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Effect of amphotericin B and fluconazole on platelet membrane glycoproteins
1National Heart, Lung, and Blood Institute, Bethesda, Maryland.
Background:
Fever, chills, and reduced platelet recovery may result when platelets are transfused simultaneously with amphotericin B. Amphotericin B reportedly increases the pitting of membranes in stored platelets.
Study Design And Methods:
The effects of amphotericin B and another antifungal agent, fluconazole, on platelet membrane glycoproteins (GP) were examined by the incubation of split aliquots of fresh and stored platelet concentrates (PCs) with these drugs for 3 days in storage bags. To determine the effect of storage, PCs were stored for 5 days, and aliquots removed on Days 1 through 5 were placed in platelet storage bags with 4 micrograms per mL of amphotericin B for 2 to 6 hours. Membrane glycoprotein expression was assessed by flow cytometry with fluorescein isothiocyanate-labeled monoclonal antibodies (MoAbs) directed against the following antigens: GPIb (CD42b), CD63 (an activation protein), P-selectin (CD62), and GPIIb/IIIa (CD41a).
Results:
Amphotericin B produced a concentration-dependent decrease in the surface binding of CD42b MoAb with no consistent changes in the binding of CD41a, CD63, or CD62 MoAbs after a 3-day exposure. Stored but not fresh PCs showed decreased binding of MoAb CD42b after a 6-hour exposure to amphotericin B (4 micrograms/mL). Fluconazole produced no changes. When the binding of MoAb CD42b to permeabilized platelets was used to measure total platelet content, amphotericin B (4 micrograms/mL) decreased MoAb CD42b binding to a similar degree in fresh and stored platelets. Inhibition of aggregation to ADP and collagen and ADP and epinephrine was seen in stored but not fresh PCs.
Conclusion:
Therapeutic levels of amphotericin B resulted in partial loss of total platelet GPIb in fresh and stored PCs, but decreased surface expression of platelet membrane GPIb only in stored platelets. This difference between fresh and stored platelets may be related to the limited reservoir of GPIb available for redistribution to the membrane in the previously stored PCs and may account for the decreased recovery of transfused platelets observed in some patients receiving amphotericin B.
Insights
Amphotericin B reduces platelet recovery by decreasing surface GPIb, especially in stored platelets. Fluconazole had no effect on platelet glycoproteins. This impacts transfusion safety.
Area of Science:
- Hematology
- Transfusion Medicine
- Pharmacology
Background:
- Platelet transfusions can be complicated by fever, chills, and reduced recovery when co-administered with amphotericin B.
- Amphotericin B is suspected to increase membrane pitting in stored platelets, potentially affecting their function.
Purpose of the Study:
- To investigate the effects of amphotericin B and fluconazole on platelet membrane glycoproteins (GP).
- To determine how storage affects the interaction between antifungals and platelet GPs.
Main Methods:
- Fresh and stored platelet concentrates (PCs) were incubated with amphotericin B or fluconazole for 3 days.
- Platelet concentrates stored for up to 5 days were exposed to amphotericin B for 2-6 hours.
- Membrane glycoprotein expression (GPIb/CD42b, CD63, P-selectin/CD62, GPIIb/IIIa/CD41a) was assessed via flow cytometry.
Main Results:
- Amphotericin B caused a dose-dependent decrease in GPIb (CD42b) surface binding, particularly in stored platelets after 6 hours.
- No significant changes were observed for CD41a, CD63, or CD62.
- Fluconazole did not alter platelet glycoprotein expression.
- Amphotericin B reduced total GPIb content similarly in fresh and stored platelets.
- Stored platelets showed inhibited aggregation responses to ADP and collagen/epinephrine.
Conclusions:
- Therapeutic amphotericin B levels lead to partial loss of total platelet GPIb and decreased surface GPIb expression in stored platelets.
- The reduced surface GPIb in stored platelets may stem from a limited GPIb reserve, explaining decreased transfused platelet recovery in patients receiving amphotericin B.