Oral abstracts session 1

The next session was the first of 2 sessions in which submitted abstracts were presented. In this session, chaired by Dr Michihiro Hide, 3 abstracts were presented:

• Unearthing hereditary angioedema in India: Epidemiology from Chandigarh and Reasi
• Evaluating the effectiveness of cascade family screening among Sri Lankan hereditary angioedema (HAE) patients
• Screening program providing outreach for testing hereditary angioedema (SPPOT-HAE): Validation and utilizing dried blood spots for family screening

Unearthing hereditary angioedema in India: Epidemiology from Chandigarh and Reasi

The first presentation, on epidemiology from the Indian regions of Chandigarh and Reasi, was given by Dr Suprit Basu. Dr Basu appeared via an online link due to an emergency situation at his hospital.

He outlined that the research aimed to highlight the challenge in diagnosing and managing HAE in resource-constrained settings by addressing the limited epidemiological data on the disease in developing countries.

Dr Basu and team began by reviewing records of all patients diagnosed with HAE between 1994 and 2023. They then conducted 2 field surveys to trace further potential patients and calculate the prevalence of HAE in Chandigarh and Reasi. 12 patients from 6 families were found in Chandigarh. In Reasi, 41 patients from 5 families were uncovered. The prevalence in Chandigarh was 1 per 100,000 population, but the rate in Reasi was 10 times this.

Dr Basu reported that all patients were HAE Type 1 in the Chandigarh cohort. All of the Reasi patients were Type 2, with laryngeal attacks and tongue swelling being more common in this group.

In conclusion, Dr Basu suggests that there is an urgent unmet need to diagnose all patients. In a brief Q&A, he clarified further that the different prevalence rates may be due to large inter-ethnic differences. The stated prevalence in these areas is the minimum, as awareness of the disease is so low in Chandigarh and Reasi. More education would increase diagnoses.

Evaluating the effectiveness of cascade family screening among Sri Lankan hereditary angioedema (HAE) patients

Speaking next was Uvini Amarasekara. She echoed Dr Basu’s work by stating that there is no consensus on HAE prevalence in Sri Lanka, with many cases remaining undiagnosed. Part of this, she said, was due to a lack of immunologists and little funding from authorities for treatment or research.

The research presented focused on 20 confirmed patients with HAE. Through family screening, 98 family members were identified, of which 28 were symptomatic but not diagnosed with HAE. Through diagnostic testing, 12 new cases of HAE were diagnosed in these 28 patients. Diagnosis rates, quality of life, and angioedema activity scores were calculated for all patients identified. The quality of life and activity scores suggested some impact on the lives of people with HAE.

In follow-up questions, Ms Amarasekara suggested that the barrier to diagnosis is a lack of awareness of the dangers of HAE. When patients are educated about the condition, they are willing to bring their whole family for screening.

Screening program providing outreach for testing hereditary angioedema (SPPOT-HAE): Validation and utilizing dried blood spots for family screening

The last presentation was given by Dr Jane Wong, who received the HAEi Young Researcher award for this scientific work.

She indicated that funding for the research was from Takeda. By way of background, she told the audience that many laboratory assays are available to diagnose HAE, but these are not readily available, especially in rural areas. In particular, she highlighted the laborious nature of C1 function testing, as samples must be tested within 2 hours and kept on dry ice. All of this is a major barrier for a lot of centers.

The concept of dry blood spot (DBS) is one potential solution to this issue. It is an existing technology, and dry blood spot has been adapted to test for C4 and C1 function and C1 inhibitor level. DBS is very stable, Dr Wong told the audience; DBS does not need to be transported on ice and it can be put in an envelope at room temperature.

“For SSPOT-HAE, you only need five drops of blood. And you can put it on your desk for a week before the FedEx people come to take it.”

This research was designed to validate if DBS compares with conventional laboratory testing for HAE. Patients with known HAE were recruited to come to the clinic and be tested using DBS. Additionally, previously untested relatives of these patients were also tested with DBS (followed by conventional lab methods). The DBS testing corroborated well for the previously diagnosed HAE patients, Dr Wong said. The DBS also seemed to encourage previously reluctant family members to attend for treatment. 9 patients in one family were screened; 2 were ultimately confirmed to have HAE.

In conclusion, Dr Wong suggested that the testing had identified no false negatives, which was a concern as it would mean patients with HAE would be falsely told they did not have the condition. Her key message, she said, was that DBS can be a good tool for family screening and be used in outreach programs to overcome some of the barriers to wider testing, such as logistics concerns inherent with existing laboratory tests.

The follow-up questions focused on the issue of false positives. Dr Wong acknowledged this is a possibility, but their concern was more with false negatives, as this would put people with HAE at risk of being untreated during attacks. Dr Wong clarified a question about blood sampling affecting the test; if there is enough blood to fill a spot on a paper, it can be tested.