Tezepelumab inhibits highly functional truncated thymic stromal lymphopoietin in chronic rhinosinusitis

Thymic stromal lymphopoietin (TSLP) and its functional cleavage products are elevated in nasal polyps (NPs) and play important roles in type 2 (T2) inflammation in chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP) by activating myeloid dendritic cells (mDCs) and group 2 innate lymphoid cells (ILC2s). However, whether tezepelumab, a human mAb against TSLP, inhibits functional cleaved TSLP and also the role of TSLP in CRS without nasal polyps (CRSsNP) have not yet been studied.

We sought to investigate the effects of tezepelumab on cleaved TSLP in CRS.

The mRNA expression levels for TSLP and T2 markers in ethmoid tissues (ETs) from 31 controls and 118 patients with CRSsNP and in NPs from 53 patients with CRSwNP were measured by quantitative RT-PCR. Cleaved TSLP was prepared from full-length recombinant TSLP by incubation with tissue extracts of NPs and CRSsNP ETs. The effects of tezepelumab on cleaved TSLP-induced inflammation were evaluated using PBMCs by monitoring the production of chemokines (CCL17 and CCL22 for mDCs) and cytokines (IL-5 and IL-13 for ILC2s).

The mRNA expression level of TSLP was elevated not only in NPs but also in ETs from T2 CRSsNP compared with non-T2 CRSsNP and controls, and was positively correlated with T2 markers in CRSsNP (P < .001). CRSsNP ET also truncated and created highly active TSLP products. The activation of mDCs and ILC2s by full-length TSLP and cleaved TSLP created by ET and NP extracts was dose-dependently inhibited by tezepelumab.

TSLP plays a role in T2 inflammation in CRSsNP and CRSwNP. Treatment with tezepelumab may benefit patients with T2 CRS by inhibiting active forms of TSLP.