Platelet counts, but not neutrophil counts, are associated with non-bleeding-related mortality in patients with hematological malignancies and post-chemotherapy febrile neutropenia.

INTRODUCTION: Neutrophils and platelets are key elements of the host immune response to sepsis, participating in both pathogen clearance and in sepsis-related tissue damage. Although it is widely recognized that patients with hematological malignancies and chemotherapy-induced febrile neutropenia are at increased risk of severe sepsis complications, the prognostic impact of neutrophil and platelet counts on sepsis-related outcomes remains controversial, with conflicting results regarding the magnitude of neutropenia. Moreover, to our knowledge, no studies have addressed the association of thrombocytopenia with outcomes in febrile neutropenia in patients with hematological malignancies. This study investigated the association of neutropenia and thrombocytopenia in a consecutive cohort of 113 patients with underlying hematological malignancies who were admitted to an academic tertiary hospital with chemotherapy-induced neutropenia.

METHODS: Neutrophil and platelet counts were obtained at fever onset and 24, 48 and 72 hours thereafter.

RESULTS: Neutrophil counts at the time of febrile neutropenia were not associated with sepsis-related mortality or other negative outcomes. However, a lower platelet count at fever onset was associated with non-bleeding sepsis-related mortality and the need of organ support. Moreover, the trajectories of both neutrophil and platelet counts in the first 72 hours after the onset of febrile neutropenia were also associated with negative outcomes.

CONCLUSION: These results highlight the heterogeneous role of platelets in the immune response and pave the way for studies exploring to what extent severe thrombocytopenia modulates the molecular and cellular mechanisms of post-febrile neutropenia sepsis in these patients.