Oral nickel exposure may induce Type I hypersensitivity reaction in nickel-sensitized subjects

• Contact dermatitis is a well-described clinical presentation of Type IV hypersensitivity induced by nickel.
• Little is known about the role of nickel sensitivity in other allergic clinical presentations.
• We showed the relation between nickel sensitivity and systemic allergic manifestations.
• The skin tests and the stimulated cytokine profile suggest the possible role of Type I hypersensitivity due to nickel.

BackgroundLittle is known about the clinical and immunological changes in the nickel allergic patients with systemic symptoms. We aimed to evaluate T helper cell responses of patients with different clinical presentations due to nickel.MethodsPatients having various allergic symptoms and positive patch test results to nickel and 20 controls underwent skin prick tests with nickel. IL-10, IL-4, IL-5 and IFN-gamma were measured in the culture supernatants of PBMC stimulated by nickel during lymphocyte proliferation test (LTT).Results69 patients (56 female, mean age: 49.2 ± 13.1), 97% having nickel containing dental devices and 20 controls (8 female, mean age 34.9 ± 12.06) were evaluated. Skin prick tests with nickel were positive in 70% of the patients (p < 0.001), being significantly higher in the patients with urticaria/angioedema (p = 0.02). The LTT stimulation index (p < 0.0001), IL-4 (p = 0.002), IFN-gamma (p = 0.01), IL-5 (p = 0.04) and IL-10 (p = 0.003) were higher in the patient group. LTT stimulation index, IL-4 and IL-10 were significantly elevated in patients having urticaria, angioedema and respiratory symptoms when compared to those who had only oral symptoms or systemic dermatitis (p = 0.004, p = 0.002 and p = 0.01, respectively).ConclusionThis study suggests the presence of Type I hypersensitivity in addition to a Type IV immune reaction in patients with chronic systemic symptoms related to nickel. Nickel containing dental alloys and oral nickel intake seem to trigger systemic symptoms in previously nickel sensitized patients.