Measurement of IgE antibodies against purified grass pollen allergens (Lol p 1, 2, 3 and 5) during immunotherapy.
BACKGROUND
IgE titres tend to rise early after the start of immunotherapy, followed by a decline to pre-immunotherapy levels or lower.


OBJECTIVE
We were interested to know whether the early increase in IgE antibodies includes new specificities of IgE, and whether these responses persist.


METHODS
Sera of 64 patients undergoing grass pollen immunotherapy were tested for IgE against four purified grass pollen allergens: Lol p 1, 2, 3, and 5. At least two serum samples were taken, one before the start of therapy and one between 5 and 18 months after the first immunization (mean: 10 months).


RESULTS
The mean IgE responses to Lol p 1, 2 and 3 showed a moderate but not significant increase. In contrast, the mean IgE response to Lol p 5 showed a significant decrease of > 30%. IgE against total Lohum perenne pollen extract moderately increased (> 20%), showing that a RAST for total pollen is not always indicative for the development of IgE against its major allergens. For > 40% of the patients it was found that IgE against one or more of the four allergens increased, while IgE against the remaining allergen(s) decreased. For 10 sera the ratio of IgE titres against at least two allergens changed by at least a factor of 5. The changes in specific IgE also included conversions from negative (< 0.1 RU) to positive (0.6 to 5.0 RU) for five patients. For two patients, the induction of these 'new' IgE antibodies against major allergens was shown to result in a response that was persistent over several years.


CONCLUSIONS
Although active induction of new IgE specificities by immunotherapy was not really proven, the observations in this study indicate that monitoring of IgE against purified (major) allergens is necessary to evaluate changes in specific IgE in a reliable way.
Van Ree
R
R
Central Laboratory of The Netherlands Red Cross Blood Transfusion Service, Amsterdam, The Netherlands.
Van Leeuwen
W A
WA
Dieges
P H
PH
Van Wijk
R G
RG
De Jong
N
N
Brewczyski
P Z
PZ
Kroon
A M
AM
Schilte
P P
PP
Tan
K Y
KY
Simon-Licht
I F
IF
Roberts
A M
AM
Stapel
S O
SO
Aalberse
R C
RC
D000485:Allergens / Q000276:immunology*; D052179:Antigens, Plant; D006801:Humans; D015151:Immunoblotting; D007073:Immunoglobulin E / Q000032:analysis*; D007167:Immunotherapy; D008129:Lolium / Q000276:immunology*; D010940:Plant Proteins / Q000276:immunology; D011058:Pollen / Q000276:immunology*; D011852:Radioallergosorbent Test; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology* / Q000628:therapy
D000485:Allergens; D052179:Antigens, Plant; C042814:Lol p I protein, Lolium perenne; C056754:Lol p II protein, Lolium perenne; C062329:Lol p III protein, Lolium perenne; C084941:Lol p V protein, Lolium perenne; D010940:Plant Proteins; D007073:Immunoglobulin E