PBMCs from both atopic asthmatic and nonatopic children show a TH2 cytokine response to house dust mite allergen.
BACKGROUND
The hypothesis that in atopic diseases the T-helper response is skewed toward a T(H)2-type cytokine response was based on studies with mitogen stimulation, T-cell clones, or both.


OBJECTIVE
Using primary cultures, we investigated (1) whether atopic asthmatic patients have a T(H)2 response and nonatopic subjects have a T(H)1 response to allergen and (2) whether atopic patients have a decreased ability to mount T(H)1 immune responses to mycobacterial antigens.


METHODS
The responses of PBMCs to allergen (house dust mite [HDM]) or purified protein derivative of Mycobacterium tuberculosis (PPD) stimulation from 10 severely and 14 moderately asthmatic patients (all allergic to HDM) were compared with those of 17 nonatopic healthy black (Xhosa) children.


RESULTS
HDM-stimulated proliferation, IL-5 release, and the IL-5/IFN-gamma ratio were significantly increased in subjects with atopic asthma, whereas IFN-gamma release was not significantly different. IL-4 levels were below the level of detection. PPD-stimulated proliferation, IL-5 release, IFN-gamma release, and the IL-5/IFN-gamma ratio were not significantly different among the groups. Each group had a significantly higher IL-5/IFN-gamma ratio in response to HDM than to PPD (a T(H)1 stimulus).


CONCLUSIONS
Our study, which used primary cultures to investigate the hypothesis that nonatopic subjects have a T(H)1 response to allergens, indicates that HDM stimulates a T(H)2 cytokine response in both atopic and nonatopic subjects but that the response is enhanced in atopic patients. Our results with PPD suggest that normal and atopic asthmatic subjects can have a T(H)1 cytokine response to mycobacteria, but there is a subgroup of atopic subjects that have a T(H)2 response.
Nurse
B
B
Allergology Unit, Department of Immunology, Groote Schuur Hospital and University of Cape Town, South Africa.
Puterman
A S
AS
Haus
M
M
Berman
D
D
Weinberg
E G
EG
Potter
P C
PC
D000485:Allergens / Q000276:immunology*; D000818:Animals; D001249:Asthma / Q000276:immunology*; D002478:Cells, Cultured; D002648:Child; D016207:Cytokines / Q000096:biosynthesis*; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis; D015848:Interleukin-5 / Q000096:biosynthesis; D008925:Mites / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology / Q000378:metabolism*; D014374:Tuberculin Test
D000485:Allergens; D016207:Cytokines; D015848:Interleukin-5; D015847:Interleukin-4; D007371:Interferon-gamma