Aerobiological studies and low allerginicity of date-palm pollen in the UAE

Date-Palm trees (Phoenix dactylifera L.) are the most abundant crop in the United Arab Emirates (UAE). The aim of this work was to conduct aerobiological studies on Date-Palm pollens and correlate that to allergenicity. An aerobiological survey was performed at three Date-Palm farms. Radioallergosorbent test (RAST) and total IgE were performed on 477 airborne allergic patients. Small mass bioactive constituents were fractionated and isolated by HPLC. Aerobiological studies demonstrate the short distance traveled by the Date-Palm pollens. Pollen counts were about 800 counts/m3 within the Date-Palm farms and decreased by about 80% just 100 meters away from the farm area and almost diminished beyond 200 meters. Scanning electron micrograph of the pollen grain showed a uniform smooth texture with an oval shape. Out of 477 airborne allergic patients having high total IgE counts, only 2.3% gave positive RAST for Date-Palm pollen. HPLC chromatogram separated the non-protein content of Date-Palm pollen into four distinct peak fractions. The present study revealed that Date-Palm pollens have a low allergic effect on airborne allergic people. The short distance traveled by the pollen, the smooth texture, the short pollination period and low molecular weight biomolecule content may be the main factors behind the low allergenicity.