title: Pollen specific immunotherapy is not a risk factor for de novo sensitization to cross-reacting allergens in monosensitized subjects.
abstract: BACKGROUND
  Some studies have suggested that specific immunotherapy (SIT) may cause de novo sensitization to allergenic proteins to which patients were not previously allergic. This event might theoretically involve cross-reacting pollen allergens, such as profilin or polcalcins, posing a risk of SIT-induced polysensitization to pollens in patients who were originally monosensitized.
  
  
  OBJECTIVE
  The aim of this study was to assess whether injection SIT with commercial pollen extract represents a risk factor for the de novo development of sensitization to different pollens in monosensitized patients.
  
  
  METHODS
  The study involved 142 subjects diagnosed as being monosensitized to a single pollen: 64 patients who were administered a 3-year course of injection SIT and 78 controls. Subjects underwent control skin prick tests (SPT) with a series of 8 seasonal airborne allergens at least 3 years after the first visit. Patients with 5 or more new sensitivities on SPT were considered to be de novo polysensitized.
  
  
  RESULTS
  At the end of the 3-year follow-up period, the proportion of polysensitized subjects was identical in previously monosensitized patients who underwent SIT and control individuals (11% and 10%, respectively). Individuals who were polysensitized were significantly younger than those who were not (mean age +/- SD, 21.6 +/- 11.0 years vs. 31.6 +/- 15.6 years; P < .05).
  
  
  CONCLUSIONS
  SIT does not represent a risk factor for progression towards multiple pollen sensitization in monosensitized pollen-allergic patients.
authors.affiliation: Ambulatorio di Allergologia, Clinica San Carlo, Paderno Dugnano, MI, Italy. r.asero@libero.it
authors.forename: R
authors.initials: R
authors.lastname: Asero
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000485:Allergens; D016022:Case-Control Studies; D002648:Child; D003429:Cross Reactions; D003888:Desensitization, Immunologic / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007114:Immunization; D008297:Male; D008875:Middle Aged; D011058:Pollen / Q000276:immunology*; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology* / Q000628:therapy*; D012307:Risk Factors; D012882:Skin Tests
chemical_list: D000485:Allergens