Clinical progression of B cell chronic lymphocytic leukemia (B-CLL) reflects the clone’s antigen receptor (BCR) and involves stroma-dependent B-CLL growth within lymphoid tissue. Uniformly elevated expression of Toll-like receptor 9 (TLR-9), occasional MYD88 mutations, and BCR specificity for DNA or antigens physically linked to DNA together suggest that TLR-9 signaling is important in driving B-CLL growth in patients. Nevertheless, reports of apoptosis following B-CLL exposure to CpG oligodeoxynucleotide (ODN) raised questions about a central role for TLR-9. Because normal memory B cells proliferate vigorously to ODN + interleukin-15 (IL-15), a cytokine found in stromal cells of bone marrow, lymph nodes, and spleen, we examined whether this was true for B-CLL cells. Through a CFSE-based assay for quantitatively monitoring in-vitro clonal proliferation/survival, we show that IL-15 precludes TLR-9-induced apoptosis and permits significant B-CLL clonal expansion regardless of the clone’s BCR mutation status. A robust response to ODN+IL-15 was positively linked to presence of chromosomal anomalies (trisomy-12 or ataxia telangiectasia mutated (ATM) anomaly + del13q14), and negatively linked to a very high proportion of CD38+ cells within the blood-derived B-CLL population. Furthermore, a clone’s intrinsic potential for in-vitro growth correlated directly with doubling time in blood, in the case of B-CLL with IGHV-unmutated BCR and <30% CD38+ cells in blood. Finally, in-vitro high-proliferator status was statistically linked to diminished patient survival. The above findings, together with immunohistochemical evidence of apoptotic cells and IL-15-producing cells proximal to B-CLL pseudofollicles in patient spleens, suggest that collaborative ODN and IL-15 signaling may promote in-vivo B-CLL growth.

Background and Aims Liver injury due to COVID-19 is being increasingly recognized. Abnormal liver chemistry tests of varying severities occur in a majority of patients. However, there is a dearth of accompanying liver histologic studies in these patients. Methods: The current report details the clinical courses of two patients having severe COVID-19 hepatitis. Liver biopsies were analyzed under light microscopy, portions of liver tissue were hybridized with a target probe to the SARS-CoV-2 S gene, and small sections from formalin-fixed paraffin embedded liver tissue were processed for electron microscopy. Results The liver histology of both cases showed a mixed inflammatory infiltrate with prominent bile duct damage, endotheliitis and many apoptotic bodies. In-situ hybridization and electron microscopy suggest the intrahepatic presence of the severe acute respiratory syndrome corona virus-2 (SARS-CoV-2), the findings of which may indicate the possibility of direct cell injury. Conclusions Based on the abundant apoptosis and severe cholangiocyte injury, these histopathological changes suggest a direct cytopathic injury. Furthermore, some of the histopathological changes may resemble acute cellular rejection occurring after liver transplantation. These two cases demonstrate that severe COVID-19 hepatitis can occur even in the absence of significant involvement of other organs.

Although the overall five-year survival of patients with pancreatic ductal adenocarcinoma (PDAC) is dismal, there are survival differences between cases with clinically and pathologically indistinguishable characteristics, suggesting that there are uncharacterized properties that drive tumor progression. Recent mRNA sequencing studies reported gene-expression signatures that define PDAC molecular subtypes that correlate with differences in survival. We previously identified Keratin 17 (K17) as a negative prognostic biomarker in other cancer types. Here, we set out to determine if K17 is as accurate as molecular subtyping of PDAC to identify patients with the shortest survival. K17 mRNA was analyzed in two independent PDAC cohorts for discovery (n = 124) and validation (n = 145). Immunohistochemical localization and scoring of K17 immunohistochemistry (IHC) was performed in a third independent cohort (n = 74). Kaplan-Meier and Cox proportional-hazard regression models were analyzed to determine cancer specific survival differences in low vs. high mRNA K17 expressing cases. We established that K17 expression in PDACs defines the most aggressive form of the disease. By using Cox proportional hazard ratio, we found that increased expression of K17 at the IHC level is also associated with decreased survival of PDAC patients. Additionally, within PDACs of advanced stage and negative surgical margins, K17 at both mRNA and IHC level is sufficient to identify the subgroup with the shortest survival. These results identify K17 as a novel negative prognostic biomarker that could inform patient management decisions.