Recapitulating primary immunodeficiencies with expanded potential stem cells: Proof of concept with STAT1 gain of function

BACKGROUND

Inborn errors of immunity (IEI) often lack specific disease models and personalized management. Signal transducer and activator of transcription (STAT)-1 gain of function (GoF) is such example of an IEI with diverse clinical phenotype with unclear pathomechanisms and unpredictable response to therapy. Limitations in obtaining fresh samples for functional testing and research further highlights the need for patient-specific ex vivo platforms.

OBJECTIVE

Using STAT1-GoF as an example IEI, we investigated the potential of patient-derived expanded potential stem cells (EPSC) as an ex vivo platform for disease modeling and personalized treatment.

METHODS

We generated EPSC derived from individual STAT1-GoF patients. STAT1 mutations were confirmed with Sanger sequencing. Functional testing including STAT1 phosphorylation/dephosphorylation and gene expression with or without Janus activating kinase inhibitors were performed. Functional tests were repeated on EPSC lines with GoF mutations repaired by CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9) editing.

RESULTS

EPSC were successfully reprogrammed from STAT1-GoF patients and expressed the same pluripotent makers as controls, with distinct morphologic differences. Patient-derived EPSC recapitulated the functional abnormalities of index STAT1-GoF patients with STAT1 hyperphosphorylation and increased expression of STAT1 and its downstream genes (IRF1, APOL6, and OAS1) after IFN-γ stimulation. Addition of ruxolitinib and baricitinib inhibited STAT1 hyperactivation in STAT1-GoF EPSC in a dose-dependent manner, which was not observed with tofacitinib. Corrected STAT1 phosphorylation and downstream gene expression were observed among repaired STAT1-GoF EPSC cell lines.

CONCLUSION

This proof-of-concept study demonstrates the potential of our patient-derived EPSC platform to model STAT1-GoF. We propose this platform when researching, recapitulating, and repairing other IEI in the future.

Feasibility of a drug allergy registry-based excipient allergy database and call for universal mandatory drug ingredient disclosure: the case of PEG

Background

Excipient allergy is a rare, but potentially lethal, form of drug allergy. Diagnosing excipient allergy remains difficult in regions without mandatory drug ingredient disclosure and is a significant barrier to drug safety.

Objective

To investigate the feasibility of a drug allergy registry-based excipient database to identify potential excipient culprits in patients with history of drug allergy, using polyethylene glycol (PEG) as an example.

Methods

An excipient registry was created by compiling the excipient lists pertaining to all available formulations of the top 50 most reported drug allergy culprits in Hong Kong. Availability of excipient information, and its relationship with total number of formulations of individual drugs were analysed. All formulations were checked for the presence or absence of PEG.

Results

Complete excipient information was available for 36.5% (729/2,000) of all formulations of the top 50 reported drug allergy culprits in Hong Kong. The number of formulations for each drug was associated with proportion of available excipient information (ρ = 0.466, p = 0.001). Out of 729 formulations, 109 (15.0%) and 620 (85.0%) were confirmed to contain and not contain PEG, respectively. Excipient information was not available for the other 1,271 (63.6%) formulations. We were unable to confirm the presence or absence of PEG in any of the top 50 drug allergy culprits in Hong Kong.

Conclusion

In countries without mandatory drug ingredient disclosure, excipient databases are unlikely able to identify potential excipient allergy in drug allergy patients. Legislations to enforce mandatory and universal ingredient disclosure are urgently needed.

Uncovering the true burden of hereditary angioedema due to C1-inhibitor deficiency: A focus on the Asia-Pacific region

Hereditary angioedema (HAE) due to C1-inhibitor deficiency or dysfunction is a rare genetic disorder that causes recurrent episodes of swelling in various parts of the body. Treatment goals of HAE aim to "normalize" life for all patients; however, lack of diagnostic facilities and limited access to effective treatment options in developing nations cause delays in diagnosis and place a significant burden on patients. In this review, we aim to highlight the burden of disease caused by C1-inhibitor HAE across the Asia-Pacific region, considering its epidemiology, morbidity and mortality, and socioeconomic and psychological impact. We also review the availability of guideline-recommended diagnostic facilities and treatments, and how patients are currently managed. Data were collected from published literature and HAE experts in the region, who provided information regarding diagnosis and management in their countries. Current practice was reviewed against international guidelines, as well as local guidelines/consensus used in Australia, Japan, and China. Suggestions are provided for improving the time to diagnosis in the region, increasing access to guideline-recommended treatments, and providing support to reduce the burden on patients and caregivers. There is an urgent need to improve HAE services and provide access to life-saving treatment in developing countries, and efforts should be made to increase awareness of guideline recommendations in high-income economies that do not currently provide long-term prophylactic treatments.

Shedding Light on Skin Autoimmunity: More than Just Skin Deep

Our skin is the largest organ of the body and the foremost defensive barrier against the external environment [...].

Inactivated COVID-19 vaccines: potential concerns of antibody-dependent enhancement and original antigenic sin

Inactivated vaccine is one of the platforms employed in COVID-19 vaccines. Inactivated vaccines have been associated with concerns of antibody-dependent enhancement (ADE) and original antigenic sin (OAS), which are related to non-neutralising or poorly neutralising antibodies against the pathogen. Since inactivated COVID-19 vaccines use whole-SARS-CoV-2 virus as the immunogen, they are expected to generate antibodies against non-spike structural proteins, which are highly conservative across variants of SARS-CoV-2. These antibodies against non-spike structural proteins have found to be largely non-neutralising or poorly neutralising in nature. Hence, inactivated COVID-19 vaccines could possibly be associated with ADE and OAS, especially as novel variants emerge. This article explores the potential concern of ADE and OAS in the context of inactivated COVID-19 vaccine, and outlines the future research directions.

Waning effectiveness against COVID-19-related hospitalisation, severe complications, and mortality with two to three doses of CoronaVac and BNT162b2: a case-control study

BACKGROUND

This study aims to evaluate waning effectiveness against severe and fatal COVID-19 with 2-3 doses of CoronaVac/BNT162b2, where data is limited.

METHODS

A case-control study included individuals aged ≥18 years, unvaccinated or received 2-3 doses of CoronaVac/BNT162b2, using electronic healthcare databases in Hong Kong. Those with first COVID-19-related hospitalisation, severe complications, or mortality between 1 January and 15 August 2022 were defined as cases and matched with up-to-10 controls by age, sex, index date, and Charlson Comorbidity Index. Vaccine effectiveness (VE) against COVID-19-related outcomes was estimated at different time intervals from second and third dose vaccination (0-13 up-to 210-240 days) using conditional logistic regression adjusted for comorbidities and medications.

RESULTS

By 211-240 days after second dose, VE against COVID-19-related hospitalisation reduced to 46.6% (40.7%-51.8%) for BNT162b2 and 36.2% (28.0%-43.4%) for CoronaVac, and VE against COVID-19-related mortality were 73.8% (55.9%-84.4%) and 76.6% (60.8%-86.0%). After third dose, VE against COVID-19-related hospitalisation decreased from 91.2% (89.5%-92.6%) for BNT162b2 and 76.7% (73.7%-79.4%) for CoronaVac at 0-13 days, to 67.1% (60.4%-72.6%) and 51.3% (44.2%-57.5%) at 91-120 days. VE against COVID-19-related mortality for BNT162b2 remained high from 0-13 days [98.2% (95.0%-99.3%)] to 91-120 days [94.6% (77.7%-98.7%)], and for CoronaVac reduced from 0-13 days [96.7% (93.2%-98.4%)] to 91-120 days [86.4% (73.3%-93.1%)].

CONCLUSIONS

Significant risk reduction against COVID-19-related hospitalisation and mortality after CoronaVac or BNT162b2 vaccination was observed for >240 and >120 days after second and third dose compared to unvaccinated, despite significant waning over time. Timely administration of booster doses could provide higher levels of protection.

Prospective Assessment of Penicillin Allergy (PAPA): Evaluating the performance of penicillin allergy testing and post-delabelling outcomes among Hong Kong Chinese

BACKGROUND

Incorrect penicillin 'allergy' labels predispose patients to adverse outcomes but are under-recognised in many Asian countries. Studies on performance and post-delabelling outcomes of penicillin allergy evaluation among Chinese remain scarce.

OBJECTIVE

To evaluate the diagnostic performance of allergy testing and post-delabelling outcomes among Chinese patients in a prospective penicillin allergy cohort - Prospective Assessment of Penicillin Allergy (PAPA).

METHODS

All adult patients (age ≥ 18 years) who underwent penicillin allergy evaluation between January 2020 to December 2021 were recruited and prospectively reviewed by both medical records and individual interviews at least 6 months after delabelling or allergy confirmation.

RESULTS

Out of 372 patients who completed penicillin allergy evaluation, 335 (90%) patients were delabelled. The overall negative predictive value of penicillin skin testing was 95%, but lower for patients with non-immediate type reactions (88%). History of non-immediate symptom onset (OR = 4.501 [95%CI = 2.085-9.716], p < 0.001) and duration since index reaction (OR = 0.942 [95%CI = 0.899-0.987], p = 0.012) were associated with positive skin testing. After at least 6 months, 60 (18%) of de-labelled patients had received penicillins again without any adverse reactions. Fluoroquinolone-use was significantly lower among delabelled patients compared to those with penicillin allergy (38[11%] vs 11[30%], p = 0.004).

CONCLUSIONS

After at least 6 months, one in six delabelled patients already received penicillins again safely, with significantly lower fluoroquinolone usage. None experienced adverse reactions. History of non-immediate onset and shorter duration since index reaction were associated with genuine allergy. In patients with severe non-immediate reactions, skin tests should be supplemented with thorough clinical history and adjunct diagnostic evaluations.

Effectiveness of Molnupiravir and Nirmatrelvir-Ritonavir in Hospitalized Patients With COVID-19 : A Target Trial Emulation Study

BACKGROUND

Whether hospitalized patients benefit from COVID-19 oral antivirals is uncertain.

OBJECTIVE

To examine the real-world effectiveness of molnupiravir and nirmatrelvir-ritonavir in hospitalized patients with COVID-19 during the Omicron outbreak.

DESIGN

Target trial emulation study.

SETTING

Electronic health databases in Hong Kong.

PARTICIPANTS

The molnupiravir emulated trial included hospitalized patients with COVID-19 aged 18 years or older between 26 February and 18 July 2022 (n = 16 495). The nirmatrelvir-ritonavir emulated trial included hospitalized patients with COVID-19 aged 18 years or older between 16 March and 18 July 2022 (n = 7119).

INTERVENTION

Initiation of molnupiravir or nirmatrelvir-ritonavir within 5 days of hospitalization with COVID-19 versus no initiation of molnupiravir or nirmatrelvir-ritonavir.

MEASUREMENTS

Effectiveness against all-cause mortality, intensive care unit (ICU) admission, or use of ventilatory support within 28 days.

RESULTS

The use of oral antivirals in hospitalized patients with COVID-19 was associated with a lower risk for all-cause mortality (molnupiravir: hazard ratio [HR], 0.87 [95% CI, 0.81 to 0.93]; nirmatrelvir-ritonavir: HR, 0.77 [CI, 0.66 to 0.90]) but no significant risk reduction in terms of ICU admission (molnupiravir: HR, 1.02 [CI, 0.76 to 1.36]; nirmatrelvir-ritonavir: HR, 1.08 [CI, 0.58 to 2.02]) or the need for ventilatory support (molnupiravir: HR, 1.07 [CI, 0.89 to 1.30]; nirmatrelvir-ritonavir: HR, 1.03 [CI, 0.70 to 1.52]). There was no significant interaction between drug treatment and the number of COVID-19 vaccine doses received, thereby supporting the effectiveness of oral antivirals regardless of vaccination status. No significant interaction between nirmatrelvir-ritonavir treatment and age, sex, or Charlson Comorbidity Index was observed, whereas molnupiravir tended to be more effective in older people.

LIMITATION

The outcome of ICU admission or need for ventilatory support may not capture all severe COVID-19 cases; unmeasured confounders, such as obesity and health behaviors, may exist.

CONCLUSION

Molnupiravir and nirmatrelvir-ritonavir reduced all-cause mortality in both vaccinated and unvaccinated hospitalized patients. No significant reduction in ICU admission or the need for ventilatory support was observed.

PRIMARY FUNDING SOURCE

Health and Medical Research Fund Research on COVID-19, Government of the Hong Kong Special Administrative Region; Research Grants Council, Collaborative Research Fund; and Health Bureau, Government of the Hong Kong Special Administrative Region.

Delabelling multiple antibiotic allergy: Practical issues

With the growing incidence of multi-drug resistant organisms, delabelling incorrect antibiotic allergies has become an integral part of antimicrobial stewardship worldwide. For example, around 90% of penicillin allergy labels are found to be inaccurate following a full allergy work-up, which deprive patients the use of effective first-line penicillin antibiotics and increase the risk of antimicrobial resistance with the use of other extended spectrum non-penicillin antimicrobials. Significant numbers of adult and paediatric patients over time are labelled with multiple penicillin and non-penicillin antibiotic allergies often during inappropriate antimicrobial use, resulting in a label of “multiple antibiotic allergy”. In contrast to delabelling penicillin allergy where oral direct provocation tests can be used for low-risk, mild reactions, and sensitivity/specificity/positive and negative predictive values of skin tests have been demonstrated, diagnostic tests for multiple antibiotic allergy often require the use of a combination of in-vivo and in-vitro tests across different antimicrobial classes for evaluation. Shared decision making with patients and informed consent are also needed when prioritising which drugs to delabel first, balancing the risks, benefits of testing vs. interim use of alternative antibiotics. Similar to delabelling penicillin allergy, the cost-effectiveness of delabelling multiple drug allergies is unknown.

Booster vaccination with inactivated whole-virus or mRNA vaccines and COVID-19-related deaths among people with multimorbidity: a cohort study

BACKGROUND

Multimorbidity is a prevalent risk factor for COVID-19-related complications and death. We sought to evaluate the association of homologous booster vaccination using BNT162b2 (Pfizer-BioNTech) or CoronaVac (Sinovac) with COVID-19-related deaths among people with multimorbidity during the initial Omicron wave of the COVID-19 pandemic.

METHODS

Using routine clinical records from public health care facilities in Hong Kong, we conducted a territory-wide retrospective cohort study comparing people aged 18 years or older with 2 or more chronic conditions who received a homologous booster (third) dose with those who received only 2 doses, between Nov. 11, 2021, and Mar. 31, 2022. The primary outcome was death related to COVID-19.

RESULTS

We included 120 724 BNT162b2 recipients (including 87 289 who received a booster), followed for a median of 34 (interquartile range [IQR] 20-63) days and 127 318 CoronaVac recipients (including 94 977 who received a booster), followed for a median of 38 (IQR 22-77) days. Among BNT162b2 recipients, booster-vaccinated people had fewer COVID-19-related deaths than those who received 2 doses (5 v. 34, incidence rate 1.3 v. 23.4 per million person-days, weighted incidence rate ratio [IRR] 0.05, 95% confidence interval [CI] 0.02-0.16). We observed similar results among recipients of CoronaVac booster vaccination compared with those who received only 2 doses (26 v. 88, incidence rate 5.3 v. 53.1 per million person-days, weighted IRR 0.08, 95% CI 0.05-0.12).

INTERPRETATION

Among people with multimorbidity, booster vaccination with BNT162b2 or CoronaVac was associated with reductions of more than 90% in COVID-19-related mortality rates compared with only 2 doses. These results highlight the crucial role of booster vaccination for protecting vulnerable populations as the COVID-19 pandemic continues to evolve.

COVID-19 Vaccine Allergy Safety Track (VAS-Track) pathway: real-world outcomes on vaccination rates and antibody protection

BACKGROUND

Misdiagnosed vaccine-related "allergies" lead to unnecessary vaccine deferrals and incomplete vaccinations, leaving patients unprotected against COVID-19. To overcome limitations and queues for Allergist assessment, the "VAS-Track" pathway was developed to evaluate patients via a multi-disciplinary triage model including nurses, non-specialists, and Allergists.

OBJECTIVE

We assessed the effectiveness and safety of VAS-Track and evaluate its real-world impact in terms of vaccination rates and COVID-19 protection.

METHODS

Patients referred to VAS-Track between September 2021 and March 2022 were recruited. Subgroup analysis was performed with prospective pre- and post-clinic antibody levels.

RESULTS

Nurse-assisted screening identified 10,412 (76%) referrals as inappropriate. 369 patients were assessed by VAS-Track. Overall, 100% of patients were recommended to complete vaccination and 332 (90%) completed their primary series. No patients reported any significant allergic reactions following subsequent vaccination. Vaccination completion rates between patients seen by non-specialists and additional Allergist review were similar (90% vs. 89%, p = 0.617). Vaccination rates were higher among patients with prior history of immediate-type reactions (odds ratio: 2.43, p = 0.025). Subgroup analysis revealed that only 20% (56/284) of patients had seropositive COVID-19 neutralizing antibody levels (≥ 15 AU/mL) prior to VAS-Track, which increased to 92% after vaccine completion (pre-clinic antibody level 6.0 ± 13.5 AU/mL vs. post-clinic antibody level 778.8 ± 337.4 AU/mL, p > 0.001).

CONCLUSIONS

A multi-disciplinary allergy team was able to streamline our COVID-19 VAS services, enabling almost all patients to complete their primary series, significantly boosting antibody levels and real-world COVID-19 protection. We propose similar multidisciplinary models to be further utilized, especially in the settings with limited allergy services.

Chronic Spontaneous Urticaria in Hong Kong: Clinical Characteristics, Real-World Practice and Implications for COVID-19 Vaccination

PURPOSE

The real-world management and clinical characteristics of chronic spontaneous urticaria (CSU) in Hong Kong and its implications for coronavirus disease 2019 (COVID-19) vaccination are unknown. We investigated the clinical characteristics of patients with CSU and the role of an immunologist-led Urticaria Clinic as well as the impact of CSU on COVID-19 vaccine uptake in Hong Kong.

METHODS

Longitudinal clinical data of 257 CSU patients were collected and analyzed. Association analyses were performed to identify the relationships between variables and factors associated with COVID-19 vaccine uptake.

RESULTS

After the immunologist review, the Weekly Urticaria Activity Score (UAS7) was significantly lower than baseline (median: 0.00 vs. 12.0, P < 0.001). Changes in UAS7 were significantly greater among patients with baseline UAS7 ≥ 16 compared to those with UAS7 < 16 (median: -24.0 vs. -2.00, P < 0.001). CSU patients had lower COVID-19 vaccination rates than the general population with only 176 (68.5%) and 165 (65.0%) receiving at least one dose and 2 doses of vaccination, respectively. The presence of concomitant suspected drug allergy was associated with lower COVID-19 vaccine uptake (odds ratio [OR], 0.47; P = 0.010), while regular pharmacological treatment was associated with higher COVID-19 vaccine uptake among CSU patients (OR, 3.79; P = 0.010).

CONCLUSIONS

A dedicated immunologist-led Urticaria Clinic may effectively improve CSU management and outcomes in Hong Kong.

Effectiveness of BNT162b2 and CoronaVac vaccinations against mortality and severe complications after SARS-CoV-2 Omicron BA.2 infection: a case-control study

Data regarding protection against mortality and severe complications after Omicron BA.2 infection with CoronaVac and BNT162b2 vaccines remains limited. We conducted a case–control study to evaluate the risk of severe complications and mortality following 1–3 doses of CoronaVac and BNT162b2 using electronic health records database. Cases were adults with their first COVID-19-related mortality or severe complications between 1 January and 31 March 2022, matched with up-to 10 controls by age, sex, index date, and Charlson Comorbidity Index. Vaccine effectiveness against COVID-19-related mortality and severe complications by type and number of doses was estimated using conditional logistic regression adjusted for comorbidities and medications. Vaccine effectiveness (95% CI) against COVID-19-related mortality after two doses of BNT162b2 and CoronaVac were 90.7% (88.6–92.3) and 74.8% (72.5–76.9) in those aged ≥65, 87.6% (81.4–91.8) and 80.7% (72.8–86.3) in those aged 50–64, 86.6% (71.0–93.8) and 82.7% (56.5–93.1) in those aged 18–50. Vaccine effectiveness against severe complications after two doses of BNT162b2 and CoronaVac were 82.1% (74.6–87.3) and 58.9% (50.3–66.1) in those aged ≥65, 83.0% (69.6–90.5) and 67.1% (47.1–79.6) in those aged 50–64, 78.3% (60.8–88.0) and 77.8% (49.6–90.2) in those aged 18–50. Further risk reduction with the third dose was observed especially in those aged ≥65 years, with vaccine effectiveness of 98.0% (96.5–98.9) for BNT162b2 and 95.5% (93.7–96.8) for CoronaVac against mortality, 90.8% (83.4–94.9) and 88.0% (80.8–92.5) against severe complications. Both CoronaVac and BNT162b2 vaccination were effective against COVID-19-related mortality and severe complications amidst the Omicron BA.2 pandemic, and risks decreased further with the third dose.

Prevalence and impact of misdiagnosed drug allergy labels among patients with hereditary angioedema

Introduction

Hereditary angioedema (HAE) is a rare condition with presents with episodic attacks of angioedema, which is often misdiagnosed as allergy, and associated with significant morbidity and mortality. Misdiagnosed drug allergy (DA) labels are also associated with a multitude of adverse clinical outcomes. However, the prevalence and impact of incorrect DA labels on HAE remains unknown.

Methods

Data from the clinical records of all HAE patients in Hong Kong were collected and analysed. All HAE patients with DA labels on their medical records were recruited to proceed with DA testing, including confirmatory drug provocation tests (DPT).

Results

Nine (22%) out of a total of 41 HAE patients carried at least one DA label. Five of nine (56%) patients had more than 1 DA label and there was a total number of 16 DA labels. The most common DA label was to beta-lactams (37.5%). Presence of DA label was associated with delay in HAE diagnosis (23.8 ± 11.1 vs. 10.2 ± 14.3 years, p = 0.012), likelihood of HAE attacks (100% vs. 46.9%, p = 0.005) and rate of hospitalization (3.78 ± 2.68 vs. 1.32 ± 2.61, p = 0.022) per year. All (100%) of all DA labels were disproven and removed after confirmatory DPT were performed.

Conclusion

DA labels are prevalent among HAE patients but are frequently misdiagnosed and mislabelled. Misdiagnosed DA are associated with delay in HAE diagnosis as well as adverse clinical outcomes. Immunologists/allergists should consider pre-emptively reviewing and investigate every suspicious DA label, especially among HAE patients.

Asia Pacific perspectives on the second year of the COVID-19 pandemic: A follow-up survey

Background

The Coronavirus disease 2019 (COVID‐19) pandemic is currently in its third year. This follow‐up survey was commissioned by the Asia Pacific Association of Allergy Asthma and Clinical Immunology (APAAACI) Task Force on COVID‐19 to compare and contrast changes in the epidemiology, clinical profile, therapeutics and public health measures of the pandemic in the Asia Pacific region.

Methods

A questionnaire‐based survey comprising 32 questions was electronically sent out to all 15 member countries of APAAACI using Survey Monkey® from 1 December 2021 to 28 February 2022.

Results

Seventeen responses were received from 14/15 (93.4%) member countries and 3 individual members. Mild‐to‐moderate COVID‐19 predominated over severe infection, largely contributed by COVID‐19 vaccination programmes in the region. The incidence of vaccine adverse reactions in particular anaphylaxis from messenger ribonucleic acid (mRNA) vaccines was no longer as high as initially anticipated, although perimyocarditis remains a concern in younger males. Novel therapeutics for mild‐to‐moderate disease including neutralizing antibodies casirivimab/imdevimab (REGEN‐COV®) and sotrovimab (Xevudy®), anti‐virals Paxlovid® (nirmatrelvir and ritonavir) and Molnupiravir pre‐exposure prophylaxis for high‐risk persons with Tixagevimab and Cilgavimab (Evusheld) are now also available to complement established therapeutics (e.g., remdesivir, dexamethasone and baricitinib) for severe disease. In the transition to endemicity, public health measures are also evolving away from containment/elimination strategies.

Conclusions

With access to internationally recommended standards of care including public health preventive measures, therapeutics and vaccines among most APAAACI member countries, much progress has been made over the 2‐year period in minimizing the morbidity and mortality from COVID‐19 disease.

Conventional and Biologic Disease-Modifying Antirheumatic Drugs Are Not Associated With Increase in or Progression of Cervical Neoplasia Among Patients With Spondyloarthritis

OBJECTIVES

Using a centralized electronic database, we investigated the risk of cervical neoplasia (CN) and progression of cervical intraepithelial neoplasia (CIN) among patients with spondyloarthritis (SpA) receiving disease-modifying antirheumatic drugs (DMARDs).

METHOD

A total of 951 patients with SpA were reviewed. Incidence and progression of CN and clinical data including age, ethnicity, smoking and drinking status, dates of first and last follow-up, history of psoriasis, inflammatory bowel disease, medications used, mean dose and duration of medications, and comorbidities were reviewed. Cox regression models were used to evaluate the individual risk of DMARDs with CN and the risk of CIN progression.

RESULTS

During a mean follow-up duration of 9.2 ± 5.9 years, 34 patients had developed CN, which translates to an incidence for development of CN in patients with SpA of 3.9 per 1000 patient-years. Univariate Cox regression analyses showed no differences in clinical characteristics (psoriasis hazards ratio [HR] = 0.92, p = 0.82; inflammatory bowel disease HR = 0.05, p = 0.61; diabetes mellitus HR = 2.82, p = 0.21; chronic kidney disease HR = 0.39, p = 0.35) and medications exposure (sulfasalazine HR = 0.49, p = 0.30; methotrexate HR = 0.52, p = 0.11; leflunomide HR = 0.52, p = 0.37; adalimumab HR = 0.83, p = 0.80; certolizumab HR = 0.05, p = 0.74; etanercept HR = 0.40, p = 0.36; golimumab HR = 0.05, p = 0.32; infliximab HR = 0.05, p = 0.39; secukinumab HR = 1.00, p = 1.00; ustekinumab HR = 0.05, p = 0.78) between patients who had and had not develop CN during the study period. Progression of CIN was independently associated with higher grades of CIN lesion (HR = 6.20; p = 0.05).

CONCLUSIONS

There was low risk of development and progression of CN in patients with SpA on conventional or biologic DMARD therapy.

Experience of the first 1127 COVID-19 Vaccine Allergy Safety patients in Hong Kong - Clinical outcomes, barriers to vaccination, and urgency for reform

INTRODUCTION

Hong Kong has had a low incidence of COVID-19 vaccine related anaphylaxis, partly due to its Vaccine Allergy Safety (VAS) guidelines for screening those at higher risk of COVID-19 vaccine-associated allergic reactions. We characterize the initial experience of the VAS clinics, as well as the impact of unnecessary referrals to the vaccination program.

METHODS

All patients attending the VAS Clinics of the public and private health services between February and June 2021 were reviewed.

RESULTS

Out of 1127 patients assessed at VAS clinics, 1102 (97.8%) patients were recommended for vaccination. Out of those contacted, more than 80% (450/558) received vaccination successfully; the remaining had not yet booked their vaccinations. The majority (87.5%) of patients not recommended was due to potential excipient allergies. Males were significantly more likely to be recommended (OR = 5.822, 95% CI = 1.361-24.903, p = 0.007), but no other features were associated with recommendation for vaccination. Almost half (45.1%) of public service referrals were rejected due to insufficient information or incorrect indications for referral. The majority of cases (56.2%) of patients referred for suspected "anaphylaxis" did not fulfil diagnostic criteria.

DISCUSSION

COVID-19 vaccination is very safe and 98% of high-risk patients were recommended for vaccination. Barriers to VAS include a high proportion of inappropriate referrals, inaccurate diagnoses of anaphylaxis and inability to diagnose excipient allergies. Our data validates that a prior history of COVID-vaccine unrelated anaphylaxis should be removed as a precaution for vaccination. Closer collaborations between primary care and allergy specialists and changes in pharmaceutical legislation should be made a priority to promote vaccination uptake.

Ten-year population trends of immunoglobulin use, burden of adult antibody deficiency and feasibility of subcutaneous immunoglobulin (SCIg) replacement in Hong Kong Chinese

Background

Adult antibody deficiency remains under-recognised and under-studied - especially among Asian populations. Patterns of immunoglobulin use and the feasibility of subcutaneous immunoglobulin (SCIg) replacement among Chinese patients remains unclear.

Objective

To investigate the trends of immunoglobulin use, burden of adult antibody deficiency and the outcomes of patients on SCIg compared to intravenous immunoglobulin (IVIg) replacement in Hong Kong through a retrospective observational study.

Methods

Population-wide data of immunoglobulin recipients in Hong Kong between 2012 and 2021, and longitudinal clinical data of adult immunodeficiency patients at Queen Mary Hospital were collected and analysed.

Results

Total immunoglobulin consumption and recurrent immunoglobulin recipients increased continuously from 175,512g to 298,514g (ρ=0.99, p<0.001) and 886 to 1,508 (ρ=0.89, p=0.001) between 2012-21 in Hong Kong. Among 469 immunoglobulin recipients at Queen Mary Hospital in 2021, 344 (73.3%) were indicated for replacement. Compared to those on IVIg (n=14), patients on SCIg replacement (n=8) had fewer immunodeficiency-related hospitalisations (IRR=0.11) and shorter duration of hospitalisation stay (IRR=0.10) per year, as well as better quality of life (SF-36v2 Health Survey and Life Quality Index). Estimated annual healthcare cost of SCIg replacement per patient was lower than that of IVIg (HKD196,850 [USD25,096] vs HKD222,136 [USD28,319]).

Conclusion

There was a significantly increasing burden of adult antibody deficiency and immunoglobulin consumption in Hong Kong. SCIg was feasible and more cost-effective when compared to IVIg, with SCIg patients experiencing better clinical outcomes and quality of life. Future prospective studies to confirm the long-term efficacy and superiority of SCIg are required.

Long-Term Results of Triple Immunosuppression With Tacrolimus Added to Mycophenolate and Corticosteroids in the Treatment of Lupus Nephritis

Introduction

Addition of a calcineurin inhibitor (CNI) to corticosteroids and mycophenolate increased the renal response rate in lupus nephritis (LN) because of proteinuria reduction, but there is little long-term efficacy and safety data on this triple immunosuppressive regimen.

Methods

This is a cohort study of patients with class III/IV/V LN whose proteinuria persisted despite initial standard therapy with mycophenolate mofetil (MMF) and prednisolone (PRED), in whom tacrolimus (TAC) was added (target 12-hour trough TAC plasma levels of 4–6 μg/l).

Results

A total of 22 patients with LN treated with triple immunosuppression were included, with follow-up of 61.1 ± 28.1 months. Achieved trough levels of TAC and mycophenolic acid (MPA) were 3.8 to 5.7 μg/l and 1.3 to 2.1 mg/l respectively. Significant proteinuria reduction occurred after 6 months and was sustained up to 5 years. Complete response (CR) and partial response (PR) rates at 12, 24, and 36 months was 59.1%, 72.7%, and 77.3% respectively. The slope of estimated glomerular filtration rate (eGFR) over time did not change after TAC was added. A total of 7 patients (31.8%) showed progressive chronic kidney disease (CKD). Two patients reached end-stage kidney disease during follow-up. Renal survival rate at -, 3, and 5 years was 100.0%, 95.0%, and 88.7% respectively. Two patients (9.1%) had renal relapse after 8.5 ± 0.7 months. A total of 5 patients (22.7%) showed worsening of hypertension, and 3 (13.6%) had worsened hyperlipidemia. Other key adverse events included infection (n = 16, 1 in 7 patient-years) and gastrointestinal upset (n = 6).

Conclusion

Triple immunosuppression with the addition of TAC to mycophenolate and PRED resulted in further proteinuria reduction and sustained disease quiescence in patients with LN whose proteinuria did not respond optimally to standard therapy.

Epidemiology, mortality and effectiveness of prophylaxis for Pneumocystis jiroveci pneumonia among rheumatic patients: a territory-wide study

Background

Pneumocystis jiroveci pneumonia (PJP) is an opportunistic infection affecting immunocompromised individuals. However, evidence regarding the burden and effectiveness of prophylaxis among rheumatic patients remains limited. Delineating the epidemiology and efficacy of prophylaxis among rheumatic patients is urgently needed.

Methods

We performed a territory-wide cohort study of rheumatic patients in Hong Kong. All patients with a diagnosis of anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV), immune-mediated myositis (IMM), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic sclerosis (SSc), or spondyloarthritis (SpA) between 2015 and 2019 were included. Prevalence, frequency of prophylaxis and mortality of PJP were calculated. Number needed to treat (NNT) analysis was also performed.

Results

Out of 21,587 patients (54% RA, 25% SLE, 13% SpA, 5% IMM, 2% AAV and 1% SSc), 1141 (5.3%) patients were prescribed PJP prophylaxis. 48/21,587 (0.2%) developed PJP. No patients who developed PJP received prophylaxis prior to infection. The incidence of PJP was highest among SSc, AAV, and IMM patients. Among these diseases, the majority of PJP occurred while patients were on glucocorticoids at daily prednisolone-equivalent doses of 15 mg/day (P15) or above. PJP prophylaxis was effective with NNT for SSc, AAV and IIM being 36, 48 and 114 respectively. There were 19 PJP-related mortalities and the mortality rate was 39.6%.

Conclusion

PJP is an uncommon but important infection among rheumatic patients, PJP prophylaxis is effective and should be considered in patients with SSc, AAV and IMM, especially those receiving glucocorticoid doses above P15.

Genome-wide association study reveals a quantitative trait locus and two candidate genes on Sus scrofa chromosome 5 affecting intramuscular fat content in Suhuai pigs

Intramuscular fat content (IFC) is an essential quantitative trait of meat, affecting multiple meat quality indicators. A certain amount of IFC could not only improve the sensory score of pork but also increase the flavour, tenderness, juiciness and shelf-life. To dissect the genetic determinants of IFC, two methods, including genome-wide efficient mixed-model analysis (GEMMA) and linkage disequilibrium adjusted kinships (LDAKs), were used to carry out genome-wide association studies for IFC in Suhuai pig population. A total of 14 and 18 significant single nucleotide polymorphisms (SNPs) were identified by GEMMA and LDAK, respectively. The results of these two methods were highly consistent and all 14 significant SNPs in GEMMA were detected by LDAK. Seven of the 18 SNPs reached the genome-wide significance level (P < 9.85E-07) while 11 cases reached the suggestive significance level (P < 1.77E-05). These significant SNPs were mainly distributed on Sus scrofa chromosome (SSC) 5, 3, and 7. Moreover, one locus resides in a 2.27 Mb (71.37-73.64 Mb) region on SSC5 harbouring 13 significant SNPs associated with IFC, and the lead SNP (rs81302978) also locates in this region. Linkage disequilibrium (LD) analysis showed that there were four pairs of complete LD (r² = 1) among these 13 SNPs, and the remaining 9 SNPs with incomplete LD (r² ≠ 1) were selected for subsequent analyses of IFC. Association analyses showed that 7 out of 9 SNPs were significantly associated with IFC (P < 0.05) in 330 Suhuai pigs, and the other 2 SNPs tended to reach a significant association level with IFC (P < 0.1). The phenotypic variance explained (PVE) range of these 9 SNPs was 0.92-3.55%. Meanwhile, the lead SNP was also significantly associated (rs81302978) with IFC (P < 0.05) in 378 commercial hybrid pigs (Pietrain × Duroc) × (Landrace × Yorkshire) (PDLY), and the PVE was 1.38%. Besides, two lipid metabolism-relevant candidate genes, the leucine rich repeat kinase 2 (LRRK2) and PDZ domain containing ring finger 4 (PDZRN4) were identified in the 2.27 Mb region on SSC5. In conclusion, our results may provide a set of markers useful for genetic improvement of IFC in pigs and will advance the genome selection process of IFC on pig breeding programmes.

Cardiovascular risk in patients with spondyloarthritis and association with anti-TNF drugs

Background:

Cardiovascular (CVS) diseases are the leading cause of death worldwide and patients with rheumatic diseases have an increased CVS. CVS risk factors and CVS events are common in spondyloarthritis (SpA). Delineating the CVS risk in patients with SpA and identifying modifiable risk factors would be useful.

Methods:

Patients with SpA and patients with non-specific back pain (NSBP) were identified in rheumatology and orthopedics clinics, respectively. Clinical information and CVS events were retrieved. Baseline characteristics and incidence rates of CVS events were compared between two groups of patients using an age- and sex-matched cohort. Propensity score adjustment and Cox regression analysis were performed to determine the CVS risk associated with SpA.

Results:

A total of 5046 patients (SpA 2616 and NSBP 2430) were included from eight centers. Over 56,484 person-years of follow up, 160 strokes, 84 myocardial infarction (MI) and 262 major adverse cardiovascular events (MACE) were identified. Hypercholesterolemia was more prevalent in SpA (SpA 34.2%, NSBP 28.7%, p < 0.01). Crude incidence rates of MACE and stroke were higher in SpA patients. SpA was associated with a higher risk of MACE [hazard ratio (HR) 1.70; 95% confidence interval (CI) 1.29–2.26; p < 0.01] and cerebrovascular events (HR 1.50; 95% CI 1.08–2.07; p = 0.02). SpA patients with anti-TNF use had a reduced risk of MACE (HR 0.37, 95%CI 0.17–0.80, p = 0.01) and cerebrovascular events (HR 0.21, 95%CI 0.06–0.78, p = 0.02) compared with SpA patients without anti-TNF use.

Conclusion:

SpA is an independent CVS risk factor. Anti-tumor necrosis factor (TNF) drugs were associated with a reduced CVS risk in these patients.

[Clinical characteristics of anti-CV2 antibody-associated neurological diseases]

This study reviewed the clinical data of patients who were hospitalized in the Department of Neurology of Henan Provincial People's Hospital from January 2017 to October 2020. A total of 46 patients with positive serum anti-CV2 antibody were included. The average age of the patients was (54±15) years old, with a male to female ratio of 1.88∶1. Twenty-six patients were diagnosed with paraneoplastic neurological syndrome (PNS). The most malignant tumors were thymoma, small cell lung cancer, and prostate cancer. The most common PNS included myasthenia gravis, subacute cerebellar degeneration, and subacute/chronic sensorimotor neuropathies. Twenty non-PNS patients exhibited subacute/old cerebral infarction, Parkinson's disease, Alzheimer's disease, and so on. Among them, brain magnetic resonance imaging (MRI) of 10 cases showed different degrees of white matter demyelination, some of which were accompanied by brain atrophy. The current study found that the positive predictive value of anti-CV2 antibody for the diagnosis of PNS was 56.5%, which was relatively weak. As an accompanying antibody, it may be a coincidence, and it may also be related to the involvement of family members in the pathological process of the diseases.

Epidemiology and outcomes of geriatric and non-geriatric patients with drug allergy labels in Hong Kong

INTRODUCTION

Adverse drug reactions are more common in geriatric patients than in younger patients, but there have been insufficient studies concerning the epidemiology or burden of drug allergy labels in geriatric patients. We prospectively investigated the prevalence and outcomes of geriatric patients with drug allergy labels in a cohort of hospitalised patients.

METHODS

Patients admitted to a regional hospital over a 6-month period were recruited for this study. All patients with drug allergy labels were prospectively followed until discharge; clinical data were anonymously extracted for analyses. Patients were categorised into either geriatric (aged ≥65 years) or non-geriatric (aged <65 years) groups. Demographic characteristics, clinical outcomes, and prevalences of drug allergy labels were compared between groups.

RESULTS

There were 4361 admissions involving 3641 patients during the 6-month study period. Overall, 492 patients (13.5%) had drug allergy labels, consisting of 151 non-geriatric patients (30.7%) and 341 geriatric patients (69.3%). The prevalence of drug allergy labels did not significantly differ between geriatric and non-geriatric patients (13.5% vs 13.5%, P=0.976). Significantly more patients in the geriatric group had drug allergy labels to cardiovascular system drugs (15.5% vs 4.6%, P=0.001). Geriatric patients had a significantly lower rate of direct discharge from the hospital (73.0% vs 88.1%, P<0.001) and required transfers to convalescent or rehabilitation care for further management.

CONCLUSIONS

More than 13% of hospitalised geriatric patients had drug allergy labels. The leading causes of drug allergy labels were similar between geriatric and non-geriatric patients. Geriatric patients with drug allergy labels had significantly more labelled allergies to cardiovascular system drugs and adverse clinical outcomes.

Piperacillin-Tazobactam Allergies: An Exception to Usual Penicillin Allergy

Purpose

The majority of penicillin allergy labels are false, and skin tests (ST) have high negative predictive value (NPV) of up to 90%. Piperacillin-tazobactam (PT) allergy has been suspected to be an exception to this, but existing literature is scarce. We investigate the epidemiology, clinical characteristics, testing outcomes and predictive value of ST in patients referred for suspected PT allergies.

Methods

The records of all patients referred for suspected PT allergy testing and prescription rates of PT in all Hong Kong public hospitals (2015–2019) were analyzed.

Results

There was an increase in both PT prescriptions and number of newly reported PT allergies between 2015 and 2019. The majority (91.1%) of patients with suspected PT allergy had at least 1 underlying medical co-morbidity or immunosuppressant use leading to increased risk of infections. Thirty-six patients with suspected PT allergy completed ST. Two patients had positive ST, and 32/34 patients with negative ST underwent drug provocation testing (DPT). Nine of these patients were diagnosed with PT allergy based on positive DPT. Overall, 11/34 (32.4%) were diagnosed with PT allergy and the NPV of ST was 71.9%.

Conclusions

There is growing utilization of PT and corresponding cases of suspected allergies. The majority of suspected PT allergies had increased risk for recurrent infections. Unlike other penicillin allergy, there is a high rate of genuine PT allergy (up to 30%) and a poor NPV of ST (up to 70%). DPT remains the gold standard for accurate diagnosis, and all patients with a suspected allergy should undergo thorough allergy workup.

Diagnostic utility of whole spine and thoracic spine MRI corner inflammatory lesions in axial spondyloarthritis

Background:

The presence of ⩾3 corner inflammatory lesions has been proposed as the definition of a positive spinal magnetic resonance imaging (MRI) for axial spondyloarthritis (axSpA), but subsequent studies showed inconclusive findings. Our objective was to evaluate whether locations of corner inflammatory lesions (CILs) would affect the diagnostic utility of MRI in axSpA.

Method:

Two groups were consecutively recruited from eight rheumatology centers in Hong Kong. The ‘axSpA’ group included 369 participants with a known diagnosis of axSpA. The ‘non-specific back pain’ (NSBP) control group consisted of 117 participants. Clinical, biochemical, and radiological parameters were collected and all patients underwent MRI of the spine and sacroiliac joints. CILs were assessed based on their locations (cervical, thoracic or lumbar) to determine the optimal cutoff for diagnosis.

Results:

The cutoff of ⩾5 whole spine CILs (W-CILs) and ⩾3 thoracic spine CILs (T-CILs) had comparable specificity to MRI sacroiliitis. Of 85/369 axSpA patients without sacroiliitis on conventional radiograph or MRI, 7 had ⩾5 W-CILs and 11 had ⩾3 T-CILs. Incorporating the proposed cutoffs into Assessment of SpondyloArthritis international Society axSpA criteria, ⩾5 W-CILs and ⩾3 T-CILs had similar performance when added to the imaging criteria for sacroiliitis (sensitivity 0.79 versus 0.80, specificity 0.92 versus 0.91).

Conclusion:

Spinal MRI provided little incremental diagnostic value in unselected axSpA patients. However, in patients without sacroiliitis on MRI or radiographs, 8–13% might be diagnosed by spinal MRI. Thoracic and whole spine MRI had similar diagnostic performance using the proposed cutoff of ⩾5 W-CILs and ⩾3 T-CILs.

Increasing incidence of anaphylaxis in Hong Kong from 2009 to 2019-discrepancies of anaphylaxis care between adult and paediatric patients

BACKGROUND

Anaphylaxis has been increasing in developed countries but there is very little published data on the burden of anaphylaxis and the pattern of adrenaline autoinjector (AAI) prescription from Asia. We aim to determine the incidence rates of anaphylaxis and prescription rates of AAI over the past decade in Hong Kong.

METHODS

Using a centralized electronic database of Hong Kong's sole public-funded healthcare provider, we obtained and analysed all patients between 2009 and 2019 with physician-reported diagnosis of anaphylaxis. Incidence rates were calculated using population statistics as the denominator. Patients' prescriptions on discharge were collected to determine the AAI prescription rates.

RESULTS

The overall 10-year estimated incidence rate of anaphylaxis was 3.57 per 100,000 person-years. An increasing trend over time across both paediatric and adult populations from 2009 to 2014 was found, which remained stable until 2019. This was more marked among the paediatric population (paediatric vs adult incidence rate ratio in 2019: 3.51 [95% CI 1.12-2.66] vs 1.82 [95% CI 1.05-1.60]). There was an overall increasing rate of AAI prescription for patients admitted for anaphylaxis, but the overall AAI prescription rate was less than 15% and was significantly less likely to be prescribed for the adult compared to paediatric patients (36.5% vs. 89.4%, p < 0.001).

CONCLUSIONS

An increasing trend of anaphylaxis incidence rates over the past decade is evident in Asian populations, with a discrepantly low rate of AAI prescription, particularly in the adult patients.

Prevalence and Impact of Reported Drug Allergies among Rheumatology Patients

Background: Drug allergies (DA) are immunologically mediated adverse drug reactions and their manifestations depend on a variety of drug- and patient-specific factors. The dysregulated immune system underpinning rheumatological diseases may also lead to an increase in hypersensitivity reactions, including DA. The higher prevalence of reported DA, especially anti-microbials, also restricts the medication repertoire for these already immunocompromised patients. However, few studies have examined the prevalence and impact of reported DA in this group of patients. Methods: Patients with a diagnosis of rheumatoid arthritis (RA), spondyloarthritis (SpA), or systemic lupus erythematosus (SLE) were recruited from the rheumatology clinics in a tertiary referral hospital between 2018 and 2019. Prevalence and clinical outcomes of reported DA among different rheumatological diseases were calculated and compared to a cohort of hospitalized non-rheumatology patients within the same period. Results: A total of 6081 patients (2541 rheumatology patients: 1286 RA, 759 SpA, and 496 SLE; and 3540 controls) were included. DA was more frequently reported among rheumatology patients compared to controls (23.8% vs. 13.8%, p < 0.01). Antibiotics and non-steroidal anti-inflammatory drugs (NSAIDs) were the two most commonly reported categories of DA with a prevalence of 12.0% and 5.1%, respectively. Reported antibiotics allergies were more frequent in patients with RA (OR = 1.20, 95% CI = 1.02–1.62, p = 0.03) and SLE (OR = 4.69, 95% CI = 3.69–5.95, p < 0.01); and associated with increased infection-related admissions among rheumatology patients (OR = 1.79, 95% CI = 1.09–2.95, p = 0.02). Among the subgroup of patients referred for allergy testing, 85.7% of beta-lactam antibiotic allergy labels were found to be inaccurate and de-labelled after negative drug provocation testing. Conclusion: The prevalence of reported DA was significantly higher in rheumatology patients. Reported antibiotic allergy was associated with increased rate of infection-related admissions. However, the rate of genuine antibiotic allergy was low. Further studies are needed to guide proper assessment of reported DA and impact of comprehensive allergy testing in this group of patients.

Diagnostic procedures & practices in drug allergy/hypersensitivity: a survey of 13 Asian countries

BACKGROUND

The issues and challenges in the diagnosis of drug allergy/hypersensitivity among children and adults in Asia are likely to be different from non-Asian countries.

OBJECTIVE

To study the diagnostic modalities used in the evaluation and management of drug allergy/drug hypersensitivity reactions (DHRs) among member societies of the Asia Pacific Association of Allergy, Asthma and Clinical Immunology (APAAACI).

METHODS

A questionnaire comprising 41 questions was circulated electronically to member societies and individual members of APAAACI between January 23, 2020 and March 6, 2020.

RESULTS

Twenty-six respondents from 15 member societies and 1 individual member responded. European DHR guidelines were most commonly used. Skin prick and intradermal testing was used by 100%, with only 60% having access to commercial penicillin skin test reagents. In vitro-specific IgE tests were used by 75%, and basophil activation test by 56.3% for immediate DHR. Patch tests were used by 75% in contrast to lymphocyte transformation tests by 25% for nonimmediate DHR. Drug provocation tests were used by 68.8%, the most common indication being to exclude hypersensitivity where history/symptoms were not suggestive of drug hypersensitivity/allergy (93.3%). Human leukocyte antigen (HLA) genotype testing was mandatory among 25% respondents before new carbamazepine prescriptions, and 8.3% for allopurinol prescriptions.

CONCLUSIONS

There was increased use of skin testing for iodinated contrast media hypersensitivity and patch testing for nonimmediate DHR. HLA genotype testing prior to new carbamazepine, allopurinol and abacavir prescriptions remain variable despite strong associations for severe cutaneous adverse reactions with Asian ethnicity. Results of this survey form a useful framework for developing educational and training needs and for improving access to drug allergy diagnostic and treatment modalities across APAAACI member societies.

Differences in omega-5-gliadin allergy: East versus West

Background

Omega-5-gliadin (O5G) allergy, also known as wheat-dependent exercise-induced anaphylaxis, is commonly reported in the Western, but not Asian, populations. Although significant differences in O5G allergy presentation across different populations are likely but there have been no previous reports on this important topic.

Objective

To report on the prevalence and characteristics of O5G allergy in Hong Kong (HK) compared with the United Kingdom (UK).

Methods

O5G allergy patients attending Queen Mary Hospital (HK cohort), and Guy's and St Thomas' Hospital, London (UK cohort) were studied and compared.

Results

A total of 46 O5G allergy patients (16 HK; 30 UK) were studied. In the HK cohort, 55% of all patients previously labeled as “idiopathic anaphylaxis” were diagnosed with O5G allergy. Exercise was the most common cofactor in both cohorts, followed by alcohol and nonsteroidal anti-inflammatory drugs (NSAID). A higher proportion of the HK cohort reported NSAID as a cofactor (13% vs. 0%, p = 0.048). In the HK cohort, more patients presented with urticaria and cardiovascular manifestations (100% vs. 77%, p = 0.036; 100% vs. 70%, p = 0.015, respectively); the range of presentation was more diverse in the UK cohort. In HK fewer patients adhered to wheat avoidance (50% vs. 87%, p = 0.007) and more patients avoided cofactors only (44% vs. 10%, p = 0.008).

Conclusion

O5G allergy appears relatively underdiagnosed in HK. Urticaria and cardiovascular manifestations are common; NSAID plays an important role as a cofactor and patients are less concordant with dietary avoidance measures than in the Western population.

Drug hypersensitivity reactions in Asia: regional issues and challenges

There are geographical, regional, and ethnic differences in the phenotypes and endotypes of patients with drug hypersensitivity reactions (DHRs) in different parts of the world. In Asia, aspects of drug hypersensitivity of regional importance include IgE-mediated allergies and T-cell-mediated reactions, including severe cutaneous adverse reactions (SCARs), to beta-lactam antibiotics, antituberculous drugs, nonsteroidal anti-inflammatory drugs (NSAIDs) and radiocontrast agents. Delabeling of low-risk penicillin allergy using direct oral provocation tests without skin tests have been found to be useful where the drug plausibility of the index reaction is low. Genetic risk associations of relevance to Asia include human leucocyte antigen (HLA)-B*1502 with carbamazepine SCAR, and HLA-B*5801 with allopurinol SCAR in some Asian ethnic groups. There remains a lack of safe and accurate diagnostic tests for antituberculous drug allergy, other than relatively high-risk desensitization regimes to first-line antituberculous therapy. NSAID hypersensitivity is common among both adults and children in Asia, with regional differences in phenotype especially among adults. Low dose aspirin desensitization is an important therapeutic modality in individuals with cross-reactive NSAID hypersensitivity and coronary artery disease following percutaneous coronary intervention. Skin testing allows patients with radiocontrast media hypersensitivity to confirm the suspected agent and test for alternatives, especially when contrasted scans are needed for future monitoring of disease relapse or progression, especially cancers.

Beta-lactam allergy in Chinese patients and factors predicting genuine allergy

Introduction

Beta-lactams (BL) are the most frequently reported drug allergy, but the vast majority of patients are found not to be genuinely allergic after evaluation. Few studies have investigated the clinical predictors of genuine BL allergy, and the prevalence in hospitalized Chinese patients is unknown.

Methods

Patients admitted to a tertiary hospital in Hong Kong (HK) were analyzed to identify the prevalence and factors associated with the presence of BL allergy labels among hospitalized Chinese patients. A combined cohort of patients having completed allergy investigation for suspected BL allergies in the United Kingdom (UK) and HK were analyzed to identify predictors of genuine allergy.

Results

The prevalence of BL allergy labels in hospitalized HK Chinese was 5%, which was associated with female gender and concomitant non-BL antibiotic allergy labels. The rate of genuine BL allergy patients referred for suspected allergies in the UK and HK cohort was only 14%. History of anaphylaxis and interval of less than a year since the index reaction were independent clinical predictors of genuine BL allergy. The negative predictive value of penicillin skin testing was 90%, confirming the need for drug provocation testing after negative skin testing. There was a high rate of confirmed piperacillin-tazobactam allergy.

Discussion

The estimated true prevalence of genuine BL allergy in hospitalized HK Chinese is around 0.5%. This high rate of BL mislabeling highlights the need for comprehensive allergy evaluation and screening. History of anaphylaxis and duration since the index reaction are important predictors of genuine allergy. Piperacillin-tazobactam allergy may pose a unique challenge in this population with a high prevalence of suspected allergies, surging antibiotic resistance, and lack of testing available.

The unmet provision of allergy services in Hong Kong impairs capability for allergy prevention-implications for the Asia Pacific region

INTRODUCTION

There is a high and rising prevalence of many allergic diseases in the Asia Pacific, including Hong Kong (HK), which is unmatched by a commensurate provision of clinical allergy services.

METHOD

This review highlights progress and deficiencies in allergy service and training in HK. The allergy work force was estimated from the numbers of doctors practicing allergy registered with the HK Medical Council Specialist Register in Immunology and Allergy; Paediatric Immunology and Infectious Diseases (includes allergy); Paediatrics; and Immunology (as a discipline of Pathology). The numbers of trainees were estimated from the trainee lists of the Hong Kong Colleges of Physicians, Paediatrics and Pathology. The numbers of allergy clinics were estimated from existing services in Hospital Authority public hospitals in HK.

RESULTS

In the last 3 years, two new drug allergy clinics have been established in public hospitals, and for the first time in 20 years, Hong Kong has a trainee in adult allergy. The current ratio of allergists per head of population has improved slightly from 1:1.46 million in 2014 to 1:1.17 million, but it is still low compared to many countries. There are 5-fold more paediatric allergists than adult allergists per head of population in HK.

DISCUSSION

Hong Kong is not equipped to take advantage of major public health advances in allergy prevention. If the unbalance of adult to paediatric allergists remains uncorrected, continuing care for allergic children as they grow into adulthood will be an increasing problem.

CONCLUSION

Hong Kong still has an unmet need for allergy specialists and is ill equipped to exploit recently discovered public health opportunities to prevent allergy. This review provides recommendations to improve allergy service provision and training, including the creation of Centres of Excellence in allergy to drive the growth of the specialty.

Identifying Low-Risk Beta-Lactam Allergy Patients in a UK Tertiary Centre

BACKGROUND

There are marked geographical as well as temporal differences in patient sensitization profiles to β-lactams (BL).

OBJECTIVE

To determine the utility of skin test reagents and identify a cohort of patients where skin testing can be safely omitted in a cohort of patients referred to a UK tertiary referral center.

METHODS

A retrospective study of the clinical characteristics of 1092 patients referred for BL allergy testing was analyzed using multivariate regression analysis. The effectiveness of skin test reagents was also evaluated.

RESULTS

Multivariate logistic regression identified that a history of anaphylaxis (odds ratio [OR] 10.98, P = .001) and the patients' recall of the index drug (apart from ampicillin and meropenem, OR 3.51-12.43, P < .05) were independent predictors of type I BL allergic status and a time of less than 1 year elapsed since index reaction significantly increasing the odds of a patient with a history of anaphylaxis, having a type I BL allergy (OR 38.66, P = .003). An absence of anaphylactic severity, unknown name of the index drug and a reaction occurring more than 1 year before testing, has a negative predictive value (NPV) of 98.4%, which was similar to the NPV of skin testing of 98.9% for type I BL allergy. The NPV of skin testing with benzylpenicillin + amoxicillin ± index BL was similar with (98.9%) or without (98.1%) the use of benzylpenicillin polylysine and minor determinant for type I BL allergy.

CONCLUSION

We identified a "low risk" cohort of patients where the history is of similar reliability to skin testing in predicting nonallergic status for BL allergy.

Hong Kong Institute of Allergy and Hong Kong Society for Paediatric Immunology Allergy & Infectious Diseases joint consensus statement 2018 on vaccination in egg-allergic patients

Vaccination of egg-allergic individuals has been a historical concern, particularly for influenza and measles-mumps-rubella-varicella vaccines that are developed in chicken egg embryos or chicken cell fibroblasts. The egg proteins in these vaccines were believed to trigger an immediate allergic reaction in egg-allergic individuals. However, recently published international guidelines have updated their recommendations and now state that these vaccines can be safely administered to egg-allergic individuals. This joint consensus statement by the Hong Kong Institute of Allergy and the Hong Kong Society for Paediatric Immunology Allergy & Infectious Diseases summarises the updates and provides recommendations for local general practitioners and paediatricians. Hong Kong Institute of Allergy and Hong Kong Society for Paediatric Immunology Allergy & Infectious Diseases joint consensus statement 2018 on vaccination in egg-allergic patients Background.

Diffusion-weighted imaging versus short tau inversion recovery sequence: Usefulness in detection of active sacroiliitis and early diagnosis of axial spondyloarthritis

Objective

To compare the utility of Diffusion weighted imaging (DWI) with short tau inversion recovery (STIR) sequence in the diagnosis of early axial spondyloarthritis (SpA).

Methods

Three hundred and five patients with chronic back pain were recruited consecutively from 3 rheumatology centers. Clinical, radiological and blood parameters were recorded. Patients with back pain duration no more than 3 years were classified as having early disease. STIR sequence and DWI of the sacroiliac joints were obtained and assessed using the Spondyloarthritis Research Consortium of Canada (SPARCC) method. The Assessment in Spondyloarthritis international Society definition was used to define positive STIR and DWI. Results were compared to expert diagnosed axial SpA.

Results

When compared to STIR sequence, DWI had similar sensitivity (STIR 0.29, DWI 0.30) and specificity (STIR 0.97, DWI 0.92) in diagnosing sacroiliitis. However, STIR sequence had better reliability (STIR 0.78, DWI 0.61). In early disease group, DWI was not better than STIR sequence in detecting active sacroiliitis (sensitivity DWI vs STIR: 0.34 vs 0.36; specificity DWI vs STIR: 0.93 vs 0.93; positive predictive value DWI vs STIR: 0.92 vs 0.92; negative predictive value DWI vs STIR: 0.36 vs 0.37). Using the Assessment in SpondyloArthritis international Society (ASAS) classification criteria, 67/98 patients with early disease (sensitivity 0.91 specificity 0.90) and 221/305 overall (sensitivity 0.90; specificity 0.92) were classified as axial SpA. Among the expert diagnosed axial SpA patients who did not meet the ASAS criteria, only 2 had positive DWI.

Conclusion

DWI and STIR have similar sensitivity in diagnosing axSpA in early disease. However, the use of DWI is limited by poorer reliability when compared with STIR.

Identification of an (AC)n microsatellite in the Six1 gene promoter and its effect on production traits in Pietrain × Duroc × Landrace × Yorkshire pigs

The Sine oculis homeobox 1 (Six1) gene is important for skeletal muscle growth and fiber specification; therefore, it is considered as a promising candidate gene that may influence porcine growth and meat quality traits. Nevertheless, the association of Six1 with these processes and the mechanisms regulating its expression remain unclear. The objectives of this study were to identify variant sites of Six1 in different pig breeds, conduct association analysis to evaluate the relationship between polymorphisms of these variants and porcine production traits in Pietrain × Duroc × Landrace × Yorkshire commercial pigs, and explore the potential regulatory mechanisms of Six1 affecting production traits. A total of 12 variants were identified, including 10 single- nucleotide variations (SNVs), 1 insertion- deletion (Indel), and 1 (AC)n microsatellite. Association analysis demonstrated that the SNV, g.1595A>G, was significantly associated with meat color (redness, a*); individuals with the G allele had greater a* values (P < 0.05). Moreover, our results demonstrated that the (AC)n polymorphism in the Six1 promoter was significantly associated with weaning weight (P < 0.05), carcass weight (P < 0.05), and thoracic and lumbar back fat (P < 0.01).In addition, we found that the (AC)n variant was closely related with Six1 expression levels and demonstrated this polymorphism on promoter activity by in vitro experiments. Overall, this study provides novel evidence for elucidating the effects of Six1 on porcine production traits as promising candidate and describes two variants with these traits, which are potential reference markers for pig molecular breeding. In addition, our data on the relationship between porcine Six1 expression and the polymorphic (AC)n microsatellite in its promoter may facilitate similar studies in other species.

Fowl adenovirus serotype 4: Epidemiology, pathogenesis, diagnostic detection, and vaccine strategies

Fowl adenovirus (FAdV) serotype-4 is highly pathogenic for chickens, especially for broilers aged 3 to 5 wk, and it has emerged as one of the foremost causes of economic losses to the poultry industry in the last 30 years. The liver is a major target organ of FAdV-4 infections, and virus-infected chickens usually show symptoms of hydropericardium syndrome. The virus is very contagious, and it is spread both vertically and horizontally. It can be isolated from infected liver homogenates and detected by several laboratory diagnostic methods (including an agar gel immunodiffusion test, indirect immunofluorescence assays, counterimmunoelectrophoresis, enzyme-linked immunosorbent assays, restriction endonuclease analyses, polymerase chain reaction (PCR), real-time PCR, and high-resolution melting-curve analyses). Although inactivated vaccines have been deployed widely to control the disease, attenuated live vaccines and subunit vaccines also have been developed, and they are more attractive vaccine candidates. This article provides a comprehensive review of FAdV-4, including its epidemiology, pathogenesis, diagnostic detection, and vaccine strategies.

Immunoglobulin G4-related disease in Hong Kong: clinical features, treatment practices, and its association with multisystem disease

INTRODUCTION

Immunoglobulin G4-related disease remains an under-recognised and evolving disease. Local data are sparse and previous publications have been limited to individual case reports or case series only. We conducted this study to review the clinical features, treatment practices, and factors associated with multisystem involvement in Hong Kong. We described the clinical features and treatment modalities of the largest cohort of immunoglobulin G4-related disease in our locality thus far.

METHODS

We retrospectively evaluated all patients with immunoglobulin G4-related disease between January 2003 and December 2015 in Queen Mary Hospital and combined this with patient data extracted from previous local publications. We analysed the clinical features, treatment practices, and factors associated with the number of organ systems involved.

RESULTS

A total of 104 patients (55 from Queen Mary Hospital and 49 from literature review) were identified. Patients were predominantly older men (mean [standard deviation] age, 61.9 [12.7] years; male-to-female ratio=3:1) and 94.4% had elevated pre-treatment serum immunoglobulin G4 levels. Hepatobiliary and pancreatic system (40.4%), salivary gland (33.7%), lymph node (29.8%), and eye (19.2%) were the most common organ systems involved. Lymphadenopathy was associated with glucocorticoid use (odds ratio=2.65; 95% confidence interval, 1.08-6.54; P=0.034). Pre-treatment serum immunoglobulin G4 levels correlated with the number of organ systems involved (β=0.347; P=0.004) and, specifically, more associated with patients having salivary gland involvement than those without (mean, 1109 mg/dL vs 599 mg/dL; P=0.012).

CONCLUSION

We identified pre-treatment serum immunoglobulin G4 to be associated with multisystem disease, especially with salivary gland involvement, highlighting its potential for disease prognostication and monitoring. Increased physician awareness and multidisciplinary efforts are required for early diagnosis and optimal management of this masquerading disease.