Amniotic bladder therapy: six-month follow up treating interstitial cystitis/bladder pain syndrome.

INTRODUCTION: Interstitial cystitis/bladder pain syndrome (IC/BPS) is characterized by chronic pelvic pain and usually accompanies lower urinary tract symptoms. We have previously reported that amniotic bladder therapy (ABT) provides symptomatic improvement in refractory IC/BPS patients for up to 3 months. Herein, we evaluated the durability of ABT up to 6 months. MATERIALS AND METHODS: Consecutive IC/BPS patients received intra-detrusor injections of 100 mg micronized amniotic membrane. Clinical evaluation and patient-reported outcome measurements including Interstitial Cystitis Symptom Index (ICSI), Interstitial Cystitis Problem Index (ICPI), Bladder Pain/ Interstitial Cystitis Symptom Score (BPIC-SS) and Overactive Bladder Assessment Tool (OAB) were assessed. RESULTS: Twenty-five consecutive recalcitrant IC/BPS patients were included in the study with an average age of 47.4 ± 14.4 years (29-67 years). After ABT, the IC/BPS symptoms improved gradually up to 3 months in all patients with an average improvement in ICSI, ICPI, BPIC-SS and OAB score of 72.8%, 71.9%, and 66.6%, (p < 0.001) respectively, at 3 months. At 4 months after ABT, 7 patients experienced a rebound in symptoms and requested another injection which resulted in a significant improvement in IC/BPS symptoms after 2, 4, and 8 weeks (p < 0.01). For the 18 patients who received only one injection, the IC/BPS symptoms were still significantly lower at 5 and 6 months compared to baseline (p < 0.01), suggesting a possible durable effect based on the ICSI, ICPI, BPIC-SS, and OAB questionnaire scores. CONCLUSIONS: ABT provided an improvement in pain and lower urinary tract symptoms up to 6 months post-treatment in some refractory IC/BPS patients.

ILT2 and ILT4 Drive Myeloid Suppression via Both Overlapping and Distinct Mechanisms.

Solid tumors are dense three-dimensional (3D) multicellular structures that enable efficient receptor-ligand trans interactions via close cell-cell contact. Immunoglobulin-like transcript (ILT)2 and ILT4 are related immune-suppressive receptors that play a role in the inhibition of myeloid cells within the tumor microenvironment. The relative contribution of ILT2 and ILT4 to immune inhibition in the context of solid tumor tissue has not been fully explored. We present evidence that both ILT2 and ILT4 contribute to myeloid inhibition. We found that although ILT2 inhibits myeloid cell activation in the context of trans-engagement by MHC-I, ILT4 efficiently inhibits myeloid cells in the presence of either cis- or trans-engagement. In a 3D spheroid tumor model, dual ILT2/ILT4 blockade was required for the optimal activation of myeloid cells, including the secretion of CXCL9 and CCL5, upregulation of CD86 on dendritic cells, and downregulation of CD163 on macrophages. Humanized mouse tumor models showed increased immune activation and cytolytic T-cell activity with combined ILT2 and ILT4 blockade, including evidence of the generation of immune niches, which have been shown to correlate with clinical response to immune-checkpoint blockade. In a human tumor explant histoculture system, dual ILT2/ILT4 blockade increased CXCL9 secretion, downregulated CD163 expression, and increased the expression of M1 macrophage, IFNγ, and cytolytic T-cell gene signatures. Thus, we have revealed distinct contributions of ILT2 and ILT4 to myeloid cell biology and provide proof-of-concept data supporting the combined blockade of ILT2 and ILT4 to therapeutically induce optimal myeloid cell reprogramming in the tumor microenvironment.

The Fibronectin-ILT3 Interaction Functions as a Stromal Checkpoint that Suppresses Myeloid Cells.

Suppressive myeloid cells inhibit antitumor immunity by preventing T-cell responses. Immunoglobulin-like transcript 3 (ILT3; also known as LILRB4) is highly expressed on tumor-associated myeloid cells and promotes their suppressive phenotype. However, the ligand that engages ILT3 within the tumor microenvironment and renders tumor-associated myeloid cells suppressive is unknown. Using a screening approach, we identified fibronectin as a functional ligand for ILT3. The interaction of fibronectin with ILT3 polarized myeloid cells toward a suppressive state, and these effects were reversed with an ILT3-specific antibody that blocked the interaction of ILT3 with fibronectin. Furthermore, ex vivo treatment of human tumor explants with anti-ILT3 reprogrammed tumor-associated myeloid cells toward a stimulatory phenotype. Thus, the ILT3-fibronectin interaction represents a "stromal checkpoint" through which the extracellular matrix actively suppresses myeloid cells. By blocking this interaction, tumor-associated myeloid cells may acquire a stimulatory phenotype, potentially resulting in increased antitumor T-cell responses.