Mapping myasthenia gravis-associated T cell epitopes on human acetylcholine receptors in HLA transgenic mice

Susceptibility to myasthenia gravis (MG) is positively linked to expression of HLA-DQ8 and DR3 molecules and negatively linked to expression of the DQ6 molecule. To elucidate the molecular basis of this association, we have induced experimental autoimmune MG (EAMG) in mice transgenic for HLA-DQ8, DQ6, and DR3, and in DQ8xDQ6 and DQ8xDR3 F(1) transgenic mice, by immunization with human acetylcholine receptor (H-AChR) in CFA. Mice expressing transgenes for one or both of the HLA class II molecules positively associated with MG (DQ8 and DR3) developed EAMG. T cells from DQ8 transgenic mice responded well to three cytoplasmic peptide sequences of H-AChR (alpha320-337, alpha304-322, and alpha419-437), of which the response to alpha320-337 was the most intense. DR3 transgenic mice also responded to this sequence very strongly. H-AChR- and alpha320-337 peptide-specific lymphocyte responses were restricted by HLA class II molecules. Disease resistance in DQ6 transgenic mice was associated with reduced synthesis of anti-AChR IgG, IgG(2b), and IgG(2c) Ab's and reduced IL-2 and IFN-gamma secretion by H-AChR- and peptide alpha320-337-specific lymphocytes. Finally, we show that DQ8 imparts susceptibility to EAMG and responsiveness to an epitope within the sequence alpha320-337 as a dominant trait.     

Somatic mutations and affinity maturation are impaired by excessive numbers of T follicular helper cells and restored by Treg cells or memory T cells

We previously reported that Cd3e‐deficient mice adoptively transferred with CD4⁺ T cells generate high numbers of T follicular helper (Tfh) cells, which go on to induce a strong B‐cell and germinal center (GC) reaction. Here, we show that in this system, GC B cells display an altered distribution between the dark and light zones, and express low levels of activation‐induced cytidine deaminase. Furthermore, GC B cells from Cd3e^–/– mice accumulate fewer somatic mutations as compared with GC B cells from wild‐type mice, and exhibit impaired affinity maturation and reduced differentiation into long‐lived plasma cells. Reconstitution of Cd3e^–/– mice with regulatory T (Treg) cells restored Tfh‐cell numbers, GC B‐cell numbers and B‐cell distribution within dark and light zones, and the rate of antibody somatic mutations. Tfh‐cell numbers and GC B‐cell numbers and dynamics were also restored by pre‐reconstitution of Cd3e^–/– mice with Cxcr5^–/– Treg cells or non‐regulatory, memory CD4⁺ T cells. Taken together, these findings underline the importance of a quantitatively regulated Tfh‐cell response for an efficient and long‐lasting serological response.     

Candida and dysbacteriosis: A cytologic,population‐based study of 100,605 asymptomatic women concerning cervical carcinogenesis

BACKGROUND.

The objective of this study was to investigate whether the presence of vaginal Candida or dysbacteriosis predisposes women to an increased susceptibility for (pre)neoplasia over time.

METHODS.

A retrospective, longitudinal, cohort study was performed and was conducted in a population of 100,605 women, each of whom had 2 smears taken over a period of 12 years as part of the Dutch Cervical Screening Program. From these women, a cohort of 1439 women with Candida and a cohort of 5302 women with dysbacteriosis were selected as 2 separate study groups. The control cohort consisted of women who had completely normal cervical smears (n = 87,903 women). These groups were followed retrospectively over time. The odds ratios (OR) for squamous abnormalities in the follow‐up smear for the women in these 3 cohorts were established.

RESULTS.

The dysbacteriotic cohort was significantly more likely to have low‐grade squamous intraepithelial lesions (LSIL) and high‐grade squamous intraepithelial lesions (HSIL+) in their follow‐up smear (OR, 1.85; 95% confidence interval [95% CI], 1.28–2.67 and OR, 2.00; 95% CI, 1.31–3.05, respectively) compared with women in the control group. In contrast, the Candida cohort had no significantly increased or decreased risk of developing SIL. The equivocal diagnosis ‘atypical squamous cells of undetermined significance’ was rendered significantly more often in the follow‐up smear of both study cohorts (Candida cohort: OR, 1.42; 95% CI, 1.03–1.95; dysbacteriotic cohort: OR, 1.44; 95% CI, 1.22–1.71).

CONCLUSIONS.

The results from this study indicated that the presence of Candida vaginalis was not associated with an increased risk for SIL over time. In contrast, women with dysbacteriosis had a significantly increased risk of developing (pre)neoplastic changes. These findings should be taken into account in further research concerning predisposing factors for cervical carcinogenesis. Cancer (Cancer Cytopathol) 2007. © 2007 American Cancer Society.     

Canonical nuclear factor kappaB pathway inhibition blocks myeloma cell growth and induces apoptosis in strong synergy with TRAIL.

PURPOSE: Intrinsic activation of nuclear factor kappaB (NF-kappaB) characterizes various hematologic malignancies. In this study, we specifically address the role of NF-kappaB blockade in mediated antimyeloma activity using the IkappaB kinase-2 pharmacologic inhibitor, AS602868. EXPERIMENTAL DESIGN: Human myeloma cell lines (n = 16) and primary myeloma cells (n = 10) were tested for their sensitivity to AS602868 in terms of proliferation and apoptosis. Both in vitro and in vivo experiments were conducted. Functional mechanisms regarding the apoptotic pathways triggered by AS602868 were studied. The potential proapoptotic synergy between AS602868 and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) was also evaluated. RESULTS: Our results show that AS602868 efficiently targeted the canonical NF-kappaB pathway in myeloma cells and potently inhibited their growth in inducing apoptosis through Bax and caspase-3 activation. AS602868 also induced apoptosis in primary myeloma cells even in the presence of bone marrow mononuclear cells. Moreover, the IkappaB kinase-2 inhibitor targeted the paracrine effect on the bone marrow environment. Indeed, it decreased the intrinsic and myeloma-induced secretion of interleukin-6 from bone marrow stromal cells. In addition, AS602868 inhibited myeloma cell growth in the MM.1S xenograft myeloma model. Of particular interest, AS602868 strongly increased myeloma sensitivity to TRAIL in blocking TRAIL-induced NF-kappaB activation and in decreasing the expression of antiapoptotic proteins such as cFLIP and cIAP-1/2. CONCLUSIONS: Taken together, our data point out the interest to inhibit the canonical NF-kappaB pathway in myeloma and clearly encourage clinical evaluation of novel therapies based on targeting NF-kappaB, especially in combination with TRAIL.     

A pharmacogically guided phase I study of carboplatin in combination with methotrexate and vinblastine in advanced urothelial cancer

 Carboplatin is an alternative for cisplatin in the treatment of urothelial cancers. A pharmacologically guided phase I study of carboplatin in combination with methotrexate (30 mg/m²) and vinblastine (4 mg/m²) was conducted in ten patients by increment of the area under the plasma concentration versus time curve (AUC) for ultrafilterable carboplatin using the Calvert formula. The maximal tolerated AUC was 5 mg ml^-1 min, with neutropenia being the dose-limiting toxicity. There was a significant linear correlation between the percentage of decrease in neutrophil count and the carboplatin AUC. Determination of the glomerular filtration rate by the isotopic method allowed us to adapt the dose of carboplatin given to patients suffering from urothelial cancer, who frequently have impaired renal function. The recommended AUC for phase II study is 4 mg ml^-1 min. Received: 9 May 1994/Accepted: 16 August 1994     

Increase in signal-to-noise ratio of > 10,000 times in liquid-state NMR

A method for obtaining strongly polarized nuclear spins in solution has been developed. The method uses low temperature, high magnetic field, and dynamic nuclear polarization (DNP) to strongly polarize nuclear spins in the solid state. The solid sample is subsequently dissolved rapidly in a suitable solvent to create a solution of molecules with hyperpolarized nuclear spins. The polarization is performed in a DNP polarizer, consisting of a super-conducting magnet (3.35 T) and a liquid-helium cooled sample space. The sample is irradiated with microwaves at approximately 94 GHz. Subsequent to polarization, the sample is dissolved by an injection system inside the DNP magnet. The dissolution process effectively preserves the nuclear polarization. The resulting hyperpolarized liquid sample can be transferred to a high-resolution NMR spectrometer, where an enhanced NMR signal can be acquired, or it may be used as an agent for in vivo imaging or spectroscopy. In this article we describe the use of the method on aqueous solutions of [13C]urea. Polarizations of 37% for 13C and 7.8% for 15N, respectively, were obtained after the dissolution. These polarizations correspond to an enhancement of 44,400 for 13C and 23,500 for 15N, respectively, compared with thermal equilibrium at 9.4 T and room temperature. The method can be used generally for signal enhancement and reduction of measurement time in liquid-state NMR and opens up for a variety of in vitro and in vivo applications of DNP-enhanced NMR.     

Suppressed clinical experimental autoimmune myasthenia gravis in bm12 mice is linked to reduced intracellular calcium mobilization and IL-10 and IFN-gamma release by acetylcholine receptor-specific T cells

Class II MHC mutant bm12 mice have an increased resistance to experimental autoimmune myasthenia gravis (EAMG) compared to C57BL/6 mice. In vitro, this relative resistance was mainly associated with a reduced cytokine response to acetylcholine receptor (AChR) and its dominant pathogenic peptide alpha 146-162, whereas the response to the epitope alpha 111-126 remained intact. Calcium mobilization after stimulation of AChR-immune T cells with AChR or alpha 146-162 peptide, but not alpha 111-126 peptide, was decreased in bm12 compared to C57BL/6. Thus, the reduced incidence of clinical EAMG in bm12 is linked to lower IFN-gamma and IL-10 release, and intracellular calcium mobilization by alpha 146-162-specific T cells.     

Expression of tumour necrosis factor-related apoptosis-inducing ligand death receptors in sporadic and hereditary colorectal tumours: potential targets for apoptosis induction

Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) and antibodies against TRAIL receptors death receptor 4 (DR4) and death receptor 5 (DR5) are under investigation for cancer therapy. To study the potential application of these agents, the expression of DR4 and DR5 were studied immunohistochemically in colorectal adenomas and carcinomas from patients with sporadic disease (n=74 and 56, respectively), familial adenomatous polyposis (FAP, n=41 and 4, respectively) and hereditary non-polyposis colorectal cancer (HNPCC, n=50 and 21, respectively). BAX, which is frequently mutated in tumours with high-frequency microsatellite instability (MSI-H) may play a role in sensitivity to TRAIL. Therefore, MSI-H carcinomas (n=42, of which 27 sporadic and 15 HNPCC) were analysed for apoptotic activity, assessed by M30 immunoreactivity, and BAX mutations. Most adenomas from all three patient groups expressed DR4 and DR5. Most carcinomas expressed DR4, except for six cases, all with mucinous histology. All carcinomas, including mucinous carcinomas, showed DR5 expression. BAX mutations were found in 6/42 MSI-H cancers with similar apoptotic indices and expression of DR4, DR5 and TRAIL in BAX mutant and wild-type cases. Since most sporadic and hereditary colorectal neoplasms express DR4 and DR5, targeting of these receptors may be a potential prevention or treatment strategy.     

Gastric metastasis from ovarian carcinoma revealed by a gastro-splenic perforation

Metastatic disease involving the stomach is unusual. We report the case of a gastric metastasis from ovarian cancer revealed by gastro-splenic perforation. The gastric metastasis was diagnosed 17 years after the diagnosis of primary cancer.     

So-called "superficial" bladder tumors. Which classification in 2003? Part 1: Papillary tumors

The so-called superficial tumors of the urinary bladder three types of tumors: non infiltrating papillary tumors (pTa), tumors infiltrating the lamina propria (pT1) and carcinoma in-situ. Even if they all need conservative treatment, they belong to three distinct categories of tumors with their own recurrence and progression risks. All these tumors are evaluated according to TNM stages and morphological grades. The reproducibility of the grading has been recently discussed; the International Society of Urological Pathology (ISUP) and the World Health Organization (WHO) have proposed new criteria for new classifications in 1998 and 1999 respectively. These classifications have not been approved by most pathologists and they are discussed and commented here, including the recent point of view defending the refinement of the WHO 1973 classification for the grading. To understand well pT1 bladder carcinomas, the discussion of sub-staging (pT1a and pT1b) is exposed.