Genetic ablation of the preptin-coding portion of Igf2 impairs pancreatic function in female mice

Preptin is a 34-amino acid peptide derived from the E-peptide of pro-insulin-like growth factor 2 and is co-secreted with insulin from β-cells. Little is understood about the effects of endogenous preptin on whole body glucose metabolism. We developed a novel mouse model in which the preptin portion of Igf2 was genetically ablated in all tissues, hereafter referred to as preptin knockout (KO), and tested the hypothesis that the removal of preptin will lead to a decreased insulin response to a metabolic challenge. Preptin KO and wild-type (WT) mice underwent weekly fasting blood glucose measurements, intraperitoneal insulin tolerance tests (ITT) at 9, 29, and 44 wk of age, and an oral glucose tolerance test (GTT) at 45 wk of age. Preptin KO mice of both sexes had similar Igf2 exon 2-3 mRNA expression in the liver and kidney compared with WT mice, but Igf2 exon 3-4 (preptin) expression was not detectable. Western blot analysis of neonatal serum indicated that processing of pro-IGF2 translated from the KO allele may be altered. Preptin KO mice had similar body weight, body composition, β-cell area, and fasted glucose concentrations compared with WT mice in both sexes up to 47 wk of age. Female KO mice had a diminished ability to mount an insulin response following glucose stimulation in vivo. This effect was absent in male KO mice. Although preptin is not essential for glucose homeostasis, when combined with previous in vitro and ex vivo findings, these data show that preptin positively impacts β-cell function.NEW & NOTEWORTHY This is the first study to describe a model in which the preptin-coding portion of the Igf2 gene has been genetically ablated in mice. The mice do not show reduced size at birth associated with Igf2 knockout suggesting that IGF2 functionality is maintained, yet we demonstrate a change in the processing of mature Igf2. Female knockout mice have diminished glucose-stimulated insulin secretion, whereas the insulin response in males is not different to wild type.

Prognostically distinct phenotypes of metabolic health beyond obesity in aortic stenosis

Background

Whilst current evidence are in favour of metabolic health and non-obesity in the reduction of incident cardiovascular disease, little is known regarding the prognosis across the metabolic phenotypes once cardiovascular disease occurs. This study examined the prognosis of patients with significant aortic stenosis (AS) based on the presence of metabolic health and obesity.

Methods

This retrospective cohort on consecutive patients presenting with moderate-to-severe AS to a tertiary hospital between 2010 and 2015. Patients were allocated into 4 groups based on obesity and metabolic health: metabolically healthy obese (MHO), metabolically healthy non-obese (MHNO), metabolically unhealthy obese (MUO) and metabolically unhealthy non-obese (MUNO). Metabolic health was defined in accordance to Program Adult Treatment Panel III criteria. The primary outcome was all-cause mortality. Cox regression examined independent associations between mortality and metabolic phenotypes, adjusting for aortic valve area, ejection fraction, age, sex, chronic kidney disease and AVR as a time-dependent covariate.

Results

Of 727 patients, the majority (51.6%) were MUNO, followed by MUO (32.7%), MHNO (11.4%), and MHO (4.3%). MHNO had the highest mortality (43.0%), followed by the MUNO (37.5%), MUO (30.0%) and MHO (6.9%) groups (p=0.001). Compared to MHNO, MHO (HR 0.159, 95% CI 0.038–0.668, p=0.012) and MUO (HR 0.614, 95% CI 0.403–0.937, p=0.024) were independently associated with lower all-cause mortality rates, after adjusting for confounders. In obese patients, metabolic health had favourable survival compared to metabolically unhealthy (p=0.015), but this protective impact of metabolic health was not observed in overweight or normal weight individuals. Obesity had favourable survival compared to overweight and normal weight, in both metabolically health (p=0.002) and unhealthy (p=0.007) patients,

Conclusion

MHO patients with AS have the most favourable prognosis whilst the seemingly healthy MHNO group had the worst survival. There should be a paradigm shift towards prioritising metabolic health rather than weight reduction in patients with significant AS.

Funding Acknowledgement

Type of funding sources: None.

Endothelial-T cell crosstalk contributes to vascular injury in fatty liver disease

 

Cardiovascular complications are often the fundamental causes of death in non-alcoholic fatty liver disease (NAFLD) patients. While there are known systemic mediators in NAFLD that may induce vascular inflammation, the mechanism of endothelial dysfunction remain understudied. In this work, we harnessed the replicative potential of blood outgrowth endothelial cells (BOECs) to develop personalized cell lines from NAFLD patients and healthy controls. Our transcriptomic analysis showed that the top interactome network enriched in NAFLD BOECs comprised of several C-C and C-X-C chemokine ligands involved in immune cell chemotaxis. We previously reported T cell infiltration in mouse model of non-alcoholic steatohepatitis, and here, we confirmed enhanced endothelial chemokine signatures in arterial histological sections. To elucidate endothelial-immune crosstalk, we performed single-cell analysis on human peripheral blood mononuclear cells and found T cell intensification in NAFLD patients compared to healthy controls. Our immunoprofiling by flow cytometry further revealed that NAFLD patients possessed higher levels CD8+ memory cells. Functionally, T cells, instead of monocytes, adhered more pronouncedly to NAFLD BOECs. In evaluating the CXCL12-CXCR4 axis in chemotaxis, CXCR4 antagonist (AMD3100) substantially modulated the migration of patient-derived CD8+ T cells towards NAFLD BOECs, which was not observed in healthy endothelial-T cell chemotaxis coculture. Finally, we validated NAFLD-associated endothelial dysfunction by enumerating two folds more circulating endothelial cells, a biomarker of vascular injury, in the blood samples of NAFLD patients than healthy controls. Our work provides insights for translation to restore blood vessel health and potentially mitigate adverse vascular events in NAFLD.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Industrial Alignment Fund Pre-Positioning grant from the Agency for Science, Technology and Research, Singapore Endothelial-T cell crosstalk in NAFLD

Admission triage tool for adult intensive care unit admission in Hong Kong during the COVID-19 outbreak

Intensive care is expensive, and the numbers of intensive care unit (ICU) beds and trained specialist medical staff able to provide services in Hong Kong are limited. The most recent increase in coronavirus disease 2019 (COVID-19) infections over July to August 2020 resulted in more than 100 new cases per day for a prolonged period. The increased numbers of critically ill patients requiring ICU admission posed a capacity challenge to ICUs across the territory, and it may be reasonably anticipated that should a substantially larger outbreak occur, ICU services will be overwhelmed. Therefore, a transparent and fair prioritisation process for decisions regarding patient ICU admission is urgently required. This triage tool is built on the foundation of the existing guidelines and framework for admission, discharge, and triage that inform routine clinical practice in Hospital Authority ICUs, with the aim of achieving the greatest benefit for the greatest number of patients from the available ICU resources. This COVID-19 Crisis Triage Tool is expected to provide structured guidance to frontline doctors on how to make triage decisions should ICU resources become overwhelmed by patients requiring ICU care, particularly during the current COVID-19 pandemic. The triage tool takes the form of a detailed decision aid algorithm based on a combination of established prognostic scores, and it should increase objectivity and transparency in triage decision making and enhance decision-making consistency between doctors within and across ICUs in Hong Kong. However, it remains an aid rather than a complete substitute for the carefully considered judgement of an experienced intensive care clinician.

P2832Outcomes of catheter ablation for atrial fibrillation based on sex: data from the cabana trial

Background

Sex-specific outcomes may differ amongst patients receiving catheter ablation for atrial fibrillation (AF).

Purpose

Assess sex-specific outcomes in the patients randomized to catheter ablation or drug therapy in CABANA.

Methods

CABANA randomized 2204 pts with AF to catheter ablation or drug therapy (rate/rhythm-control). The outcomes of combined death, disabling stroke, severe bleeding, or cardiac arrest (intention to treat-ITT) or all-cause death were not different. But, ablation significantly improved combined death or CV hospitalization. This analysis compares clinical characteristics by sex and determines sex-specific hazard ratios based on a comparison of ablation vs drug therapy.

Results

Females were 37.3% of ablation and 37.0% of drug therapy patients. Females were older, more often white race, had less CAD, or sleep apnea, but had higher NYHA Class, higher CHA2DS2VASc, and more often had paroxysmal (v. persistent) AF, and prior AF hospitalization. (Table) HTN, CVA and diabetes were the same (Table).

For the CABANA primary endpoint, an ITT comparison of ablation vs. drug therapy, showed a female hazard ratio (HR) of 1.14 (95% confidence interval (CI) 0.70–1.86), and a male HR of 0.74, (95% CI 0.52–1.06). For all-cause mortality, the female HR was 0.75 (95% CI 0.41–1.40) and male HR was 0.91 (95% CI 0.59–1.40) and for all-cause mortality or CV hospitalization, the female HR was 0.90 (95% CI 0.75–1.09) and male HR was 0.79 (95% CI 0.69–0.92). All interaction p values were non-significant.

Recurrent AF (post 90-day blanking) was significantly reduced for both females and males: female HR 0.64 (95% CI 0.51–0.82), male HR 0.46 95% CI 0.39–0.56), p=0.035

Clinical Characteristics and Outcomes Baseline Characteristics Female (N=818) Male (N=1385) p-value Age: Median (Q1, Q3) 69 (65, 74) 66 (60, 71) <0.001 White 766 (93.9%) 1259 (91.0%) 0.015 CAD 92 (11.2%) 332 (24.0%) <0.001 NYHA ≥II 345 (42.4%) 433 (31.5%) <0.001 Sleep apnea 136 (16.6%) 372 (26.9%) <0.001 CHA2DS2-VASc: Median (Q1, Q3) 3 (3, 4) 2 (1, 3) <0.001 Paroxysmal AF 406 (49.6%) 540 (39.0%) <0.001 Persistent AF 412 (50.4%) 845 (61.0%) AF Hospitalization 353 (43.2%) 521 (37.7%) 0.011

Conclusion

Significant sex-specific outcomes differences were not observed. Sex should not be used as a determining factor in selecting patients for AF therapy.

Acknowledgement/Funding

NIH, St Jude Medical Foundation and Corporation, Biosense Webster Inc., Medtronic Corporation, and Boston Scientific Corporation

P4427Cardiovascular outcomes among runners of a marathon race - a 17 years' experience

Introduction

Over the past 17 years (2002–2018), 898,831 people participated in the Hong Kong Standard Chartered Marathon (HKSCM).

Purpose

We aim to study the incidence of marathon-related sudden cardiac arrest (SCA) and non-fatal myocardial injury (NFMI).

Methods

All the HKSCM related admissions between 2002 and 2017 were retrieved from the accident and emergency department admission records. We reviewed the data of HKSCM runners admitted for SCA and NFMI.

Results

Fourteen and thirty-nine runners were admitted for SCA (Mean age 38±13 years-old, 12 men) and NFMI (Mean age 42±12 years-old; 34 men) respectively.

Among the SCA runners, the arrest rhythms could not be retrieved in 3 cases. In the remaining 11 SCA runners, the arrest rhythms were ventricular fibrillation (VF) (N=6), pulseless-electrical activity (PEA) (N=3), and asystole (N=2). Nine of the 14 SCA runners were successfully resuscitated. Only 2 out of the 14 SCA runners had significant atherosclerotic coronary artery disease (CAD) requiring coronary angioplasty. Among the SCA runners, the etiologies of cardiac arrest were myocardial infarction (MI) (N=2), ischemic cardiomyopathy with VF (N=1), idiopathic VF (N=3), malignant coronary anomaly (N=1), and idiopathic (N=5). Percutaneous coronary intervention (PCI) was performed in 2 SCA runner with MI. Implantable cardioverter-defibrillators were implanted in 1 resuscitated runner with VF. Postmortem examination of the 3 deceased runners showed significant CAD in two and was unrevealing in one.

Among the 39 NFMI runners, coronary angiograms (CAG) or CT coronary angiogram were performed in 14 cases (36%), which showed minor CAD or unremarkable findings in 7 runners, and significant CAD in 7 runners. PCI and coronary artery bypass were performed in 5 and 2 NFMI runners respectively. Only 8 out of 39 NFMI runners reported chest pain. Significant ischemic ECG changes were detected in 9 out of 39 NFMI runners. Invasive CAGs were not performed in the remaining NFMI runners due to low pre-test likelihood of CAD and normal non-invasive test results.

Conclusions

The incidence of SCA and mortality among HKSCM runners was 1.56 per 100,000 and 0.56 per 100,000 respectively. The incidence of NFMI was 4.3 per 100,000. Coronary artery disease, coronary anomaly and idiopathic VF were the commonest etiologies of SCA.

484Impact of AF type on the outcome of atrial fibrillation ablation: insights from the CABANA trial

Background

Prior studies suggest that catheter ablation (ABL) for atrial fibrillation (AF) is a treatment option for patients (pts) with paroxysmal AF (PAF). Pts with persistent (Per) or long-standing persistent (LSP) were routinely excluded from most ABL based clinical trials. The effectiveness of ABL compared to drug therapy (MED) in relation to underlying AF type has not been evaluated in a large randomized clinical trial.

Objective

To assess the impact of AF type on clinical outcomes of ABL vs. MED in pts with AF.

Methods

The CABANA trial randomized 2204 pts with AF at 126 sites worldwide to ABL vs. MED with rate or rhythm control drugs. The primary endpoint was a composite of death, disabling stroke, severe bleeding, or cardiac arrest. Key secondary endpoints included mortality and recurrence of AF. Outcomes of ABL vs. MED were compared within subgroups defined by AF type using Intention-to-Treat (ITT) analyses.

Results

Of the 2204 pts, 946 had PAF, 1042 had Per and 215 presented with LSP. There were baseline differences among AF types in age, gender, HTN, LVH, CHF and NYHA Class. For the primary endpoint, there were no significant differences between ABL and MED in pts with PAF (hazard ratio (HR) 0.82; 95% confidence interval (CI) 0.51, 1.31), Per (HR 0.87; 95% CI 0.59, 1.28), or LSP (HR 1.01, 95% CI 0.39, 2.61). Likewise, there were no significant treatment differences in mortality; PAF (HR 0.84; 95% CI 0.46, 1.52), Per (HR 0.90; 95% CI 0.56, 1.46) and LSP (HR 0.67, 95% CI 0.23, 1.94). Post-blanking AF (time to first recurrence) was significantly reduced by ABL compared to MED across all AF types (PAF by 51%), (Per by 47%) and (LSP by 36%).

Clinical Characteristics and Outcomes Clinical Outcomes Comparing ABL vs. MED (HR and 95% CI) Interaction p-value Primary Endpoint 0.82 (0.51, 1.31) 0.87 (0.59, 1.28) 1.01 (0.39, 2.61) 0.925 Mortality 0.84 (0.46, 1.52) 0.90 (0.56, 1.46) 0.67 (0.23, 1.94) 0.881 Recurrent AF 0.49 (0.38, 0.62) 0.53 (0.43, 0.65) 0.64 (0.41, 1.01) 0.564

Conclusion

Pts with LSP have a lower proportion of women, and a higher proportion with manifestations of heart failure despite lower CHA2DS2VASc scores. By ITT analysis, there is no significant effect of ABL compared to MED in the primary endpoint or mortality in any AF group. However, ABL is more effective than MED for reducing recurrences of AF regardless of AF type, but with a greater effect in PAF vs Per vs LSP.

Acknowledgement/Funding

NIH, St Jude Medical Foundation and Corporation, Biosense Webster Inc., Medtronic Corporation, and Boston Scientific Corporation

Daytime versus Night Time Intentional Drug Overdose: The Outcome is Different

Introduction

In drug overdose, it is generally perceived that the dosage can predict the clinical outcome. Are the dosages of intentional drug overdosing the same between day and night? If so, are these overdoses followed by similar clinical outcomes? Answers to these two questions might affect resource allocation and clinical judgment. The present study was performed to establish whether daytime patients and night time patients report similar drug doses, and see which group of patients would have a higher incidence of severe outcomes.

Method

A retrospective observational study on intentional drug overdose was performed. The reported numbers of total tablets ingested and the incidences of major outcomes, in terms of death and intensive care unit admissions, were compared between daytime and night time.

Results

A total of 400 patients were included. The reported number of ingested tablets in daytime had no statistical difference with that at night time. The numbers of severe outcomes had no differences between the patients presenting to the emergency department at daytime or night time. Yet overdosing at night time was more likely associated with severe outcomes.

Conclusions

We advise a higher index of suspicion at the emergency department on the reliability of the dosages reported by patients who overdose during night time. The larger number of severe outcomes may also be related to more toxic drug exposures in the night time. More resources in the community could be allocated to self-harm prevention at night time.

Re-epithelialization of large wound in paedomorphic and metamorphic axolotls

Axolotls (Ambystoma mexicanum) may heal their skin wounds scar-free in both paedomorphs and metamorphs. In previous studies on small punch skin wounds, rapid re-epithelialisation was noted in these two axolotl morphs. However, large wound size in mammals may affect wound healing. In this study, large circumferential full thickness excision wounds on the hind limbs were created on juvenile paedomorphic and metamorphic axolotls. The results showed re-epithelialisation was more quickly initiated in paedomorphs than in metamorphs after wounding. The migrating rate of epidermis on the wound bed was faster in paedomorphs than in metamorphs and thus completion of re-epithelialisation was faster in paedomorphs than in metamorphs. Within these re-epithelialisation periods, neither basement membrane nor dermis was reformed. Epidermal cell proliferation was detected by EdU-labelling technique. In the normal unwounded skin, epidermal proliferation rate was higher in paedomorphs than in metamorphs. After wounding, the epidermal proliferation rate was significantly lower in the migrating front on the wound bed than in the normal skin in paedomorphs. The EdU-labelling rate between normal skin and migration front was not different in metamorphs. Lacking of more proliferating epidermal cells on the wound bed indicated that the new epidermis here derived rather from migrating epidermal cells than from cell proliferation in situ. In conclusion, re-epithelialisation in the large wound might be fully completed in both morphs despite it was initiated earlier and with faster rate in paedomorphs than in metamorphs. The new epidermis on the wound bed derived mainly from cell migration than by cell proliferation in the re-epithelialisation period. J. Morphol. 278:228-235, 2017. © 2016 Wiley Periodicals,Inc.

Is there an ethnic difference in the prevalence of lupus cystitis? A report of six cases

Lupus cystitis was rare but frequently resulted in obstructive uropathy and had a strong association with gastrointestinal(GI) symptoms. We treated six patients with systemic lupus erythematosus(SLE) and obstructive uropathy from January 1996 to December 2001 in a university hospital. Evidence of cystitis was obtained from cystoscopic biopsy or the presence of thickened bladder wall in image study. Similar to other reports, five patients had GI manifestations such as abdominal pain, nausea/vomiting, diarrhoea or ileus. In addition, mesenteric lymphadenopathy or pancreatitis was noted in three patients. Two patients had been treated for idiopathic thrombocytopenicpurpura (ITP), four and 20 years ago, respectively. All six patients had antibodies to double-stranded DNA (dsDNA). Five patients each had antibodies to cardiolipin (IgG aCL) or SSA. The high prevalence of anti-SSA had also been reported in Chinese lupus patients with intestinal pseudo-obstruction, a clinical manifestation frequently associated with bilateral ureterohydronephrosis. Two patients died of intractable infection after the surgical procedures for persistent ureterohydronephrosis and both patients had antibodies to ribosomal P proteins. Lupus cystitis might not be so rare in Chinese patients with SLE. The diagnosis should be kept in mind when lupus patients have urinary and/or GI symptoms.

The development of the Hong Kong Heat Index for enhancing the heat stress information service of the Hong Kong Observatory

This paper presents a study to develop a heat index, for use in hot and humid sub-tropical climate in Hong Kong. The study made use of hospitalization data and heat stress measurement data in Hong Kong from 2007 to 2011. The heat index, which is called Hong Kong Heat Index (HKHI), is calculated from the natural wet bulb temperature, the globe temperature, and the dry bulb temperature together with a set of coefficients applicable to the high humidity condition in the summer of Hong Kong. Analysis of the response of hospitalization rate to variation in HKHI and two other heat indices, namely Wet Bulb Globe Temperature (WBGT) and Net Effective Temperature (NET), revealed that HKHI performed generally better than WBGT and NET in reflecting the heat stress impact on excess hospitalization ratio in Hong Kong. Based on the study results, two reference criteria of HKHI were identified to establish a two-tier approach for the enhancement of the heat stress information service in Hong Kong.

Acquired factor V inhibitor in a patient receiving venous-venous extracorporeal membrane oxygenation for Legionella pneumonia

We report a rare complication of factor V deficiency in a patient having Legionella pneumonia. This patient also had other complications like severe acute respiratory distress syndrome, acute kidney injury, and septic shock that required venous-venous extracorporeal membrane oxygenation support. This is the first reported case of acquired factor V deficiency in a patient receiving extracorporeal membrane oxygenation for Legionella pneumonia. With the combined use of intravenous immunoglobulin, rituximab and plasma exchange, we achieved rapid clearance of the factor V inhibitor within 1 week so as to allow safe decannulation of extracorporeal membrane oxygenation.

Detection of human parvovirus 4 viremia in the follow-up blood samples from seropositive individuals suggests the existence of persistent viral replication or reactivation of latent viral infection

Background

The transmission routes for human parvovirus 4 (PARV4) infections in areas with high seroprevalence are not known. In the work described here, persistent PARV4 viral replication was investigated by conducting a longitudinal study.

Methods

Ten healthcare workers each provided a blood sample at the beginning of the study (first sample) and 12 months later (second sample). The paired samples were tested for PARV4-positivity by immunoblotting analysis and nested polymerase chain reactions.

Results

IgG antibodies against PARV4 were detected in six participants, three of whom also had IgM antibodies against PARV4. The immunoblotting results did not vary over time. PARV4 DNA was detected in the first blood sample from one participant who had IgG antibodies against PARV4 and in the second blood samples from 2 participants who had IgG and IgM antibodies against PARV4.

Conclusions

Detection of PARV4 DNA in the second blood samples from two seropositive participants suggests the existence of persistent PARV4 replication or reactivation of inactive virus in the tissues. The finding of persistent or intermittent PARV4 replication in individuals with past infections provides an important clue toward unraveling the non-parenteral transmission routes of PARV4 infection in areas where the virus is endemic.

Acute appendicitis complicating Amyand's hernia: imaging features and literature review

Acute appendicitis complicating Amyand's hernia is an extremely rare condition, in which the appendix herniates into the inguinal sac and, subsequently, gets inflamed. The condition is difficult to diagnose clinically. Imaging is valuable for its diagnosis and detection of the associated complications. In this article, we will discuss the imaging features of acute appendicitis complicating Amyand's hernia and the results of a literature review on the condition.

Coherent forward scattering peak induced by Anderson localization

Numerical simulations show that, at the onset of Anderson localization, the momentum distribution of a coherent wave packet launched inside a random potential exhibits, in the forward direction, a novel interference peak that complements the coherent backscattering peak. An explanation of this phenomenon in terms of maximally crossed diagrams predicts that the signal emerges around the localization time and grows on the scale of the Heisenberg time associated with the localization volume. Together, coherent back and forward scattering provide evidence for the occurrence of Anderson localization.

Identification of critical amino acids in an immunodominant IgE epitope of Pen c 13, a major allergen from Penicillium citrinum

Background

Pen c 13, identified as a 33-kDa alkaline serine protease, is a major allergen secreted by Penicillium citrinum. Detailed knowledge about the epitopes responsible for IgE binding would help inform the diagnosis/prognosis of fungal allergy and facilitate the rational design of hypoallergenic candidate vaccines. The goal of the present study was to characterize the IgE epitopes of Pen c 13.

Methodology/Principal Findings

Serum samples were collected from 10 patients with mold allergy and positive Pen c 13 skin test results. IgE-binding epitopes on rPen c 13 were mapped using an enzymatic digestion and chemical cleavage method, followed by dot-blotting and mass spectrometry. A B-cell epitope-predicting server and molecular modeling were used to predict the residues most likely involved in IgE binding. Theoretically predicted IgE-binding regions were further confirmed by site-directed mutagenesis assays. At least twelve different IgE-binding epitopes located throughout Pen c 13 were identified. Of these, peptides S16 (A¹⁴⁸–E¹⁶⁶) and S22 (A²⁴³–K²⁷⁴) were recognized by sera from 90% and 100% of the patients tested, and were further confirmed by inhibition assays. Peptide S22 was selected for further analysis of IgE-binding ability. The results of serum screening showed that the majority of IgE-binding ability resided in the C-terminus. One Pen c 13 mutant, G270A (T²⁶¹–K²⁷⁴), exhibited clearly enhanced IgE reactivity, whereas another, K274A, exhibited dramatically reduced IgE reactivity.

Conclusions/Significance

Experimental analyses confirmed in silico-predicted residues involved in an important antigenic region of Pen c 13. The G270A mutant of Pen c 13 has the potential to serve as an additional tool for the diagnosis/prognosis of mold allergy, and the K274A mutant, as a hypoallergenic form of the epitope, may provide a framework for the design and development of a safe and efficient therapeutic strategy for treating human allergic diseases.