Mohammad Vasei

Epithelial cell adhesion molecule (Ep-CAM; CD326) is used as a target by many immunotherapeutic approaches, but little data are available about Ep-CAM expression in major human malignancies with respect to level, frequency, tumour stage, grade, histologic tumour type and impact on survival. We analysed by immunohistochemical staining tissue microarrays with 4046 primary human carcinoma samples from colon, stomach, prostate and lung cancers for both frequency and intensity of Ep-CAM expression under highly standardised conditions. A total of 3360 samples were analysable. High-level Ep-CAM expression was observed in 97.7% (n=1186) of colon, 90.7% of gastric (n=473), and 87.2% of prostate cancers (n=414), and in 63.9% of lung cancers (n=1287). No detectable Ep-CAM staining was found with only 0.4% of colon, 2.5% of gastric, 1.9% of prostate cancers, and 13.5% of lung cancers. The only significant correlation of Ep-CAM expression with tumour grading was observed in colon cancer where high-level Ep-CAM expression on grade 3 tumours was down to 92.1% (P<0.0001). Adenosquamous and squamous carcinomas of the lung had a lower percentage of high-level Ep-CAM expression compared to adenocarcinomas with 35.4 and 53.6%, respectively, and with 45.5 and 17.3% of tumours being Ep-CAM negative. With the exception of moderately differentiated colon carcinoma, where patients not expressing Ep-CAM on their tumours showed an inferior survival (P=0.0014), correlation of Ep-CAM expression with survival did not reach statistical significance for any of the other cancer indications and subgroups. In conclusion, the data strongly support the notion that Ep-CAM is a prime target for immunotherapies in major human malignancies. This is because the most common human cancers show (i) a low frequency of Ep-CAM-negative tumours, (ii) a high frequency of Ep-CAM expression on cells of a given tumour, and (iii) for most cancers, an insignificant influence of tumour staging, grading and histology on Ep-CAM expression.

The possible immunomodulatory role of polymorphonuclear leukocytes (PMN) in CD4+ T lymphocyte differentiation in mice was examined by studying the effect of transient depletion of PMN during the early phase after Leishmania major delivery. A single injection of the PMN-depleting NIMP-R14 mAb 6 h before infection with L. major prevented the early burst of IL-4 mRNA transcription otherwise occurring in the draining lymph node of susceptible BALB/c mice. Since this early burst of IL-4 mRNA transcripts had previously been shown to instruct Th2 differentiation in mice from this strain, we examined the effect of PMN depletion on Th subset differentiation at later time points after infection. The transient depletion of PMN in BALB/c mice was sufficient to inhibit Th2 cell development otherwise occurring after L. major infection. Decreased Th2 responses were paralleled with partial resolution of the footpad lesions induced by L. major. Furthermore, draining lymph node-derived CD4+ T cells from PMN-depleted mice remained responsive to IL-12 after L. major infection, unlike those of infected BALB/c mice receiving control Ab. PMN depletion had no effect when the NIMP-R14 mAb was injected 24 h postinfection. The protective effect of PMN depletion was shown to be IL-12 dependent, as concomitant neutralization of IL-12 reversed the protective effect of PMN depletion. These results suggest a role for an early wave of PMN in the development of the Th2 response characteristic of mice susceptible to infection with L. major.

BACKGROUND: Acute respiratory distress syndrome (ARDS) is a fatal complication of coronavirus disease 2019 (COVID-19). There are a few reports of allogeneic human mesenchymal stem cells (MSCs) as a potential treatment for ARDS. In this phase 1 clinical trial, we present the safety, feasibility, and tolerability of the multiple infusions of high dose MSCs, which originated from the placenta and umbilical cord, in critically ill COVID-19-induced ARDS patients. METHODS: human umbilical cord MSCs (UC-MSCs; 6 cases) or placental MSCs (PL-MSCs; 5 cases). FINDINGS: There were eight men and three women who were 42 to 66 years of age. Of these, six (55%) patients had comorbidities of diabetes, hypertension, chronic lymphocytic leukemia (CLL), and cardiomyopathy (CMP). There were no serious adverse events reported 24-48 h after the cell infusions. We observed reduced dyspnea and increased SpO2 within 48-96 h after the first infusion in seven patients. Of these seven patients, five were discharged from the ICU within 2-7 days (average: 4 days), one patient who had signs of acute renal and hepatic failure was discharged from the ICU on day 18, and the last patient suddenly developed cardiac arrest on day 7 of the cell infusion. Significant reductions in serum levels of tumor necrosis factor-alpha (TNF-α; P < 0.01), IL-8 (P < 0.05), and C-reactive protein (CRP) (P < 0.01) were seen in all six survivors. IL-6 levels decreased in five (P = 0.06) patients and interferon gamma (IFN-γ) levels decreased in four (P = 0.14) patients. Four patients who had signs of multi-organ failure or sepsis died in 5-19 days (average: 10 days) after the first MSC infusion. A low percentage of lymphocytes (< 10%) and leukocytosis were associated with poor outcome (P = 0.02). All six survivors were well with no complaints of dyspnea on day 60 post-infusion. Radiological parameters of the lung computed tomography (CT) scans showed remarkable signs of recovery. INTERPRETATION: We suggest that multiple infusions of high dose allogeneic prenatal MSCs are safe and can rapidly improve respiratory distress and reduce inflammatory biomarkers in some critically ill COVID-19-induced ARDS cases. Patients that develop sepsis or multi-organ failure may not be good candidates for stem cell therapy. Large randomized multicenter clinical trials are needed to discern the exact therapeutic potentials of MSC in COVID-19-induced ARDS.