Cytokine production in nickel-sensitized individuals analysed with enzyme-linked immunospot assay: possible implication for diagnosis.
BACKGROUND
Patients with suspected allergic contact dermatitis still have to undergo patch testing for a correct diagnosis. As this has several disadvantages there is a need for additional methods, preferentially those that can be performed in vitro. Objectives To investigate the possibility of diagnosing contact allergy to nickel (Ni2+) using the enzyme-linked immunospot (ELISpot) assay that allows the analysis of cytokines at a single-cell level in ex vivo activated peripheral blood mononuclear cells (PBMC).


METHODS
Eleven female patients and nine age- and sex-matched healthy volunteers participated in the study. All patients had a history of nickel allergy and a positive patch test reaction to NiSO4, while the controls' test was negative. PBMC were cultured in the presence or absence of NiCl2. Cell proliferation was measured with [3H]thymidine incorporation, and the number of cytokine-producing cells analysed with the ELISpot assay.


RESULTS
The proliferative response of PBMC to Ni2+, expressed as stimulation index, was significantly higher in the nickel-allergic patients than in the control group. Using the ELISpot assay, we found that PBMC from nickel-allergic individuals responded to Ni2+ with significantly greater production of interleukin (IL)-4, IL-5, IL-13 and interferon-gamma, but not IL-12, compared with the healthy controls. The number of IL-4- and IL-5-producing cells correlated with the number of IL-13-producing cells in the nickel-allergic patients, but Ni2+-induced PBMC proliferation did not correlate with the number of cytokine-producing cells for any of the cytokines tested.


CONCLUSIONS
Our results indicate that the ELISpot assay could be a tool in the discrimination between nickel-allergic and non-allergic individuals.
Occupational Dermatology, National Institute for Working Life, Stockholm, Sweden.
E
E
Jakobson
K
K
Masjedi
N
N
Ahlborg
L
L
Lundeberg
A-T
AT
Karlberg
A
A
Scheynius
D000328:Adult; D016022:Case-Control Studies; D018929:Cell Culture Techniques; D002455:Cell Division / Q000276:immunology; D016207:Cytokines / Q000096:biosynthesis*; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis* / Q000276:immunology; D004306:Dose-Response Relationship, Immunologic; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis; D007378:Interleukins / Q000096:biosynthesis; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008213:Lymphocyte Activation; D008875:Middle Aged; D009532:Nickel / Q000276:immunology*
D016207:Cytokines; D007378:Interleukins; D009532:Nickel; D007371:Interferon-gamma