The Janus face of cathelicidin in tumorigenesis

Cathelicidin is a host defense peptide with multiple innate immunity-related functions. Recent findings indicate that cathelicidin is frequently dysregulated in human cancers where it plays a paradoxical yet dominant role in the regulation of tumor malignancy. In this review, the regulation of malignant phenotypes by cathelicidin in relation to the activation of its receptors and intracellular signaling is discussed.

An 11-year retrospective experience of antibodies against the voltage-gated potassium channel (VGKC) complex from a tertiary neurological centre

Acquired diseases classically associated with VGKC-complex antibodies include peripheral nerve hyperexcitability (PNH), Morvan's syndrome, limbic encephalitis (LE), and epilepsy. However, not all such patients have VGKC-complex antibodies and antibodies have been reported in patients without a defined immune-mediated syndrome. To analyse the clinical relevance of positive VGKC-complex antibodies requested on the basis of initial clinical suspicion. We retrospectively analysed patients with positive VGKC-complex antibodies (>100 pM) referred to our institution between 2001 and 2011. 1,614 VGKC-complex assays were performed in 1,298 patients. Titres >100 pM were detected in 57/1,298 (4 %) patients. A classic VGKC-complex channelopathy (60 %) was associated with VGKC-complex antibody titres >400 pM (p = 0.0004). LGI1 or CASPR2 antibodies were only detected in classic VGKC-complex channelopathies (LE; n = 3/4 and PNH; n = 1/5). VGKC-complex antibody titres <400 pM were seen with PNH (n = 15/22; 68 %) but also a heterogeneous range of central and/or peripheral nervous system disorders. Electromyography was supportive of PNH in 65 % of cases and symptomatic treatment was beneficial in 46 % of patients. Irrespective of titre, the rate of malignancy in patients with VGKC-complex antibodies was higher than the age-matched national incidence of malignancy (OR 19.9, 95 % CI 8.97-44.0 p<0.0001). Clinical phenotyping and antibody titres >400 pM can help determine VGKC-complex antibody relevance. Antibody titres <400 pM are associated with PNH but also a more heterogeneous clinical spectrum. The antibody association in the latter is of doubtful clinical relevance. The rate of malignancy was significantly higher than the national incidence irrespective of titre.

Validity of EuroQOL-5D, time trade-off, and standard gamble for age-related macular degeneration in the Singapore population

BACKGROUND/AIMS

Utility values of age-related macular degeneration (AMD) in Asian patients are unknown. This study aims to assess utility values and construct validity of the EuroQOL-5D (EQ-5D), time trade-off (TTO), and standard gamble (SG) instruments in the Singapore multi-ethnic AMD population.

METHODS

Cross-sectional, two-centre, institution-based study. Visual acuity (VA), clinical AMD severity, and utility scores on the EQ-5D, TTO, and SG were obtained from 338 AMD patients. VA was analysed in terms of the better-seeing eye (BEVA), worse-seeing eye (WEVA), and weighted average of both eyes (WVA). We evaluated SG on the perfect health-death (SG(death)) and binocular perfect vision-binocular blindness (SG(blindness)) scales. Construct validity was determined by testing a priorihypotheses relating the EQ-5D, TTO, and SG utility scores to VA and clinical AMD severity.

RESULTS

The mean utilities on the EQ-5D, TTO, SG(death), and SG(blindness) were 0.89, 0.81, 0.86, and 0.90, respectively. EQ-5D scores correlated weakly with BEVA, WEVA, and WVA (Pearson's correlation coefficients -0.291, -0.247, and -0.305 respectively, P<0.001 for all). SG(death) and SG(blindness) demonstrated no correlation with BEVA, WEVA, or WVA (Pearson's correlation coefficients, range -0.06 to -0.125). TTO showed weak association only with WEVA and WVA (correlation coefficients -0.237, -0.228, P<0.0001), but not with BEVA (correlation coefficient -0.161). Clinical AMD severity correlated with EQ-5D and SG(death), but not with TTO and SG(blindness) (P=0.004, 0.002, 0.235, and 0.069, respectively).

CONCLUSIONS

AMD has a negative impact on utilities, although utility scores were high compared with Western cohorts. EQ-5D, TTO, and SG showed suboptimal construct validity, suggesting that health status utilities may not be sufficiently robust for cost-utility analyses in this population.

Tim1 and Tim3 are not essential for experimental allergic asthma

Background

Initial studies suggested that polymorphisms in Tim1 and Tim3 contribute to the development of airway hyperreactivity (AHR) in an acute mouse model of asthma. This was also mirrored in human genetic studies where polymorphisms in Tim1 and Tim3 have been associated with atopic populations.

Objective

Further studies using anti-Tim1 or -Tim3 antibodies, or Tim fusion proteins, have also suggested that these molecules may function as regulators of type-1 and type-2 immunity. However, their role in the development of AHR and airway inflammation remains unclear. Given the proposed roles for Tim1 and Tim3 in type-1 and type-2 responses, we sought to determine whether these molecules were important in regulating antigen-driven lung allergy and inflammation.

Method

We used Tim1- and Tim3-deficient mice and determined how the development of allergic lung inflammation was affected.

Results

AHR was induced normally in the absence of both Tim1 and Tim3, although Tim1-deficient mice did show a small but significant decrease in cell infiltration in the lung and blood eosinophilia. Although Tim3 was expressed on CD4⁺ T cells in the allergic lung, Tim1 expression was restricted to CD86⁺ B cells.

Conclusions and clinical relevance

Thus, Tim1 and Tim3 are not essential for the induction of the type-2 response in lung allergy. This is contrary to what was proposed in a number of other studies using neutralizing and activating antibodies and questions the clinical relevance of Tim1 and Tim3 for novel allergy therapies.

Cite this as: J. L. Barlow, S. H. Wong, S. J. Ballantyne, H. E. Jolin and A. N. J. McKenzie, Clinical & Experimental Allergy, 2011 (41) 1012–1021.

An effective immunotherapy regimen for VGKC antibody-positive limbic encephalitis

BACKGROUND

Voltage-gated potassium channel antibody-positive limbic encephalitis (VGKC+LE) frequently improves with immunotherapy, although the optimum regimen is unknown. The effectiveness of a combination immunomodulatory regimen was tested in consecutive VGKC+LE patients.

METHODS

This was an open-label prospective study of nine VGKC+LE patients. All patients had plasma exchange (50 ml/kg), intravenous immunoglobulin (2 g/kg) and intravenous methylprednisolone (1 g×3), followed by maintenance oral prednisolone (1 mg/kg/day). Mycophenolate (2 g/day) was used in the first three patients. Assessments included serial clinical, cognitive, brain MRI and VGKC antibody testing.

RESULTS

Within 1 week, seizures and hyponatraemia remitted in all affected patients. Cognitive function improved in all patients within 3 months. MRI appearances improved substantially within 9 months, with remission of inflammation in the majority of patients. All achieved immunological remission with normal VGKC antibody titres within 1-4 months. Major adverse events of therapy included one septicaemia and one thrombosis on plasma exchange and one death from sepsis after incidental bowel surgery. One patient remains in remission after 40 months of follow up, 26 months after being off all treatment.

CONCLUSIONS

Our immunotherapy regimen was effective for the treatment of the clinical, cognitive and immunological features of VGKC+LE. Radiological improvement was seen in the majority. Pending randomised controlled trials, this regimen is proposed for the treatment of VGKC+LE.

Brain biopsy in the management of neurology patients

BACKGROUND AND METHODS

To evaluate the value of brain biopsy for neurology patients in our unit, we conducted a retrospective audit of neurology patients referred for brain biopsies for non-neoplastic disease from 1993 to 2007.

RESULTS

64 patients [median (range) age 51 (16-74) years] were included. The clinical presentation was diffuse encephalopathy for 40 patients, focal for 13 and multifocal for 11. The biopsy was diagnostic in 34 patients, abnormal but non-diagnostic in 21 and normal in 9. There was a statistically significant association between clinical presentation and biopsy result (p = 0.004); diagnostic biopsies were more common in patients with focal or multifocal clinical presentations. Twenty patients (31%) had alterations of management as a result of their brain biopsy, comprising specific treatment (11 patients) or prognosis/diagnosis of untreatable conditions (9 patients). Diagnoses of treatable conditions included Whipple's disease, tuberculoma, progressive multifocal leukoencephalopathy, and neurosarcoidosis. Five patients (7.8%) had complications.

CONCLUSIONS

Brain biopsy is useful and relatively safe in the management of neurology patients, with a diagnostic yield of 53% in our series; some led to significant changes in management, including treatment of infections. Patients with focal or multifocal presentation are more likely to yield a diagnostic biopsy result.

Andrographolide regulates epidermal growth factor receptor and transferrin receptor trafficking in epidermoid carcinoma (A-431) cells

BACKGROUND AND PURPOSE

Andrographolide is the active component of Andrographis paniculata, a plant used in both Indian and Chinese traditional medicine, and it has been demonstrated to induce apoptosis in different cancer cell lines. However, not much is known about how it may affect the key receptors implicated in cancer. Knowledge of how andrographolide affects receptor trafficking will allow us to better understand new mechanisms by which andrographolide may cause death in cancer cells.

EXPERIMENTAL APPROACH

We utilized the well-characterized epidermal growth factor receptor (EGFR) and transferrin receptor (TfR) expressed in epidermoid carcinoma (A-431) cells as a model to study the effect of andrographolide on receptor trafficking. Receptor distribution, the total number of receptors and surface receptors were analysed by immunofluorescence, Western blot as well as flow-cytometry respectively.

KEY RESULTS

Andrographolide treatment inhibited cell growth, down-regulated EGFRs on the cell surface and affected the degradation of EGFRs and TfRs. The EGFR was internalized into the cell at an increased rate, and accumulated in a compartment that co-localizes with the lysosomal-associated membrane protein in the late endosomes.

CONCLUSION AND IMPLICATIONS

This study sheds light on how andrographolide may affect receptor trafficking by inhibiting receptor movement from the late endosomes to lysosomes. The down-regulation of EGFR from the cell surface also indicates a new mechanism by which andrographolide may induce cancer cell death.

Characterization of cytotoxic T-lymphocyte epitopes and immune responses to SARS coronavirus spike DNA vaccine expressing the RGD-integrin-binding motif

Integrins are critical for initiating T‐cell activation events. The integrin‐binding motif Arg‐Gly‐Asp (RGD) was incorporated into the pcDNA 3.1 mammalian expression vector expressing the codon‐optimized extracellular domain of SARS coronavirus (SARS‐CoV) spike protein, and tested by immunizing C57BL/6 mice. Significant cell‐mediated immune responses were characterized by cytotoxic T‐lymphocyte ⁵¹Cr release assay and interferon‐gamma secretion ELISPOT assay against RMA‐S target cells presenting predicted MHC class I H2‐Kb epitopes, including those spanning residues 884–891 and 1116–1123 within the S2 subunit of SARS‐CoV spike protein. DNA vaccines incorporating the Spike‐RGD/His motif or the Spike‐His construct generated robust cell‐mediated immune responses. Moreover, the Spike‐His DNA vaccine construct generated a significant antibody response. Immunization with these DNA vaccine constructs elicited significant cellular and humoral immune responses. Additional T‐cell epitopes within the SARS‐CoV spike protein that may contribute to cell‐mediated immunity in vivo were also identified. J. Med. Virol. 81:1131–1139, 2009. © 2009 Wiley‐Liss, Inc.

Recurrent Thunderclap Headaches and Multilobar Intracerebral Haemorrhages: Two Cases of Reversible Cerebral Vasoconstriction Syndrome (RCVS)

We describe two patients with thunderclap headaches due to reversible cerebral vasoconstriction syndrome (RCVS). The first patient illustrates multilobar intracerebral haemorrhages as an under-appreciated feature of RCVS, and the second illustrates recurrent thunderclap headache (presumed recurrent RCVS) after a long interval of 4 years. These cases demonstrate the spectrum of presentation of RCVS, a clinically under-recognized condition.

Lactoferrin is a survival factor for neutrophils in rheumatoid synovial fluid

OBJECTIVES

Lactoferrin is an iron-binding protein that is released from activated neutrophils at sites of inflammation and has anti-microbial as well as anti-inflammatory properties. This study set out to determine whether lactoferrin can delay neutrophil apoptosis and could act as a survival factor for neutrophils in SF.

METHODS

Human peripheral blood and SF neutrophils were incubated with iron-free lactoferrin and apoptosis determined after 9 h. SF from patients with RA was added to isolated neutrophils, with or without immunodepletion of lactoferrin, and effects on neutrophil apoptosis determined. Levels of lactoferrin in SF were assessed and related to disease duration and markers of disease activity.

RESULTS

Iron-free lactoferrin significantly delayed apoptosis of peripheral blood neutrophils, in a concentration-dependent manner after 9 h in culture (P < 0.04). Lactoferrin could also delay apoptosis of neutrophils isolated from SF of patients with RA. SF from patients with established RA delayed apoptosis of peripheral blood neutrophils and this effect was significantly reduced by depletion of lactoferrin (P < 0.03). Lactoferrin levels in SF from patients with established RA did not correlate with disease severity, but did correlate with markers of inflammation (CRP) and with the presence of RF. SF from patients with arthritis of <12 weeks duration did not contain significant levels of lactoferrin.

CONCLUSION

Lactoferrin contributes to extended neutrophil survival in the rheumatoid joint in the established phase of RA but not in very early arthritis.

Clinical utility of 64-row multislice CT angiography in the detection of cerebral aneurysms in acute subarachnoid haemorrhage

CT angiography (CTA) is a fast examination performed with a time-optimised contrast injection to enhance the cerebral arteries. Being a new imaging modality in our hospital, evaluation of the effectiveness of 64-row multislice CTA in detecting intracranial aneurysms in ruptured subarachnoid haemorrhage (SAH) cases is necessary. We conducted a descriptive prospective study by recruiting 30 consecutively operated SAH cases from May 2005 until November 2006. CTA findings were studied by radiologist and neurosurgeon and these were compared with operative findings. The sensitivity and specificity of CTA were 94.4% and 97.2% respectively. Approximately half of the patients were scanned within four hours and operated within 24 hours. In conclusion, CTA proves to be highly sensitive and specific in the diagnosis of intracranial aneurysms in our study.

Intracranial aneurysms in Sarawak General Hospital over a 30-month period

This is a prospective study conducted from February 2000 to July 2002 in a single neurosurgeon neurosurgical service in the state of Sarawak, Malaysia. There were 66 cases of subarachnoid hemorrhage or intracranial aneurysm presenting to this hospital over the study period. Fifty cases had their aneurysms clipped. Eighty percent of our patients were operated within 48 h of presentation. Forty-four percent presented with poor WFNS grades of 4 and 5. We had a 20% operative mortality and 29% total management mortality. Twenty-nine (58%) of the operated cases had a favorable outcome with a mean follow-up of 32 weeks. Multiple aneurysms were less common. The diagnosis of aneuysmal subarachnoid hemorrhage and clipping of aneurysms have increased dramatically over the previous two and half years indicating an increased awareness of the diagnosis and treatment. This series supports the previously reported beliefs that the lower rate of aneurymal subarachnoid hemorrhage in developing countries is likely due to both underdiagnosis and undertreatment. Good results can be achieved in developing countries with early diagnosis and intensive management.

Murray valley encephalitis mimicking herpes simplex encephalitis

We describe a patient with serologically proven Murray Valley encephalitis (MVE), whose presentation was clinically and radiologically characteristic of Herpes simplex encephalitis (HSE). The reports of MRI abnormalities in MVE, and the closely related Japanese Encephalitis and West Nile virusii are mostly of bilateral thalamic or grey matter involvement. The MRI scan findings in this case instead showed the typical temporal lobe changes of HSE. Our case report highlights that MVE can mimic HSE, both clinically and radiologically. Therefore it is important to collect an accurate and detailed travel history from patients where there is a risk of exposure to MVE virus. If suspected, antibody testing of serum and CSF, and CSF for MVE-RNA if available, should be undertaken. This case also highlights the potential under-diagnosis of Murray Valley encephalitis.

Cerebral amyloid angiopathy presenting with vasculitic pathology

We present an elderly patient with an unusual extensive multifocal central nervous system mass lesion, with dramatic imaging changes but only minor disturbance of cerebral function. Cerebral biopsy revealed an unexpected finding of severe cerebral amyloid angiopathy with secondary florid vasculitic appearances, which is a very rare but recognised association. Immunosuppression has produced significant sustained clinical and radiological remission.

Sodium ramping reduces hypotension and symptoms during haemodialysis

OBJECTIVES

To evaluate the effectiveness of sodium ramping (profiling) in reducing hypotensive episodes and symptoms during haemodialysis.

DESIGN

Prospective study.

SETTING

Regional hospital, Hong Kong.

PATIENTS

Thirteen patients who experienced frequent episodes of hypotension and/or symptoms such as cramps, dizziness, chest pain, nausea, vomiting, and headache during haemodialysis in the preceding 4 weeks.

INTERVENTIONS

Each patient was switched from standard haemodialysis with a constant dialysate sodium concentration of 135 to 140 mmol/L to a ramped sodium haemodialysis for a period of 4 weeks. During this time the dialysate sodium concentration was ramped linearly downwards from 150 mmol/L at the beginning of dialysis to 140 mmol/L at the end of dialysis.

MAIN OUTCOME MEASURES

Intradialytic hypotensive episodes, intradialytic symptoms, nursing interventions, systolic and diastolic blood pressures, and interdialytic weight gain.

RESULTS

A total of 248 haemodialysis sessions undertaken by 13 patients were analysed. Switching from constant sodium haemodialysis to ramped sodium haemodialysis resulted in a significant reduction in the number of intradialytic hypotensive episodes from 5.8 (standard deviation, 6.4) to 2.2 (3.3) [P<0.05], the total number of intradialytic symptoms from 7.1 (3.4) to 0.9 (1.3) [P<0.01], and nursing interventions from 11.3 (6.3) to 1.7 (3.9) [P<0.01]. Post-dialysis systolic and diastolic blood pressures were higher during ramped sodium haemodialysis compared with constant sodium haemodialysis (systolic blood pressure, 139 [standard deviation, 23] vs 133 [22] mm Hg, P<0.001; diastolic blood pressure, 77 [11] vs 74 [13] mm Hg, P<0.01), and there was a trend towards a smaller drop in blood pressure after dialysis. The interdialytic weight gain with sodium ramping haemodialysis was greater compared with constant sodium haemodialysis (3.1 [standard deviation, 1.0] vs 2.7 [1.1] kg, P<0.001).

CONCLUSION

Sodium ramping during haemodialysis effectively reduces hypotensive episodes and intradialytic symptoms. Post-dialysis blood pressure is better maintained. A side-effect of sodium ramping is a greater interdialytic weight gain.

Early events in spontaneous neutrophil apoptosis

Neutrophils are very abundant, short-lived leucocytes and their death by apoptosis is central to homoeostasis and the resolution of inflammation, yet the trigger for apoptosis is still a topic of debate. Depolarization of the mitochondrial membrane has been supposed to initiate neutrophil spontaneous apoptosis, as neutrophils gradually lose the anti-apoptotic protein Mcl-1 and Bax translocates and inserts into the mitochondrial membrane. However, other reports show that caspase 8 is required for neutrophil apoptosis, suggesting the involvement of DR (death receptor) signalling. As DR ligation is not required for neutrophil apoptosis, this raises the intriguing possibility that activation of caspase 8 during neutrophil apoptosis occurs via a novel mechanism. In the present paper, we discuss the current evidence for mechanisms occurring in neutrophil apoptosis, which could trigger DR signalling in the absence of DR ligation.

Primary immunosuppression with tacrolimus and low-dose mycophenolate mofetil in renal transplant recipients

Both tacrolimus and mycophenolate mofetil (MMF) are potent immunosuppressive agents used in combination for prevention of acute rejection in renal transplantation. We studied the efficacy and safety of tacrolimus/MMF-based primary immunosuppression as well as their pharmacokinetics (PK) in Chinese renal transplant recipients. Oral tacrolimus was initiated at about 0.2 mg/kg/d, dose which was adjusted to achieve target trough levels of 10 to 20 ng/mL at 3 months and 5 to 10 ng/mL thereafter. The patients also received MMF (0.5 g bid) and prednisolone. PK profiles were studied at 1 week, and 1, 3, and 6 months posttransplant. Blood samples were taken at 0 (predose), 20, 40, 60, 75, and 90 minutes and 2, 4, 6, 8, 10, and 12 hours postdose for each profile. Plasma MPA and whole blood tacrolimus levels were determined by HPLC and EMIT methods respectively. Eight patients were studied with mean follow-up of 16.1 +/- 2.4 months. One patient (12.5%) experienced a borderline acute rejection episode. Both 1-year graft and patient survival rates were 100%. Posttransplant diabetes, diarrhea, and hand tremor occurred in 12.5%, 12.5%, and 37.5%, respectively. No patient had an opportunistic infection. Tacrolimus trough concentrations showed a fair correlation with AUC(0-12h) (R(2) = 0.587). Mean MPA AUC values at 1, 3, and 6 months were 40.5 +/- 9.4, 44.4 +/- 17.3, and 57.2 +/- 20.7 mug*h/mL, respectively (P = .0486, n = 7). In conclusion, primary immunosuppression with tacrolimus, low-dose MMF (0.5 g bid), and prednisolone is effective and safe with adequate systemic MPA exposure in renal transplant recipients.