Management of endolymphatic sac tumors: sporadic cases and von Hippel-Lindau disease.

OBJECTIVE: To analyze the difference between the endolymphatic sac tumors (ELSTs) in sporadic cases and in von Hippel-Lindau (VHL) disease. STUDY DESIGN: Retrospective case review in a tertiary referral center. PATIENTS AND METHODS: Fourteen cases of ELST, occurring since 1998, were reviewed. We analyzed the initial symptoms, characteristics of the tumor, treatment, sequelae, and follow-up for each group. RESULTS: The ELSTs were sporadic in 6 cases and associated with VHL disease in 8 cases. The mean age at the time of the first surgery was 26 years (range, 12-41). All except two of the patients presented with a unilateral tumor. The initial symptoms were hearing loss (n = 9), tinnitus (n = 7), and/or vertigo (n = 5). Hearing loss was more prevalent in the sporadic cases. Preoperative arteriography was performed for 4 patients, with embolization performed for 1 patient. The size of the tumor was significantly larger in the sporadic cases (31.7 mm) than in the cases of VHL disease (19.3 mm). The surgical approach was more extensive in the sporadic cases. The surgeons found 2 types of tumors. Cystic tumors with massive bleeding invading the surrounding structures (the dura mater or jugular bulb) were more common in the sporadic cases. Fibrous tumors that infiltrate the bone and have moderate bleeding were more common in the cases associated with VHL disease.Two patients with small lesions were not operated on but were followed for 6 years without tumor growth. They died of metastasis from gastric and kidney cancer. Four recurrences occurred during the 14 years of follow-up. Four facial palsies and 8 cases of profound deafness were encountered postoperatively. CONCLUSION: Sporadic tumors are more aggressive than those associated with VHL disease. Complete surgical resection should be the goal of treatment. Preoperative angiography with embolization is recommended. In some cases, embolization may be impossible, and preoperative or postoperative radiotherapy should be discussed.

Induction of B cell-activating factor by viral infection is a general phenomenon, but the types of viruses and mechanisms depend on cell type.

B cell-activating factor of the TNF family (BAFF) plays a key role in promoting B lymphocyte activation and survival. We previously showed in primary Sjögren's syndrome that salivary gland epithelial cells (SGECs), the resident targeted cells of autoimmunity in this disease, can produce BAFF after infection with a double-stranded RNA (dsRNA) virus by a protein kinase RNA (PKR)-dependent mechanism. This study aimed to assess the effect of different viruses on various cell types - SGECs but also dendritic cells (DCs) and monocytes - in the induction of BAFF. BAFF induction was observed after Sendai virus infection of monocytes and SGECs, as well as poly(I:C) stimulation of DCs. However, PKR inhibition by 2-aminopurine failed to reduce BAFF expression in these infected or stimulated cells. Conversely, in Sendai virus-infected monocytes, blocking type 1 interferon (IFN) receptor by anti-IFNAR1 antibody strongly inhibited BAFF expression. These results provide additional data suggesting that both dsRNA virus stimulation of DCs and single-stranded RNA virus infection of SGECs or monocytes can induce BAFF expression, but through a PKR-independent mechanism for these 3 cell types and a type 1 IFN-dependent mechanism in monocytes and SGECs. Thus, BAFF induction by viral infection is a general phenomenon, but the types of viruses and mechanisms of the induction depend on the cell type.

B-cell-activating factor expressions in salivary epithelial cells after dsRNA virus infection depends on RNA-activated protein kinase activation.

B-cell-activating factor (BAFF) plays a key role in promoting activation of autoimmune B cells. This cytokine may be expressed in and secreted by salivary gland epithelial cells (SGEC) after stimulation with type I IFN or viral or synthetic dsRNA. Because this BAFF expression depends only in part on endosomal TLR and type I IFN, we investigated whether other dsRNA sensors could be implicated in BAFF expression. Using human SGEC, we confirmed the partial dependence of BAFF expression on TLR-3 by replicating the partial inhibition of BAFF expression observed upon endosomal inhibition using TLR-3 or Toll/IL-1R domain-containing protein inducing IFN-beta silencing mRNA, but not with TLR-7 silencing mRNA. Melanoma differentiation-associated gene 5 silencing mRNA had no effect on BAFF expression, but retinoic acid-inducible gene I silencing mRNA had a slight effect observed following infection with dsRNA reovirus-1. Inhibition of RNA-activated protein kinase (PKR) by 2-aminopurine completely abolished both BAFF mRNA and protein production after reovirus-1 infection and poly(I:C) stimulation through NF-kappaB and p38 MAPK pathways, with the latter implicated only after poly(I:C) stimulation. Thus, PKR is the dsRNA sensor implicated in BAFF induction in SGEC after dsRNA stimulation. In autoimmune diseases, PKR may be an interesting target for preventing BAFF following the induction of innate immunity.

Viruses induce high expression of BAFF by salivary gland epithelial cells through TLR- and type-I IFN-dependent and -independent pathways.

B cell activating factor (BAFF) plays a key role in promoting B lymphocyte activation. We investigated whether danger signals induce BAFF secretion by cultured salivary gland epithelial cells (SGEC), which are the target of primary Sjögren's syndrome, a prototypic systemic autoimmune disease. SGEC cultures were established from minor salivary glands obtained from ten patients with pSS or sicca symptoms. BAFF mRNA and protein were measured after stimulation of the different Toll-like receptors (TLR) by agonists or viruses. The expression of TLR2, -3, and -7 was detected in SGEC. Poly (I:C) (a synthetic TLR3 agonist) and reovirus-1 (a dsRNA virus) induced high expression of BAFF mRNA (multiplied by a factor of 246 +/- 39 (SEM) and 347 +/- 66, respectively) and of BAFF protein secretion (58.49 +/- 4.34 pg/mL and 69.73 +/- 5.67). Inhibition of both the endosomal (by chloroquine) and IFN (by anti-IFNAR antibody) pathways partly inhibited BAFF expression. Treatment with both dsRNA virus and poly (I:C) induced high levels of BAFF mRNA and protein expression by SGEC, through pathways dependent on and independent of TLR and dependent on and independent of IFN. BAFF induction by target organs of autoimmune diseases after viral infection may be a link between innate immunity and autoimmunity.

B cell-activating factor of the tumor necrosis factor family (BAFF) is expressed under stimulation by interferon in salivary gland epithelial cells in primary Sjögren's syndrome.

B cell-activating factor (BAFF) has a key role in promoting B-lymphocyte activation and survival in primary Sjögren's syndrome (pSS). The cellular origin of BAFF overexpression in salivary glands of patients with pSS is not fully known. We investigated whether salivary gland epithelial cells (SGECs), the main targets of autoimmunity in pSS, could produce and express BAFF. We used quantitative RT-PCR, ELISA and immunocytochemistry in cultured SGECs from eight patients with pSS and eight controls on treatment with IL-10, tumor necrosis factor alpha (TNF-alpha), IFN-alpha and IFN-gamma. At baseline, BAFF expression in SGECs was low in pSS patients and in controls. Treatment with IFN-alpha, IFN-gamma and TNF-alpha + IFN-gamma increased the level of BAFF mRNA in pSS patients (the mean increases were 27-fold, 25-fold and 62-fold, respectively) and in controls (mean increases 19.1-fold, 26.7-fold and 17.7-fold, respectively), with no significant difference between patients and controls. However, in comparison with that at baseline, stimulation with IFN-alpha significantly increased the level of BAFF mRNA in SGECs of pSS patients (p = 0.03) but not in controls (p = 0.2), which suggests that SGECs of patients with pSS are particularly susceptible to expressing BAFF under IFN-alpha stimulation. Secretion of BAFF protein, undetectable at baseline, was significantly increased after IFN-alpha and IFN-gamma stimulation both in pSS patients (40.8 +/- 12.5 (+/- SEM) and 47.4 +/- 18.7 pg/ml, respectively) and controls (24.9 +/- 8.0 and 9.0 +/- 3.9 pg/ml, respectively), with no significant difference between pSS and controls. Immunocytochemistry confirmed the induction of cytoplasmic BAFF expression after stimulation with IFN-alpha and IFN-gamma. This study confirms the importance of resident cells of target organs in inducing or perpetuating autoimmunity. Demonstrating the capacity of SGECs to express and secrete BAFF after IFN stimulation adds further information to the pivotal role of these epithelial cells in the pathogenesis of pSS, possibly after stimulation by innate immunity. Our results suggest that an anti-BAFF therapeutic approach could be particularly interesting in pSS.

Activation of IFN pathways and plasmacytoid dendritic cell recruitment in target organs of primary Sjögren's syndrome.

Gene expression analysis of target organs might help provide new insights into the pathogenesis of autoimmune diseases. We used global gene expression profiling of minor salivary glands to identify patterns of gene expression in patients with primary Sjögren's syndrome (pSS), a common and prototypic systemic autoimmune disease. Gene expression analysis allowed for differentiating most patients with pSS from controls. The expression of 23 genes in the IFN pathways, including two Toll-like receptors (TLR8 and TLR9), was significantly different between patients and controls. Furthermore, the increased expression of IFN-inducible genes, BAFF and IFN-induced transmembrane protein 1, was also demonstrated in ocular epithelial cells by quantitative RT-PCR. In vitro activation showed that these genes were effectively modulated by IFNs in salivary gland epithelial cells, the target cells of autoimmunity in pSS. The activation of IFN pathways led us to investigate whether plasmacytoid dendritic cells were recruited in salivary glands. These IFN-producing cells were detected by immunohistochemistry in all patients with pSS, whereas none was observed in controls. In conclusion, our results support the pathogenic interaction between the innate and adaptive immune system in pSS. The persistence of the IFN signature might be related to a vicious circle, in which the environment interacts with genetic factors to drive the stimulation of salivary TLRs.

Ambulatory sleep recording in a healthcare network: a feasibility study.

Sleep disorders have a high prevalence: around 20% of insomniacs, 10% hypersomnolent including 2 to 4% of sleep disordered breathing in the general adult population. The low availability of sleep centres implies the research of alternative recording techniques in the natural setting of the patient. The objective was to evaluate an ambulatory recorder and its integration in a managed healthcare network. Fifteen patients had a full set-up at home and ten patients were hooked-up in the hospital but recorded at home. Technical failures occurred in 2/15 with full polysomnographic recordings. Integration within an experimental sleep network is in progress. This managed care network will include training of general practitioners, teletransmissions between GP and sleep specialists for a graded use of available resources including ambulatory monitoring.