Gastrointestinal sensitivity to soy and milk proteins in patients with IgA nephropathy.
BACKGROUND
sensitivity to food antigens has been postulated as a contributing factor to the pathogenesis of IgA nephropathy (IgAN).


METHODS
in this study we used a recently developed mucosal patch technique to evaluate rectal mucosal sensitivity to soy and cow's milk (CM) proteins in IgAN patients (n = 28) 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 analyzed for IgA and IgG antibodies to alpha-lactalbumin, beta-lactoglobulin, casein and soy.


RESULTS
14 of 28 (14/28) patients experienced a rectal mucosal reaction, measured by increased NO and/or MPO levels, upon rectal challenge with soy and/or cow's milk proteins. The levels of IgG antibodies to alpha-lactalbumin, beta-lactoglobulin and casein were significantly higher in CM sensitive as compared with non-sensitive IgAN patients, whereas the mean serum levels of IgA antibodies were similar. No differences were seen in serum levels of IgA or IgG antibodies to soy.


CONCLUSIONS
it is concluded that approximately half of our IgAN patients have a rectal mucosal sensitivity to soy or CM, and that an immune reactivity against antigens may be involved in the pathogenesis of IgAN in this subgroup of patients.
Kloster Smerud
H
H
Departments of Nephrology, Uppsala University Hospital, Uppsala, Sweden. hilde.smerud@medsci.uu.se
Fellström
B
B
Hällgren
R
R
Osagie
S
S
Venge
P
P
Kristjánsson
G
G
D056704:Adaptive Immunity; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002364:Caseins / Q000009:adverse effects; D047150:Eosinophil Cationic Protein / Q000378:metabolism; D005260:Female; D005512:Food Hypersensitivity / Q000453:epidemiology* / Q000276:immunology; D005922:Glomerulonephritis, IGA / Q000453:epidemiology* / Q000276:immunology / Q000503:physiopathology; D006801:Humans; D007113:Immunity, Innate; D018928:Immunity, Mucosal; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007159:Immunologic Tests; D007413:Intestinal Mucosa / Q000276:immunology*; D007668:Kidney / Q000503:physiopathology; D007768:Lactalbumin / Q000009:adverse effects; D007782:Lactoglobulins / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D016269:Milk Hypersensitivity / Q000453:epidemiology* / Q000276:immunology; D008894:Milk Proteins / Q000009:adverse effects* / Q000276:immunology; D009569:Nitric Oxide / Q000378:metabolism; D009195:Peroxidase / Q000378:metabolism; D011507:Proteinuria / Q000453:epidemiology; D012007:Rectum; D030262:Soybean Proteins / Q000009:adverse effects* / Q000276:immunology; D013548:Sweden / Q000453:epidemiology; D013997:Time Factors; D055815:Young Adult
D002364:Caseins; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007782:Lactoglobulins; D008894:Milk Proteins; D030262:Soybean Proteins; D009569:Nitric Oxide; D007768:Lactalbumin; D009195:Peroxidase; D047150:Eosinophil Cationic Protein; C479220:RNASE3 protein, human