Laboratory diagnosis of allergic contact dermatitis to nickel: The benefits of combining the highly sensitive ELISPOT assay with modified cell culture conditions

Introduction: One of the obstacles in developing a reliable in vitro method for the diagnosis of allergic contact dermatitis (ACD) is low sensitivity of the detection assays. This may be overcome by enhancing allergen-specific response of lymphocytes and/or applying more sensitive assays. In the present study, we have combined both approaches.

Aims: To establish culture conditions that enhance nickel-specific secretion of cytokines by lymphocytes, as measured with ELISPOT.

Material and methods: Leucocytes of 14 patients with ACD to nickel and 14 controls were analysed for their response to nickel (Ni) in the presence of various combinations of IL-7 (anti-apoptotic cytokine), IL-4 (Th2/Tc2 enhancer) and IL-12 (Th1/Tc1 enhancer). Production of IFN-gamma, IL-2, IL-5, IL-13 was measured using the highly sensitive Enzyme-Linked Immunospot (ELISPOT) Assay.

Results: Without cytokines added, the median number of cells secreting IL-5 in response to Ni was 10 per million in ACD patients and 0 in controls (p=0.007). In the presence of IL-7 and IL-4, the numbers were respectively 140 and 15 (p=0.001). A similar pattern was found for IL-13. The median number of cells secreting IL-2 in response to Ni was 67.5 in ACD and 7.5 in controls (p=0.001), with no influence of added cytokines. As for IFN-gamma, differences between ACD patients and controls remained non-significant in all conditions tested.

Conclusions: Testing nickel-specific response of Th2/Tc2 lymphocytes cultured in the presence of IL-7 and IL-4 with the use of ELISPOT assay, offers a relevant progress in the in vitro detection of contact allergy to nickel.

Related articles:

1. Spiewak R, Moed H, von Blomberg BME, Bruynzeel DP, Scheper RJ, Gibbs S, Rustemeyer T. Allergic contact dermatitis to nickel: Modified in vitro test protocols for better detection of allergen-specific response. Contact Dermatitis 2007, 56 (2): 63-69.
2. Spiewak R. Patch testing for contact allergy and allergic contact dermatitis. Open Allergy J 2008, 1: 42-51.
3. Spiewak R. Atopy and contact hypersensitivity: a reassessment of the relationship using objective measures. Ann Allergy Asthma Immunol 2005, 95 (1): 61-65.
4. Spiewak R. Allergic contact dermatitis in childhood - a review and meta-analysis. Allergologie 2002, 25 (7): 374-381.
5. Spiewak R, Pietowska J, Curzytek K. Nickel: a unique allergen - from molecular structure to European legislation. Expert Rev Clin Immunol 2007, 3 (6): 851-859.

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