The time-course of milk antigen-induced TNF-alpha secretion differs according to the clinical symptoms in children with cow's milk allergy.

BACKGROUND: TNF-alpha secretion by blood mononuclear cells stimulated with cow's milk proteins is significantly higher in infants with active cow's milk allergy (CMA) manifested by digestive symptoms than in children who have recovered from CMA. OBJECTIVE: The current study was undertaken to analyze the kinetics of TNF-alpha secretion and to evaluate the usefulness of the measurement of TNF-alpha release in whole blood cultures in the prediction of clinical outcome after milk challenge. METHODS: Blood samples were obtained from 83 children maintained on a cow's milk-free diet and examined just before a cow's milk provocation. Children were divided into 4 groups according to clinical outcome: group I (active CMA with cutaneous symptoms), group II (active CMA with predominantly digestive symptoms), group III (children recovered from CMA), and group IV (control). The kinetics of TNF-alpha secretion was measured in blood cultured for 1 to 5 days at different cow's milk protein concentrations. RESULTS: On day 1 TNF-alpha secretion was significantly higher in group I (485 [453] pg/mL, mean [SD], P <.005) and in group II (269 [102] pg/mL, P <. 005) than that observed in groups III and IV (149 [95] and 87 [71] pg/mL, respectively). Then TNF-alpha was rapidly degraded and a second peak of secretion was observed on day 5 but only in group II (278 [221] pg/mL), whereas in groups I, III, and IV a low secretion was observed (70 [61], 45 [40], and 11 [12] pg/mL, respectively, P <. 02). CONCLUSION: These results show that the pattern of TNF-alpha secretion in response to cow's milk proteins is different in CMA infants with cutaneous or digestive symptoms and suggest that TNF-alpha release might predict clinical relapse on challenge.

Effect of terfenadine on TNF alpha release from peripheral blood mononuclear cells during cow's milk allergy.

BACKGROUND: In infants with cow's milk allergy and intestinal symptoms, peripheral blood mononuclear cells stimulated in vitro with cow's milk proteins, secrete large amounts of the proinflammatory cytokine TNF alpha thus altering intestinal barrier capacity. Terfenadine, an antihistaminic drug, inhibits the release of several inflammatory mediators, including histamine, prostaglandins and leukotrienes. OBJECTIVES: To test the potential ability of terfenadine to inhibit TNF alpha secretion by mononuclear cells from infants with cow's milk allergy. METHODS: Mononuclear cells from infants allergic to cow's milk proteins were stimulated in vitro for 6 days by a mixture of milk proteins (beta-lactoglobulin, alpha-lactalbumin and casein) with or without terfenadine (0.1-1 microM) and culture supernatants were assayed for TNF alpha by enzyme immunoassay. The effect of culture supernatants on intestinal barrier capacity was evaluated by measuring the electrical resistance (index of integrity) of filter-grown HT29-19 A intestinal cells in Ussing chambers. RESULTS: During active cow's milk allergy, mononuclear cells stimulated with cow's milk proteins secreted large amounts of TNF alpha which significantly reduced the electrical resistance of HT29-19 A intestinal cells. There was a dose-dependent decrease in TNF alpha secretion in the presence of terfenadine, with a maximal inhibition of 62% of this secretion at 1 microM. Accordingly, terfenadine-treated mononuclear cells supernatants did not alter the electrical resistance of intestinal HT29.19 A cells. CONCLUSION: These results indicate that in infants with intestinal dysfunction due to cow's milk allergy, terfenadine is a potent inhibitor of the TNF alpha secretion induced by sensitizing milk protein antigens. This inhibition prevents the degradation of intestinal function as measured in an intestinal cell line, in vitro.

The threshold for immune cell reactivity to milk antigens decreases in cow's milk allergy with intestinal symptoms.

BACKGROUND: In cow's milk allergy (CMA) with intestinal symptoms, peripheral blood mononuclear cells (PBMCs) secrete tumor necrosis factor-alpha (TNF-alpha), altering intestinal function. However, the type of cow's milk protein (CMP) that triggers symptoms (intact or intestinally processed) is not known, and neither is the minimal amount required. METHODS: PBMCs were isolated from infants with active CMA or cured infants just before a new challenge and stimulated with intact or intestinally processed CMP. Supernatants were tested for cytokine content and for their ability to perturb intestinal barrier capacity, measured in Using chambers in HT29-19A intestinal cells. RESULTS: PBMCs from infants with active CMA secreted more TNF-alpha, when they were stimulated with intact rather than intestinally processed CMPs, and more TNF-alpha than PBMCs from cured infants. Accordingly, supernatants from PBMCs stimulated with intact but not intestinally processed CMPs significantly increased intestinal permeability. The CMP concentration required to trigger TNF-alpha secretion capable of altering intestinal function was very small in infants with active CMA (approximately 2 micrograms/ml), but about 300 times higher in cured infants. CONCLUSION: Intact rather than intestinally processed proteins stimulate PBMCs to release TNF-alpha and alter intestinal barrier capacity. The threshold for PBMC reactivity to milk antigens drops considerably during active CMA with intestinal symptoms.

Intestinal transport and processing of immunoglobulin G in the neonatal and adult rat.

The proximal intestine of neonatal rats expresses a specific receptor (RFcn) that binds immunoglobulin G (IgG) and is no longer expressed after weaning. The aim of this study was to quantify and compare the intestinal transport and processing of IgG in intestinal fragments with or without RFcn, with the fluid-phase transport of horseradish peroxidase (HRP). The mucosal to serosal transport and degradation of IgG and HRP were measured in neonatal and adult rats in vitro in Ussing chambers. IgG transcytosis occurred without degradation in the proximal intestine of neonatal rats, where RFcn is expressed, up to a luminal concentration of 300 micrograms/ml. At higher mucosal IgG concentrations, a degradative pathway was also involved. The immunoreactive IgG fluxes across the proximal intestine of neonatal rats were higher than those observed in the distal neonatal intestine or those in the proximal and distal adult intestine. The rate of HRP transcytosis was higher than that of IgG but it involved a mainly degradative pathway. These results suggest that in the proximal intestine of the neonatal rat, where RFcn is expressed, the transcytotic rate for IgG is not increased, but the nondegradative transport of immunoreactive IgG is favored, especially at low luminal concentrations.