HUMAN
SENSITIZATION TO PROSOPIS JULIFLORA ANTIGEN
IN SAUDI ARABIA
Al-Frayh,
Abdulrahman
College of Medicine & King Khalid University
Hospital, Riyadh, Saudi Arabia
Objectives: Allergenicity to Prosopis
juliflora pollen antigen has been reported from only a few countries,
including the US, South Africa, India and Kuwait. In some parts of Saudi
Arabia, species of Prosopis have
been introduced by the millions of roadside ornamentation. There appear to
be four flowering seasons during which pollen grains float in all
directions. However, the role of Prosopis
pollen as the sensitizing and/or triggering agent of allergic asthma
and/or rhinitis in the Kingdom has never been evaluated.
Methods: A total of
473 allergic patients suffering from bronchial asthma in four different
geographical regions (Abha, Qassim, Hofuf and Gizan), and attending allergy
clinics and chest disease centers of university and Ministry of Health
hospitals in the region were tested for immediate hypersensitivity reaction
to Prosopis juliflora allergens.
Airborne pollen grains at one center were also studied for one full year,
using volumetric sampling techniques.
Results: 76.1%
patients in Qassim, 37.5% in Gizan, 29% in Abha and 11% in Hofuf reacted
positively to Prosopis antigen.
Multiple sensitivities to other pollen antigens were detected in all
patients. The level of airborne Prosopis
pollen detected in Gizan exceeded 90 grains m-3 of air.
Conclusion: In view of the documented evidence of
Prosopis-involved allergenicity,
the role of Prosopis pollen as a
sensitizing factor in Saudi Arabia has been confirmed. However, the cause
of elicitation of symptoms in many multiple sensitive patients, together
with the question of cross-reactivities, needs thorough and detailed
investigation. In vitro
confirmation of all positive results is also required to incriminate Prosopis as one of the major
allergens in parts of Saudi Arabia.
Supported by a grant from King
Abdulaziz City for Science & Technology (KACST A.R. 17-65)