Immunoglobulin G4 antibodies to rat urinary allergens, sensitization and symptomatic allergy in laboratory animal workers

Background and objectives We have previously reported that high rat urinary allergen (RUA) exposure was not associated with increased risk of rat allergy in long‐term‐exposed laboratory animal (LA) workers. We aimed to assess whether strong allergen‐specific IgG4 responses could explain the absence of a dose response in these subjects. We investigated whether IgG4 was associated with allergen exposure and prevalence of sensitization or respiratory symptoms to rats. The longitudinal relation between IgG4 and rat allergy was studied using data obtained during 2 years of follow‐up. Methods Five hundred and twenty‐nine LA workers answered a questionnaire on respiratory symptoms and occupational history and participated in skin prick testing. Blood samples were analysed for specific IgG4 and IgE to RUA. Exposure to RUA was estimated based on personal air samples. The relation between IgG4 and newly occurring sensitization or rat allergy was studied in workers who were not sensitized or did not report respiratory symptoms to rats. Results IgG4 titres were higher in atopic than in non‐atopic subjects, and increased with higher allergen exposure. Titres were highest in subjects who were sensitized and reported respiratory symptoms to rats when compared with those who were not (geometric mean [geometric standard deviation]=202 [5.7] vs. 8.4 [18.3] AU). The association between IgG4 and sensitization or symptomatic rat allergy was independent of estimated allergen exposure. IgG4 was a strong predictor of newly occurring sensitization and symptomatic rat allergy during follow‐up in atopic and rat‐sensitized subjects. Conclusion High exposure to RUA is associated with a strong allergen‐specific IgG4 antibody response. High anti‐RUA IgG4 is a strong predictor of prevalent and incident sensitization and symptomatic rat allergy in atopic and rat‐sensitized subjects. IgG4 can therefore not explain the absence of a dose response between allergen exposure and allergy in long‐term‐exposed workers. We consider anti‐RUA IgG4 to be a marker that combines aspects of exposure and susceptibility

Ontogenic development of kidney, thymus and spleen and phenotypic expression of cd3 and cd4 receptors on the lymphocytes of cobia (rachycentroncanadum)

In the present study was evaluated the ontogenic of immunocompetent organs of cobia up to 53 days after hatching (dah) through histology and immunohistochemistry techniques. The kidney was the first lymphohematopoietic organ to appear, at 1 dah, followed by the spleen at 5 dah and the thymus at 7 dah. The first CD3 receptors on the lymphocytes were observed in 27% of the thymic tissue at 7 dah and in 99% at 53 dah. The phenotypic expression of CD3 receptors was registered in 10% of the kidney at 8 dah and in 32% at 53 dah. CD4 receptors were observed in 5% and 63% of the thymic area at 7 and 53 dah, respectively. In the kidney, T4 lymphocytes were first observed at 13 dah in 9% of the organ and in 28% at 53 dah, defining the functional development of the specific system associated with immunological memory capacity