Human serum albumin (HSA) is a commonly used colloid for volume expansion and albumin replacement. Colloids are an uncommon cause of anaphylaxis, and cases of hypersensitivity reactions to HSA are extremely rare.

A 53 yo patient was admitted to ICU for severe thermal burns and was treated with 20 % HSA infusion (Vialabex®, LFB). He exhibited a grade II (Ring and Messmer) one hour after the second administration. He was treated with epinephrine and corticosteroids, and recovered rapidly. Tryptase kinetics were consistent with mast cell degranulation (t0′40′’=18,6μg/L, t2′40′’=19,1μg/L, t24′40′’=5,4μg/L). The main objective was to investigate this HSA reaction and determine the most reliable diagnosis for patient management.

To determine the immunological pathway and the culprit allergen, two HAS batches were tested with skin tests (ST) and basophil activation tests (BAT). SDS-PAGE 1D electrophoresis (1DE) and time-of-flight mass spectrometry (MS-TOF) were performed to investigate the composition of these batches.

The patient's HSA batch (batch 1) was identified as positive by ST and BAT indicating a reactivity of 59 % (control: 1 %). In contrast, batch 2 and two healthy controls tested were negative. These results indicated a discrepancy in the composition of the HSA batches and corroborated the diagnosis of moderate anaphylaxis resulting from IgE-mediated hypersensitivity to the administered batch. No difference was observed in the migration profile of the two HSA batches with 1DE. TOF-MS revealed the presence of additional peaks in the batch 1. The patient may have been sensitised to a hapten bound to HSA or to a contaminant protein present in this batch. The identity of these peaks remains to be determined.

We report a case of IgE-mediated hypersensitivity to a restricted batch of HAS. BAT was a diagnostic tool equivalent to the ST in the investigation of anaphylaxis to HSA. It can be used to do not dispose of a needed treatment wrongly. Early diagnosis with the culprit batch is important as this patient may require a repeat HSA infusion. In this case, a prior BAT should be performed.