Systemic reactions occurring during immunotherapy with standardized pollen extracts

Specific immunotherapy with standardized extracts administered by a rush protocol can induce systemic reactions (SRs). A prospective study was conducted in 454 pollen-allergic patients (aged 5 to 62 years) (1) to compare the incidence of SRs during a 3-day rush or step protocol, (2) to determine if patients presenting pollen asthma or those allergic to multiple pollen species would have an increased incidence of SRs, and (3) to attempt to decrease SRs. According to their sensitivity, patients received standardized extracts of orchard grass, and/or Parietaria, and/or olive, and/or plane-tree pollen with the same allergenically bioequivalent maintenance dose. Patients 10 years of age and older received 2000 BU; patients younger than 10 years, 1000 BU. The occurrence of SRs was carefully monitored. The incidence of SRs per patient ranged from 2.6% to 31.1%. With the rush protocol, there was a significant decrease in SRs after premedication (p less than 0.015). Severe SRs decreased further when the increase in doses was stopped because large local reactions occurred. Step protocol was only slightly better tolerated than rush protocol. Bronchial adverse reactions occurred more often in patients presenting asthma during previous pollen seasons. No reaction started 45 minutes or later after the last injection.