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Polysensitised patients, a problem for immunotherapy

Allergy vaccines are currently the only medical treatment able to alter the natural history of allergic rhinoconjunctivitis as they reduce the risk of progression to asthma and prevent further sensitisations; in addition, the benefits obtained persist for at least 5 years after their termination.1-3  However, in order for these vaccines to be effective, it is necessary to have a good representation at high concentrations of the allergens that are the true causes of the disease4. This task is often difficult as the health professional is usually dealing with patients who present positive skin tests to 4 or more different types of pollen. These are the so-called  polysensitised patients and, according to a multicentre study performed by the Aerobiology Committee of the Spanish Society of Allergology, they represent 80% of the patients living in the interior regions of Spain. Fig. 1

When a doctor is treating a hay fever patient who presents positive tests to 4 or 5 different types of pollen, treatment options are extremely limited, because:

  • A vaccine that contains 4 or 5 types of pollens cannot be prescribed, as the final concentration of each one would be very dilute and would therefore be ineffective.

  • The patient could be prescribed 5 different vaccines, but obviously this would be a very expensive and uncomfortable treatment and, most importantly, a number of these vaccines would probably not be effective.

  • It could be decided not to prescribe any vaccine and only to use symptomatic treatment (antihistamines and/or corticosteroids), but this would condemn the patient to having to take medication during all pollen seasons for most of the rest of his/her life.

Is there any solution?

Yes, because in the majority of these patients only 1 or perhaps 2 of the pollens that give positive results in the skin tests are the actual cause of most of the symptoms of hay fever. We call this pollen the "DOMINANT POLLEN" and we recognise that it can differ from one patient to another. Thus, when we are treating a polysensitised patient, our initial strategy is to attempt to identify whether a dominant pollen is actually present and, if this is the case, the following step is to try to create an immune therapy based purely and exclusively on this pollen.5-10

How can we find the dominant pollen?

One approach is to attempt to correlate the daily atmospheric pollen counts with the patient's daily symptoms count and with the result of the skin tests.

Is there a simple way to do this in daily practice?

Using a programme called Alercon, which performs these operations automatically.

How does Alercon work?

  • The doctor must install Alercon on the PC in the clinic. A programme called PrickFilm must also be installed in order to perform the skin tests.

  • Using Alercon, the doctor generates a small programme called "Electronic Symptoms Record Card" which is automatically sent to the patient by e-mail. Fig. 2

  • The patient installs this programme on his/her PC and, from that moment, the programme will ask the patient to fill in a rhinitis and/or asthma symptoms score and a score for the medication taken each day. It will only take the patient a few seconds to do this each day and, on closing the programme, the data are automatically sent to the doctor via the Internet.

  • When the doctor reviews the patient's data in Alercon, the symptom counts and the pollen counts (sent via the Internet) and the results of the skin tests (sent by PrickFilm) are entered automatically. As this is an automatic process, the system does not require any effort by the doctor and/or nurses to introduce these data. Fig.3

  • The programme automatically correlates the patient's symptom curves with the pollen curves, but only for those pollens that give a positive result in the skin tests.

Isn't it a nuisance for the patient to have to fill in the record card every day?

No, as the programme encourages the patient to fill it in in several ways:

  1. Each day it asks him/her to do it, automatically showing the day to be filled in.

  2. If the patient has had no symptoms on that day, all that has to be done is close the programme (a single click).

  3. If symptoms occurred, entering the score shouldn't take more than a few seconds.

  4. If the patient hasn't filled in the record card for more than a week, the doctor's Alercon automatically sends the patient a reminder by e-mail.

  5. Any correlation between the patient's symptoms curve and a specific type of pollen can be detected, thus identifying that patient's dominant pollen.

  6. The programme checks how high the pollen counts are, so as to maximise the preventive and therapeutic measures.

  7. It can show whether the vaccine has been effective by presenting the changes in the patient's reactivation threshold year by year.

What happens if the patient does not have a computer?

Alercon can work with paper record cards that are printed by the programme. The data must then be introduced into the computer using a conventional scanner. Obviously this does not take advantage of the automatic features of the electronic record cards.

What happens if pollen counts are not taken in my town?

In this case, the system cannot be used. Fortunately, however, most major European cities have pollen collectors. Before providing you with the Alercon programme, we will confirm that counts are available for your town/city.

Can you show me an example of how Alercon is used to prescribe immune therapy with a dominant pollen?

A 39-year-old woman was seen in our clinic in November 2005. She presented a 3 year history of symptoms of rhinoconjunctivitis during a large part of the year but was unable to state accurately in which months.

Tests were performed with a standard battery of allergens (PrickFilm), finding sensitisation to multiple pollens. Treatment was prescribed with oral antihistamines and nasal corticosteroids by spray for use as required, and she was sent an "ELECTRONIC SYMPTOMS RECORD CARD" by e-mail.

She returned to follow-up 6 months later and, during the visit, using Alercon, the doctor was able to observe in real time the symptoms that the patient had suffered between 1st January and 2nd July. The programme showed graphically that although there were 4 pollens which gave positive skin test results (Cupressaceae, Platanus, Olea and grasses), only the first showed a significant correlation with the patients symptoms (p<0.05). The doctor therefore decided to try immune therapy with Cupressus in this patient. Fig. 4

Can you show me an example of the use of Alercon to confirm the efficacy of immune therapy with a dominant pollen?

A 41-year old man who came to our clinic for symptoms of asthma during the spring. As with the previous patient, he was unable to state accurately the weeks or months of spring in which he was affected.

Tests were performed with a battery of aeroallergens (PrickFilm) and it was observed that he presented positive skin tests to Platanus and grass pollens. Treatment was prescribed with inhaled beta-2 agonists as required, and he was sent a SYMPTOMS RECORD CARD. 

Eight months later, at the next follow-up, it was observed that his asthma symptoms correlated with the Platanus count but not with the grasses (Fig. 5). On this basis, the patient was prescribed Platanus vaccine in addition to treatment with beta-2 agonist inhalers and inhaled corticosteroids for use when his asthma symptoms started. Naturally, the patient was encouraged to fill in his symptoms record card during the months of March-April.

In the successive follow-up visits, Alercon showed that his reactivation threshold (the minimum dose capable of causing the initial symptoms of asthma) has risen from 18 grains of Platanus/m3 (before the immune therapy) to 2,830 grains/m3 after 4 years of immune therapy. Furthermore, after the fifth year (the year in which the immune therapy was suspended) the patient had no further symptoms of asthma. Thanks to Alercon, it was possible to confirm that the vaccination strategy with his dominant pollen appears to have been successful. (Fig. 6)

What other uses does Alercon have?

The programme allows the symptom curves of two different groups of patients to be compared. This is of interest when we want to compare the response to a certain treatment between an active group and a control group. (Fig. 7)

Are there any other uses?

The programme can show the percentage of reactivations among patients sensitised to a given pollen. This datum is of interest in order to assess the intensity of the season in real time. (Fig. 8)

How can I acquire Alercon?

You can request it from our Centre (by e-mail or telephone: 91 561 55 94) or else from the software company Yellow, which will install it in your consulting rooms and show you how to use it.

How much does Alercon cost?

The price of the complete system (Alercon and PrickFilm) with installation is 1,100 euros. This price is for Madrid, Spain; for other cities, the software expert's travelling expnses are invoiced separately. Alercon has an annual licence fee of 299 euros in Madrid, which includes rental of the server and the pollen counts. For other towns/cities, the cost of the licence can vary slightly according to the prices charged for the counts.

More information?

www.yellow.ms/alercon

Do you want to see the Alercon video?

Please clic here

References:

  1. Möller C, Dreborg S, Ferdousi HA, Halken S, Høst A, Jacobsen L, Koivikko A, Koller DY, Niggemann B, Norberg LA, Urbanek R, Valovirta E, Wahn U. Pollen immunotherapy reduces the development of asthma in children with seasonal rhinoconjunctivitis (the PAT-study). J Allergy Clin Immunol. 2002 Feb;109(2):251-6.

  2. Des Roches A, Paradis L, Menardo JL, Bouges S, Daures JP, Bousquet J. Immunotherapy with a standardized Dermatophagoides pteronyssinus extract. VI. Specific immunotherapy prevents the onset of new sensitizations in children. J Allergy Clin Immunol 1997; 99: 450-453.

  3. Durham SR, Walker SM, Varga EM, Jacobson MR, O'Brien F, Noble W, Till SJ, Hamid QA, Nouri-Aria KT.  Long-term clinical efficacy of grass-pollen immunotherapy. N Engl J Med. 1999 Aug 12;341(7):468-75

  4. Van Metre T.E. et al. A comparison of immunotherapy schedules for injection treatment of ragweed pollen hay fever. J.Allergy Clin. Immunol. 1982;69:181-93

  5. Subiza J. Pollen counts as a tool for clinical research. In: Basomba A and Sastre J eds. Postgraduate courses and practical workshops; Syllabus. ECACI-95. 1995: 305-311

  6. Subiza et al. Seasonal asthma caused by airborne Platanus pollen. Clin Exp Allergy 1994;24:1123-1129

  7. Zapata C. Interpretación de los recuentos de pólenes (Alercón). Alergol Inmunol Clin 2003; 18 (Extraordinario Núm.3):50-56

  8. Subiza J, Barjau C, Narganes MJ, Bolea B. Alercón una nueva herramienta para el clínico. Alergol Inmunol Clin 2004

  9. Subiza J. Inmunoterapia con Platanus. Update in Allergy 2007

  10. Subiza J. A software to unify pollen counts, symptom counts and skin test results. Alergol J. 2006;15

  11. Subiza J. Alercon una nueva herramienta para el clínico en el manejo de la polinosis. In. Polinosis III (Valero A, Cadahia A eds) Barcelona. Meranini Lab. 2008

  12. Subiza J. Pollen counts as a tool for allergists: utility of the Alercon software  Workshop 18 - Indoor and Outdoor Aerobiology  EAACI. 2008

   

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