In mid January, Irish researchers from Beaumont Hospital and the Royal College of Surgeons in Ireland announced findings from a study of patients with hereditary emphysema, a disease due to a deficiency of the enzyme alpha-1 antitrypsin (AAT).
Dr Michael Beckles
, Consultant in Respiratory Medicine
at The Physicians' Clinic reviews the research and explains its implications not only for patients with hereditary emphysema and their families, but also for people with more common disorders such as rheumatoid arthritis.
About hereditary emphysema
“Alpha-1 antitrypsin deficiency is an inherited disorder that affects the lung, liver and skin. AAT is an enzyme that inhibits the breakdown of proteins within tissue; in the lungs it protects the delicate tissue from damage from particles, pollutants and other substances we breathe in. When the level AAT falls below a critical point, the lungs can show signs of inflammation, which can lead to shortness of breath and more serious problems unless it is treated.” explains Dr Beckles.
Although AAT deficiency is inherited, lifestyle choices such as being a smoker can impact on how severe the lung problems are and how fast they progress. Severe deficiency of AAT is a significant risk factor for early onset breathing difficulties with emphysema. However, a severely deficient enzyme level does not necessarily mean that emphysema will develop.
Risk factors that lead to emphysema progression
The significant risk factors that make it more likely that someone with an AAT deficiency will develop lung problems include:
- Cigarette smoking.
- A dusty working environment.
- A family history of chronic obstructive pulmonary disease (COPD).
- A personal history of asthma, chronic bronchitis or pneumonia.
“AAT deficiency is often unrecognised, but there is a blood test to measure the amount of enzyme that someone produces. Once genetic tests are performed to establish the genotype, and the blood levels of AAT are available, treatment can focus on replacing the AAT enzyme to prevent the disease progressing,” comments Dr Beckles.
The Physicians' Clinic's approach to hereditary emphysema
“Registries of alpha-1 antitrypsin-deficient patients are active in the UK, and, at The Physicians’ Clinic, we have facilities to diagnose these patients and refer them on to the specialist centre for entering into clinical trials, if required and if the patients want to do this.”
“For patients with any of the known risk factors listed above, we always recommend spirometry, together with measurement of lung volumes and gas transfer. Treatment is then initiated as necessary and we are very interested in participating in clinical trials and furthering understanding of hereditary emphysema.”
Why more research into hereditary emphysema is needed
“Many questions remain to be answered,” says Dr Beckles. “Which patients benefit from treatment is still the subject of a great deal of research. Treatment can be given via infusion of pooled human alpha-1 antiproteinase, but there are limited data regarding this treatment. One interesting feature of this illness is that we don't yet understand is why some patients, who have severely depleted enzyme levels, have normal lung function.”
The Irish study suggests that patients with low AAT levels are likely to develop a form of autoimmunity because their white blood cells release extra proteins into the blood. These proteins, which are not normally present in blood, initiate an immune response, which may contribute to the inflammation seen in lung and other tissues.
The researchers also think that hereditary emphysema may affect more tissues in the body that previously thought, and that AAT replacement therapy may actually be beneficial for patients with other autoimmune disorders – such as rheumatoid arthritis.
“This could be a very exciting development but one that will require many years of research and clinical trial,” concludes Dr Beckles.