The lymphoproliferative response to enzymatically digested gelatin in subjects with gelatin hypersensitivity.
BACKGROUND
This study was designed to evaluate the immunogenic characteristics of enzymatically digested gelatin, 'FreAlagin', employing the lymphoproliferative response in subjects with gelatin hypersensitivity. Our purpose was to assess the response of primed lymphocytes to the newly developed FreAlagin and compare it to the response to conventional gelatin.


METHODS
A gelatin-specific lymphocyte proliferation test (LPT) was performed in 110 children with adverse reactions to gelatin-containing vaccines, who showed positive gelatin-specific cell-mediated immunity and were thus diagnosed as having gelatin hypersensitivity. Gelatin-specific IgE was measured in all subjects. The antigenic activity of FreAlagin to lymphocytes was compared with that of conventional bovine gelatin. Positive and negative control specimens were obtained from the patients with anaphylaxis and from subjects inoculated with gelatin-free vaccine who showed no adverse reactions in order to establish the fluorometric ELISA system to determine IgE antibody to gelatin and LPT.


RESULTS
The lymphocyte activity against FreAlagin was much less than that to Wako gelatin and more than half of the subjects who reacted positively to Wako gelatin had a negative LPT to FreAlagin. Although 47% of the subjects had positive LPTs to FreAlagin, all but two still had lower SIs to FreAlagin compared with Wako gelatin.


CONCLUSIONS
We conclude that the antigenic activity of FreAlagin as measured by the cell-mediated immune response is significantly less than that of conventional bovine gelatin. However, it is still necessary to perform clinical trials to show a reduced or absent clinical reactivity to FreAlagin in sensitized patients to conventional gelatin.
Kumagai
T
T
Paediatric Allergy and Infectious Diseases Society of Sapporo, Sapporo, Hokkaido, Japan.
Nakayama
T
T
Kamada
M
M
Igarashi
C
C
Yuri
K
K
Furukawa
H
H
Wagatuma
K
K
Tsutsumi
H
H
Chiba
S
S
Kojima
H
H
Saito
A
A
Okui
T
T
Yano
S
S
D000818:Animals; D002417:Cattle; D002675:Child, Preschool; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000009:adverse effects; D005260:Female; D005780:Gelatin / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D006967:Hypersensitivity / Q000209:etiology*; D007073:Immunoglobulin E / Q000097:blood; D007223:Infant; D008213:Lymphocyte Activation; D008297:Male
D015721:Diphtheria-Tetanus-Pertussis Vaccine; D007073:Immunoglobulin E; D005780:Gelatin