Sci. Transl. Med. 10, eaar2227 (2018)

A microneedle-based technology is a minimally invasive technique for monitoring immune responses directly in tissue.

Currently, systemic immune monitoring of individuals is carried out by blood draws. Localized monitoring of tissue-resident immunity can be assayed by delayed hypersensitivity tests, but these lack quantitative and phenotypic information regarding the local immune response.

Mandal et al. develop a microneedle-based technology for longitudinal sampling of cells from the skin, which takes the form of a porous matrix inserted into the skin allowing monitoring of skin tissue–resident memory T cells.

The technology could be used as a diagnostic in autoimmune disorders or to monitor responses to vaccines.