The pulmonary fibrosis of HPS is life limiting.  Currently, the only treatment is lung transplant and without this life expectancy is typically between 45-55 years.


What causes the pulmonary fibrosis ?


It is not known what causes the pulmonary fibrosis of HPS but it involves inflammation of the lung tissue which results in scaring.   A substance called Ceroid lipofucin tends to accumulate in the lung tissue of those who are affected.  Also, there tend to be higher than expected numbers of white bloods (lymphocytes and macrophages) found in the lung tissues of those effected.  However, it is not known if either of these play a role in causing the inflammation and fibrosis.


The PF of HPS is a restrictive lung disease.  It affects the lungs in a number of ways that make breathing more difficult and less efficient.  The lung tissues become stiffer and the fine structures become thicker.  These changes limit the ability of oxygen to pass from the lungs and into the body’s bloodstream.


  1. Think of a sponge that you use for jobs around the house.  When you squeeze it and then let go the shape of the sponge bounces back.  Lungs have this elasticity when they are healthy.  As PF develops the lungs become inflamed and the tissues are damaged and become less ‘springy’ as inelastic scar tissue (collagen) develops.
  2. When you breath in (inhale) the air is carried to tiny sacks at the end of fine tubes.  The sacks (or Alveoli) have very thin walls and are surrounded by lots of very fine blood vessels.   The Oxygen that your body needs passes through the walls of the alveoli and into the blood vessels so that it can be taken around the body.  At the same time carbon dioxide passes from the blood vessels into the alveoli and is breathed out (exhaled).  When PF develops the walls of the alveoli and blood vessels become thicker and the gasses have more difficulty passing through the walls of the air sacks and blood vessels.











Above Left,  Diagram showing the movement of Oxygen (O2) and Carbon dioxide (CO2) between the air sacks (Alveoli) and surrounding capillary blood vessels  in lung tissue. Above Right, Model of capillary  (with red blood cells inside) surrounding the thin wall of an alveolus.


What tests can doctors do to monitor pulmonary fibrosis


How well a person’s lungs are working can be measured using Pulmonary Function Tests (PFTs). The Forced Vital Capacity (or FVC) and ‘Gas Transfer factors’ (DLco or TLco) can be used to track the progression of the pulmonary fibrosis over a period of time.  In the early stage the PF cannot be seen on a standard chest X-ray.  However, the early signs can be seen by doctors using a High Resolution CT scanner (HR-CT).  Read more about pulmonary function tests.
















Looking after your lungs


It is important for all persons with HPS to take reasonable steps to care for their lungs and avoid respiratory infections and environments likely to cause chest irritation.  Here are some simple steps you might like to consider in addition to other precautions:





Treatment



Clinical trials


The National Institutes of Health (NIH) in the United States are currently carrying out research into the PF of HPS - as well as other aspects of the syndrome such as the GI problems.  For instance, one of the research protocols (the Multi Drug Trial) aims to investigate the effectiveness of currently available drugs in slowing down the progress of advanced PF.


Individuals or families interested in participating in trials and research related to HPS should contact either:


Dr. William Gahl

Dr. Thomas Markello

Mr Kevin O'Brien


On:   001-301-435-2824  or   001-301-451-1305.


Information about various ‘protocols’, and the ongoing Natural History Protocol, is available through the NIH clinical trials website: www.clinicaltrials.gov

Top of page

The symptoms of Pulmonary Fibrosis (PF) in HPS are shortness of breath and abnormal fatigue during exertion and exercise.  It is known to occur in three types of Hermansky-Pudlak Syndrome:  HPS-1, HPS-2, and HPS-4. It is a ‘restrictive’ and progressive lung disease.  The symptoms are typically seen during the 30’s but can start much earlier. During the early stages the rate at which the PF progresses varies. Some people experience a slow progression while others can experience rapid changes. However, the progression becomes more predictable during the later stages of the disease process.


It is important that you inform your doctor of the possibility of this lung disease if you have HPS. People with HPS may develop a chronic dry cough .  Many persons with HPS are initially misdiagnosed with asthma.  


Organ damage may occur if oxygen levels are severely low or continue to be low and uncorrected over a long time.

Above: Picture showing the equipment used for Pulmonary Function Tests (PFT’s). Left, A Gas analyser.  Right. A Barometric chamber.

Picture of equipment used for pulmonary function tests, a gas analyzer and a barometric chamber. Model of alveius and capillary showing their close association. diagram of an Alveolus and capillary showing the passage of oxygen and carbon dioxide across the thin walls.

The pulmonary fibrosis of Hermansky-Pudlak Syndrome