title: Gluten sensitivity in patients with IgA nephropathy.
abstract: BACKGROUND
  Coeliac disease is more frequent in IgA nephropathy (IgAN) patients compared to the healthy population. Several hypotheses postulate that food antigens like gluten may be involved in the onset of IgAN.
  
  
  METHODS
  In this study, we used a recently developed mucosal patch technique to evaluate the rectal mucosal inflammatory reaction to gluten in patients with IgAN (n = 27) compared to healthy subjects (n = 18). The rectal mucosal production of nitric oxide (NO) and release of myeloperoxidase (MPO) and eosinophil cationic protein (ECP) were measured. Serum samples were analysed for IgA and IgG antigliadin antibodies (AGA), IgA antibodies against tissue transglutaminase and IgA endomysium antibodies.
  
  
  RESULTS
  Gluten reactivity, defined as increase in MPO and/or NO after gluten exposure, was observed in 8 of 27 IgAN patients. The prevalence of HLA-DQ2 and DQ8 was not increased among gluten-sensitive patients, and the total prevalence among IgAN patients was the same as for the normal population. An elevated serum IgA AGA response was seen in 9 of 27 IgAN patients. The increase in IgA AGA did not correlate with the gluten sensitivity as measured by NO and/or MPO. A specific serum IgG AGA response was seen in one patient only. Antibodies against tissue transglutaminase and endomysium were not observed.
  
  
  CONCLUSIONS
  It is concluded that approximately one-third of our IgAN patients have a rectal mucosal sensitivity to gluten, but without signs of coeliac disease, and we hypothesize that such sub-clinical inflammation to gluten might be involved in the pathogenesis of IgAN in a subgroup of patients.
authors.affiliation: Section of Nephrology, Department of Medical Sciences, Uppsala University Hospital, Uppsala, Sweden. hilde.kloster.smerud@smerud.com
authors.forename: Hilde Kloster
authors.initials: HK
authors.lastname: Smerud
authors.forename: Bengt
authors.initials: B
authors.lastname: Fellström
authors.forename: Roger
authors.initials: R
authors.lastname: Hällgren
authors.forename: Sonia
authors.initials: S
authors.lastname: Osagie
authors.forename: Per
authors.initials: P
authors.lastname: Venge
authors.forename: Gudjón
authors.initials: G
authors.lastname: Kristjánsson