This study aimed to investigate sinonasal cytotoxic cells, their mediators, and cell-specific distribution of these mediators in patients with CRSwNP and CRS patients without nasal polyp (CRSsNP).

Blood and sinus tissue samples were taken from patients with CRSsNP and CRSwNP at the time of surgery. Control subjects underwent surgery for cerebrospinal fluid leak repair or removed non-hormone-secreting pituitary tumors.

We observed no significant differences in plasma or peripheral blood immune cell numbers or specific levels of GrB or perforin among the groups. The overall reduction in GrB and perforin in the sinonasal mucosa of the patients with CRSsNP and the patients with CRSwNP decreased T cell production. There was no difference in total NK cell count or expression of perforin or GrB among all the groups.

The study concluded that total levels of sinonasal GrB and perforin were decreased in the sinonasal mucosa of both the patients with CRSwNP and the patients with CRSsNP compared with the controls. In contrast, sinonasal CD8+ T cells, intracellular stores of GrB, and perforin were reduced in the patients with CRSwNP compared with the controls.