title: Repeated low-dose intradermal allergen injection suppresses allergen-induced cutaneous late responses.
abstract: BACKGROUND
  Subcutaneous immunotherapy with high-dose grass pollen was first described more than 100 years ago. This treatment suppresses allergen-induced cutaneous late responses, with lesser effects on early responses. In contrast, low-dose subcutaneous immunotherapy has not shown clinical benefit. Uncontrolled reports from the early 20th century describe low-dose allergen inoculation directly into the dermis, an immunologically active area containing abundant dendritic cells and lymphatics.
  
  
  OBJECTIVE
  We sought to investigate the effect of low-dose intradermal grass pollen administration on cutaneous reactivity to allergen.
  
  
  METHODS
  Thirty adults sensitized to grass and tree pollens were randomized to receive (1) 6 repeat intradermal injections at 2-week intervals of grass pollen extract (estimated 7 ng of the major grass allergen Phl p 5 per injection), (2) 2 intradermal injections separated by 10 weeks, or (3) a single intradermal injection at 10 weeks. At the end of the study, cutaneous early and late responses were measured after double-blind intradermal injection with grass and birch pollen.
  
  
  RESULTS
  Participants who received 6 fortnightly intradermal grass pollen injections had markedly smaller cutaneous late responses to grass pollen than control subjects who received 2 injections separated by 10 weeks (P < .01) or a single injection (P < .001) and showed induction of grass pollen-specific IgG antibodies. Suppression was observed whether late responses were measured on the arms or the back. However, early responses were equivalent in all groups.
  
  
  CONCLUSIONS
  Low-dose intradermal allergen, like conventional subcutaneous high-dose immmunotherapy, suppresses allergen-induced cutaneous late responses in a manner that is allergen specific, systemic, and associated with induction of IgG antibodies.
authors.affiliation: Allergy and Clinical Immunology, National Heart and Lung Institute, Imperial College London, London, United Kingdom.
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Rotiroti
authors.forename: Mohamed
authors.initials: M
authors.lastname: Shamji
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Durham
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Till
mesh_terms: D000279:Administration, Cutaneous; D000328:Adult; D000485:Allergens / Q000008:administration & dosage*; D003713:Dendritic Cells / Q000276:immunology; D003888:Desensitization, Immunologic; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D006109:Poaceae / Q000276:immunology*; D011058:Pollen / Q000276:immunology*; D012867:Skin / Q000276:immunology*; D014611:Vaccination
chemical_list: D000485:Allergens; D007074:Immunoglobulin G