Food antibodies, intestinal permeability and HLA status in IgA deficient blood donors identified by a new rapid screening test

Abstract

Abstract. Circulating food antibodies, intestinal permeability and HLA status were studied in twelve blood donors previously identified as being selectively IgA deficient from screening 10 000 donations by means of a latex agglutination inhibition test, and confirmed by laser nephelometry. Assessment of intestinal function also included clinical history and standard laboratory tests. The donors proved to be healthy with no evidence of autoimmune disease or allergy. Nine donors (75%) had precipitins to food antigens. None had increased intestinal permeability as measured by the cellobiose/mannitol absorption test. HLA‐A, B and DR antigen distribution was normal. IgG sub‐class distribution was normal with the exception of an IgG2 level slightly below normal in one donor (0·9 g/1). An unexpected finding was a return of IgA levels to normal in four donors (33%) within 6 months.

Multireactive pattern of serum autoantibodies in asymptomatic individuals with immunoglobulin A deficiency

“…The high frequencies of autoantibodies in sera of subjects with IgA deficiency have been attributed to the following: suppressed T-cell activity (35,54); increased absorption of food and other exogenous antigens, leading to chronic anti-genemia and the resultant production of cross-reactive antibodies (21,51); genetic factors, such as the HLA-A1, -B8, and -DR-3 phenotype (3, 49) commonly observed both in patients with autoimmune disorders and in healthy autoantibody-positive relatives of patients with autoimmune diseases (55); and immunoregulatory defects in healthy individuals (54).…”

“…Indeed, IgA-deficient subjects have increased intestinal permeability to macromolecules (40), and some have large amounts of dietary proteins in their serum (16). Moreover, precipitating antibodies against cow's milk antigens (casein, ␣-lactalbumin, ␤-lactoglobulin, and BSA) are found in 36 to 75% of IgA-deficient individuals, but in only 0.3% of controls (15,21,31). Antibodies to other dietary antigens such as fish, egg yolks, chicken, and pork serum are also detectable in IgA-deficient subjects (6).…”

“…sIgAD is generally considered a permanent genetically determined state with multifactorial etiologies (37). Despite the fact that the majority of sIgAD subjects are asymptomatic, this relatively benign immunodeficiency is associated with certain disease states and is found with increased frequency in patients with allergies, recurrent upper respiratory tract infections, gastrointestinal diseases, malignancies, and autoimmune diseases (4,5,13,14,17,18,21,23,33,39,57).…”