In-vitro-leukotrienproduktion gemessen im CAST-ELISA über einen beobachtungszeitraum von 5 monaten

Background: The Cellular Antigen Stimulation Test (CAST; Bühlmann Laboratory AG, CH) is a diagnostic tool to quantify the In-vitro-Cystinly-Leukotriene production (= CysLT: LTC₄, LTD₄, LTE₄) from isolated leukocytes. The leukotrienes are responsible for the early inflammatory response with mucosal edema and smooth muscle contraction, clinically resulting in allergic diseases such as asthma and rhinitis. Qbjective: To evaluate seasonal effects of the in-vitro CysLT release. Population and methods: Blood samples were taken monthly from 9 children and young adults (7-18 years; 3 without allergic sensitization, 2 with sensitization to house dust mite and 4 with grasspollen sensitization) from February to June. Leukocytes were separated using Dextran sedimentation and stimulated either with medium alone (negative control), or with an Anti-IgE-receptor-antibody (Anti-IgE-rAK; 0.5 μg/mL; positive control) or with grasspollen allergen (Six-Gras-MIX, GX1, 20 ng/ml). The CysLT release (LTC₄, LTD₄, LTE₄) was quantified using ELISA technique (CAST-ELISA, Bühlmann Laboratory AG, Schönenbuch, Switzerland). Results: After stimulation with Anti-IgE-rAK in-vitro CysLT-production increased from March (range: 1163 und 6187 pg/ml) to May (range: 2048 and 7620 pg/ml; median increase 63%; range: 35%-114%; p=0.012). In response to grasspollen allergen we observed a similar increase from March (158 und 208 pg/ml) to May (337 und 7057 pg/ml; median increase 49.9%; range: 38-133%;p=0.004). The median in-vitro CysLT-concentrations after stimulation with grasspollen was 6137 pg/ml (range: 4249-7620) in grass-pollen sensitized persons and 2130 pg/ml (2048-5421) in persons, who are not allergic to grasspollen. Conclusion: We observed a significant higher in-vitro CysLT production in May compared to March. Seasonal effects of the CysLT release must be considered performing longitudinal studies.