Passive immune basophil activation test for the identification of allergic episodes from various adverse events elicited by haematopoietic cell transplantation: A pilot study.

BACKGROUND AND OBJECTIVES: Haematopoietic cell transplantation (HCT) therapy tends to be associated with various complications including engraftment failure, regimen-related toxicities, and infectious diseases. In addition, HC infusion itself occasionally elicits adverse events (AEs), one of the most common AEs is an allergic reaction. As appropriate laboratory tests have not yet been established to distinguish allergy-mediated AEs from other complications, clinical responses for HCT-related AEs can only be nonspecific. In this pilot study, using passive immune basophil activation test (pi-BAT), we attempted to distinguish an HC infusion-induced allergic reaction from various HCT-related AEs. MATERIALS AND METHODS: Using pi-BAT, we examined 34 patients who underwent HCT, that is, 11 with AEs and 23 without AEs as controls. RESULTS: Two of the eleven AE cases were pi-BAT positive and, the rest of nine AE cases were negative, while all non-AE cases were negative. Both of the two positive cases showed erythema, tachycardia, plus cough. Because erythema is one of the representative symptom of allergy, those cases could be classified as allergic reaction cases or anaphylaxis cases if tachycardia and cough were concomitant symptoms of erythema. Among the nine AEs with pi-BAT negative result, four cases showed urticaria, four showed vomiting plus diarrhoea, and one showed cough. Urticaria case was strongly suspected of allergy, however, the AE cases were pi-BAT negative. CONCLUSION: The pi-BAT may be useful as an auxiliary diagnostic tool to confirm the possible involvement of HC infusion in HCT-related AEs and identify an immunologic mechanism for HCT-related hypersensitivity reactions.

Possible Utility of the Basophil Activation Test for the Analysis of Mechanisms Involved in Allergic Transfusion Reactions.

Allergic transfusion reactions (ATRs) are the most common adverse reactions occurring during transfusion of blood components. Although most reactions are mild and involve cutaneous manifestations, severe ATRs including life-threatening anaphylaxis may also occur. The mechanisms of ATRs are largely unknown because they have not been well studied. One of the reasons for this may be the absence of a standard assay system for investigating these processes. Basophils and/or mast cells are key effector cells in immediate-type allergic reactions. They possess the unique ability to degranulate upon cross-linking of specific IgE bound on the membrane-bound, high-affinity IgE receptor or upon direct stimulation by exposure to allergens. Basophils are present in peripheral blood, unlike mast cells which are located in tissues. Therefore, basophils are valuable for the clinical testing of allergy. Consequently, the basophil activation test (BAT) was developed as a simple blood test for the diagnosis of allergic reactions to substances such as foods, inhalants, medicines and venom. In the last decade, the BAT has also been applied to transfusion medicine; 5 pilot studies revealed that the supernatants of the responsible blood products activated basophils in the BAT in 13 ATR cases, suggesting a causal relationship between ATRs and transfusion. In this review, we describe those cases and explore the potential utility of the BAT as a test performed in reference laboratories for the analysis of ATRs. We also describe the weaknesses, pitfalls, and unanswered issues of this assay.

Clinical utility of a passive immune basophil activation test for the analysis of allergic transfusion reactions.

BACKGROUND: In previous studies, we demonstrated that the basophil activation test, which is performed using patient blood and the supernatants from transfused blood components, was able to elucidate not only the causative relationship between allergic transfusion reactions and the transfusion but also the mechanisms behind allergic transfusion reactions. However, for a large number of allergic transfusion reactions, patients are in a state of myelosuppression, and the basophil activation test cannot be performed for these patients because there are insufficient numbers of peripheral blood basophils. STUDY DESIGN AND METHODS: To overcome this obstacle, we developed a passive immune basophil activation test, in which patient plasma and residually transfused blood are used as the patient's sources of immunoglobulin E and allergen, respectively, whereas healthy volunteer basophils serve as the responder cell source. The passive immune basophil activation test was performed for two patients who had severe allergic transfusion reactions, using supernatants of the residual platelet concentrates and the patients' own immunoglobulin E. RESULTS: There were no differences in either surface immunoglobulin E or activation in response to allergens between untreated basophils and so-called quasi-basophils, in which immunoglobulin E was replaced by a third party's immunoglobulin E. In these patients, the supernatants of the residual platelet concentrates exclusively activated basophils in response to quasi-basophils onto which the patients' immunoglobulin E, but not a third party's immunoglobulin E, was bound. CONCLUSION: The passive immune basophil activation test may help clarify the causal relationship between allergic transfusion reactions and transfused blood, even when patients experience myelosuppression.