Since the coronavirus disease 2019 (COVID-19) pandemic has hit the entire world, there is ample knowledge regarding its clinical course and prognostic biomarkers. Still, the pathophysiology of COVID-19 is poorly understood. Since the first guidelines published in February 2020 for autopsy of both confirmed and suspected COVID-19 cases, there has been an increasing number of autopsies and literature reporting histopathological findings. However, our knowledge about the immunological response of various organ systems to the virus, as well as response patterns, is inadequate but is essential to understand and initiate timely and targeted antiviral, anti-inflammatory, or anticoagulative therapy. Although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is primarily considered a respiratory virus, current evidence shows that it causes life-threatening complications in almost all organ systems including the heart, brain, kidney, spleen, liver, and eyes. Hence, in this article, we reviewed the published case reports and case series in order to increase our understanding of COVID-19 pathophysiology. The main histopathological findings of the lungs include diffuse alveolar damage with activated type II pneumocytes, fibroblasts, protein-rich exudate, and hyaline membranes. Other significant histopathological findings include cardiomegaly, right ventricular dilation, splenic pulp atrophy, kidneys with severe podocytopathy, and collapsing glomerulopathy, and the brain showed hypoxic changes in the cerebellum and cerebrum. Furthermore, in this review, we also explained different pathological findings of SARS-CoV and MERS and compared them to SARS-CoV-2. This comprehensive review will improve our understanding of COVID-19 pathophysiology and various disease stages, hence promoting the application of targeted therapy.

Introduction/Objective Bariatric surgery for morbid obesity is dramatically increasing, and large number of sleeve gastrectomies is examined histopathologically. The GIPS guidelines recommend using a visual gestalt to identify substantial inflammation for prompting further ancillary testing for H. pylori microorganisms, and a recent study proposed an “Objective Visual Analog Scale” that justifies additional work-up for H. Pylori infection in gastric biopsies. Our study aims to establish a potential correlation between the number of plasma cells in the IFAs and the presence of H. pylori infection in sleeve gastrectomy specimens. Methods/Case Report We retrospectively reviewed 338 patients who underwent sleeve gastrectomy for morbid obesity at our institution from 2016-2021. Only 105 of 338 cases were included which demonstrated mild to marked lymphoplasmacytic infiltrate in the IFAs of the lamina propria on H&E stain. The number of plasma cells identified in the more expanded IFAs of the lamina propria was assessed by “drawing an imaginary horizontal line” and the number of plasma cells under the “line” were counted. H. pylori immunostain was performed in all cases. Statistical analyses were performed using IBM SPSS statistics Version 26. Results (if a Case Study enter NA) H. pylori like organisms were identified in 49 of 105 cases (20 cases on H&E stain and 29 cases on H. pylori immunostain). Receiver operator characteristic curve (ROC) showed that the identification of 8 or more plasma cells in expanded IFAs is both highly sensitive (93.9%; 46/49) and specific (83.9%; 47/56) for predicting H. Pylori infection with a positive predictive value of 83.6% (46/55) and area under the curve (AUC) of 0.94 (CI:0.89-0.99, p-value= 0.00). Conclusion In the light of above results, we propose that in sleeve gastrectomies specimens, in which H. pylori is not identified on H&E sections, the linear identification of 8 or more plasma in the more expanded IFAs is highly predictive of H. pylori infection and justify additional workup for H. pylori infection.