The effect of plasma auto-IgGs on CD4+ T cell apoptosis and recovery in HIV-infected patients under antiretroviral therapy

The link between chronic cocaine use, B cell perturbations, and blunted immune recovery in HIV-infected individuals on suppressive ART

Background

We recently reveal that anti-CD4 autoantibodies contribute to blunted CD4+ T cell reconstitution in HIV+ individuals on antiretroviral therapy (ART). Cocaine use is common among HIV+ individuals and is associated with accelerated disease progression. However, the mechanisms underlying cocaine-induced immune perturbations remain obscure.

Methods

We evaluated plasma levels of anti-CD4 IgG and markers of microbial translocation, as well as B-cell gene expression profiles and activation in HIV+ chronic cocaine users and non-users on suppressive ART, as well as uninfected controls. Plasma purified anti-CD4 IgGs were assessed for antibody-dependent cytotoxicity (ADCC).

Results

HIV+ cocaine users had increased plasma levels of anti-CD4 IgGs, lipopolysaccharide (LPS), and soluble CD14 (sCD14) versus non-users. An inverse correlation was observed in cocaine users, but not non-drug users. Anti-CD4 IgGs from HIV+ cocaine users mediated CD4+ T cell death through ADCC in vitro. B cells from HIV+ cocaine users exhibited activation signaling pathways and activation (cycling and TLR4 expression) related to microbial translocation versus non-users.

Conclusions

This study improves our understanding of cocaine associated B cell perturbations and immune failure and the new appreciation for autoreactive B cells as novel therapeutic targets.

Neonatal immunization prevents the development of a chronic autoimmune response against CD4 caused by HIV-1 gp120 in rats

The AIDS autoimmune hypothesis suggests that suppression of the autoimmunity against CD4 T lymphocytes should positively affect the course of HIV infection. The aim of this study was to determine whether neonatal immunization can be used to prevent induction of anti-CD4 autoimmune response triggered by HIV-1. The induction of anti-CD4 lymphocytes in HIV infection proceeds via their idiotypic interactions with anti-gp120 lymphocytes; therefore, the creation of tolerance to gp120 by means of neonatal immunization with gp120 may prevent subsequent induction of anti-CD4 lymphocytes. Neonatal immunization with CD4 may also be effective, since it can increase natural tolerance to CD4 and prevent its subsequent breakdown by gp120. Thus, anti-gp120 lymphocytes and anti-CD4 lymphocytes are potential neonatal stimulation targets. To determine which of these targets can be manipulated during the neonatal period, a computer model of the immune network was used. The computer model predictions were tested in a rat model of autoimmune CD4 T lymphocytopenia induced by gp120. The in silico studies predicted that stimulating a clone against an external antigen that is in idiotype-anti-idiotype interactions with an autoclone, when stimulation is performed during the time that the dynamic behavior type of the immune network is being established, changes the autoimmune response from self-perpetuating to transient. Experimental studies confirmed the predictions of the computer model and showed that neonatal immunization with gp120 suppresses anti-CD4 autoantibody production and prevents the development of autoimmune CD4 T lymphocytopenia triggered in adult rats by gp120. Neonatal HIV-1 gp120 immunization enhances natural tolerance to CD4.

Anti-CD4 autoantibodies in immunological non-responder people living with HIV: Cause of CD4+ T-cell depletion?

OBJECTIVE

We aimed to evaluate the anti-CD4 IgG role in the poor immune recovery of immunological nonresponder people with HIV (INR).

DESIGN

INR display low CD4+ T-cell increase despite long-term undetectable viremia. Among other factors, autologous anti-CD4 IgG-dependent cellular cytotoxicity (ADCC) by natural killer (NK) cells has been proposed to cause CD4+ T-cell depletion.

METHODS

Plasma anti-CD4 IgG levels were quantified and purified by chromatography columns for the subsequent use in a coculture of CD4+ T and NK cells. We analyzed NK cell degranulation markers (CD107a, perforin and granzyme B) and IFN-γ release, and CD4+ T-cell death. Binding affinity of anti-CD4 IgG for CD4+ T cells was also assessed.

RESULTS

A total of 168 individuals were enrolled (INR, 56; immunological responders, 40; treatment-naive, 39; and healthy controls, 33). The highest anti-CD4 IgG levels were found in treatment-naive PWH, followed by participants on treatment. There were no correlations between anti-CD4 IgG levels and CD4+ T-cell counts. In a 15-participant subgroup (naive, immunological responders, and INR), anti-CD4 IgG induced a slight NK-cell expression of degranulation markers and IFN-γ; however, the percentage of CD4+ T-cell death was negligible. Consistently, no significant changes in NK cell polyfunctionality were observed. In addition, purified anti-CD4 IgG showed scarce binding affinity for CD4+ T cells. These results were similar in all analyzed participant groups.

CONCLUSION

Our results suggest that autologous anti-CD4 IgG neither trigger CD4+ T-cell death by ADCC nor are responsible for CD4+ lymphocyte depletion in INR.

VIDEO ABSTRACT

http://links.lww.com/QAD/C518.

Elevated Cerebrospinal Fluid Anti-CD4 Autoantibody Levels in HIV Associate with Neuroinflammation

The mechanisms of persistent central nervous system (CNS) inflammation in people with HIV (PWH) despite effective antiretroviral therapy (ART) are not fully understood. We have recently shown that plasma anti-CD4 IgGs contribute to poor CD4⁺ T cell recovery during suppressive ART via antibody-mediated cytotoxicity (ADCC) against CD4⁺ T cells, and that plasma anti-CD4 IgG levels are associated with worse cognitive performance and specific brain area atrophy. However, the role of anti-CD4 IgGs in neuroinflammation remains unclear. In the current study, plasma and cerebrospinal fluid (CSF) samples from 31 ART-naive and 26 treated, virologically suppressed PWH, along with 16 HIV-seronegative controls, were evaluated for CSF levels of anti-CD4 IgG, white blood cell (WBC) counts, soluble biomarkers of neuroinflammation, and neurofilament light chain (NfL). We found that 37% of the PWH exhibited elevated CSF anti-CD4 IgG levels, but few or none of the PWH were observed with elevated CSF anti-CD4 IgM, anti-CD8 IgG, or anti-double-strand DNA IgG. CSF anti-CD4 IgG levels in PWH were directly correlated with neuroinflammation (WBC counts, neopterin, and markers of myeloid cell activation), but not with CSF NfL levels. Using cells from one immune nonresponder to ART, we generated a pathogenic anti-CD4 monoclonal IgG (JF19) presenting with ADCC activity; JF19 induced the production of soluble CD14 (sCD14) and interleukin-8 (IL-8) in human primary monocyte-derived macrophages via CD4 binding in vitro. This study demonstrates for the first time that elevated CSF anti-CD4 IgG levels present in a subgroup of PWH which may play a role in neuroinflammation in HIV.

IMPORTANCE This study reports that an autoantibody presents in the CNS of HIV patients and that its levels in the CSF correlate with some markers of neuroinflammation.

Polymorphisms in TNF-α/TNFR1 pathway genes are associated with CD4+ T cells recovery in HIV-1-infected individuals on antiretroviral therapy

BACKGROUND

Antiretroviral therapy (ART) is an important hallmark of HIV-1 treatment, enabling viral load suppression to undetectable levels and CD4+ T cells recovery. However, some individuals do not recover the CD4+ T cell count to normal levels, despite viral suppression. We hypothesize that variation in genes involved in extrinsic apoptosis pathways may influence interindividual immune recovery during ART.

METHODS

We assessed clinic-epidemiological variables, and the allelic/genotypic distribution of functional single nucleotide polymorphisms in genes involved in extrinsic apoptosis pathways (TNFRSF1A: rs1800692, rs767455; TNFAIP3: rs2270926; NFKBIA: rs8904; TNF-α: rs1800629) and their relationship with immune recovery in ART treated (one year) HIV-1-infected individuals. We enrolled 155 HIV-1 infected individuals, 102 showing immunological success and 53 with immunological failure.

RESULTS

Through univariate analysis, we observed that the male sex (60.4%, p=0.002) showed higher median of age at treatment onset (34.8 years, p=0.034) and higher time until virological suppression (6 months, p=0.035), both risk factors for immune failure. Survival analysis revealed that individuals who started ART treatment with T CD4+ cells count <200 cells/mm3 took a longer time to immunological recovery (median time = 27 months, p=0.029). ART containing zidovudine (AZT) also was associated with immune recovery in univariate e multivariate analysis. Variants in TNFRSF1A (rs767455: T, TT; rs1800692-rs767455: T-T combination) and NFKBIA (rs8904: A) genes associated with immune failure, while NFKBIA (rs8904: GA) and TNF-α (rs1800629: GA), with CD4+ T cells recovery.

CONCLUSIONS

Clinic-epidemiological and variants in genes involved in extrinsic apoptosis pathways might influence the CD4+ T cells immune recovery.

A link between IL-23 and anti-CD4 autoantibody production in antiretroviral-treated HIV-infected individuals

Potential mechanisms of poor CD4+ T cell reconstitution after viral suppression with antiretroviral therapy (ART) in HIV disease have been extensively investigated. We recently discovered that anti-CD4 autoantibody plays a role in impaired CD4+ T cell recovery from ART in HIV-infected individuals with viral suppression, which accounts for a mechanism specific for CD4+ T cell depletion. However, the mechanism of pathologic anti-CD4 autoantibody production in treated HIV disease remains unknown. Here we report that seasonal influenza vaccination induced IgG anti-CD4 autoantibodies, predominant IgG3 subclass, in some viral-suppressed ART-treated HIV+ subjects. To explore the mechanism of anti-CD4 antibody production in this population, we performed and analyzed gene profiles in isolated B cells using a gene microarray and plasma 32 cytokines. Notably, both gene expression and multiple cytokine analyses showed pre-vaccination plasma level of IL-23 was the key cytokine linked to IgG anti-CD4 antibody production in response to immunization in vivo Exogenous rIL-23 increased autoreactive IgG binding on CD4+ T cells from HIV+ subjects in vitro Results from this study may reveal a role of IL-23 in anti-CD4 autoantibody production in treated HIV.IMPORTANCEIn our published studies, we determine that pathological anti-CD4 IgGs from immunologic non-responders on virally-suppressive ART (CD4 cell counts < 350 cells/μL) mediated CD4+ T cell death via antibody-mediated cytotoxicity (ADCC), which play a role in poor CD4+ T cell recovery from ART. Up to 25% of HIV-infected individuals are non-responders and demonstrate increased morbidity and mortality. However, the mechanism of anti-CD4 autoantibody production in treated HIV remains unknown. In this study, we report that IL-23 may be the key cytokine to promote anti-CD4 autoantibody production after immunization in ART-treated HIV-infected individuals.

Effects of Early and Delayed Antiretroviral Therapy on Plasma Anti-CD4 Autoreactive IgG and Its Association With CD4+ T-Cell Recovery in Acute HIV-Infected Individuals

Background

Plasma levels of anti-CD4 autoantibodies are increased in chronically HIV-infected patients and inversely correlated with CD4⁺ T-cell recovery under viral-suppressive antiretroviral therapy (ART). However, it remains unknown the effect of early ART on plasma anti-CD4 autoantibody levels in acute HIV infection (AHI).

Methods

In this cohort study, we evaluated the effect of early and delayed initiation of ART on plasma anti-CD4 autoantibody levels in AHI individuals (n = 90). Blood samples were collected from men who had sex with men (MSM) with acute infection, pre-ART, and 4, 24, 48, and 96 weeks after ART. Plasma levels of anti-CD4 immunoglobulin G (IgG) were measured by ELISA.

Results

We found that plasma anti-CD4 IgG levels were significantly increased in AHI individuals compared with healthy controls (HCs) prior to ART. Notably, early ART decreased plasma anti-CD4 IgG to the levels similar to HCs starting at 24 weeks (W). However, delayed initiation of ART did not significantly reduce plasma anti-CD4 IgG levels in AHI individuals. Moreover, the peripheral CD4⁺ T-cell counts were inversely correlated with plasma anti-CD4 IgG levels in AHI individuals at 48 and 96 W after early ART but not after delayed ART.

Conclusions

Taken together, our findings demonstrate for the first time that early ART, but not delayed initiation of ART, is effective in influencing anti-CD4 autoantibody production and recovering CD4⁺ T-cell counts in AHI individuals.