Cytokine production, lymphocyte proliferation and T-cell receptor Vbeta expression in primary peripheral blood mononuclear cell cultures from nickel-allergic individuals.

BACKGROUND: Clinical history and patch test constitute the two cornerstones in the diagnosis of nickel (Ni) allergy. Due to technical and interpretative limits of the patch test, the in vitro lymphocyte transformation test (LTT) has been developed for confirming contact allergy; however, most studies show an overlap in lymphocyte proliferation between Ni-allergic and nonallergic subjects using the LTT. The aim of this study was to see if the secretion of cytokines, especially interleukin (IL)-10 and IL-17, or the use of T-cell receptor (TCR) Vbeta families in Ni-stimulated primary peripheral blood mononuclear cell (PBMC) cultures might be more useful for discriminating between allergic and nonallergic subjects. METHODS: Ni(2+)-stimulated primary PBMC cultures derived from female subjects diagnosed as Ni-allergic (n = 5) or nonallergic (n = 5) on the basis of a positive or negative patch test were assessed for cell proliferation by tritiated thymidine incorporation and for production of interferon-gamma, IL-4, IL-10 and IL-17 in the culture supernatant by ELISA. The immunophenotype and TCR-Vbeta family affiliation of the Ni(2+)-induced lymphoblasts were determined by flow cytometry. RESULTS: Lymphocytes from Ni-allergic individuals challenged with a high and a low concentration of Ni showed significantly higher cell proliferation than lymphocytes from nonallergic individuals, but all subjects showed a positive LTT result (stimulation index >2). We found a significantly higher release of IL-10 in Ni(2+)-treated cultures from Ni-allergic compared with nonallergic subjects that provided better separation between individuals in the two groups than did lymphocyte proliferation. The proliferating lymphoblasts were predominantly CD4+, and in 2 of the 5 Ni-allergic subjects, but in none of the 5 nonallergic subjects, the CD4+ lymphoblasts showed a dominance of TCR-Vbeta17. CONCLUSIONS: Determination of IL-10 production in primary PBMC cultures is a potentially promising in vitro method for discrimination of Ni allergy in females, as compared with cell proliferation.

Characterization of primary recall in vitro lymphocyte responses to bacampicillin in allergic subjects.

BACKGROUND: Antigen-specific cell lines or clones are often used as models of drug-specific allergy. However, cloning procedures are time consuming, and the repeated antigen stimulation cycles as well as the addition of various growth enhancers may affect the in vivo relevance of these systems. OBJECTIVE: Using bacampicillin-allergic subjects, we wanted to investigate the applicability of primary recall in vitro lymphocyte responses to characterize type I and type IV allergy. The sensitivity and specificity of LTT (Lymphocyte transformation test), when used as an in vitro diagnostic tool, were also assessed. METHODS: A total of 39 patients with symptoms of type I (rhinitis) or type IV (allergic contact dermatitis, ACD) allergy following occupational exposure to bacampicillin, were included. Ten individuals without penicillin allergy or occupational exposure to bacampicillin served as controls. All subjects were LTT tested. Four patients with rhinitis and two patients with ACD were available for studying the immunophenotype and the TCR-Vbeta repertoire of bacampicillin induced lymphoblasts as well as the cytokine profiles and expression of the activation markers CD23 and CD134 in primary PBMC cultures. RESULTS: LTT was positive in 87% and at least one of the skin tests was positive in 85% of the patients with allergic symptoms. 69% of the patients with type I allergies were patch test-positive. Results from LTT and skin test correlated in 87% of the cases. The combined sensitivity of LTT and skin tests was 92%. The specificity of LTT was 90% in healthy controls. Bacampicillin induced lymphoblasts were mainly CD4 + in both ACD and rhinitis patients. The TCR-Vbeta profiles of the predominant CD4 + lymphoblasts were heterogeneous with individual skewing towards Vbeta2, Vbeta3, Vbeta5.1 and/or Vbeta14. An increased expression of IFNgamma was detected in bacampicillin treated PBMC cultures from the ACD but not from rhinitis patients. IL-5 was detected in bacampicillin exposed PBMC cultures from all patients but not from healthy controls. This Th2 environment could also be verified by CD23 and CD134 expression. CONCLUSION: LTT and skin tests are equally sensitive in identifying bacampicillin allergic subjects. When the two tests are combined, the sensitivity increases. The patch test is useful not only for detection of type IV but also for the identification of type I allergies. When using primary PBMC cultures, IFNgamma is the most suitable cytokine to discriminate between type I and type IV allergy. IL-5 can possibly be used as a general marker for bacampicillin induced allergy. Thus, primary cell cultures may be considered as an alternative to T-cell lines or clones for the study of drug induced allergy.