CDKN2A germline mutations in familial pancreatic cancer

OBJECTIVE: To evaluate the prevalence of mutations in the CDKN2A gene encoding p16 and p14 in familial pancreatic cancer (FPC). SUMMARY BACKGROUND DATA: The genetic basis of FPC is still widely unknown. Recently, it has been shown that germline mutations in the p16 tumor suppressor gene can predispose to pancreatic cancer. The presence of p14 germline mutations has yet not been determined in this setting. METHODS: Eighteen families with at least two first-degree relatives with histologically confirmed pancreatic cancer and five families with at least one patient with pancreatic cancer and another first-degree relative with malignant melanoma of the German National Case Collection for Familial Pancreatic Cancer were analyzed for CDKN2A germline mutations including p16 and p14 by direct DNA sequencing. All participating family members were genetically counseled and evaluated by a three-generation pedigree. RESULTS: None of 18 FPC families without malignant melanoma revealed p16 mutations, compared to 2 of 5 families with pancreatic cancer and melanoma. Truncating p16 germline mutations Q50X and E119X were identified in the affected patients of pancreatic cancer plus melanoma families. None of the 23 families revealed p14 germline mutations. CONCLUSIONS: CDKN2A germline mutations are rare in FPC families. However, these data provide further evidence for a pancreatic cancer-melanoma syndrome associated with CDKN2A germline mutations affecting p16. Thus, all members of families with combined occurrence of pancreatic cancer and melanoma should be counseled and offered screening for p16 mutations to identify high-risk family members who should be enrolled in a clinical screening program.     

Immunoadsorption in dermatology

Immunoadsorption (IA), also termed immunoapheresis, has been established as effective and specific tool advantageous to plasmapheresis to remove immunoglobulin and immune complexes and in cytapheresis, immune cells from the circulation. IA was successfully used in various autoantibody-mediated diseases, e.g. acquired hemophilia, myasthenia gravis, dilated cardiomyopathy, and Guillain–Barré syndrome. In dermatology, IA has been applied as an effective adjuvant treatment for autoimmune bullous diseases. Autoimmune blistering disorders are a heterogeneous group of diseases that are associated with autoantibodies to desmosomal (pemphigus group) and basal membrane zone proteins (pemphigoid group, epidermolysis bullosa acquisita). Because the pathogenic relevance of autoantibodies was clearly demonstrated in the majority of these disorders, removal of autoantibodies, therefore, appears to be a rational therapeutic approach for these patients. IA has been shown to effectively lower the autoantibody levels and leads to rapid clinical responses in patients with immunobullous disorders. Here, clinical effects and adverse events of IA in more than 50 reported patients with autoimmune blistering disorders are reviewed. In addition, an overview of the available IA systems and treatment protocols is provided and guidelines of a recent consensus of German, Austrian, and Swiss experts for the use of IA in autoimmune bullous diseases are summarized.     

Immunogenicity of rituximab in patients with severe pemphigus

Pemphigus is a life-threatening autoimmune bullous disease associated with autoantibodies to desmoglein 1 and/or 3. The anti-CD20 chimeric mouse monoclonal antibody rituximab has previously been successfully applied in more than 130 reported pemphigus patients with severe and/or refractory disease. Since antibodies against other therapeutics such as IFNα and β, erythropoietin, and TNFα antagonists had led to decreased efficacy of these drugs, we determined anti-rituximab antibodies in 11 patients with pemphigus before rituximab administration as well as 3, 9, and 15 months thereafter. For this purpose, a novel, affinity capture elution assay was established using rabbit IgG against the F(ab)₂ fragment of rituximab. In addition, serum levels of rituximab were determined by a competition ELISA. In 2 of 11 pemphigus patients, antibodies to rituximab were detected. In both patients, only a partial remission was observed under treatment. In addition, when followed over a longer period of time, the occurrence of anti-rituximab antibodies paralleled an increase in disease activity. Of the 9 patients without development of antiantibodies to rituximab, in 5, all lesions healed and in 4, partial remissions were seen. These observations show that antibodies to rituximab are generated in some patients during rituximab treatment and may be associated with a less favourable response to treatment.     

Specific immunoadsorption of pathogenic autoantibodies in pemphigus requires the entire ectodomains of desmogleins

Pemphigus foliaceus (PF) and pemphigus vulgaris (PV) are life‐threatening autoimmune blistering skin diseases. They are characterized by circulating autoantibodies which bind to the ectodomains of desmoglein (Dsg) 1 and Dsg3. These antibodies induce acantholysis in skin and mucous membranes. In severe cases of pemphigus, immunoadsorption is applied to remove total IgG from patient plasma using protein A or other ligands. To develop a specific adsorber for anti‐Dsg antibodies, epitope mapping studies of Dsg1 and Dsg3 ectodomains were conducted. Dsg variants were expressed on the surface of HEK‐293 cells and analysed for reactivity with pemphigus and control sera by indirect immunofluorescence technique. For Dsg1, a construct consisting of domain 1 directly fused to domain 5, seemed to be suitable for specific immunoadsorption of anti‐Dsg1 antibodies. The recognized epitopes were mainly conformation‐dependent. However, adsorption of pemphigus foliaceus IgG using this protein coupled to a Sepharose matrix did not completely remove pathogenicity from the sera, as proven by a keratinocyte dissociation assay. In contrast, full‐length Dsg1 and Dsg3 ectodomains were able to specifically adsorb anti‐Dsg antibodies and to efficiently eliminate pathogenicity. Therefore, the complete and correctly folded ectodomains of both desmogleins are required for therapeutic immunoadsorption.     

Similar renal outcomes in children with ADPKD diagnosed by screening or presenting with symptoms

Autosomal dominant polycystic kidney disease (ADPKD) in children is sometimes considered to be a benign condition, with morbidity manifesting in adulthood. Therefore, diagnostic screening of children at risk is controversial. The aim of our study was to to compare the manifestations of ADPKD in children diagnosed by postnatal ultrasound (US) screening versus those presenting with symptoms. This was a retrospective chart review of children with ADPKD assessed in a single centre between 1987 and 2007. Age and reason for diagnosis were noted, and children were separated into two groups: (1) those diagnosed on the basis of family-based screening; (2) those presenting with a symptom. The two groups were compared for renal size, number of cysts, estimated glomerular filtration rate (eGFR), the presence of hypertension and microalbuminuria. In the 47 children with ADPKD (21 females) from 33 families who satisfied the enrollment criteria, mean (standard deviation) age at referral and last follow-up was 7.2 (4.4) and 12.9 (5.1) years, respectively, and the mean follow-up duration was 5.7 (3.6) years. Diagnosis was based on postnatal US screening in 31 children, whereas 16 were diagnosed after presenting with symptoms. The proportions of children with nephromegaly, hypertension, microalbuminuria and decreased eGFR, respectively, were similar in both groups. Based on these results, we conclude that renal-related morbidities, including hypertension and microalbuminia, do occur in children with ADPKD and at a similar frequency in those diagnosed after presenting with symptoms and those diagnosed upon postnatal screening. We suggest that at-risk children should have regular checks to detect hypertension. Moreover, affected children may benefit from novel therapies to minimise cystic disease progression.     

Oxidative stress in hemodialysis patients: is NADPH oxidase complex the culprit?

Oxidative stress results from an imbalance between oxidant production, including reactive oxygen species (ROS), reactive nitrogen species (RNS), chlorinated compounds, and antioxidant defense mechanisms. Most reports prove that oxidative stress is present in ESRD patients. Several studies tend to accreditate the hypothesis by which oxidative stress is a strong co-factor for the development of complications related to long-term HD such as atherosclerosis, amyloidosis, malnutrition, anemia, and infection. In order to evaluate the rationale for curative action against oxidative damage in chronic renal failure patients, we reviewed the putative factors involved in this process. Antioxidant systems are severely impaired in uremic patients and gradually altered with the degree of renal failure. Moreover, the inflammatory state caused by the hemoincompatibility of the dialysis system plays a critical role in the activation of NADPH oxidase, aggravating the pro-oxidant status of uremic patients. Prevention of ROS overproduction by improvement of dialysis biocompatibility, an important component of adequate dialysis, might be completed by antioxidant supplementation.     

Synthesis of (aminoalkylamine)-N-aminoalkyl)azanonaborane(11) derivatives for boron neutron capture therapy

New boron-containing polyamine have been synthesized: (aminoalkylamine)-N-(aminoalkyl)azanonaborane(11) derivatives [H(2)N(CH(2))(n)H(2)NB(8)H(11)NH(CH(2))(n)NH(2)], where n = 4-6 and 12, and [H(2)N(CH(2))(3)H(2)NB(8)H(11)NH(CH(2))(4)NH(2)]. (4-Aminobutylamine)-N-(4-aminobutyl)azanonaborane and (3-aminopropylamine)-N-(4-aminobutyl)azanonaborane were less toxic in vitro (LD(50) of approximately 700 and approximately 1100 microM, respectively) than spermine, while (4-aminobutylamine)-N-isopropylazanonaborane with its hydrophobic isopropyl group and those with n = 5, 6, and 12 were already toxic under similar conditions (LD(50) < 500 microM). These compounds may be useful as delivery agents for boron neutron capture therapy.