Methods: Freeze dried IHRs were developed for the allergenic extracts of Dermatophagoides pteronyssinus (VALERGEN-DP), Dermatophagoides siboney (VALERGEN-DS) and Blomia tropicalis (VALERGEN-BT) House Dust mite vaccines (BIOCEN, Cuba). The references were characterized regarding in-vivo (Prick-Test) and in vitro allergenic activity (IgE ELISA), protein and allergen composition (SDS-PAGE and Western Blotting, respectively). The activity is expressed in Biological Units (BU), which are related to the skin reaction size produced by Histamine 10mg/mL.
Results: The allergenic potency for Blomia tropicalis was 115600 UB (CI95%: 69900-191200); for Dermatophagoides pteronyssinus: 81800 UB (CI95%: 64740 - 103450), and for Dermatophagoides siboney: 128700 UB (CI95%: 111920 - 148080). Replacement of old IHR batches by new ones has been accomplished by both, in-vivo and in-vitro comparative tests, using the parallel line statistical approach. Stability was assessed by means of an accelerated study at 4 temperatures (-70°, 4°C, 37°C and 60°C) during one year (0, 3, 6, 9 and 12 months).
Conclusions: The results predicted the stability at -70°C for more than 10 years. At 60°C, despite a change in cake appearance, the allergenic activity was kept during the first 6 months within the specified limits. The on-going stability of the first IHR batches was confirmed by tests during 10 years.