Studies on allergen and allergoid preparations from purified timothy (Phleum pratense) pollen extracts. III. Comparative investigations by skin prick tests and nasal provocation tests.

The allergenic activities of allergen (GEN) and allergoid (GOID) preparations from partially purified timothy pollen extract were investigated in quantitative skin prick tests and nasal provocation tests. In skin prick test GOID yielded significantly less activity than GEN. Approximately 90 times more protein of GOID than of GEN was necessary to elicit wheals of the same mean size as 1 mg/ml histamine control solution (1 HEP). In nasal provocation the patients seemed to react differently with respect to their nasal sensitivity to GOID. One group of patients showed equal sensitivity to GOID and GEN, whereas the second group showed higher thresholds to GOID. These differences in nasal sensitivity to GOID could be of practical value to predict the optimal dosage schedule for the treatment of patients with GOID.