The Use of Salmonella Typhim Vaccine to Diagnose Antibody Deficiency.

PURPOSE: The specific antibody response to the unconjugated 23-valent pneumococcal polysaccharide vaccine is one of the most common tests used to assess for possible humoral immunodeficiency. The results can be difficult to interpret because most people have been immunized with one or more of the pneumococcal vaccines and there is controversy regarding what constitutes a normal response. To circumvent this problem, we developed an ELISA to measure IgG-specific antibodies to the Salmonella Vi Typhim (S. Typhim) vaccine, a pure polysaccharide vaccine, which is a neoantigen for the vast majority of people in the USA. METHODS: We compared the pre- and post-vaccination serum titers to the Vi Typhim vaccine in healthy controls (n = 22), patients previously diagnosed with a primary immunodeficiency (n = 30), and patients referred for possible humoral immune deficiency (n = 29). We also determined if the S. Typhim vaccine could be used to assess specific antibody responses in people on antibody replacement therapy. RESULTS: Following immunization with the S. Typhim vaccine, we found that a 2-fold increase in titers is 100% sensitive and specific in detecting known humoral immune deficiencies as determined by ROC curve analysis. This cut-off value was successfully applied to possible immune deficiency patients (n = 29), resulting in the diagnosis of seven subjects with humoral immunodeficiency. The use of immunoglobulin replacement therapy did not affect the median response ratios compared to subjects not receiving gammaglobulin. CONCLUSION: This study suggests that measurement of the specific antibody response to the S. Typhim vaccine may have advantages over pneumococcal vaccination in the evaluation of the humoral immune response.

Severe tomato allergy (Lycopersicon esculentum).

Although tomatoes are a commonly consumed food, severe allergic reactions to tomatoes are unusual or rarely reported. Previously reported allergic manifestations to tomato include urticaria/angioedema, dermatitis, oral allergy syndrome, rhinitis, and abdominal pain. The aim of this study was to report two patients with significant immediate hypersensitivity reactions to tomato and characterize the responsible allergen. We reviewed the history and documentation of tomato-specific immunoglobulin E (IgE) of two patients with adverse symptoms after ingesting tomato. Fresh tomato extracts prepared from the skin, seeds, and flesh of red, ripe tomatoes were evaluated for total protein content and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed to characterize the tomato protein. IgE enzyme-linked immunosorbent assay (ELISA) using the patients' serum against the various tomato extracts was accomplished and IgE immunoblot was performed. Percutaneous skin tests or radioallergosorbent tests (RASTs) were positive to tomato in both patients. Both adults experienced laryngeal edema and one had anaphylaxis. Similar total protein contents were found in each of the tomato extracts and gel electrophoresis revealed similar protein profile for skin and seed extracts with protein bands discernible at molecular weights of 21, 33, and 43 kDa. One patient reacted specifically to a 43-kDa protein band on IgE immunoblot. The two cases show that severe allergic reactions to tomato occur in adults and one is associated with IgE binding to a 43-kDa protein.