IgE cross-reactivity between Ascaris and domestic mite allergens: the role of tropomyosin and the nematode polyprotein ABA-1

BACKGROUND

Analysis of cross-reactivity between the nematode Ascaris ssp. and dust mites, two important allergen sources in the tropics, will contribute in understanding their influence on asthma and atopy. The objective of this study was to investigate immunoglobulin E (IgE) cross-reactivity between Ascaris and two domestic mites in the tropics.

METHODS

Sera from 24 asthmatic patients were used in ELISA and immunoblotting IgE-binding inhibition assays using Ascaris, Blomia tropicalis and Dermatophagoides pteronyssinus extracts and the recombinants Blo t 10, ABA-1 and Blo t 13 as competitors. Identification of Ascaris allergens was confirmed by mass spectrometry (LC-MS/MS).

RESULTS

We detected at least 12 human IgE-binding components in Ascaris extract. Blomia tropicalis and D. pteronyssinus inhibited 83.3% and 79% of IgE-binding to Ascaris, while Ascaris inhibited 58.3% and 79.3% to B. tropicalis and D. pteronyssinus respectively. Mite tropomyosin inhibited 85% of IgE-binding to Ascaris. Affinity-purified human IgE to rBlo t 10 identified an allergen of 40 kDa in Ascaris extract, further confirmed as tropomyosin by LC-MS/MS. We found no evidence of IgE cross-reactivity between rABA-1 and any allergen component in mite extracts, including rBlo t 13.

CONCLUSIONS

There is cross-reactivity between Ascaris and mites, determined by several allergens including tropomyosin and glutathione-S-transferase. In addition to its potential impact on asthma pathogenesis, Ascaris infection and mite allergy diagnosis relying on the determination of specific IgE could be affected by this cross-reactivity. ABA-1 has no cross-reactive counterpart in mite extracts, suggesting its usefulness as a more specific marker of Ascaris infection.

Vulvar plasmablastic lymphoma in a HIV-positive child: a novel extraoral localisation

Plasmablastic lymphoma (PBL) has been characterised by the World Health Organization as a new entity. This report describes an unusual case of PBL in a 3-year-old HIV-infected patient showing a cutaneous vulvar lesion with 9 months of evolution and prolapsed vulvovaginal mucosa. Histopathological examination of a biopsy sample showed diffuse submucosal infiltration by large cells with a cohesive growth pattern, and round and vesicular nuclei with fine chromatin centrally or eccentrically placed with one or more prominent nucleoli. Immunohistochemical staining in neoplastic cells was positive for multiple melanoma oncogene (MUM1), CD138, CD45 and epithelial membrane antigen (EMA). The diagnosis was PBL, stage III. Epstein-Barr virus (EBV) expression was positive by EBV encoded RNAs in situ hybridisation. This is believed to be the third case of paediatric HIV-associated PBL reported in the literature, and the first with vulvar localisation, which is a new anatomical location for this entity.

[Diagnosis of vitamin B12 deficiency: a case illustrating diagnostic pitfalls]

INTRODUCTION

Vitamin B12 deficiency is a longstanding public health problem which affects more than 20% of the elderly population. Among multiple causes of vitamin B12 deficiency, Biermer's disease is currently mentioned in about 25% of the cases.

OBSERVATION

We report the case of a 71-year-old woman, taking folate substitution therapy who, over 2 years, progressively developed spinal combined sclerosis, subacute dementia and severe neuropathy leading to a bedridden state. The initial assessment revealed normocytic anemia, without vitamin B12 deficiency and without increased plasma level of biological markers. The plasma folate level was high. Vitamin B12 assay was repeated leading to the diagnosis of deficiency associated with the presence of intrinsic factor antibodies.

DISCUSSION

This observation illustrates the broad spectrum of clinical presentations of vitamin B12 deficiency. In the present case, the lack of sensitivity of biological markers delayed diagnosis and had a dramatic impact on outcome. This case highlights the importance of promoting factors such as isolated folate substitution in B12 deficient patients.

[Severe drug hypersensitivity syndrome due to sulphasalazine in patient with rheumatoid arthritis]

Drug Hypersensitivity Syndrome, also known as Drug Rash with Eosinophilia and Systemic Symptoms is a severe adverse reaction characterized by clinical manifestations including fever, skin eruption, lymphoadenopathy, associated with eosinophilia, leukocytosis and multiple visceral involvement, with 10% of mortality due to development of multiple organ failure. This reaction usually occurs between two and six-eight weeks after the beginning of the treatment and may not resolve with interruption of the suspected drug. Sulfonamides, anticonvulsant, allopurinol are the most frequently involved molecules, but recently cases have been described also with gabapentin and strontium ranelate. In the present report we describe a case of a patient with rheumatoid arthritis who presented severe drug hypersensitivity syndrome, with liver and kidney involvement due to sulphasalazine.

Treatment of glioblastoma in Venezuela: Limitations using the current standard of care

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Background: The EORTC/NCIC phase III clinical trial using chemoirradiation with temozolomide (TMZ) 75 mg m-2 x 42d, followed by adyuvant TMZ 150–200 mg m-2 daily x 5d q28d x six cycles set a new standard of care for newly diagnosed glioblastoma (GBM). The applicability of this regimen in developing countries can be problematic. Objectives: To review our experience in Venezuela, contrasting overall survival (OS), 6-month progression-free survival (6PFS), and toxicity in our patients with corresponding outcomes from the EORTC/NCIC trial. Methods: We treated 30 patients with this regimen from March 2001 through July 2004. Results: The median age was 51 years; 17 (60%) were men; 27 (90%) had biopsy or partial resection; 27 (90%) took prophylactic anticonvulsants; and 23 (77%) had prophylaxis against P. jiroveci. Most patients (83%) took the full TMZ treatment during radiation, 7% interrupted TMZ during RT, and 10% could not afford the drug. One patient had Stevens-Johnson syndrome and did not complete RT. Twelve (40%) patients had stereotactic radiosurgery for recurrent disease during the adjuvant phase. The 24-month OS was 30%, median OS was 7.5 months, median PFS was 5 months, and 6PFS was 41%. SRS did not have any effect on OS (p = 0.17, logrank). Grade 3–4 hematologic toxicity was seen in two patients (7%). Conclusions: Except for differences in median OS (7.1 mo) and in 6-PFS (12.6 percentage points) all other measures were reasonably close to the EORTC/NCIC trial. Of concern is the high rate of anticonvulsant prophylaxis using enzyme-inducing drugs and the difficult access to TMZ.

No significant financial relationships to disclose.

Phase I study of vandetanib (V) and bevacizumab (B) combination therapy evaluating the VEGF and EGF signal transduction pathways in adults with solid tumors and NHL

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Background: (V), a small molecule tyrosine kinase inhibitor, has strong inhibitory activity against VEGFR-2 and the EGF RTK. (B), a humanized anti-VEGF monoclonal antibody, blocks the binding of human VEGF to its receptors. We proposed that dual blockade of the VEGF pathway provides an added therapeutic effect compared with either agent alone. Methods: A standard 3–6 pt/cohort design, dose-escalation Phase I study was performed. (V) was self-administered PO, days 1–21 of each 21-day cycle. (B) was administered by IV infusion Q 3 wks. Objectives: Determine the toxicity profile and the MTD of the combination of (V+B); evaluate (V) pharmacokinetics, changes in tumor vascularity by dynamic contrast enhanced MRI (DCE-MRI) and effects of (V+B) treatment on circulating endothelial progenitors and mature circulating endothelial cells. Eligibility: ECOG ≤ 2, adequate organ function. The MTD is the dose level at which no more than 1 of 6 patients experience DLT during the first 2 cycles of treatment, and the dose below at which at least 2 (of ≤6) patients have DLT due to drug treatment. Results: 9 pts have been accrued to date. Diagnosis: pancreatic-1, NSCLC-1, colorectal-3, peritoneal mesothelioma-1, melanoma-1, NHL-1, jejunal adenocarcinoma (JAC)-1. 1 DLT (gr 3 Allergic reaction) was observed at DL 2. HTN was the most common toxicity at DL 2. Other gr 2–3 toxicities seen beyond 2 cycles included: diarrhea, elevated creatinine, leucopenia, anemia, thrombocytopenia, hemorrhage, prolonged QTc interval, proteinuria, rash (hand-foot syndrome / acneiform). Partial Response (PR) was achieved in 2 pts (pancreatic 14 mos + and JAC 6 mos); disease stabilization in 5 pts (4 mos +). DCE-MRI results showed a reduction in the parameters of permeability, (ktrans and kep), associated with one PR. Conclusions: We decided not to escalate beyond DL 2 due to the gr 2–3 toxicities observed with chronic therapy. We recommend (V): 200mg daily and (B): 5mg/kg IV q3 weeks as the Phase II dose.

[Table: see text]

No significant financial relationships to disclose.

Safety, tolerability, pharmacodynamics and pharmacokinetics of albiglutide, a long-acting glucagon-like peptide-1 mimetic, in healthy subjects

AIMS

Albiglutide is a glucagon-like peptide-1 (GLP-1) mimetic generated by genetic fusion of a dipeptidyl peptidase-IV-resistant GLP-1 dimer to human albumin. Albiglutide was designed to retain the therapeutic effects of native GLP-1 while extending its duration of action. This study was conducted to determine the pharmacokinetics and initial safety/tolerability profile of albiglutide in non-diabetic volunteers.

METHODS

In this single-blind, randomized, placebo-controlled trial, 39 subjects (18-60 years, body mass index 19.9-35.0 kg/m(2)) received placebo (n = 10) or escalating doses of albiglutide (n = 29) on days 1 and 8 in the following sequential cohorts: cohort 1: 0.25 + 1 mg; cohort 2: 3 + 6 mg; cohort 3: 16 + 24 mg; cohort 4: 48 + 60 mg; and cohort 5: 80 + 104 mg. Dose proportionality was evaluated based on area under the plasma drug concentration versus time curve [area under the curve (AUC((0-7 days)))] and maximum plasma drug concentration (C(max)) for cohorts 2-5 during week 1.

RESULTS

Albiglutide had a terminal elimination half-life (T(1/2)) of 6-8 days and time to maximum observed plasma drug concentration (T(max)) of 3-4 days. A greater-than-dose proportional increase in albiglutide exposure was observed. Albiglutide demonstrated a dose-dependent trend in reductions of glucose weighted mean AUC and fructosamine levels in healthy subjects. The incidence and severity of adverse events (AEs) was similar between placebo and albiglutide groups. Headache was the most frequent drug-related AE, followed by constipation, flatulence and nausea.

CONCLUSIONS

Albiglutide has a half-life that favours once weekly or less frequent dosing with an acceptable safety/tolerability profile in non-diabetic subjects.

GAB2 gene does not modify the risk of Alzheimer's disease in Spanish APOE 4 carriers

OBJECTIVES

The genetic basis of Alzheimer's disease (AD) is being analyzed in multiple whole genome association studies (WGAS). The GAB2 gene has been proposed as a modifying factor of APOE epsilon 4 allele in a recent case-control WGAS conducted in the US. Given the potential application of these novel results in AD diagnostics, we decided to make an independent replication to examine the GAB2 gene effect in our series.

DESIGN

We are conducting a multicenter population-based study of AD in Spain.

PARTICIPANTS

We analyzed a total of 1116 Spanish individuals. Specifically, 521 AD patients, 475 controls from the general population and 120 neurologically-normal elderly controls (NNE controls).

METHODS

We have genotyped GAB2 (rs2373115 G/T) and APOE rs429358 (SNP112)/rs7412 (SNP158) polymorphisms using real time-PCR technologies.

RESULTS

As previously reported in Spain, APOE epsilon 4 allele was strongly associated with AD in our series (OR=2.88 [95% C.I. 2.16- 3.84], p=7.38E-11). Moreover, a large effect for epsilone 4/epsilone 4 genotype was also observed (OR=14.45 [95% C.I., 3.34-125.2], p=1.8E-6). No difference between the general population and the NNE controls series were observed for APOE genotypes (P > 0.61). Next, we explored GAB2 rs2373115 SNP singlelocus association using different genetic models and comparing AD versus controls or NNE controls. No evidence of association with AD was observed for this GAB2 marker (p > 0.17). To evaluate GAB2-APOE genegene interactions, we stratified our series according to APOE genotype and case-control status, in accordance with the original studies. Again, no evidence of genetic association with AD was observed in any strata of GAB2-APOE loci pair (p > 0.34).

CONCLUSION

GAB2 rs2373115 marker does not modify the risk of Alzheimer's disease in Spanish APOE epsilon 4 carriers.

Heavy metal content in soils under different wastewater irrigation patterns in Chihuahua, Mexico

An area near the city of Chihuahua has been traditionally irrigated with wastewater to grow forage crops. It has been hypothesized that metal levels could be found in these soils high enough to cause potential health problems to the population. The objective of this study was to determine heavy metal concentrations in different soils due to irrigation practices. Four soil types were evaluated; a soil with a past and present history of wastewater irrigation (S1), a soil with a history of wastewater irrigation until 2003 (S2), a soil with no irrigation history (S3), and a soil similar to S1 and adjacent to the river where the wastewater is transported (S11). Three soil depths were evaluated; 0-15, 15-30 and 30-50 cm. Consequently, a total of 150 soil samples were analyzed evaluating pH, EC, OM and the following elements; Na, K, Cd, Pb, Ni, Cr, Cu and Fe. The pH (P=0.000) and EC (P=0.000) were different for each soil type but no differences were noted for soil depth and the interaction. Maximum pH levels were noted in S3 with a value of 8.74 while maximum EC was observed in S1 with a value of 0.850 dSm-1. The OM level was different for soil type (P=0.000), soil depth (P=0.005) and the interaction (P=0.014). S1 and S11 obtained maximum levels of OM while minimum levels were noted in S3. Maximum OM levels were observed at the 0-15 cm depth followed by the 15-30 cm depth and finally at the 30-50 cm depth. The highest concentration of metals was as follows: K in S1 (359.3 mg kg-1); Cd in S1 (4.48 mg kg-1); Pb in S11 (155.83 mg kg-1); Ni in S1 (10.74 mg kg-1); Cu in S1 (51.36 mg kg-1); B in S3 (41.5 mg kg-1); Fe in S3 (20,313.0 mg kg-1), Cr in S3 (44.26 mg kg-1) and Na in S3 (203.0 mg kg-1). The conclusion is that some metals are present in the soils due to anthropogenic activities but others are present in natural forms.

Calcium pyrophosphate dihydrate crystal deposition disease: sonographic findings

High-resolution sonography is a rapidly evolving technique that is gaining an increasing success in the assessment of crystalline arthropathies. In calcium pyrophosphate dihydrate crystal deposition disease, the sonographic features of crystal deposition include hyperchoic spots within hyaline cartilage and/or fibrocartilage and soft tissue calcifications. The aim of this pictorial essay was to present the main findings evocative of crystal deposition in patients with pyrophosphate arthropathy.

Multiple pilomatricomas: cutaneous marker for myotonic dystrophy

We report an interesting case of multiple pilomatricomas (MPs) in a patient with myotonic dystrophy. Pilomatricoma (calcifying epithelioma of Malherbe) is a benign tumor of hair matrix derivation. It usually occurs as a solitary, firm, asymptomatic nodule on the face, neck, or proximal upper extremity. Most pilomatricomas have activating mutations in the ss-catenin gene (encoded by CTNNB1), leading to involvement of the WNT signaling pathway. The resulting gene product activates transcription leading to tumorigenesis [1]. Since the onset of MPs may precede the signs of myotonic dystrophy, they can serve as potential early cutaneous markers for this systemic disease.