Abstract 2735: Role of SEMA3A and SEMA3C in tumor progression and metastatic processes in PDAC

Pancreatic ductal adenocarcinoma (PDAC) has a 5-years survival rate less than 8% and is predicted to become the second leading cause of cancer-related death by 2030. Recent genome-wide analyses have highlighted the involvement of genes belonging to axon guidance (AG) pathway in the progression of PDAC. Among AG genes, semaphorins were originally identified as axon guidance factors for the developing nervous system but a role for them is described also outside of the nervous system; several semaphorins have been found amplified in a subset of PDAC (around 18%) and elevated expression of SEMA3A, in particular, has been previously correlated to poor prognosis. The aim of this study is to assess the role of the axon guidance genes SEMA3A and SEMA3C in PDAC progression and metastasization using organoid models of the disease, in order to identify either biomarkers predictive of disease recurrence or metastases prevention strategies.

Data mining has been performed using the ICGC (PACA-AU) and the TCGA (PAAD) databases; RNA in situ hybridization (ISH) has been performed on FFPE of non-neoplastic and tumor tissue sections using the RNAscope 2.5 HD Duplex Detection Kit. Perturbation analysis has been performed by overexpressing and silencing Semaphorins (Sema3a and Sema3c) by transduction of tumor-derived organoid cultures with ORF and inducible CRISPR/Cas9 vectors, respectively. For orthotopic transplantation, a small incision in the skin of the upper left quadrant of the abdomen of C57BL/6J and NSG mice has been made; 5 × 105 cells/mouse have been injected into the parenchyma of the pancreas. Tumor growth has been monitored once a week with the VEVO 2100 system.Expression of SEMA3A and SEMA3C was enriched in the basal like/squamous subtype and was correlated to poor survival in both the ICGC and TCGA cohorts. However, in silico microdissection of bulk sequencing data (ICGC and TGCA) revealed that Semaphorins were particularly expressed in the stromal compartment. Accordingly, mRNA in situ hybridization analyses of human PDAC tissues showed that SEMA3A is almost exclusively expressed in cancer-associated fibroblasts (CAFs), while SEMA3C is expressed both in the neoplastic and in CAFs. We further analyzed expression of semaphorins in human tumor-derived organoids and CAFs to confirm that those genes were abundant in CAFs and less expressed in squamous/basal-like organoids. Consistently with in silico and in vitro data, transplantation of mouse tumor organoids overexpressing semaphorins showed reduced tumor growth and lack of metastatic competence as compared to mock transfected cultures, while organoids lacking either Sema3a or Sema3c showed accelerated tumor development and metastasization.These data suggest that SEMA3A and SEMA3C are preferentially expressed by CAFs in PDAC and that their high stromal expression contributes to aggressive molecular subtype of PDAC.

Citation Format: Francesca Lupo, Pietro Delfino, Dea Filippini, Caterina Vicentini, Vincenzo Corbo. Role of SEMA3A and SEMA3C in tumor progression and metastatic processes in PDAC [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2735.

Organoid-Transplant Model Systems to Study the Effects of Obesity on the Pancreatic Carcinogenesis in vivo

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer-related mortality among adults in developed countries. The discovery of the most common genetic alterations as well as the development of organoid models of pancreatic cancer have provided insight into the fundamental pathways driving tumor progression from a normal cell to non-invasive precursor lesion and finally to widely metastatic disease, offering new opportunities for identifying the key driver of cancer evolution. Obesity is one of the most serious public health challenges of the 21st century. Several epidemiological studies have shown the positive association between obesity and cancer-related morbidity/mortality, as well as poorer prognosis and treatment outcome. Despite strong evidence indicates a link between obesity and cancer incidence, the molecular basis of the initiating events remains largely elusive. This is mainly due to the lack of an accurate and reliable model of pancreatic carcinogenesis that mimics human obesity-associated PDAC, making data interpretation difficult and often confusing. Here we propose a feasible and manageable organoid-based preclinical tool to study the effects of obesity on pancreatic carcinogenesis. Therefore, we tracked the effects of obesity on the natural evolution of PDAC in a genetically defined transplantable model of the syngeneic murine pancreatic preneoplastic lesion (mP) and tumor (mT) derived-organoids that recapitulates the progression of human disease from early preinvasive lesions to metastatic disease. Our results suggest that organoid-derived transplant in obese mice represents a suitable system to study early steps of pancreatic carcinogenesis and supports the hypothesis that inflammation induced by obesity stimulates tumor progression and metastatization during pancreatic carcinogenesis.

Identification of Resistance Pathways Specific to Malignancy Using Organoid Models of Pancreatic Cancer

PURPOSE

KRAS is mutated in the majority of pancreatic ductal adenocarcinoma. MAPK and PI3K-AKT are primary KRAS effector pathways, but combined MAPK and PI3K inhibition has not been demonstrated to be clinically effective to date. We explore the resistance mechanisms uniquely employed by malignant cells.

EXPERIMENTAL DESIGN

We evaluated the expression and activation of receptor tyrosine kinases in response to combined MEK and AKT inhibition in KPC mice and pancreatic ductal organoids. In addition, we sought to determine the therapeutic efficacy of targeting resistance pathways induced by MEK and AKT inhibition in order to identify malignant-specific vulnerabilities.

RESULTS

Combined MEK and AKT inhibition modestly extended the survival of KPC mice and increased Egfr and ErbB2 phosphorylation levels. Tumor organoids, but not their normal counterparts, exhibited elevated phosphorylation of ERBB2 and ERBB3 after MEK and AKT blockade. A pan-ERBB inhibitor synergized with MEK and AKT blockade in human PDA organoids, whereas this was not observed for the EGFR inhibitor erlotinib. Combined MEK and ERBB inhibitor treatment of human organoid orthotopic xenografts was sufficient to cause tumor regression in short-term intervention studies.

CONCLUSIONS

Analyses of normal and tumor pancreatic organoids revealed the importance of ERBB activation during MEK and AKT blockade primarily in the malignant cultures. The lack of ERBB hyperactivation in normal organoids suggests a larger therapeutic index. In our models, pan-ERBB inhibition was synergistic with dual inhibition of MEK and AKT, and the combination of a pan-ERBB inhibitor with MEK antagonists showed the highest activity both in vitro and in vivo.

Geometric Flow Control Lateral Flow Immunoassay Devices (GFC-LFIDs): A New Dimension to Enhance Analytical Performance

The nitrocellulose (NC) membrane based lateral flow immunoassay device (LFID) is one of the most important and widely used biosensor platforms for point-of-care (PoC) diagnostics. However, the analytical performance of LFID has limitations and its optimization is restricted to the bioassay chemistry, the membrane porosity, and the choice of biolabel system. These bottom neck technical issues resulted from the fact that the conventional LFID design principle has not evolved for many years, which limited the LFID for advanced biosensor applications. Here we introduce a new dimension for LFID design and optimization based on geometric flow control (GFC) of NC membranes, leading to highly sensitive GFC-LFID. This novel approach enables comprehensive flow control via different membrane geometric features such as the width (w) and the length (l) of a constriction, as well as its input angle (θ₁) and output angle (θ₂). The GFC-LFID (w=0.5 mm, l=7 mm, θ₁= 60°, θ₂= 45°) attained a 10-fold increase in sensitivity for detection of interleukin-6 (IL-6), compared with conventional LFID, whereas reducing by 10-fold the antibody consumption. The GFC-LFID detects IL-6 over a linear range of 0.1–10 ng/mL with a limit of detection (LoD) of 29 pg/mL, which even outperforms some commercial IL-6 LFIDs. Such significant improvement is attained by pure geometric control of the NC membrane, without additives, that only relaying on a simple high throughput laser ablation procedure suitable for integration on regular large-scale manufacturing of GFC-LFIDs. Our new development on GFC-LFID with the combination of facile scalable fabrication process, tailored flow control, improved analytical performance, and reduced antibodies consumption is likely to have a significant impact on new design concept for the LFID industry.

Apheresis treatment of cryoglobulinemic vasculitis: A multicentre cohort study of 159 patients

OBJECTIVE

To assess the effectiveness of apheresis therapy (AT) in treating the clinical manifestations of patients with complicated cryoglobulinemic vasculitis (CV).

METHODS

A retrospective cohort study of 159 CV patients attending 22 Italian Centers who underwent at least one AT session between 2005 and 2015. The response to AT was evaluated on the basis of a defined grading system.

RESULTS

Peripheral neuropathy was the most frequent clinical condition leading to AT. Therapeutic plasma exchange was used in 70.4% of cases. The outcome of AT was rated very good in 19 cases, good in 64, partial/transient in 40, and absent/not assessable in 36. Life-threatening CV-related emergencies and renal impairment independently correlated with failure to respond to AT. The independent variables associated with an increased risk of death were age at the time of the first AT session, multi-organ life-threatening CV, the presence of renal impairment and failure to respond to AT. The time-dependent probability of surviving until CV-related death in the second year was 84%, with an AHR in patients with absent/not assessable response to AT of 11.25.

CONCLUSION

In this study AT is confirmed to be a safe procedure in patients with CV. Early AT should be considered in patients with severe CV, especially in cases with impending renal involvement, in order to prevent irreversible kidney damage. Although its efficacy in patients with multi-organ failure is limited, AT is the only treatment that can rapidly remove circulating cryoglobulins, and should be considered an emergency treatment.

Enhancer Reprogramming Promotes Pancreatic Cancer Metastasis

Pancreatic ductal adenocarcinoma (PDA) is one of the most lethal human malignancies, owing in part to its propensity for metastasis. Here, we used an organoid culture system to investigate how transcription and the enhancer landscape become altered during discrete stages of disease progression in a PDA mouse model. This approach revealed that the metastatic transition is accompanied by massive and recurrent alterations in enhancer activity. We implicate the pioneer factor FOXA1 as a driver of enhancer activation in this system, a mechanism that renders PDA cells more invasive and less anchorage-dependent for growth in vitro, as well as more metastatic in vivo. In this context, FOXA1-dependent enhancer reprogramming activates a transcriptional program of embryonic foregut endoderm. Collectively, our study implicates enhancer reprogramming, FOXA1 upregulation, and a retrograde developmental transition in PDA metastasis.

Abstract B64: Using pancreatic organoids to infer therapeutic resistance and sensitivity

Pancreatic ductal adenocarcinoma (PDA) is a lethal disease with a 5-year survival rate less than 6%. The late diagnosis of the disease and poor efficacy of systemic treatments are major factors for this poor prognosis, and highlight the need for novel PDA models better able to predict resistance/sensitivity to treatment. To fulfill this need, our laboratory developed a three-dimensional culture system that enables the rapid growth of both mouse and human pancreatic ductal organoids. Organoids can be established from healthy or neoplastic tissues using both large (surgical material) and small (fine needle biopsy) samples, thereby providing a novel platform for therapeutic testing for all stages of disease. In this study, we use organoids to evaluate the therapeutic efficacy of the simultaneous inhibition of MEK and AKT kinases, which are activated in PDA by KRAS mutations. Tumor-derived organoids were resistant to both single agents and combination treatment. Genetically engineered mouse models of pancreatic cancer (KPC) also only exhibited a brief response to dual inhibition of MEK and AKT. To assess the potential mechanism of resistance, we evaluated the activation of a number of receptor tyrosine kinases by interrogating both mouse and organoid treated tissues. Members of the ERBB family were activated in KPC animals and tumor-derived organoids treated with both MEK and AKT inhibitors. Accordingly, the addition of an irreversible pan-ERBB inhibitor to the combination of MEK and AKT inhibitors, or MEK inhibitor alone, prevented ERBB-mediated resistance and improved tumor sensitivity to therapeutic intervention. This new therapeutic strategy is efficacious both ex-vivo and in vivo using human tumor-derived organoids and their associated transplant model. Finally, we show that human PDA organoids can be used in high throughput therapeutic screening for the identification of patient-specific therapeutic sensitivities. In summary, pancreatic organoids represent a system that can be used to predict drug sensitivity as well as to identify mechanism of resistance.

*Equal contribution

Citation Format: Herve Tiriac*, Mariano Ponz-Sarvise*, Vincenzo Corbo*, Kristopher K. Frese*, Dannielle D. Engle*, Daniel Ohlund, Tobiloba Oni, Chang-il Hwang, Abram Handly-Santana, Brinda Alagesan, Dea Filippini, Kevin Wright, Kenneth H. Yu, Youngkyu Park, David A. Tuveson.{Authors}. Using pancreatic organoids to infer therapeutic resistance and sensitivity. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2016 May 12-15; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(24 Suppl):Abstract nr B64.

NRF2 Promotes Tumor Maintenance by Modulating mRNA Translation in Pancreatic Cancer

Pancreatic cancer is a deadly malignancy that lacks effective therapeutics. We previously reported that oncogenic Kras induced the redox master regulator Nfe2l2/Nrf2 to stimulate pancreatic and lung cancer initiation. Here, we show that NRF2 is necessary to maintain pancreatic cancer proliferation by regulating mRNA translation. Specifically, loss of NRF2 led to defects in autocrine epidermal growth factor receptor (EGFR) signaling and oxidation of specific translational regulatory proteins, resulting in impaired cap-dependent and cap-independent mRNA translation in pancreatic cancer cells. Combined targeting of the EGFR effector AKT and the glutathione antioxidant pathway mimicked Nrf2 ablation to potently inhibit pancreatic cancer ex vivo and in vivo, representing a promising synthetic lethal strategy for treating the disease.

HER2/neu gene determination in women screened for breast carcinoma: how screening programs reduce the skyrocketing cost of targeted therapy

Few data on Human Epidermal Growth Factor Receptor 2 (HER2)-positive breast carcinomas have been reported for screen-detected breast carcinoma. Assessing the impact of a targeted intervention with anti-HER2 inhibitors on costs is required in order to plan for better strategies in screening programs. A total of 54,472 women were screened and 323 cases were found to be invasive cancer. We performed immunophenotypical-fluorescent in situ hybridization (FISH) analysis. Among 153 evaluable breast carcinomas, tumours displayed a 3+ scoring status 3+ in 16 (10%), 2+ in 12 (8%), 1+ in 29 (19%) and 0 in 96 (63%) of cases, respectively. All 3+ HER2+ cases and 2/12 2+ (17%) cases exhibited HER2/neu gene amplification, the remaining cases did not. In contrast to the higher incidence reported at the population level, 20-30% HER2-positive cases for metastatic carcinomas, and only 11% of the screen-detected breast carcinomas displayed HER2/neu gene amplification. Breast cancer detection by screening programs hijacks the skyrocketing cost of the use of targeted therapy in HER2-positive carcinoma.

A randomized controlled trial of rituximab for the treatment of severe cryoglobulinemic vasculitis

OBJECTIVE

To conduct a long-term, prospective, randomized controlled trial evaluating rituximab (RTX) therapy for severe mixed cryoglobulinemia or cryoglobulinemic vasculitis (CV).

METHODS

Fifty-nine patients with CV and related skin ulcers, active glomerulonephritis, or refractory peripheral neuropathy were enrolled. In CV patients who also had hepatitis C virus (HCV) infection, treatment of the HCV infection with antiviral agents had previously failed or was not indicated. Patients were randomized to the non-RTX group (to receive conventional treatment, consisting of 1 of the following 3: glucocorticoids; azathioprine or cyclophosphamide; or plasmapheresis) or the RTX group (to receive 2 infusions of 1 gm each, with a lowering of the glucocorticoid dosage when possible, and with a second course of RTX at relapse). Patients in the non-RTX group who did not respond to treatment could be switched to the RTX group. Study duration was 24 months.

RESULTS

Survival of treatment at 12 months (i.e., the proportion of patients who continued taking their initial therapy), the primary end point, was statistically higher in the RTX group (64.3% versus 3.5% [P < 0.0001]), as well as at 3 months (92.9% versus 13.8% [P < 0.0001]), 6 months (71.4% versus 3.5% [P < 0.0001]), and 24 months (60.7% versus 3.5% [P < 0.0001]). The Birmingham Vasculitis Activity Score decreased only after treatment with RTX (from a mean ± SD of 11.9 ± 5.4 at baseline to 7.1 ± 5.7 at month 2; P < 0.001) up to month 24 (4.4 ± 4.6; P < 0.0001). RTX appeared to be superior therapy for all 3 target organ manifestations, and it was as effective as conventional therapy. The median duration of response to RTX was 18 months. Overall, RTX treatment was well tolerated.

CONCLUSION

RTX monotherapy represents a very good option for severe CV and can be maintained over the long term in most patients.

Toll-like receptor 4 (TLR4) gene polymorphisms in Italian patients with Behçet's disease

OBJECTIVE

To investigate potential associations between toll-like receptor 4 (TLR4) gene polymorphisms and susceptibility to, clinical features, and severity of Behçet's disease (BD).

METHODS

A total of 189 Italian patients who satisfied the International Study Group criteria for BD and 210 healthy age- and sex-matched blood donors were genotyped for two coding single nucleotide polymorphisms of TLR4 (Asp299Gly and Thr399Ile) by molecular methods. The patients were subgrouped according to the presence or absence of clinical manifestations. Severity score was calculated.

RESULTS

The distribution of allele and genotype frequencies did not differ significantly between the BD patients and the healthy controls. No significant associations were found when BD patients with and those without clinical manifestations were compared. No association between TLR4 polymorphisms and severity score was observed.

CONCLUSION

Our data suggest that the TLR4 gene polymorphisms are not associated with susceptibility to, clinical expression of, and severity of BD in Italian patients.

Protein Z G79A and A-13G gene polymorphisms in Italian patients with Behçet's disease

OBJECTIVE

To investigate potential associations between A-13G and G79A polymorphisms of the protein Z gene and venous thrombosis and other clinical manifestations in Italian patients with Behçet's disease (BD).

METHODS

176 Italian patients who satisfied the International Study Group criteria for BD and 134 healthy age- and sex- matched blood donors were genotyped for A-13G and G79A polymorphisms of the protein Z gene by molecular methods. 113 and 112 of the 176 BD patients were also genotyped for factor V Leiden and prothrombin gene G20210A polymorphisms. Serological HLA class B51 typing was performed by a standard microlymphocytotoxicity technique. The patients were subgrouped according to the presence or absence of clinical manifestations.

RESULTS

The distribution of allele and genotype frequencies of A-13G and G79A polymorphisms did not differ significantly between BD patients and healthy controls.The frequencies of carriage rates of protein Z G79A and A-13G polymorphisms in BD patients with and without DVT were similar. Similarly, no associations between thrombotic events and the protein Z gene polymorphisms studied were observed in BD patients carrying factor V Leiden or prothrombin gene G20210A mutations. No significant associations were observed between protein Z polymorphisms and the occurrence of specific clinical findings.

CONCLUSION

No association between DVT and A-13G or G79A polymorphisms of the protein Z gene was found in Italian BD patients. Furthermore, these protein Z polymorphisms in BD do not seem to increase the risk of DVT due to factor V Leiden or prothrombin gene G20210A mutations.

Lack of association of the 463 G/A myeloperoxidase promoter polymorphism with Behcet's disease in Italian patients

OBJECTIVE

To investigate potential associations between the -463 G/A myeloperoxidase (MPO) promoter polymorphism and susceptibility to, and clinical expression of, Behçet's disease (BD).

METHODS

One hundred and seventy-five Italian patients who satisfied the International Study Group criteria for BD and 235 healthy age- and sex-matched blood donors were genotyped for the -463 G/A promoter polymorphism of the MPO gene by molecular methods. The patients were subgrouped according to the presence or absence of clinical manifestations.

RESULTS

The distribution of allele and genotype frequencies of the MPO -463A/G polymorphism did not differ significantly between the BD patients and the healthy controls. Carriers of the -463 A allele (A/A or A/G) [odds ratio (OR) 0.7, 95% confidence interval (CI) 0.5-1.1] and homozygosity for A allele (OR 0.3, 95% CI 0.1-1.3) were less frequent among BD patients than among the controls, but the difference was not statistically significant. No significant associations were found when BD patients with and those without clinical manifestations were compared.

CONCLUSION

Our data suggest that the -463 G/A promoter polymorphism of the MPO gene is not associated with susceptibility to, and clinical expression of, BD in Italian patients.

Computer screen photoassisted off-null ellipsometry

The ellipsometric measurement of thickness is demonstrated using a computer screen as a light source and a webcam as a detector, adding imaging off-null ellipsometry to the range of available computer screen photoassisted techniques. The results show good qualitative agreement with a simplified theoretical model and a thickness resolution in the nanometer range is achieved. The presented model can be used to optimize the setup for sensitivity. Since the computer screen serves as a homogeneous large area illumination source, which can be tuned to different intensities for different parts of the sample, a large sensitivity range can be obtained without sacrificing thickness resolution.

Measurement strategy and instrumental performance of a computer screen photo-assisted technique for the evaluation of a multi-parameter colorimetric test strip

A measuring strategy for the evaluation of a seven parameters colorimetric test using a computer screen photo-assisted technique (CSPT) is demonstrated. CSPT is a versatile approach aimed at point of care or home tests that uses regular computer sets and web cameras as the whole instrument. Issues such as the stability and the equivalency on different platforms of the determinations have been addressed in the present work. The method uses an embedded local reference simultaneously measured with the tests and solves the evaluation as a classification problem. The achieved performance tested along 580 classifications covering all the ranges of the assay, using synthetic samples, yielded 97.2% correct determinations compared with 89.7% for the case of colorimetric determinations. The errors were concentrated in only two parameters that show a significant correlation with a set of quality indices used to assess the performance of the classification.

Effect of fingerprint conformation and spectral scaling on the performance of computer screen photo-assisted experiments

The use of computer screens as controlled light sources and web cameras as image detectors (the so-called computer screen photo-assisted technique, CSPT) is an ubiquitous alternative for the evaluation of colorimetric quick tests at homes or in primary care units. The performance of CSPT for such evaluations depends on several factors, from which the most relevant are the composition of illuminating sequences and the conformation of CSPT substance signatures. In this work, with the aid of a CSPT model, the effect of the construction of the substance signatures on the classification performance of different representative substance sets is studied. The correlation of illuminating colors with such classification is investigated, allowing one to determine redundancy and limitations with respect to visible spectroscopy. The concept of spectral scaling is introduced and its properties compared with standard procedures.

ELISA test for anti-neutrophil cytoplasm antibodies detection evaluated by a computer screen photo-assisted technique

The computer screen photo-assisted technique (CSPT), a method for substance classification based on spectral fingerprinting, which involves just a computer screen and a web camera as measuring platform is used here for the evaluation of a prospective enzyme-linked immunosorbent assay (ELISA). A anti-neutrophil cytoplasm antibodies (ANCA-ELISA) test, typically used for diagnosing patients suffering from chronic inflammatory disorders in the skin, joints, blood vessels and other tissues is comparatively tested with a standard microplate reader and CSPT, yielding equivalent results at a fraction of the instrumental costs. The CSPT approach is discussed as a distributed measuring platform allowing decentralized measurements in routine applications, whereas keeping centralized information management due to its natural network embedded operation.

Clinical manifestations of Behçet's disease in 137 Italian patients: results of a multicenter study

OBJECTIVE

To determine the type and frequency of clinical features of Behçet's disease in a population of Italian patients.

METHODS

We retrospectively studied 137 Italian patients (76 males and 61 females, age at onset 29.6 +/- 12.2 [mean +/- SD] years) seen consecutively in nine different referral centers. The duration of follow-up at study entry was 10.9 +/- 8.2 years. Virtually all patients fulfilled the classification criteria developed by the International Study Group for Behçet's disease. The clinical manifestations of the patients were recorded by the attending physicians using specifically designed forms.

RESULTS

The most frequent manifestations at disease onset were oral (78.3%) and genital aphthae (29.2%) followed by inflammatory ocular involvement (20%) and arthritis (14.2%). The commonest (>50% of cases) manifestations observed throughout the disease course were oral aphthae (99.3%), genital aphthae (62.8%), various cutaneous lesions including erythema nodosum (81.8%), and inflammatory ocular disease (60.6%). Panuveitis and posterior uveitis/retinitis occurred more frequently in males compared with females (28.9% versus 11.5% and 57.9% versus 36.1%, respectively; p < 0.05). 61.6% of our patients were HLA-B51 positive.

CONCLUSION

Behçet's disease in Italian patients is characterized by a variety of clinical manifestations in agreement with the medical literature. Panuveitis and posterior uveitis/retinitis occur more frequently in male patients.

[Central nervous system involvement in patients with HCV-related cryoglobulinemia: literature review and a case report]

INTRODUCTION

Few well-documented cases of central nervous system involvement in patients with mixed cryoglobulinemia and/or HCV infection have been reported. We can distinguish between acute or subacute diffuse and focal lesions (transient ischemic attack-like syndromes and cerebrovascular accidents).

METHODS

A search of two electronic databases (Medline and EMBASE) was conducted from the year of their inception (1966 for Medline and 1988 for EMBASE) to September 2000. The search strategy employed entailed combining these terms: Cryoglobulinemia, Central Nervous System, Hepatitis C, Chronic Hepatitis. Cryoglobulinemia and Central Nervous System were also used as free test words. We analysed articles with case reports and the most frequent articles on the references list.

PATHOGENESIS

The main pathophysiologic mechanism of cerebral involvement is ischemia (or rarely hemorrhage) due to diffuse or segmental vasculitis of the small cerebral vessels. In these cases a brain MRI usually shows single or multiple increased T2 signals. Furthermore an occasional occlusive vasculopathy without vasculitis was documented histologically. In these patients ischemia could be started or enhanced by the engorgement of the microvasculature by clumps of red cells and by aggregates of cryoglobulins. In the same patients vasculitis and hemorheological abnormalities can affect the clinical picture of the cerebral involvement in mixed cryoglobulinemia. Finally, the detection of HCV in the lesions induces a hypothesis that, in some cases, CNS involvement could be directly related to chronic HCV infection, even in the absence of cryoglobulin production.

CASE REPORT

We describe a 63 year-old woman with acute severe encephalopathy. Laboratory evaluation revealed a high positive test result for rheumatoid factor (3390 U/ml) and hypocomplementemia (C4 less than 1.67 mg/dl). Protein immunofixation electrophoresis demonstrated 5% monoclonal proteins (IgM/k and IgG/k), 3% cryoglobulins were present, HCV antibody and HCV-RNA (type 2a-2c) were positive. Cryoglobulins were never typed, because they disappeared after plasma exchanges. Liver enzymes, renal function and findings on cerebrospinal fluid were normal. Cerebral CT and MRI were also normal. Antinuclear antibodies, anti nDNA antibodies, antiphospholipid antibodies, lupus anticoagulant, ANCA, Lyme disease serology, complete tests for thrombophilia were negative. Bone aspiration was normal. The patient, in coma, was treated with two plasma exchanges. During the first treatment she recovered consciousness. Prednisone (1 mg/Kg/day) and cyclophosphamide (400 mg iv for three days) were added. After a week two plasma exchanges were performed again. Liver enzymes and rheumatoid factor were analysed monthly for six months and than every two months for another six month period up to the present. Liver enzymes were always normal, rheumatoid factor was always at a lower level than the first evaluation (now it's 311 U/ml). At present she is taking Prednisone 5 mg once a day, neurologic symptoms are absent and neurologic examination is normal.

DISCUSSION

We can conclude that: central neurologic involvement may be the clinical presentation of HCV infection and mixed cryoglobulinemia. HCV serologic tests and cryoglobulins should be considered in patient with encephalopathy of non-obvious cause; plasma exchange is the treatment of choice in acute severe forms; in some patients HCV could involve directly CNS, even in the absence of cryoglobulin production.

U86, a novel snoRNA with an unprecedented gene organization in yeast

The Xenopus laevis Nop56 gene (XNOP56), coding for a snoRNP-specific factor, belongs to the 5'-TOP gene family. XNOP56, as many 5'-TOP genes, contains an intron-encoded snoRNA. This previously unidentified RNA, named U86, was found as a highly conserved species in yeast and human. While in human it is also encoded in an intron of the hNop56 gene, in yeast it has an unprecedented gene organization: it is encoded inside an open-reading frame. Both in X. laevis and yeast, the synthesis of U86 snoRNA appears to be alternative to that of the cotranscribed mRNA. Despite the overall homology, the three U86 snoRNAs do not show strong conservation of the sequence upstream from the box D and none of them displays significant sequence complementarity to rRNA or snRNA sequences, suggesting a role different from that of methylation.

Association of MICA alleles and HLA-B51 in Italian patients with Behçet's disease

OBJECTIVE

To evaluate the distribution of the MHC class I chain related gene A transmembrane (MICA-TM) alleles in Italian patients with Behçet's disease (BD), and to investigate the relative contribution of MICA alleles and HLA-B51 in the susceptibility and specific clinical features of BD.

METHODS

A total of 69 consecutive Italian patients who satisfied the International Study Group criteria for BD were followed at rheumatology, ophthalmology, and neurology units during a 3 year period (1997-99). We selected 130 healthy subjects from the same geographic areas as controls. All patients and controls were examined for MICA microsatellite polymorphisms using polymerase chain reaction. Serological HLA class B51 typing was performed by a standard microlymphocytotoxicity technique.

RESULTS

A strong association with HLA-B51 was observed in patients with BD (OR 5.7, 95% CI 2.8-11.3). The MICA-TM allele A6, in linkage disequilibrium with HLA-B51, was only slightly increased in patients compared to controls (60.9% vs 50.8%; p = NS). No significant associations between HLA-B51 or MICA-TM alleles and clinical subgroups, particularly central nervous system or eye involvement, were found.

CONCLUSION

HLA-B51 is the most important susceptibility gene in BD. Association with MICA-A6, when it exists, is secondary to the strong linkage disequilibrium with HLA-B51.

Intercellular adhesion molecule-1 gene polymorphisms in Behçet's Disease

OBJECTIVE

Intercellular adhesion molecule 1 (ICAM-1) is strongly expressed in vascular endothelial cells and perivascular inflammatory infiltrates in immunopathologic studies of Behçet's disease (BD) lesions. ICAM-1 genes may contribute to the inflammatory events responsible for the vessel damage in BD. We examined potential associations of ICAM-1 gene polymorphisms with BD susceptibility.

METHODS

Case patients were 74 consecutive Italian patients with BD who were followed at the Bologna, Ferrara, Milano, Potenza, Prato, Reggio Emilia, and Trento rheumatology, ophthalmology, and neurology units over a 3 year period (1997-99) who satisfied the International Study Group criteria for BD; 228 healthy Italian blood donors from the same geographic areas were selected as control groups. All BD patients and controls were genotyped by polymerase chain reaction and allele-specific oligonucleotide techniques for ICAM-1 polymorphisms at codon 241 (exon 4) and codon 469 (exon 6).

RESULTS

The frequency of R241 was significantly higher in BD patients than in controls (20.3% vs 5.7%; p = 0.001, pcorr = 0.002, OR 4.2, 95% CI 1.9-9.3). The distribution of E/K 469 genotype was similar in patients and controls. Comparing patients with different clinical features, we found only a trend to higher frequency of R241 in patients with articular manifestations (21.4% vs 12.5%; p = 0.08).

CONCLUSION

Our findings show that G/R 241 polymorphism of ICAM-1 is associated with BD susceptibility.

Extra-articular manifestations in 587 Italian patients with rheumatoid arthritis

The aim of the study was to evaluate the frequency of extra-articular manifestations (EAMs) of rheumatoid arthritis (RA) in a series of patients from nine Italian rheumatology clinics. A total of 587 patients underwent direct questioning, complete physical evaluation, and review of medical records and laboratory data. The relationships between EAMs and the eosinophilic count, IgM rheumatoid factor (RF), and antinuclear antibodies (ANA) were studied. EAMs were present in 240/587 (40.9%) patients. The most common features were sicca syndrome (17.5%) and rheumatoid nodules (16.7%). EAMs were significantly more frequent in male patients (OR = 1.68), patients with ANA positivity (OR = 2.82), high anatomical class (OR = 2.3), and rheumatoid factor seropositivity (OR = 2.22). EAMs were more common in patients from southern Italy than in those from northern Italy (P < 0.001). EAMs seem to be rarer in Italy than in the Anglo-Saxon populations of northern Europe and the USA. Differences in prevalence of EAMs can exist even within the same country.

p62, a novel Xenopus laevis component of box C/D snoRNPs

U16 belongs to the family of box C/D small nucleolar RNAs (snoRNAs) whose members participate in ribosome biogenesis, mainly acting as guides for site-specific methylation of the pre-rRNA. Like all the other members of the family, U16 is associated with a set of protein factors forming a ribonucleoprotein particle, localized in the nucleolus. So far, only a few box C/D-specific proteins are known: in Xenopus laevis, fibrillarin and p68 have been identified by UV crosslinking and shown to require the conserved boxes C and D for snoRNA interaction. In this study, we have identified an additional protein factor (p62), common to box C/D snoRNPs, that crosslinks to the internal stem region, distinct from the conserved box C/D "core motif," of U16 snoRNA. We show here that, although the absence of the core motif and, as a consequence, of fibrillarin and p68 binding prevents processing and accumulation of the snoRNA, the lack of the internal stem does not interfere with the efficient release of U16 from its host intron and only slightly affects snoRNA stability. Because this region is likely to be the binding site for p62, we propose that this protein plays an accessory role in the formation of a mature and stable U16 snoRNP particle.