Association of acute thrombocytopenia with anaphylaxis

Abstract

A commonly seen phenomenon in the hospital and critical care setting is anaphylaxis. This acute systemic inflammatory reaction can lead to anaphylactic shock in severe cases and potentially be fatal. The role of platelets in anaphylactic reactions is not well established; however, platelets, among other mediators such as platelet-activating factor, have been shown to promote a prothrombotic state shortly after an acute hypersensitivity reaction. In addition, the aggregation of platelets promoted by platelet-activating factor and other mediators can also lead to thrombocytopenia. We present a case of a 57-year-old woman who developed severe anaphylaxis while receiving chemotherapy with paclitaxel suspended in Cremophor, a well-known allergen. She was profoundly thrombocytopenic following the reaction and was treated with therapeutic anticoagulation, with no thrombus formation.

Genes involved in platelet aggregation and activation are downregulated during acute anaphylaxis in humans

“…Bleeding during trauma, and activation of the coagulation cascade, is a potential confounder which likely contributes to low platelet counts seen in this group. Despite limitations, findings from this study support recent literature suggesting an association between platelet activation and aggregation, and severe allergy and anaphylaxis 4,15,29,30 . Specifically, we have demonstrated for the first time the downregulation of platelet‐related genes during the acute anaphylactic reaction in humans.…”

“…Similarly, in a human cohort with drug‐induced anaphylaxis, platelet activation and consequent reduction in circulating platelets were shown to be associated with reaction severity 4 . Case series have also demonstrated lowered platelet numbers post anaphylaxis 29,30 . Combined, this evidence suggests that platelet aggregation and subsequent reduction in circulating platelets is a physiological response to anaphylaxis, which may be linked to downregulation of genes involved in these processes as is observed in this study.…”

“…In contrast to results finding downregulation of platelet genes during anaphylaxis, experimental and observational studies have demonstrated the activation of platelets and subsequent aggregation during anaphylaxis 4,29,30 . We therefore hypothesise that observed downregulation of genes involved in platelet activation and aggregation is a negative feedback response to enhanced platelet activity during anaphylaxis.…”

“…Despite limitations, findings from this study support recent literature suggesting an association between platelet activation and aggregation, and severe allergy and anaphylaxis. 4,15,29,30 Specifically, we have demonstrated for the first time the downregulation of platelet-related genes during the acute anaphylactic reaction in humans. Our results suggest this involvement occurs early during the acute reaction, and we hypothesise this is a negative feedback response to platelet activation and aggregation.…”

“…In contrast to results finding downregulation of platelet genes during anaphylaxis, experimental and observational studies have demonstrated the activation of platelets and subsequent aggregation during anaphylaxis. 4,29,30 We therefore hypothesise that observed downregulation of genes involved in platelet activation and aggregation is a negative feedback response to enhanced platelet activity during anaphylaxis. This negative feedback is initiated early during platelet activation and involves downregulation of platelet adhesive receptors to regulate platelet aggregation, as suggested by the downregulation of GP1BA.…”