Please Sign In or Create an account
HIV infection is associated with the aberrant expression of B cell receptors for cytokines that regulate B cell activation and differentiation

HIV infection is associated with the aberrant expression of B cell receptors for cytokines that regulate B cell activation and differentiation

HIV infection causes B cell activation and dysfunction that deplete memory B cells and impair isotype diversification of IgG antibodies. Cytokines are critical for B cell activation (e.g. interleukin (IL)-6, interferon (IFN)-γ, IFN-α) and immunoglobulin isotype diversification (e.g. IL-21). As aberrant expression of cytokine receptors, such as the IL-7 receptor, is a characteristic abnormality of CD4+ T cells in HIV patients, we have examined cytokine receptor expression on B cells to gain further insights into B cell dysfunction.

Methods: Expression of receptors for IL-6, IFN-γ (IFNGR1 and IFNGR2), IFN-α (IFNAR1 and IFNAR2) and IL-21 was examined on B cell subpopulations (naïve, switched memory and marginal-zone-like (MZL)), defined by expression of IgD and CD27, in cryopreserved peripheral blood mononuclear cells from HIV patients who were ART naïve (n=10) or ART-treated (n=10) and non-HIV controls (n=10). results: IFNAR1 was increased on naïve (IgD+, CD27-), switched memory (IgD-, CD27+) and marginal zone-like (IgD+, CD27+) B cells (p<0.008) and did not decline on ART. IFNAR2 was also increased on switched memory B cells (p=0.04) but was lower on MZL B cells (p=0.01), returning to normal on ART. IFNGR1 and IFNGR2 were lower on MZL B cells alone (p=0.02 and p=0.005, respectively) and normalised with ART, whereas IFNGR2 was increased on switched memory B cells. IL-21R was increased on all B cell subpopulations (p<0.03) while IL-6R was increased only on switched memory B cells (p=0.04).

Conclusions: B cells of HIV patients exhibit aberrant expression of IFN-α receptors to a greater extent than the IL-6R, suggesting that IFN-α may be more significant than IL-6 in B cell activation. Impaired isotype diversification of IgG antibodies is not associated with decreased IL-21R expression on B cells. Aberrant expression of some receptors persists on ART and might be used as a marker of ongoing B cell dysfunction.

Conference: ASHM 2013
Areas of Interest / Categories: AIDS 2013, Anti RetroViral Therapy, HIV

AIDS 2013

Reinvigorating evidence for action and capacity in community HIV programs (REACH Project)

REACH was a collaborative research and practice initiative to develop evidence building frameworks, capacity, tools and resources with the Victorian HIV community partnership.

The impact of immune activation on natural killer cells in the setting of HIV infection

HIV disease is associated with chronic inflammation and activation of the innate immune system. This state, as measured using plasma markers of inflammation, persists following suppression of HIV viremia using antiretroviral therapy, and may increase risk of non-AIDS co-morbidities. The causes of innate immune activation in the setting of virological suppression are unclear. Natural killer (NK) cells are innate immune cells that kill virus-infected and transformed cells without prior sensitization. We have shown that NK cells are activated both phenotypically (elevated expression of HLA-DR) and functionally (increased spontaneous degranulation measured by CD107a surface expression) in virologically suppressed (VS) HIV+ individuals. NK cells also lose expression of CD16, the receptor which mediates antibody-dependent cellular cytotoxicity.

Men who take more risks avoid HIV testing due to structural barriers

Regular HIV testing is recommended in men who take sexual risks. We assessed the relationship between perceived barriers to HIV testing, and frequency of testing among men who engaged in unprotected anal intercourse with casual partners (UAIC), to inform HIV testing strategies.

Delayed HIV diagnoses among gay and bisexual men in Australia

The majority of HIV diagnoses including delayed diagnoses in Australia occur among men who report homosexual contact – hereafter called gay and bisexual men (GBM). Delayed diagnosis is strongly associated with increased HIV-related mortality and morbidity. People who are unaware of their HIV-positive status may also be unwittingly transmitting HIV. We assessed trends in delayed HIV diagnoses among GBM in Australia.

Complex case report that illustrates the paucity of data for long term management of Visceral Leishmania-HIV co-infection.

HIV-associated leishmaniasis, endemic in the Mediterranean basin is a growing problem in India, Brazil and East Africa. Despite surviving for than 20 years, the clinical course of our visceral-leishmania (VL)-HIV co-infected patient illustrates several management challenges including diagnosis, speciation and drug resistance; monitoring burden of disease; access to and use of VL-treatments; end-organ toxicity and the combined immunosuppressive effects of HIV-VL.

Clinical factors associated with suboptimal adherence to antiretroviral therapy in Asia

Adherence to combination antiretroviral therapy (cART ) plays an important role on treatment outcomes. The TREAT Asia Studies to Evaluate Resistance – Monitoring Cohort Study (TASER-M) collects patients’ adherence based on a Visual Analogue Scale. The aim of this analysis was to assess the rates of, and factors associated with, suboptimal adherence in the first 24 months of initial cART in Asian patients.

Definitions of early first sexual intercourse

Early first sexual intercourse has been proposed as an important marker of later sexual and reproductive health. Discussions of what constitutes early sexual debut in this context, however, have been limited.