Selective IgA Deficiency

Immunoglobulin A (IgA) deficiency is the most common primary immunodeficiency defined as decreased serum level of IgA in the presence of normal levels of other immunoglobulin isotypes. Most individuals with IgA deficiency are asymptomatic and identified coincidentally. However, some patients may present with recurrent infections of the respiratory and gastrointestinal tracts, allergic disorders, and autoimmune manifestations. Although IgA is the most abundant antibody isotype produced in the body, its functions are not clearly understood. Subclass IgA1 in monomeric form is mainly found in the blood circulation, whereas subclass IgA2 in dimeric form is the dominant immunoglobulin in mucosal secretions. Secretory IgA appears to have prime importance in immune exclusion of pathogenic microorganisms and maintenance of intestinal homeostasis. Despite this critical role, there may be some compensatory mechanisms that would prevent disease manifestations in some IgA-deficient individuals. In IgA deficiency, a maturation defect in B cells to produce IgA is commonly observed. Alterations in transmembrane activator and calcium modulator and cyclophilin ligand interactor gene appear to act as disease-modifying mutations in both IgA deficiency and common variable immunodeficiency, two diseases which probably lie in the same spectrum. Certain major histocompatibility complex haplotypes have been associated with susceptibility to IgA deficiency. The genetic basis of IgA deficiency remains to be clarified. Better understanding of the production and function of IgA is essential in elucidating the disease mechanism in IgA deficiency

Attending to warning signs of primary immunodeficiencies disease across the range of clinical practices

Purpose: Patients with primary immunodeficiency diseases (PIDD) may present with recurrent infections affecting different organs, organ-specific inflammation/autoimmunity, and also increased cancer risk, particularly hematopoietic malignancies. The diversity of PIDD and the wide age range over which these clinical occurrences become apparent often make the identification of patients difficult for physicians other than immunologists. The aim of this report is to develop a tool for educative programs targeted to specialists and applied by clinical immunologists. Methods: Considering the data from national surveys and clinical reports of experiences with specific PIDD patients, an evidence-based list of symptoms, signs, and corresponding laboratory tests were elaborated to help physicians other than immunologists look for PIDD. Results: Tables including main clinical manifestations, restricted immunological evaluation, and possible related diagnosis were organized for general practitioners and 5 specialties. Tables include information on specific warning signs of PIDD for pulmonologists, gastroenterologists, dermatologists, hematologists, and infectious disease specialists. Conclusions: This report provides clinical immunologists with an instrument they can use to introduce specialists in other areas of medicine to the warning signs of PIDD and increase early diagnosis. Educational programs should be developed attending the needs of each specialty.Fil: Costa Carvalho, Beatriz Tavares. Universidade Federal de São Paulo; BrasilFil: Sevciovic Grumach, Anete. Fundação ABC. Faculdade de Medicina; BrasilFil: Franco, José Luis. Universidad de Antioquia; ColombiaFil: Espinosa Rosales, Francisco Javier. Instituto Nacional de Pediatría. Unidad de Investigación en Inmunodeficiencias; MéxicoFil: Leiva, Lily E.. State University of Louisiana; Estados UnidosFil: King, Alejandra. Hospital de Niños Doctor Luis Calvo Mackenna. Unidad de Inmunología; ChileFil: Porras, Oscar. Hospital Nacional de Niños “Dr. Carlos Sáenz Herrera”; Costa RicaFil: Bezrodnik, Liliana. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Oleastro, Mathias. Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; ArgentinaFil: Sorensen, Ricardo U.. State University of Louisiana; Estados Unidos. Universidad de La Frontera. Facultad de Medicina; MéxicoFil: Condino Neto, Antonio. Universidade de Sao Paulo; Brasi

Subsensitivity to insulin in adipocytes from rats submitted to foot-shock stress

We examined the effect of three daily foot-shock stress sessions on glucose homeostasis, insulin secretion by isolated pancreatic islets, insulin sensitivity of white adipocytes, and glycogen stores in the liver and soleus muscle of rats. Stressed rats had plasma glucose (128.3 +/- 22.9 mg/dL) and insulin (1.09 +/- 0.33 ng/mL) levels higher than the controls (glucose, 73.8 +/- 3.5 mg/dL; insulin, 0.53 +/- 0.11 ng/mL, ANOVA plus Fisher's test; p < 0.05). After a glucose overload, the plasma glucose, but not insulin, levels remained higher (area under the curve 8.19 &PLUSMN; 1.03 vs. 4.84 &PLUSMN; 1.33 g/dL 30 min and 102.7 &PLUSMN; 12.2 vs. 93.2 &PLUSMN; 16.1 ng/mL 30 min, respectively). Although, the area under the insulin curve was higher in stressed (72.8 &PLUSMN; 9.8 ng/mL) rats than in control rats (34.9 &PLUSMN; 6.9 ng/mL) in the initial 10 min after glucose overload. The insulin release stimulated by glucose in pancreatic islets was not modified after stress. Adipocytes basal lipolysis was higher (stressed, 1.03 &PLUSMN; 0.14; control, 0.69 &PLUSMN; 0.11 &mu;mol of glycerol in 60 min/100 mg of total lipids) but maximal lipolysis stimulated by norepinephrine was not different (stressed, 1.82 &PLUSMN; 0.35; control, 1.46 &PLUSMN; 0.09 &mu;mol of glycerol in 60 min/100 mg of total lipids) after stress. Insulin dose-dependently inhibited the lipolytic response to norepinephrine by up to 35% in adipocytes from control rats but had no effect on adipocytes from stressed rats. The liver glycogen content was unaltered by stress, but was lower in soleus muscle from stressed rats than in control rats (0.45 &PLUSMN; 0.04 vs. 0.35 &PLUSMN; 0.04 mg/100 mg of wet tissue). These results suggest that rats submitted to foot-shock stress develop hyperglycemia along with hyperinsulinemia as a consequence of insulin subsensitivity in adipose tissue, with no alteration in the pancreatic sensitivity to glucose. Foot-shock stress may therefore provide a useful short-term model of insulin subsensitivity.80878378

Influence of melatonin on the development of functional nicotinic acetylcholine receptors in cultured chick retinal cells

The influence of melatonin on the developmental pattern of functional nicotinic acetylcholine receptors was investigated in embryonic 8-day-old chick retinal cells in culture. The functional response to acetylcholine was measured in cultured retina cells by microphysiometry. The maximal functional response to acetylcholine increased 2.7 times between the 4th and 5th day in vitro (DIV4, DIV5), while the Bmax value for [125I]-alpha-bungarotoxin was reduced. Despite the presence of alpha8-like immunoreactivity at DIV4, functional responses mediated by alpha-bungarotoxin-sensitive nicotinic acetylcholine receptors were observed only at DIV5. Mecamylamine (100 µM) was essentially without effect at DIV4 and DIV5, while dihydro-ß-erythroidine (10-100 µM) blocked the response to acetylcholine (3.0 nM-2.0 µM) only at DIV4, with no effect at DIV5. Inhibition of melatonin receptors with the antagonist luzindole, or melatonin synthesis by stimulation of D4 dopamine receptors blocked the appearance of the alpha-bungarotoxin-sensitive response at DIV5. Therefore, alpha-bungarotoxin-sensitive receptors were expressed in retinal cells as early as at DIV4, but they reacted to acetylcholine only after DIV5. The development of an alpha-bungarotoxin-sensitive response is dependent on the production of melatonin by the retinal culture. Melatonin, which is produced in a tonic manner by this culture, and is a key hormone in the temporal organization of vertebrates, also potentiates responses mediated by alpha-bungarotoxin-sensitive receptors in rat vas deferens and cerebellum. This common pattern of action on different cell models that express alpha-bungarotoxin-sensitive receptors probably reflects a more general mechanism of regulation of these receptors