A New Twist on a Classic: Enhancing Radioiodine Uptake in Advanced Thyroid Cancer.

Advanced differentiated thyroid cancer that is resistant to radioactive iodine therapy may become responsive with a unique treatment combination of chloroquine and vorinostat. This treatment was demonstrated in cellular and animal models of thyroid cancer to inhibit endocytosis of the plasma membrane-bound iodine transporter, NIS, and restore iodine uptake. See related article by Read et al., p. 1352.

The Effect of Apalutamide on Thyroid Function in Prostate Cancer Patients.

Context: Apalutamide (APT) is a nonsteroidal antiandrogen medication used to treat metastatic castrate-sensitive and nonmetastatic castrate-resistant prostate cancer. Early clinical trials of APT identified thyroid dysfunction as a common adverse effect of therapy, but the clinical presentation and management of APT-induced hypothyroidism has not been studied. Objective: The objective of our study is to elucidate the clinical presentation and treatment approach of APT-associated thyroid dysfunction in prostate cancer patients. Methods: We report a case series of 16 patients with APT-associated thyroid dysfunction during prostate cancer treatment at 2 academic medical centers. Patient clinical parameters, thyroid function laboratory data, and thyroid hormone requirements over the course of APT treatment were analyzed. Results: Among the 16 patients in our case series with APT-associated hypothyroidism, 3 had no prior thyroid disease and 13 had preexisting hypothyroidism. The patterns of thyroid dysfunction included overt and subclinical hypothyroidism. The median time from APT initiation to thyroid function test abnormality was 19 weeks, but occurred in some cases as early as 2 to 4 weeks. Hypothyroidism was effectively managed with thyroid hormone replacement using levothyroxine (LT4), though some patients with preexisting hypothyroidism required a 2- to 3-fold dose increase while on APT to achieve a euthyroid state. In the subset of patients who completed or stopped APT therapy, thyrotropin levels fell at a median of 11 weeks post APT therapy and thyroid hormone requirements decreased to near pre-APT levels. Conclusion: APT-associated thyroid dysfunction presents as new or worsening hypothyroidism and should prompt initiation or increase in thyroid hormone replacement. Monitoring of thyroid function tests is recommended every 1 to 2 months for all patients on APT and 2 to 3 months after completion of APT.

A pathologically expanded, clonal lineage of IL-21 producing CD4+ T cells drives Inflammatory neuropathy.

Inflammatory neuropathies, which include CIDP (chronic inflammatory demyelinating polyneuropathy) and GBS (Guillain Barre Syndrome), result from autoimmune destruction of the peripheral nervous system (PNS) and are characterized by progressive weakness and sensory loss. CD4+ T cells play a key role in the autoimmune destruction of the PNS. Yet, key properties of pathogenic CD4+ T cells remain incompletely understood. Here, we use paired scRNAseq and scTCRseq of peripheral nerves from an inflammatory neuropathy mouse model to identify IL-21 expressing CD4+ T cells that are clonally expanded and multifunctional. These IL-21-expressing CD4+ T cells are comprised of two transcriptionally distinct expanded populations, which express genes associated with Tfh and Tph subsets. Remarkably, TCR clonotypes are shared between these two IL-21-expressing populations, suggesting a common lineage differentiation pathway. Finally, we demonstrate that IL-21 signaling is required for neuropathy development and pathogenic T cell infiltration into peripheral nerves. IL-21 signaling upregulates CXCR6, a chemokine receptor that promotes CD4+ T cell localization in peripheral nerves. Together, these findings point to IL-21 signaling, Tfh/Tph differentiation, and CXCR6-mediated cellular localization as potential therapeutic targets in inflammatory neuropathies.

A pathologically expanded, clonal lineage of IL-21-producing CD4+ T cells drives inflammatory neuropathy.

Inflammatory neuropathies, which include chronic inflammatory demyelinating polyneuropathy (CIDP) and Guillain Barré syndrome (GBS), result from autoimmune destruction of the PNS and are characterized by progressive weakness and sensory loss. CD4+ T cells play a key role in the autoimmune destruction of the PNS. Yet, key properties of pathogenic CD4+ T cells remain incompletely understood. Here, we used paired single-cell RNA-Seq (scRNA-Seq) and single-cell T cell receptor-sequencing (scTCR-Seq) of peripheral nerves from an inflammatory neuropathy mouse model to identify IL-21-expressing CD4+ T cells that were clonally expanded and multifunctional. These IL-21-expressing CD4+ T cells consisted of 2 transcriptionally distinct expanded cell populations, which expressed genes associated with T follicular helper (Tfh) and T peripheral helper (Tph) cell subsets. Remarkably, TCR clonotypes were shared between these 2 IL-21-expressing cell populations, suggesting a common lineage differentiation pathway. Finally, we demonstrated that IL-21 receptor-KO (IL-21R-KO) mice were protected from neuropathy development and had decreased immune infiltration into peripheral nerves. IL-21 signaling upregulated CXCR6, a chemokine receptor that promotes CD4+ T cell localization in peripheral nerves. Together, these findings point to IL-21 signaling, Tfh/Tph differentiation, and CXCR6-mediated cellular localization as potential therapeutic targets in inflammatory neuropathies.