Validation of IgA1 and IgA2 measurements by a solid-phase immunoradiometric assay in serum and secretions

We describe specific, sensitive and reproducible immunoradiometric assays to measure total IgA and IgA subclass levels in biological fluids, which take into account the problem that polymeric forms are differently recognized in immunoassays. Sera from subjects totally deficient in one of the IgA subclasses allowed us to ensure the specificity of the subclass assays and to define the proportions of IgA1 (84%) and IgA2 (16%) in the normal pooled serum (from 30 blood donors) used as standard. With purified milk 11-S secretory IgA1 and 11-S secretory IgA2, we determined a correction factor for the corresponding polymeric forms using, respectively, monomeric IgA1 and monomeric IgA2 from pooled serum as standards. With the monoclonal antibodies used, purified 11-S secretory IgA1 was similarly recognized by both the total IgA assay and the IgA1 assay; both total IgA and IgA1 concentrations were underestimated compared with monomeric IgA or monomeric IgA1. In contrast, 11-S secretory IgA2 was better recognized by the IgA2 assay than by the total IgA assay and the values were thus overestimates. Considering this problem of recognition, we fractionated saliva and lung secretions by sucrose density gradient ultracentrifugation before measuring their IgA1 and IgA2 levels

IgA subclasses and molecular size in children with vertically transmitted HIV infection

SCOPUS: cp.jinfo:eu-repo/semantics/publishe

Relationship between inflammatory processes and gas exchanges in pulmonary sarcoidosis.

In the present study, we investigated whether the analysis of cells and proteins collected by bronchoalveolar lavage (BAL) could accurately reflect the degree of functional impairment in pulmonary sarcoidosis. Eighteen patients with biopsy-proven sarcoidosis were prospectively evaluated. An inverse relationship was demonstrated between BAL coefficient of excretion relative to albumin (RCE) values of IgG and IgA and diffusion for carbon monoxide (Dco). A similar negative correlation existed with PaO2 at the end of a maximal exercise. Steroid therapy in five patients lowered concomitantly BAL RCE of IgA and IgG while Dco values increased. Immunoperoxidase studies in three lung biopsies revealed numerous Ig-containing cells within the lung parenchyma. We suggest that these BAL Ig values reflected the mononuclear cell infiltration of the bronchiolovascular sheaths and lung interstitium. This cellular infiltration likely induces a distortion of the capillary bed and may affect the gas exchanges in a reversible way

Effects of intrajejunal perfusion and chronic ingestion of Lactobacillus johnsonii strain La1 on serum concentrations and jejunal secretions of immunoglobulins and serum proteins in healthy humans

Objectives. - Link-Amster reported an increase in serum IgA when healthy subjects ingested a fermented dairy product containing Lactobacillus johnsonii La1. We aimed to assess the effects of La1 on the jejunal secretions and serum concentrations of total and specific immunoglobulins and proteins. Methods. - Twelve healthy volunteers ingested a fermented milk containing La1 or a control from day 1 till day 28, following a randomised double blind protocol. At days 0 and 28, the jejunum was successively perfused with a control solution and with a La1 suspension. The serum concentrations and jejunal secretions of albumin, orosomucoid, transferrin, alpha 2-macroglobulin, m-IgA, p-IgA, IgG, IgM, secretory component, and specific antibodies against La1 were assessed. Results. - Serum concentrations of IgA slightly increased between d0 and d28 in the group receiving La1 (1.85 +/- 0.64 g/L vs 1.76 +/- 0.76; P = 0.02). The other parameters were not altered. Conclusion. - This study shows that the immunomodulating effects of La1 ingestion in man are not due to modification of jejunal protein permeability

IgA subclasses and molecular size in children with vertically transmitted HIV infection.

SCOPUS: cp.jinfo:eu-repo/semantics/publishe

Jejunal Immunoglobulin Secretion in Alcoholic Patients With and Without Cirrhosis

Alcoholic liver diseases are associated with an elevation of serum immunoglobulin A (IgA). This could be the result of increased IgA production by the intestinal mucosa. Serum and jejunal immunoglobulin, albumin and orosomucoid were measured in 13 alcoholic patients with (n = 6) and without (n = 7) cirrhosis and compared to 11 controls. Jejunal secretions were obtained by segmental perfusion under an occluding balloon. High levels of serum monomeric and polymeric IgA were only found in patients with cirrhosis. Alcoholics with and without cirrhosis had normal monomeric and polymeric IgA jejunal secretion rates. Jejunal clearances of albumin, orosomucoid and immunoglobulin G were significantly higher in both non-cirrhotic and cirrhotic patients than in controls. These findings indicate normal jejunal IgA secretion and increased permeability to plasma proteins, such as albumin and immunoglobulin G in alcoholics

[Jejunal Secretion of Immunoglobulins and Secretory Component in 3 Cases of Immunoglobulin Deficiency]

Jejunal secretion of albumin, immunoglobulins and secretory component was studied using the segmental perfusion technique with an occluding balloon, in two patients with common variable hypogammaglobulinemia and one patient with selective immunoglobulin A deficiency. Results were compared with those of twenty-two controls previously studied under the same conditions. In all three cases, jejunal secretion rate of immunoglobulin A was nil and secretion rates of albumin and immunoglobulin G were increased as compared to controls. Jejunal secretion rate of immunoglobulin M was increased in the patient with selective immunoglobulin A deficiency, normal in one case of common variable hypogammaglobulinemia and almost nil in the other case. Secretory component was secreted in the jejunal lumen mostly or exclusively under a free form depending on partial or total absence of immunoglobulin A and M. This study allowed to confirm in vivo that secretion of secretory component is independent of the presence of immunoglobulins. Intestinal perfusion might be a useful tool in the investigation of immunological diseases of the intestinal tract