title: Immune response to pneumococcal polysaccharide vaccine in adults with chronic plaque psoriasis treated with alefacept.
abstract: BACKGROUND
  Alefacept is a T cell-modulating biologic therapy for psoriasis that could affect patients' ability to mount immune responses.
  
  
  OBJECTIVE
  This open-label, phase IV, multicenter study assessed the ability of adults with chronic plaque psoriasis receiving alefacept to generate antibodies to a pneumococcal polysaccharide vaccine (PPV).
  
  
  METHODS
  Patients were treated with a standard 12-week course of alefacept and administered the 23-valent PPV at week 6. Antipneumococcal antibodies were measured at baseline and weeks 6, 9, 12, and 33. The primary end point was the percentage of patients with a 2-fold or greater increase from prevaccination (week 6) to 6 weeks postvaccination (week 12) in antibody titers to 2 or more of 5 designated PPV antigens.
  
  
  RESULTS
  Of 43 patients enrolled, 42 were included in the full analysis set, with 86% of patients exhibiting a 2-fold or greater increase and 57% of patients exhibiting a 4-fold or greater increase in antibody titers to 2 or more of 5 designated antigens from prevaccination to 6 weeks postvaccination. At 6 months postvaccination, 78% of patients had a 2-fold or greater increase and 47% of patients had a 4-fold or greater increase in antibody titers to 2 or more of the 5 designated antigens. There were statistically significant increases in mean antibody titers to all 23 antigens in PPV from prevaccination to 6 weeks postvaccination.
  
  
  CONCLUSIONS
  This was an open-label study with no comparator.
  
  
  CONCLUSIONS
  Most patients mounted immune responses to PPV; increases in antibody titers in these patients were consistent with those seen in healthy individuals.
authors: Lynde Center for Dermatology, Markham, Ontario, Canada. Electronic address: derma@lynderma.com.
authors: Charles
authors: C
authors: Lynde
authors: Total Skin and Beauty Dermatology Center, Birmingham, Alabama.
authors: James
authors: J
authors: Krell
authors: University Hospitals of Cleveland, Cleveland, Ohio.
authors: Neil
authors: N
authors: Korman
authors: University of Pennsylvania, Philadelphia, Pennsylvania.
authors: Barbara
authors: B
authors: Mathes
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000077944:Alefacept; D006801:Humans; D008297:Male; D008875:Middle Aged; D022242:Pneumococcal Vaccines / Q000276:immunology*; D011565:Psoriasis / Q000188:drug therapy* / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000627:therapeutic use*
chemical_list: C414006:23-valent pneumococcal capsular polysaccharide vaccine; D022242:Pneumococcal Vaccines; D011993:Recombinant Fusion Proteins; D000077944:Alefacept