w204 Sunflower

See also: Sunflower seed k84

IgE-mediated reactions

Sunflower pollen is a cause of asthma, allergic rhinitis and allergic conjunctivitis, and is an important occupational allergen in areas where Sunflower is grown. (1-5)

Sunflower pollen is a particularly significant aeroallergen in Korea. (6) In the Ukrainain area, Kievites pollinosis (seasonal fever) in most cases is caused by Ambrosia, Sunflower and Dandelion pollen. (6)

A study describes a 24-yr-old man who developed rhinitis and conjunctivitis over 5 years of occupational exposure to Sunflower pollens, and asthma which developed during the fifth year. All respiratory and ocular symptoms disappeared after he was removed from exposure, but he had a food-allergic reaction while he was eating honey containing 30% Sunflower pollens. (7)

Sunflower pollen has high allergenic potential, especially from close contact in occupational settings. In a study of 102 individuals working in a Sunflower processing plant, 23.5% were found to be sensitised to Sunflower pollen. (8)

Other reactions

In the case of 23 patients allergic to honey, including Sunflower honey, with symptoms ranging from itching in the oral mucosa to severe systemic symptoms to anaphylactic shock, proteins derived from secretions of pharyngeal and salivary glands of honeybee heads, along with pollen proteins, were found in the honey. The former were responsible for causing specific allergic reactions to honey. (8) Some allergic symptoms may be due to the actual Sunflower pollen present in the honey. (9,10)

Although allergic symptoms and anaphylaxis can occur to Sunflower seeds (11) (see: Sunflower seed k84), occupational asthma may result from contact with Sunflower seed dust. This needs to be differentiated from Sunflower pollen, which contains different allergens. (12)

Allergen Exposure

Four allergens have been detected in Sunflower pollen, with molecular masses of 32, 24, 55, and 55 kDa. Cross-reactivity among the four allergens was very high, and each allergen recognised IgE in a high proportion of patients sensitised to Sunflower pollen. (13)

Thirteen Sunflower-allergic patients with allergen-specific IgE values > or = 0.7 kUA/l showed 2 IgE-binding fractions at 34.0 and 42.8 kD in 65% of sera and 3 IgE-binding fractions at pI 4.9, 9.6 and 10.2 in 54% of sera. A 34-kD major allergen was purified. (1)

The following allergens have been characterised:

• Hel a 1. (1, 14, 15)
• Hel a 2, a profilin. ( 15-22)

Sunflower seed contains a 2S Albumin storage protein allergen, but this has not been detected in Sunflower pollen.

Cross Reactivity

An extensive cross-reactivity among the different individual species of the genus could be expected, as well as to a certain degree among members of the family Asteraceae (Compositae). (23)

Cross-reactivity has been demonstrated, by allergen-specific IgE and immunoblotting inhibition experiments, between Sunflower and other Asteraceae pollens: Mugwort, Marguerite, Dandelion, Golden Rod, and Short Ragweed. Mugwort pollen exhibited the greatest degree of cross-reactivity with Sunflower pollen, whereas at the other end of the spectrum, Short Ragweed showed less cross-reactivity. (24)

The major allergen Hel a 1 shows cross-reactivity with other aster members. (25)

Cross-reactivity with other non-Asteraceae plants can be expected, due to the presence of the panallergen profilin, Hel a 2. (16, 26, 27) Sunflower profilin is cross-reactive with profilins from Short ragweed, Mugwort, Olive, and Annual mercury. (25)

Sunflower pollen does not significantly cross-react with Sunflower seed. (28)

Last reviewed: May 2022