Aurelia Busca

Innate immune responses in hepatitis B virus (HBV) infection

Hepatitis B virus (HBV) infection has a low rate of chronicity compared to HCV infection, but chronic liver inflammation can evolve to life threatening complications. Experimental data from HBV infected chimpanzees and HBV transgenic mice have indicated that cytotoxic T cells are the main cell type responsible for inhibition of viral replication, but also for hepatocyte lysis during chronic HBV infection. Their lower activation and impaired function in later stages of infection was suggested as a possible mechanism that allowed for low levels of viral replication. The lack of an interferon response in these models also indicated the importance of adaptive immunity in clearing the infection. Increased knowledge of the signalling pathways and pathogen associated molecular patterns that govern activation of innate immunity in the early stages of viral infections in general has led to a re-evaluation of the innate immune system in HBV infection. Numerous studies have shown that HBV employs active strategies to evade innate immune responses and induce immunosuppression. Some of the immune components targeted by HBV include dendritic cells, natural killer cells, T regulatory cells and signalling pathways of the interferon response. This review will present the current understanding of innate immunity in HBV infection and of the challenges associated with clearing of the HBV infection.

CpG Protects Human Monocytic Cells against HIV-Vpr–Induced Apoptosis by Cellular Inhibitor of Apoptosis-2 through the Calcium-Activated JNK Pathway in a TLR9-Independent Manner

Monocytic cells survive HIV replication and consequent cytopathic effects because of their decreased sensitivity to HIV-induced apoptosis. However, the mechanism underlying this resistance to apoptosis remains poorly understood. Lymphocytic cells are exposed to microbial products because of their translocation from the gut in persons with chronic HIV infections or following coinfections. We hypothesized that activation of monocytic cells by such microbial products through interaction with corresponding TLRs may confer antiapoptotic signals. Using HIV-viral protein R (Vpr)(52–96) peptide as a model apoptosis-inducing agent, we demonstrated that unlike monocyte-derived macrophages, undifferentiated primary human monocytes and promonocytic THP-1 cells are highly susceptible to Vpr(52–96)-induced apoptosis. Interestingly, monocytes and THP-1 cells stimulated with TLR9 agonist CpG induced almost complete resistance to Vpr(52–96)-induced apoptosis, albeit through a TLR9-independent signaling pathway. Moreover, CpG selectively induced the antiapoptotic cellular inhibitor of apoptosis (c-IAP)-2 protein and inhibition of the c-IAP-2 gene by either specific small interfering RNA or synthetic second mitochondrial activator of caspases mimetic reversed CpG-induced resistance against Vpr(52–96)-mediated apoptosis. We demonstrated that c-IAP-2 is regulated by the JNK and calcium signaling pathway, in particular calmodulin-dependent protein kinase-II. Furthermore, inhibition of JNK and the calcium signaling including the calmodulin-dependent protein kinase-II by either pharmacological inhibitors or their specific small interfering RNAs reversed CpG-induced protection against Vpr(52–96)-mediated apoptosis. We also show that CpG induced JNK phosphorylation through activation of the calcium signaling pathway. Taken together, our results suggest that CpG-induced protection may be mediated by c-IAP-2 through the calcium-activated JNK pathway via what appeared to be TLR9-independent signaling pathways.

Jak/STAT and PI3K signaling pathways have both common and distinct roles in IL-7-mediated activities in human CD8+ T cells

IL‐7 plays an important role in T cell survival, function, and memory cell development, yet the role of cytokine signaling pathways in these processes has not been fully elucidated. Moreover, the underlying mechanisms for the observed impairment of IL‐7 activity in diseases, such as HIV infection, breast cancer, and autoimmunity, are not well understood. It was therefore hypothesized that IL‐7‐induced signaling molecules could be linked with distinct IL‐7‐associated activities. To address this, the activation and functional associations of IL‐7‐induced signaling pathways, specifically antigen‐independent activities that are relevant to T cell homeostasis, were examined. Low concentrations of IL‐7 (100 pg/ml) are capable of activating the Jak‐STAT and PI3K signaling pathways, whereas higher concentrations (500–1000 pg/ml) were required to induce Bcl‐2 production and glucose uptake. Even higher concentrations of IL‐7 (10,000 pg/ml) were needed to induce cell proliferation and intracellular accumulation of perforin. Inhibition of Jak activation reduced IL‐7‐induced Bcl‐2 and perforin production, whereas inhibition of Jak/STAT or PI3K pathways reduced glucose uptake and proliferation. This study suggests a complex control of IL‐7‐associated activities in the absence of antigen stimulation. These data may provide insights into mechanisms of impaired IL‐7 signaling and function in disease and could be relevant for the study of IL‐7‐based immunotherapeutics. Specifically, this study has linked STAT5 and PI3K activation to shared and distinct IL‐7‐associated activities in human CD8+ T cells.

Ifitm1 Outperforms Cd10 in Differentiating Low-grade Endometrial Stromal Sarcomas From Smooth Muscle Neoplasms of the Uterus

Distinguishing between uterine neoplasms of smooth muscle and endometrial stromal origin is a frequent diagnostic challenge. We investigated the staining pattern of interferon-induced transmembrane protein-1 (IFITM1), a novel endometrial stromal marker, in endometrial and smooth muscle uterine neoplasms and compared it with CD10 in its ability to differentiate between these two groups. Immunohistochemistry for IFITM1 and CD10 was performed in 20 cases of smooth muscle neoplasms (10 cases leiomyoma, 10 cases leiomyosarcoma), 14 cases of endometrial stromal sarcoma (ESS) (12 cases of low grade and 2 cases of high grade) and 12 cases of carcinosarcoma. Staining was scored in terms of intensity and distribution (0=absent, 1=weak/<50%, 2=moderate/50%–75%, 3=strong/>75%). A total score was obtained by adding intensity and distribution scores and classified as positive (score 3–6) or negative (score 0–2). IFITM1 was positive in 10 of 12 (83%) low-grade ESSs, 6 of 20 (30%) smooth muscle tumors (leiomyomas and leiomyosarcomas) and 11 of 12 carcinosarcomas (91.6%). The 2 cases of high-grade ESS were IFITM1 negative. While both IFITM1 (83%) and CD10 (91%) had high sensitivity in differentiating low-grade ESSs from smooth muscle neoplasms, IFITM1 (70%) had higher specificity compared with CD10 (45%). In this study IFITM1 appears to be a more specific marker of endometrial stromal differentiation compared with CD10 in differentiating low-grade ESSs from smooth muscle neoplasms. Thus, IFITM1 may be a valuable tool as part of an immunohistochemical evaluation panel in this diagnostic scenario.

The role of pathologic evaluation of endometrial ablation resections in predicting ablation failure and adenomyosis in hysterectomy

Endometrial ablation is commonly performed to manage heavy menstrual bleeding. However, failure in symptom control eventually requiring hysterectomy is frequent. Adenomyosis is common in such failure cases. Ablations using a resectoscope will produce an Endo-Myometrial Resection (EMR) specimen. The value of histopathologic examination of EMRs in predicting treatment failure and adenomyosis has not been addressed. We retrieved histologic material from subjects with failed ablation (persistent symptoms requiring hysterectomy) and subjects with ablation followed by clinical improvement and no hysterectomy (control group). Material was evaluated for features of an abnormal endometrial distribution suggestive of adenomyosis: myometrial fragments with endometrium on opposite edges, myometrium with endometrium in ≥3 edges and areas of endometrium completely surrounded by myometrium (endometrial islands). Hysterectomy specimens from the study group were evaluated for the presence of adenomyosis and its distribution (superficial/deep). Both study and control groups consisted of 18 patients each. The number of fragments with endometrium on opposite sides was significantly higher in the study group: 2.11 vs 0.94 in the control group (p=0.005). Conversely, maximum aggregate dimension (2.3cm vs 2.79cm), number of fragments with endometrium on three sides (4.5 vs 2.78) and number of fragments with endometrial islands (4.5 vs 4.11) did not significantly differ between groups. Adenomyosis was seen in 72.2% hysterectomies from the study group; 27.8% involved deep myometrium. None of the EMR features were statistically associated with adenomyosis. Certain endomyometrial distribution patterns in EMR specimens correlate with future ablation failure and need for definitive surgery. This may be explained by residual endometrial tissue not resected due to a markedly irregular endomyometrial interface. Adenomyosis is frequent in cases of ablation failure. However, a significant association between EMR patterns studied and adenomyosis was not observed.

IFITM1 Is Superior to CD10 as a Marker of Endometrial Stroma in the Evaluation of Myometrial Invasion by Endometrioid Adenocarcinoma

Abstract Background: Distinguishing myometrial invasion from adenomyosis involvement is important for staging of endometrial endometrioid adenocarcinoma. We aimed to compare CD10, which has limited value in this scenario, with interferon-induced transmembrane protein 1 (IFITM1), a recently described sensitive and specific marker of endometrial stroma. Methods: We reviewed 25 hysterectomies containing endometrial endometrioid adenocarcinoma and adenomyosis. Tumor areas were classified as unequivocally myoinvasive or unequivocally noninvasive. Foci equivocal for invasion were also recorded. Immunohistochemistry for IFITM1 and CD10 was performed and scored in terms of intensity and distribution and classified as negative or positive. Results: Unlike CD10, IFITM1 staining showed significant differences in mean intensity (P < .0001) and distribution (P < .0001) between invasive vs noninvasive areas. Sixteen (84.2%) invasive and 34 (97.1%) noninvasive areas were positive for CD10 (P = .22). In contrast, none of the invasive vs 25 (71.4%) noninvasive areas were positive for IFITM1 (P < .0001). IFITM1 had 71.4% sensitivity and 100% specificity in detecting stroma surrounding endometrioid adenocarcinoma, hence excluding myoinvasion. Eleven (45.8%) of 24 foci designated as equivocal stained with IFITM1. Conclusions: Compared with CD10, IFITM1 has superior performance distinguishing endometrial stroma of adenomyosis from mesenchyma surrounding invasive endometrial adenocarcinoma. IFITM1 expression is highly predictive of the absence of invasion and may be valuable in cases in which determining myoinvasion has staging implications.

cIAP1/2–TRAF2–SHP-1–Src–MyD88 Complex Regulates Lipopolysaccharide-Induced IL-27 Production through NF-κB Activation in Human Macrophages

The inhibitors of apoptosis (IAP) proteins, initially described in the context of apoptosis regulation as promoting cell survival, have recently emerged as key regulators of innate immune signaling. As a result, downregulation of IAP via Smac mimetics (SMM) has both survival and immunoregulatory effects. IAPs modulate cytokine production in murine models either as a single agent or in response to LPS. However, the role of SMM and the involvement of IAPs in primary human cells and in particular macrophages with respect to cytokine production and innate immune responses remain largely unknown. IL-27, a member of the IL-12 cytokine family produced by APCs such as macrophages, has broad immunoregulatory properties in both innate and adaptive immune responses. Herein, we show that cellular IAPs (cIAPs) positively regulate LPS-induced IL-27 production in both primary human monocytes and macrophages. Investigations for the signaling mechanism of cIAPs involvement in IL-27 production in human macrophages revealed that LPS-induced IL-27 production is regulated by a novel signaling complex comprising cIAP1/2, TNFR-associated factor 2 (TRAF2), SHP-1, Src, and MyD88 leading to p38, c-Jun N-terminal kinases (JNK) and Akt activation and NF-κB signaling. In cancer cells, SMM induce the production of cytokines by activating the noncanonical alternate NF-κB pathway. However, in human macrophages, SMM do not induce the production of TNF-α and other cytokines while inhibiting LPS-induced IL-27 production by inhibiting the classical NF-κB pathway. These signaling pathways may constitute novel therapeutic avenues for immune modulation of IL-27 and provide insight into the modulatory immune effects of SMM.

Myxoid Mesenchymal Tumors of the Uterus: An Update on Classification, Definitions, and Differential Diagnosis

Tumors with a predominant myxoid stroma are rare in the uterus. When encountered, however, they pose a diagnostic challenge. Traditionally myxoid leiomyosarcoma has been the most important consideration in this category, given its adverse prognosis and deceptively bland morphology. Conventional features of malignancy are variably present; in contrast, an infiltrative tumor border is a consistent pathologic characteristic. More recently, previously under-recognized lesions have been identified, in part due to our growing knowledge of their underlying molecular alterations: uterine inflammatory myofibroblastic tumor frequently harbors ALK rearrangements and a novel ZC3H7B-BCOR gene fusion has been described in a subset of myxoid high-grade endometrial stromal sarcomas. These tumors need to be distinguished from myxoid leiomyosarcoma, as by comparison have a less aggressive course and are amenable to targeted treatments. In addition, uterine mesenchymal tumors with malignant potential need to be distinguished from benign tumors and epithelial and mixed malignancies. This review aims to discuss our current understanding of the most common uterine myxoid neoplasms: their clinical features, their distinguishing histopathologic, immunohistochemical, and molecular features and the clues and pitfalls in their diagnosis.

Hemangiomas of the uterine cervix: Association with abnormal bleeding and pain in young women and hormone receptor expression. Report of four cases and review of the literature

Hemangiomas of the uterine cervix are rare with only about 55 cases reported in the literature. Increased awareness of this unusual cervical lesion can lead to early diagnosis and conservative therapeutic approaches. We present a series of four patients with cervical hemangioma with an extensive review of the existing literature on the subject. All four cervical hemangiomas were diagnosed incidentally in hysterectomy specimens performed for persistent menorrhagia or pain. The mean age at presentation was 34 years. The mean lesion size was 2.1cm and the dominant location was posterior cervix (3 cases). Immunohistochemistry for estrogen and progesterone receptors showed expression of both markers in endothelial cells and stroma, the latter marker showing a stronger and more diffuse pattern. No other significant uterine abnormality was identified in two cases. The vast majority of cervical hemangiomas reported are in reproductive age women. In addition, these lesions express hormone receptors, indicating that their growth is at least in part due to sex hormone stimulation. Although most lesions are symptomatic (mostly bleeding), the diagnosis is frequently unsuspected. Cervical hemangiomas are benign with no recurrences or adverse outcomes reported to date. Conservative treatments are usually successful, and spontaneous remission has been observed. This entity should be included in the differential diagnosis of patients with abnormal vaginal bleeding, particularly in patients of reproductive age with no other clinical and radiologic findings that would explain the symptoms.