Pine Pollen as a Potential Airborne Allergen

The rise in hay fever cases worldwide prompts the International Association of Aerobiology (IAA) to publish the International Aerobiology Newsletter twice a year, announcing international congresses and educational programs for professionals. The Pinaceae family, comprising 650 species, is known to have mildly allergenic pollen. This pollen is characterized by its large size, high volatility due to air sacs, unique palymorphology, and high pollen production. It is susceptible to climate change and environmental pollution, which is reflected in changing timing of plant phenology and pollen production, allergenic properties, and the emergence of teratomorphs. The purpose is to study the concentration of Pinaceae pollen in the air and their integrative contribution to the aerobiological spectrum of Karakol as potential pollen allergens. Airborne pollen belonging to the Pinaceae family was collected and identified during a 3-year (2015–2017) aerobiological monitoring program in Karakol, Kyrgyzstan, using a Lanzoni VPPS 2000 trap. During the study period, interannual variations in the total annual pollen index, as well as the dates of the beginning, peak, and end of the pollen season, were recorded. Season length, peak day dating, and maximum daily pollen concentrations varied significantly between years due to climate change and the peculiarities of pollen production in different years. Pinaceae pollen dominated the pollen spectrum of trees and shrubs, accounting for 68–75% of the annual total pollen count. It circulated in the air of Karakol throughout all study seasons, lasting from 108 to 130 days. Daily peaks in Pinus pollen concentration were recorded in May–June, reaching a maximum of 4,259 pollen grains/cm3. The average annual concentration over the 3-year study period was 10,555.3 pollen grains/cm3. The highest annual Pinus pollen level was reached in 2016 (16,002 pollen grains/cm3), and the lowest in the extremely hot year of 2015 (1,220 pollen grains/cm3). Thus, pine has a relatively short pollen season compared to pollen of leading aeroallergens (e.g., cereals – 171 days), but with a high pollen concentration. The high concentration of Pinus pollen in the air of Karakol and its cross-reactivity with other plant pollen allow Pinaceae pollen to be classified as potentially allergenic. The large pollen size and low protein content protected by a waxy coat are the main reasons for its low allergenicity. Under the influence of adverse anthropogenic factors and climate change, the waxy coat is destroyed, opening up allergenic proteins and allowing them to more easily penetrate mucous membranes, triggering allergic reactions.