Anti-hIgE gene therapy of peanut-induced anaphylaxis in a humanized murine model of peanut allergy.

BACKGROUND: Peanuts are the most common food to provoke fatal or near-fatal anaphylactic reactions. Treatment with an anti-hIgE mAb is efficacious but requires frequent parenteral administration. OBJECTIVE: Based on the knowledge that peanut allergy is mediated by peanut-specific IgE, we hypothesized that a single administration of an adeno-associated virus (AAV) gene transfer vector encoding for anti-hIgE would protect against repeated peanut exposure in the host with peanut allergy. METHODS: We developed a novel humanized murine model of peanut allergy that recapitulates the human anaphylactic response to peanuts in NOD-scid IL2Rgammanull mice transferred with blood mononuclear cells from donors with peanut allergy and then sensitized with peanut extract. As therapy, we constructed an adeno-associated rh.10 serotype vector coding for a full-length, high-affinity, anti-hIgE antibody derived from the Fab fragment of the anti-hIgE mAb omalizumab (AAVrh.10anti-hIgE). In the reconstituted mice peanut-specific IgE was induced by peanut sensitization and hypersensitivity, and reactions were provoked by feeding peanuts to mice with symptoms similar to those of human subjects with peanut allergy. RESULTS: A single administration of AAVrh.10anti-hIgE vector expressed persistent levels of anti-hIgE. The anti-hIgE vector, administered either before sensitization or after peanut sensitization and manifestation of the peanut-induced phenotype, blocked IgE-mediated alterations in peanut-induced histamine release, anaphylaxis scores, locomotor activity, and free IgE levels and protected animals from death caused by anaphylaxis. CONCLUSION: If this degree of persistent efficacy translates to human subjects, AAVrh.10anti-hIgE could be an effective 1-time preventative therapy for peanut allergy and possibly other severe, IgE-mediated allergies.

Hemolytic disease of the fetus and newborn caused by anti-Lan.

BACKGROUND: Antibodies to the high-incidence red blood cell (RBC) antigen Lan (Langereis) are typically immunoglobulin G and have been shown to fix complement and cause hemolysis of Lan antigen-positive RBCs. Only three cases of hemolytic disease of the fetus and newborn (HDFN) have been reported involving anti-Lan and all have been characterized as "mild." CASE REPORT: A 26-year-old Hispanic female presented in her fifth pregnancy for routine obstetric care. Due to progressively rising anti-Lan titers, middle cerebral artery (MCA) Dopplers were performed. At 32 weeks of gestation, the antibody titer had reached 128; the MCA Doppler indicated that fetal anemia was severe. An intrauterine transfusion with Lan antigen-negative RBCs was performed and a viable infant was delivered 25 days later. DISCUSSION: Three cases of HDFN associated with anti-Lan have been previously reported. While these cases have been associated with somewhat variable serologic findings, none have resulted in fetal demise or severe symptomatology requiring pre- or postnatal intervention other than routine phototherapy. The current report, however, suggests that in some instances anti-Lan can result in a more severe form of HDFN requiring more aggressive prenatal therapy. CONCLUSION: In spite of previous case reports suggesting that anti-Lan is associated with relatively mild HDFN, this case suggests that in some instances, this antibody can cause severe HDFN requiring prenatal intervention.

Use of nutritional supplements to increase the efficacy of fluoxetine in the treatment of anorexia nervosa.

OBJECTIVE: Selective serotonin reuptake inhibitor (SSRI) medication does not appear to be effective in ill, malnourished anorexia nervosa (AN) patients. However, it may be effective in preventing relapse after weight restoration. The purpose of this study was to determine whether nutritional supplements could potentiate the effects of fluoxetine in underweight AN subjects. METHOD: Twenty-six subjects with AN participated in a trial of fluoxetine. In a double-blind, placebo-controlled manner, subjects received either nutritional supplements or a nutritional placebo. The nutritional supplement included tryptophan (the precursor of serotonin), vitamins, minerals, and essential fatty acids believed to influence serotonin pathway function. RESULTS: There was no significant difference in weight gain between subjects treated with fluoxetine plus nutritional supplements versus fluoxetine plus a nutritional placebo. Moreover, there were no significant differences between groups on mean changes in anxiety or obsessive and compulsive symptoms. DISCUSSION: The results of this study suggest that supplement strategies are not a substitute for adequate nutrition and are ineffective in increasing the efficacy of fluoxetine in underweight AN subjects.