Decreased type I interferon receptor-soluble isoform in antiretroviral-treated HIV-positive children

Which NK cell populations mark the high burden of CMV present in all HIV patients beginning ART in Indonesia?

Background

Cytomegalovirus (CMV) has been linked with cardiovascular disease (CVD) in populations where some individuals are seronegative. However, effects of CMV are unclear in HIV patients who all have high levels of CMV antibodies. Other metrics of their CMV burden are needed. Amongst transplant recipients, CMV drives the expansion of NK cell populations expressing NKG2C and/or LIR1 and lacking FcRγ.

Methods

Indonesian HIV patients (n = 40) were tested before ART and after 6 months, with healthy local controls (n = 20). All patients had high CMV antibody titres. 52% started therapy with CMV DNA detectable by qPCR, providing a crude measure of CMV burden. Proportions of CD56^Hi or CD56^Lo NK cells expressing FcRγ, NKG2C or LIR1 were determined flow cytometrically. CVD was predicted using carotid intimal media thickness (cIMT). Values were correlated with levels of CMV antibodies on ART.

Results

Patients had low proportions of CD56^Lo and more CD56^Hi NK cells. However proportions of FcRγ⁻ NK cells were lowest in patients with CMV DNA, and cIMT values related inversely with FcRγ⁻ NK cells in these patients. Percentages of NKG2C⁺CD56^Lo NK cells were similar in patients and controls, but rose in patients with CMV DNA. Proportions of NKG2C⁺ CD56^Hi NK cells correlated with levels of CMV antibodies in CMV DNA-negative patients.

Conclusions

We show that the very high burdens of CMV in this population confound systems developed to study effects of CMV in other populations. FcRγ⁻ NK cells may be depleted by very high CMV burdens, but NKG2C and antibody levels may be informative in patients on ART.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12981-022-00439-2.

Active and Persistent Cytomegalovirus Infections Affect T Cells in Young Adult HIV Patients Commencing Antiretroviral Therapy

Altered T cell profiles have been linked with metrics of persistent cytomegalovirus (CMV) infections in healthy aging and older HIV patients stable on antiretroviral therapy (ART). In this study, we use CMV DNA to identify active infections, and levels of CMV-reactive antibody to assess the persistent burden of CMV in a longitudinal study of 78 young adult patients beginning ART in Jakarta, Indonesia, with <200 CD4 T cells/μL. CMV antibodies, inflammatory markers (C-reactive protein [CRP], soluble interferon-α/β receptor) and T cell phenotypes were assessed before ART (V0) and after 1, 3, 6, and 12 months (V1-V12). CMV DNA was detected in 41 patients (52%) at V0, irrespective of CD4 T cell counts, gender, age, or plasma HIV RNA. CMV DNA+ patients had higher levels of antibody reactive with CMV Immediate Early 1 (IE-1) at V0 and V12 (p = 0.04), and with CMV lysate at V12 (p = 0.01). Detectable CMV DNA did not align with inflammatory markers, but associated with lower CD4/CD8 ratios until V3. CMV antibody levels correlated inversely with proportions of naive CD4 and CD8 T cells, and directly with proportions of CD57⁺ and activated memory T cells (CD3⁺ CD45RA^-) after 3-12 months on ART. Overall, active CMV replication is common in HIV patients beginning ART in Indonesia and associates with low CD4/CD8 ratios. Elevated levels of CMV-reactive antibody measured on ART also mark a depletion of naive T cells, accumulation of memory T cells, and may be a stable metric of the burden of CMV.

γ-H2AX+CD8+ T lymphocytes cannot respond to IFN-α, IL-2 or IL-6 in chronic hepatitis C virus infection

BACKGROUND & AIMS

Age is the dominant prognostic factor influencing the natural history of hepatitis C virus (HCV) infection and treatment response. Accelerated lymphocyte telomere shortening in HCV infection correlates with adverse clinical outcomes. Critical telomere shortening generates double-stranded DNA breaks (DSB) inducing the DNA damage response, leading to replicative senescence. The phenotype and function of CD8+ T lymphocytes and the in vitro response to IFN-α in relation to the DNA damage response were investigated in patients with chronic HCV infection.

METHODS

CD8+ T lymphocytes with DSB were identified by expression of γ-H2AX (Ser-139) in 134 HCV-exposed subjects and 27 controls. Telomere length was determined by flow-FISH; cytokine expression by intracellular cytokine staining; in vitro responses to IFN-α, IL-2 or IL-6 by phospho-STAT1 (Y701) or phospho-STAT5 (Y694) expression.

RESULTS

The proportion of circulating CD8+γ-H2AX+ T lymphocytes rose with increasing fibrosis stage (p=0.0023). CD8+γ-H2AX+ T lymphocytes were enriched in liver compared to blood (p=0.03). CD8+γ-H2AX+ T lymphocytes demonstrated increased IFN-γ (p=0.02) and reduced IL-2 expression (p=0.02). CD8+γ-H2AX+ T lymphocytes failed to phosphorylate STAT1 in response to IFN-α compared to unfractionated CD8+ T lymphocytes (p <0.0001). More widespread failure of Jak/Stat signalling in CD8+γ-H2AX+ T lymphocytes was suggested by impaired phosphorylation of STAT1 with IL-6 (p=0.002) and STAT5 with IL-2 (p=0.0039) compared to unfractionated CD8+ T-lymphocytes.

CONCLUSIONS

In chronic HCV infection, CD8+γ-H2AX+ T lymphocytes are highly differentiated with shortened telomeres, are more frequent within the liver, are associated with severe fibrosis and fail to activate Jak/Stat pathways in response to IFN-α, IL-2 or IL-6, perhaps explaining treatment failure in those with severe fibrosis.

Modulation of IFNAR1 mRNA expression in multiple sclerosis patients

Interferon-beta receptor (IFNAR) is composed of 2 subunits, IFNAR1 and IFNAR2, the latter of which is expressed as functional (IFNAR2.2), non-functional (IFNAR2.1) and soluble (IFNAR2.3) isoform. Real-Time PCR analysis of mRNA for all IFNAR components in multiple sclerosis patients naïve for therapy and undergoing long-term treatment with interferon-beta shows that IFNAR1 mRNA level is lower than in healthy controls. If long-term treated patients are divided according to the production of mRNA for Myxovirus protein-A, a marker of interferon-beta bioactivity, IFNAR1 mRNA reaches the values observed in controls only in Myxovirus protein-A-induced patients. Since chronic cell stimulation by interferon-beta induces IFNAR protein down-regulation, we suggest that the increase of IFNAR1 mRNA might serve as a mechanism for counterbalancing the loss of protein receptor, enhancing, at least in this sub-group of patients, cell responsiveness to interferon-beta.