IFNα and its signature are increased in plasma of HIV-1-infected subjects not receiving ART.

<p>Plasma IFN-I bioactivity measured by the iLite™ bioassay was increased in plasma of HIV-1-infected subjects in comparison to uninfected subjects (median 1.04 IFNα2 equivalent units for HIV-1-infected subjects, median 0.89 IFNα2 equivalent units for uninfected subjects, p = 0.012) (A). IFNα was increased in plasma of HIV-1-infected subjects in comparison to uninfected subjects (median 4.27 pg/ml for HIV-1-infected subjects, median 3.13 pg/ml for uninfected subjects, p<0.001) (B). IFNβ was not increased in plasma of HIV-1-infected subjects compared to uninfected subjects (median 2.34 pg/ml for HIV-1-infected subjects, median 2.34 pg/ml for uninfected subjects, p = 0.560) (B). IFNω was not increased in plasma of HIV-1-infected subjects compared to uninfected subjects (median 4.69 pg/ml for HIV-1-infected subjects, median 4.69 pg/ml for uninfected subjects, p = 0.837) (B). Plasma IFNα levels were strongly associated with plasma IFN-I bioactivity in HIV-1-infected subjects (r = 0.711, p<0.001) (C). Plasma IP-10 was increased in plasma of HIV-1-infected subjects in comparison to uninfected subjects (median 538.2 pg/ml for HIV-1-infected subjects, median 132.6 pg/ml for uninfected subjects, p = 0.002) (D). Slight variations in sample sizes for different assays occur as results for some subjects were not available.</p

Therapeutic administration of IFNα induces increased expression of the activation marker CD38 on memory CD8 T cells in HCV-infected subjects.

<p>A longitudinal study was conducted to assess CD38 expression on memory (CD45RO+) CD8 T cells. Seven HCV-infected (HIV-1-uninfected) subjects were studied immediately prior to initiation of therapy with s.c. pegylated IFNα and oral ribavirin, and after 4 and 12 weeks of therapy. CD38-specific MFI (MFI for CD38 minus MFI for IgG1 isotype control) increased on memory CD8 T cells in all seven treated subjects at 4 weeks of therapy (p = 0.018). A further increase in CD38 was observed in five of seven subjects by week 12 of therapy (p = 0.018). The difference in CD38 expression between week 0 (prior to therapy) and week 12 was highly significant (p = 0.018).</p

IFNα mRNA expression is elevated in lymph nodes, but not peripheral blood leukocytes, of HIV-1-infected subjects.

<p>There was no significant difference in expression of IFNα mRNA in whole blood leukocytes of HIV-1-infected subjects without ART (median relative expression of 0.10) and uninfected subjects (median relative expression of 0.88) (p = 0.981) (A). Similarly, there was no significant difference in IFNβ mRNA expression in whole blood leukocytes (median relative expression of 0.003 for HIV-1-infected subjects, median relative expression of 0.001 for uninfected subjects; p = 0.298) (A). An IFN-I signature was evident in peripheral blood leukocytes, as expression of the ISG MxA was significantly increased in HIV-1-infected subjects without ART compared to uninfected subjects (median relative expression of 0.85 for HIV-1-infected subjects, median relative expression of 0.26 for uninfected subjects; p = 0.016) (A). In contrast, expression of IFNα mRNA in lymph node tissue was significantly elevated in HIV-1-infected subjects without ART (median relative expression of 0.93) relative to uninfected subjects (median relative expression of 0.12) (p = 0.037) (B). There was no statistically significant difference in IFNβ mRNA expression between the two donor groups (median relative expression of 0.20 for HIV-1-infected subjects, median relative expression of 0.06 for uninfected subjects; p = 0.728) (B). Expression of the ISG MxA was significantly increased in lymph node tissue from HIV-1-infected subjects compared to uninfected subjects (median relative expression of 1.05 for HIV-1-infected subjects vs. 0.45 for uninfected subjects; p = 0.037) (B).</p

Plasma IFNα and IFN-I bioactivity are associated with plasma HIV-1 RNA levels, CD4 T cell count and immune activation in untreated subjects with chronic HIV-1-infection.

<p>Plasma HIV-1 RNA levels in HIV-1-infected subjects without ART correlated positively with plasma IFN-I bioactivity (r = 0.329, p = 0.017) (A), as well as with plasma IFNα (r = 0.356, p = 0.008) (B). Absolute CD4 T cell count in these subjects correlated inversely with plasma IFN-I bioactivity (r = -0.426, p = 0.002) (C) and plasma IFNα (r = -0.407, p = 0.002) (D). Expression of CD38 by memory (CD45RO+) CD8 T cells in these subjects correlated positively with plasma IFN-I bioactivity (r = 0.374, p = 0.021) (E) and with plasma IFNα (r = 0.387, p = 0.01) (F).</p

Plasma IFNα and IP-10 levels are comparable between HIV-1 infected subjects on ART and uninfected subjects.

<p>IFNα and IP-10 levels were determined in the plasma of 25 individuals with chronic HIV-1 infection who received ART and responded with HIV-1 RNA below assay detection limits (<50 copies/ml) for two years or more. IFNα was detected in plasma from only one such donor, and then at trace levels (A). The difference in plasma IFNα level between HIV-1 infected subjects without ART and HIV-1-infected subjects with ART was highly significant (p<0.001). Plasma IP-10 levels in ART-treated HIV-1-infected donors were comparable to those in uninfected donors (p = 0.460) and were significantly lower in comparison to untreated HIV-1-infected donors (p<0.001) (B).</p