title: Colonic IgA producing cells and macrophages are reduced in recurrent and non-recurrent Clostridium difficile associated diarrhoea.
abstract: BACKGROUND
  In Clostridium difficile associated diarrhoea (CDAD), histological changes in the colonic mucosa range from minimal inflammation to pseudomembranous colitis (PMC). The disease also recurs in a considerable proportion of patients.
  
  
  OBJECTIVE
  To investigate mucosal immune system cells in colonic biopsies of patients with CDAD.
  
  
  METHODS
  Colonic biopsies were obtained from 12 control patients with diarrhoea, six patients with CDAD and minimal inflammation, and 10 patients with CDAD with pseudomembranous colitis (samples obtained from areas with and without inflammatory exudate). Immunohistochemical studies were performed using antibodies to T cells (CD3), macrophages (CD68), B/plasma cells (CD79alpha), and to IgA, IgM, and IgG. Labelled cells in lamina propria were quantified.
  
  
  RESULTS
  In contrast to T cells, there were significant reductions in B/plasma cell and macrophage counts in all biopsies from patients with CDAD compared with controls (p<0.001). Studies using anti-immunoglobulin antibodies showed significant reductions in IgA producing cells in CDAD biopsies (p<0.05), with the greatest reduction in samples from patients with PMC. In contrast, there was a significant increase (p<0.05) in IgG producing cells in CDAD biopsies. Only patients with PMC relapsed. In these patients, B/plasma cell and IgA producing cell counts (in biopsies with and without inflammatory exudates) were significantly lower (p<0.01) in mucosal samples from those who subsequently relapsed (five) than those who did not.
  
  
  CONCLUSIONS
  A selective reduction in mucosal IgA producing cells and macrophages is associated with colonic disease in C difficile infected patients. Severe reduction in colonic IgA producing cells may predispose to recurrence of CDAD.
authors.affiliation: Division of Gastroenterology, University Hospital, Nottingham NG7 2UH, UK.
authors.forename: S S
authors.initials: SS
authors.lastname: Johal
authors.forename: C P
authors.initials: CP
authors.lastname: Lambert
authors.forename: J
authors.initials: J
authors.lastname: Hammond
authors.forename: P D
authors.initials: PD
authors.lastname: James
authors.forename: S P
authors.initials: SP
authors.lastname: Borriello
authors.forename: Y R
authors.initials: YR
authors.lastname: Mahida
mesh_terms: D000293:Adolescent; D000368:Aged; D000369:Aged, 80 and over; D001402:B-Lymphocytes / Q000276:immunology*; D016022:Case-Control Studies; D002452:Cell Count; D016360:Clostridioides difficile; D003106:Colon; D003967:Diarrhea / Q000276:immunology / Q000382:microbiology*; D004761:Enterocolitis, Pseudomembranous / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D007150:Immunohistochemistry / Q000379:methods; D007413:Intestinal Mucosa / Q000276:immunology*; D008264:Macrophages / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012008:Recurrence
chemical_list: D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M