strongly increased frequencies of Ni-specific T cells may currently be associated with the allergic state. Adapted from [174]. Created with BioRender.com.