D2.185 - Ultrarush honeybee venom immunotherapy in patients with monoclonal mast cell activation syndrome: two case reports
Case report
Background: clonal mast cell disorders (CMD) are associated with an increased risk of hymenoptera-venom anaphylaxis (HVA). Venom immunotherapy (VIT) has been successfully performed in these patients, but poses an increased risk of systemic reactions (SRs) and reduced efficacy. Particularly, VIT with honeybee venom (HBV) is associated with an increased risk of systemic reactions, independently from other risk factors. There is little data on safety of VIT with HBV through accelerated protocols in patients with HVA and CMD.
Case 1: 57-year-old woman experienced three SRs (grade 3 according to the Ring and Messmer classification) after being stung by insects: honeybee, hornet, and an unknown insect. Tests revealed normal basal serum tryptase levels (5.94 ng/ml), low total IgE (5 kIU/L), and negative levels of specific IgE (sIgE) to honeybee, wasp and hornet venom: 0.08, 0.15 and 0.1 kIU/L, respectively (ref. <0.35 kIU/L). The levels of Api m 1, Api m 10, Ves v 1 and Ves v 5 were undetectable. Hematologic workup showed positive c-KIT D816V mutation in the peripheral blood and normal bone marrow biopsy results. The patient was diagnosed with monoclonal mast-cell activation syndrome (MMAS). As total IgE levels were low, sIgE to wasp venom was considered significant, and VIT with wasp venom was initiated by cluster protocol, with no SRs. Basophil activation test (BAT) was positive to both bee (18% at 0.1 mcg/L, 48% at 1 mcg/mL for CD63) and wasp venom (35% at 0.1 mcg/L, 61% at 1 mcg/mL for CD63). The patient was then hospitalized, and VIT with HBV was initiated by a 2-day ultrarush protocol. The maintenance dose was reached with no SRs.
Case 2: 42-year-old male patient presented with a history of a severe SR (grade 3 according to the Ring and Messmer classification) after a honeybee sting. Diagnostic workup revealed serum tryptase levels of 8.3 ng/ml, positive sIgE to honeybee (11.6 kIU/mL), wasp (0.93 kIU/mL) and hornet venom (3.32 kIU/mL). Component-resolved diagnosis showed positive sIgE to Api m 1 (1.75 kIU/L), Api m 10 (0.62 kIU/mL), and negative sIgE to Ves v 1 and Ves v 5. Based on the positive c-kit D816V mutation in peripheral blood and unremarkable bone marrow biopsy findings, the patient was diagnosed with MMAS. VIT with HBV was initiated by a 2-day ultrarush protocol, and the maintenance phase was reached uneventfully.
Written informed consent for publication was obtained from both patients.
Conclusion: VIT with HBV by ultrarush protocol may be a safe treatment option in patients with HBV anaphylaxis and CMD.
