Abstract
Thrombocytopenia is a well-known manifestation of acute tropical infectious diseases.
The role of platelets in infections has received much attention recently because of
their emerging activities in modulation of inflammatory responses, host defense, and
vascular integrity. However, while many studies have addressed thrombocytopenia in
tropical infections, abnormalities in platelet function have been largely overlooked.
This is an important research gap, as platelet dysfunction may contribute to the bleeding
tendency that characterizes some tropical infections. The development of novel platelet
function assays that can be used in thrombocytopenic conditions (e.g., flow cytometry
assays) has contributed to important new insights in recent years. In this review,
the importance of platelets in tropical infections is discussed with special emphasis
on the underlying mechanisms and consequences of thrombocytopenia and platelet dysfunction
in these infections. Special attention is paid to malaria, a disease characterized
by microvascular obstruction in which bleeding is rare, and to infections in which
bleeding is common, such as dengue, other viral hemorrhagic fevers, and the bacterial
infection leptospirosis. Given the importance of platelet function abnormalities in
these infections, the development of affordable assays for monitoring of platelet
function in low-resource countries, as well as pharmacologic interventions to prevent
or reverse platelet function abnormalities, might improve clinical care and the prognosis
of these infections.
Keywords
platelets - thrombocytopenia - malaria - dengue - leptospirosis
