Induction of Granulocyte Colony-stimulating Factor by Acute Febrile Infection but Not by Neutropenia in HIV-seropositive Individuals

The objective of this study was to assess endogenous granulocyte colony-stimulating factor (G-CSF) serum levels in HIV-seropositive individuals with persistent neutropenia or acute febrile infection. Serum levels of G-CSF were measured by enzyme-linked immunoabsorbent assay. HIV-seropositive subjects (n = 28) with afebrile neutropenia (< 1000 neutrophils/microliter) showed low G-CSF serum levels (i.e., median was below the detection limit) not different from those of healthy volunteers (n = 66) or nonneutropenic HIV-seropositive controls (n = 75). In contrast, patients with acute myeloid leukemia and afebrile neutropenia from chemotherapy (n = 17) demonstrated markedly elevated G-CSF levels (median, 264 pg/ml; p < 0.0001). However, HIV-seropositive patients with pneumonia (n = 17) showed increases of G-CSF serum levels (median, 152 pg/ml; p < 0.0001) similar to HIV-seronegative patients (n = 17) with pneumonia (median, 123 pg/ml; p = 0.97). The results suggest that there may be a contribution of low G-CSF serum levels to persistent neutropenia in HIV-seropositive individuals. Moreover, the different G-CSF serum levels in HIV-seropositive individuals in response to neutropenia or acute febrile inflammation suggest different mechanisms for the regulation of G-CSF.