CD4+ cells proliferate after peanut-extract-specific and CD8+ cells proliferate after polyclonal stimulation of PBMC of children with atopic dermatitis.
BACKGROUND
Few studies describe in vitro food-allergen induced proliferative responses and cytokine production of PBMC of children with atopic dermatitis. This is especially true for peanut-allergen.


OBJECTIVE
To analyse the specificity of the T cell in proliferative responses, in children with atopic dermatitis with or without peanut allergy and healthy age-matched children.


METHODS
Proliferative responses were measured by [3H]-thymidine incorporation and by expression of the intracellular Ki67-antigen using flow cytometry after antigen-specific stimulation of PBMC with peanut-extract (day 7) or polyclonal stimulation with Phorbol-12myristate-13acetate and Ca-ionophore (day 3). Cytokine mRNA (Interferon-gamma (IFNgamma), IL-4) was detected by semiquantitative RT-PCR. Cytokine production (IL-4, IFNgamma) was measured by ELISA.


RESULTS
Peanut-extract induced proliferative responses of PBMC from children with atopic dermatitis and peanut allergy (AD+PA+) were significantly higher as compared with the other groups studied. Ki67-antigen double staining revealed that 80-100% of the proliferating cells were CD4+. These proliferative responses correlated significantly with the increase in IL-4 mRNA expression after peanut-extract specific stimulation. After polyclonal stimulation, however, CD8+ cells preferentially proliferated. The degree of proliferation after polyclonal stimulation correlated inversely with the ratio of IL-4/IFNgamma production.


CONCLUSIONS
The principal responding population of T cells in proliferative responses is different after peanut-extract specific and polyclonal stimulation of PBMC from AD+PA+ patients. Furthermore, we found indirect evidence that the PBMC fraction of AD+PA+ children contains increased frequencies of peanut-specific T helper-2 cells.
Laan
M P
MP
Department of Immunology, Erasmus University Rotterdam, The Netherlands.
Tibbe
G J
GJ
Oranje
A P
AP
Bosmans
E P
EP
Neijens
H J
HJ
Savelkoul
H F
HF
D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology*; D010367:Arachis / Q000009:adverse effects / Q000737:chemistry; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology* / Q000276:immunology / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology* / Q000276:immunology / Q000378:metabolism; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D003876:Dermatitis, Atopic / Q000150:complications / Q000276:immunology*; D000939:Epitopes; D005260:Female; D005512:Food Hypersensitivity / Q000150:complications / Q000276:immunology; D015870:Gene Expression / Q000235:genetics; D006801:Humans; D007223:Infant; D019394:Ki-67 Antigen / Q000032:analysis / Q000187:drug effects; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D008213:Lymphocyte Activation / Q000187:drug effects* / Q000235:genetics; D008297:Male; D010641:Phenotype; D010936:Plant Extracts / Q000276:immunology / Q000494:pharmacology*
D000911:Antibodies, Monoclonal; D016207:Cytokines; D000939:Epitopes; D019394:Ki-67 Antigen; D010936:Plant Extracts