Recent advances in multiplex immunohistochemistry techniques allow for quantitative, spatial identification of multiple immune parameters for enhanced diagnostic and prognostic insight. However, applying such techniques to murine fixed tissues, particularly sensitive epitopes, such as CD4, CD8α, and CD19, has been difficult. We compared different fixation protocols and Ag-retrieval techniques and validated the use of multiplex immunohistochemistry for detection of CD3+CD4+ and CD3+CD8+ T cell subsets in murine spleen and tumor. This allows for enumeration of these T cell subsets within immune environments, as well as the study of their spatial distribution.

Purpose: Duodenal involvement in COVID-19 is poorly studied. Aim was to describe clinical and histopathological characteristics of critically ill COVID-19 patients suffering from severe duodenitis that causes a significant bleeding and/or gastrointestinal dysmotility. Methods: In 51 critically ill patients suffering from SARS-CoV-2 pneumonia, severe upper intestinal bleeding and/or gastric feeding intolerance were indications for upper gastrointestinal endoscopy. Duodenitis was diagnosed according to macroscopic signs and mucosal biopsies. Immunohistochemistry was performed to detect viral specific protein and ACE2. In situ hybridization was applied to confirm viral replication. Results: Nine of 51 critically ill patients (18%) suffering from SARS-CoV-2 pneumonia had developed upper GI bleeding complications and/or high gastric reflux. Five of them presented with minor and four (44%) with severe duodenitis. In two patients, erosions had caused severe gastrointestinal bleeding requiring PRBC transfusions. Immunohistochemical staining for SARS-CoV-2 spike protein was positive inside duodenal enterocytes in three of four patients suffering from severe duodenitis. Viral replication could be confirmed by in situ hybridization. Conclusion: Our data suggest that about 8% of critically ill COVID-19 patients may develop a severe duodenitis presumably associated with a direct infection of the duodenal enterocytes by SARS-CoV-2. Clinical consequences from severe bleeding and/or upper gastrointestinal dysmotility seem to be underestimated.

Background Preoperative bronchoscopic tumour ablation has been suggested as a beneficial treatment for bronchopulmonary carcinoid tumours, although data regarding its effects and long-term outcome are lacking. Methods In our case-matched cohort study with 208 patients with bronchopulmonary carcinoid tumours we investigated the role of preoperative bronchoscopic interventions before subsequent surgery and analysed the safety of this Procedure of Endobronchial Preparation for Parenchyma-sparing Surgery (PEPPS) based on metastasis and recurrence rates as well as survival data from 1991 to 2010. The subsequent surgery was classified into parenchyma-sparing procedures and classical lobectomies, bilobectomies and pneumonectomies. Data were obtained from the tumour registry and medical reports. Outcomes were the frequency of parenchyma-sparing surgery after bronchoscopic treatment as well as rates of metastasis, recurrence and survival. Results 132 of 208 carcinoids were located centrally. Among them, 77 patients could be recanalised preoperatively. After bronchoscopic preparation, the rate of subsequent parenchyma-sparing surgery methods was higher (p=0.021). The effect was measured by the number of segments removed. The 10-year survival rate was 89% (typical carcinoids) and 68% (atypical carcinoids), respectively. After applying PEPPS, long-term survival was slightly higher (p=0.23). Metastasis and recurrence rates showed no relevant differences between the bronchoscopically treated or non-treated groups, or between the two types of surgery classes or between the PEPPS and non-PEPPS groups. Conclusions After preoperative bronchoscopic treatment, parenchyma-sparing surgery techniques can be applied more frequently. Furthermore, we detected no negative effects after PEPPS based on metastasis, recurrence and survival rates.

Aim In patients with recurrent primary hyperparathyroidism (pHPT) or preceding thyroid operation, scintigraphic localization of the pathological parathyroid gland is sometimes unsuccessful. Reason for diagnostic failure, and its clinical relevance is poorly understood. Methods This retrospective observational study in patients suffering from a pHPT evaluated independent predictors of a negative preoperative scintigraphy (SC) result, and its relevance for intraoperative outcome using logistic regression analysis. Results Among 86 pHPT patients scheduled for parathyroid operation, 63 (73%) had a history of a preceding thyroid or parathyroid operation. Preoperative SC could not identify an adenoma in 30 patients (34.9%), and in 12 patients (14.0%), the surgeon was subsequently unable to localize abnormal parathyroid tissue. Preoperative parathyroid hormone concentration was the only significant independent predictor of a negative SC finding (non-linear and indirect association). Independent from surgical history, an unsuccessful intraoperative focus localization was exclusively predicted by preoperative ultrasonographic (US) and SC findings (OR per diagnostic category 2.98; 95%-CI 1.03–8.58, p=0.043, and OR 2.26; 95%-CI: 1.10–4.63, p=0.027, respectively). Compared to exclusive US, however, the combination of SC and US significantly increased the sensitivity and predictive power to identify patients at a high risk for a complicated surgical procedure. Conclusion In patients before parathyroidectomy, a low preoperative parathyroid hormone concentration is significantly associated with a high likelihood for a negative SC finding. Combining US with SC before operation significantly increases the chance to identify patients prone to negative intraoperative findings.

In patients with primary hyperparathyroidism (pHPT), the importance of oxyphil cells for ^99mTc-sestamibi uptake is uncertain. This retrospective observational study of pHPT patients evaluated independent associations between oxyphil cell content (OCC) and preoperative scintigraphic (SC) findings, using logistic regression analyses. We studied 76 patients with pHPT before and after operation. Preoperative SC was able to definitively identify abnormal parathyroid tissue in 47 patients (61.8%). The median relative OCC (postoperative histopathological examination) was 10% (IQR 0.25% – 40%) and the median absolute OCC was 0.09 cm³ (IQR 0.00 – 0.59 cm³). After adjustment for confounders, an iPTH concentration >200 pg/ml and increasing OCC was the only significant independent predictor of a definitively positive SC result (per category of relative OCC: adjusted odds ratio (aOR) 2.40, 95% confidence interval (CI) 1.02 – 5.65, p=0.045). In patients with pHPT, a higher OCC was associated with a significantly higher probability of a clearly positive SC finding. Received: 02 October 2024 Accepted after revision: 06 February 2025 Article published online: 06 March 2025 © 2025. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany