D2.94 - Anaphylaxis to human serum albumin in a patient with liver cirrhosis – a diagnostic challenge

Background: Human serum albumin (HSA) is widely used for volume expansion and traditionally viewed as biologically inert. In fact, adverse reactions are rare and mainly infusion-related. HSA consists of an endogenous protein, which is normally considered safe, but can act as an allergen, particularly due to the processing methods, such as pasteurization, or due added stabilizers. We presente a case of an immediate hypersensitivity reaction occurring after the administration of 20% HSA.

Case Report: A 68-year-old male, with Child-Pugh B alcoholic cirrhosis, underwent 5 liters paracentesis, followed by administration of 20% HSA. In less than an hour he developed severe hypotension (70/50 mmHg) and an erythematous maculopapular pruritic rash on the trunk and upper limbs, associated with a distinctive metallic mouth taste. These manifestations subsided after intravenous clemastine and hydrocortisone. Acute tryptase level was not assessed. Allergy workup was performed after the acute window period and in the first 6 months after the index episode and included the following procedures:

- Basophil activation test (BAT) with HSA and fresh frozen plasma (FFP) - performed twice with inconclusive results due to high CD63 expression in the negative controls;

- Skin prick tests with undiluted HSA and FFP and intradermal tests (IDT) with 1/10 dilutions, with a positive IDT with HSA (Figure 1).

We have decided to wait for the patient to need a new albumin infusion to perform an intravenous challenge with FFP.

Conclusion: Immune-mediated reactions to HSA have been previously reported in a limited number of cases. Those employing skin tests used similar concentrations for both prick and IDT. The results of our allergy work-up are highly suggestive of an IgE-mediated allergy to a commercial HSA solution.

The procedure to obtain a purified form of albumin from plasma may induce structural or conformational changes in the albumin molecule rendering it immunogenic. This may explain the negative skin tests with FFP and support our expectation of tolerance to HSA naturally present in FFP as an alternative in case our patient needs albumin infusion again.