Severe allergy to sharon fruit caused by birch pollen.
BACKGROUND
Allergy to sharon fruit (persimmon) has been only rarely reported. Cross-reactivity with pollen (profilin and Bet v 6) appeared to be involved, but Bet v 1 has not been implicated previously.


OBJECTIVE
It is our aim to identify whether Bet v 1 sensitization is linked to sharon fruit allergy.


METHODS
Two patients with a reaction upon first exposure to sharon fruit were included in the study, as well as 7 patients with birch-pollen-related apple allergy. Sensitivity was assessed by skin prick testing (SPT), a radio-allergosorbent test (RAST) and immunoblotting. RAST analysis was performed for Bet v 1, Bet v 2 and Bet v 6. Cross-reactivity was evaluated by RAST and immunoblot inhibitions. Biological activity of IgE was measured by basophil histamine release. Sharon fruit allergy was evaluated by double-blind placebo-controlled food challenge (DBPCFC) or open challenge (OC).


RESULTS
Both sharon-fruit-allergic patients demonstrated positive reactions in the RAST (8.6 and 6.2 IU/ml, respectively) and SPT (wheal area 37 and 36 mm2). Sharon fruit allergy was confirmed by DBPCFC in 1 patient. The second patient refused a challenge because of the severe initial reaction. Sera from both patients were reactive to Bet v 1 and Bet v 6, which was cross-reactive with sharon fruit by inhibition assays. The patient with the severest reactions was reactive to profilin on immunoblotting. However, profilin did not induce significant histamine release, nor did Bet v 6. Bet v 1 induce approximately 60% histamine release. An OC with sharon fruit in 7 patients allergic to birch pollen and apple, who had not eaten sharon fruit previously, was positive in 6/7 cases.


CONCLUSIONS
Birch-pollen-related allergy to sharon fruit is mediated by the known cross-reactive pollen allergens including Bet v 1 and may become more of a problem should sharon fruit consumption increase.
Bolhaar
S T H P
ST
Department of Dermatology/Allergology, University Medical Center Utrecht, Utrecht, The Netherlands. S.Bolhaar@azu.nl
van Ree
R
R
Ma
Y
Y
Bruijnzeel-Koomen
C A F M
CA
Vieths
S
S
Hoffmann-Sommergruber
K
K
Knulst
A C
AC
Zuidmeer
L
L
D000328:Adult; D029662:Betula / Q000276:immunology*; D003285:Contractile Proteins / Q000276:immunology*; D003429:Cross Reactions; D029788:Diospyros / Q000009:adverse effects* / Q000276:immunology*; D004311:Double-Blind Method; D005260:Female; D005512:Food Hypersensitivity / Q000097:blood / Q000276:immunology*; D005638:Fruit / Q000009:adverse effects / Q000276:immunology; D006636:Histamine Release; D006801:Humans; D015151:Immunoblotting; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D008297:Male; D008840:Microfilament Proteins / Q000276:immunology*; D009426:Netherlands; D011058:Pollen / Q000276:immunology*; D051304:Profilins; D011852:Radioallergosorbent Test; D012882:Skin Tests
D003285:Contractile Proteins; D008840:Microfilament Proteins; D051304:Profilins; D007073:Immunoglobulin E