A Case of Immediate Hypersensitivity Reaction to Maltitol.

BACKGROUND: Maltitol is a sugar alcohol that is frequently used as a noncaloric sweetener, although it is also used as an excipient, a plasticizer in gelatin capsules, and an emollient. It has not been previously described as an agent involved in immediate hypersensitivity reactions. METHODS: We report on an anaphylactoid reaction with pharyngeal occlusion suffered by a 60-year-old man after ingestion of a candy containing maltitol syrup. A prick-to-prick test was performed with the candy and maltitol powder. Other allergens were excluded as causative agents of the adverse reaction, although the patient refused to undergo an oral challenge test with the candy. A basophil activation test (BAT) was performed with maltitol powder, and a dose-response curve was generated. The test was also performed in 3 healthy controls. RESULTS: Both prick-to-prick tests were negative. The result of the BAT was positive at all the concentrations tested in the patient's blood and negative in all the controls. CONCLUSIONS: The BAT can help to clarify the agents implicated in an adverse reaction and can reduce the risk involved in diagnosis. The BAT can also prove useful in the study of reactions caused by low-molecular-weight antigens, for which routine diagnostic tests are not feasible.

Short-, Intermediate-, and Long-Term Changes in Basophil Reactivity Induced by Venom Immunotherapy.

PURPOSE: The basophil activation test (BAT) has been used to monitor venom immunotherapy (VIT) due to its high specificity. A previous study has reported a good correlation between a significant decrease in basophil activation during 5 years of VIT and clinical protection assessed by sting challenge. The following prospective study was performed to examine changes in basophil reactivity over a complete VIT period of 5 years. METHODS: BAT in a dose-response curve was studied prospectively in 10 hymenoptera venom-allergic patients over 5 years of VIT. BAT was performed at the time of diagnosis, 1 month after finishing the VIT build-up phase, and 3, 6, 12, 24, and 60 months after beginning treatment. The repeated measures ANOVA was applied to evaluate basophil activation changes throughout VIT. A cross-sectional study was also performed in 6 patients who received treatment for more than 3 years, and in another 12 patients who followed immunotherapy for at least 5 years. RESULTS: An early activation decrease was observed during the first 3 months of treatment, compared to pre-treatment values. This activation decrease was not maintained 6 to 18 months after treatment, but was observed again after 2 years of treatment, and maintained until the completion of the 5-year immunotherapy period. In cross-sectional analysis, the 6 patients who received treatment for 3 years, and 9 of the 12 patients who received treatment for 5 years, had negative BAT results. Three patients in this last group had positive BAT results and 2 patients had systemic reactions after field stings. CONCLUSIONS: BAT appears to be an optimal non-invasive test for close monitoring of VIT.

CD106 and activated-CD29 are expressed on myelomatous bone marrow plasma cells and their downregulation is associated with tumour progression.

Malignant plasma cells (PC) from multiple myeloma (MM) patients characteristically home to the bone marrow (BM). High numbers of tumour cells are found in the peripheral blood (PB) only at end-stage disease (secondary plasma cell leukaemia, PCL) in a minority of patients. Using flow cytometric and fluorescence in situ hybridization (FISH) analysis, a high percentage of tumoral BM PC from untreated patients was found to express CD106. In addition, these cells also expressed an activated form of CD29, as determined using the CD29 activation reporter monoclonal antibody HUTS-21. Adhesion-binding experiments showed that CD106+-activated CD29+ BM PC from these patients adhered to fibronectin (FN) in a CD29/CD49d-dependent manner. In contrast, marrow PC from progressive patients and BM or circulating malignant cells from secondary PCL patients expressed lower levels or were negative for CD106 and activated CD29, respectively, with a decreased or zero ability to adhere to FN. The expression of constitutive CD29 and CD49d, however, was similar during disease progression. We conclude that BM myelomatous cells co-express CD106 and a functionally active form of CD29. Moreover, our results suggest that the loss of expression and/or function of these antigens are associated with the progression of MM and may explain the exit of tumoral cells from the BM.