Lack of polarized type 1 or type 2 cytokine profile in asymptomatic HIV-1-infected patients during a two-year bimonthly follow-up

Pro- and anti-inflammatory cytokines in human immunodeficiency virus infection and acquired immunodeficiency syndrome

In persons with human immunodeficiency virus (HIV) infection and/or acquired immunodeficiency syndrome (AIDS), the immune system becomes dysfunctional in many ways. There is both immunodeficiency due to the loss of CD4-positive T helper cells and hyperactivity as a result of B-cell activation. Likewise, both decreases and increases are seen in the production and/or activity of cytokines. Cytokine changes in HIV infection have been assessed by a variety of techniques, ranging from determination of cytokine gene expression at the mRNA level to secretion of cytokine proteins in vivo and in vitro. Changes in cytokine levels in HIV-infected persons can affect the function of the immune system, and have the potential to directly impact the course of HIV disease by enhancing or suppressing HIV replication. In particular, the balance between the pro-inflammatory cytokines interleukin (IL)-1, IL-6, and tumor necrosis factor-alpha, which up-regulate HIV expression, and IL-10, which can act both as an anti-inflammatory cytokine and a B-cell stimulatory factor, may play an important role in the progression to AIDS. In light of its ability to suppress the production of pro-inflammatory cytokines and, under some conditions, suppress HIV replication, increased IL-10 may be viewed as beneficial in slowing HIV disease progression. However, an association between increased IL-10 and the development of AIDS-associated B-cell lymphoma highlights the bifunctional nature of IL-10 as both an anti-inflammatory and B-cell-stimulatory cytokine that could have beneficial and detrimental effects on the course of HIV infection and AIDS.

The interferon antagonist sarcolectin in the progress of HIV-1 infection and in AIDS

Sarcolectin (SCL) is a nonspecific stimulator of cellular DNA synthesis that was found in all animal sera tested to date. It inhibits the established interferon (IFN)-dependent antiviral state, restoring cells to their normal status. In this study, we examined the excretion/secretion of the IFN antagonist SCL in sera from healthy donors and in sera collected during different periods of human immunodeficiency virus type 1 (HIV-1) infection. We followed HIV-1-infected patients during all stages of development (seroconversion, initial and advanced phases of AIDS) and found a significant increase in SCL in sera of HIV-infected patients compared with seronegative subjects used as controls. This increase was established during seroconversion, and then the titers leveled off. In the final stage of the disease, the SCL titer increased again very significantly. We attribute this rapid rise to the virus-dependent destruction of T cells that can no longer be repaired. The high SCL level observed at this final stage, which is most predictive of the disease's progression, suggests that the action, rather than the production, of IFN is impaired.

T(H)1 to T(H)2 shift of cytokines in peripheral blood of HIV-infected patients is detectable by reverse transcriptase polymerase chain reaction but not by enzyme-linked immunosorbent assay under nonstimulated conditions

BACKGROUND

Dysregulation of cytokines has been implicated in the pathogenesis of HIV infection. Therefore, we determined tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), IL-4, IL-10, and interferon-gamma (IFN-gamma) mRNA and serum levels in HIV-infected patients under nonstimulated conditions.

MATERIAL AND METHODS

Blood samples of 32 HIV-infected patients and 10 healthy HIV-negative controls were analyzed. Cytokine serum levels were quantified by enzyme-linked immunosorbent assay (ELISA). Cytokine mRNA levels were determined semiquantitatively by competitive reverse transcriptase polymerase chain reaction (RT-PCR) and expressed as ratios relative to those of beta-actin.

RESULTS

Competitive RT-PCR was shown to be more sensitive than protein ELISA in analyzing cytokine production. We found a significant correlation between steady-state mRNA ratios and serum protein levels for TNF-alpha. Significantly higher cytokine mRNA ratios were found in those patients with IL-10 and IFN-gamma levels detectable by ELISA. Steady-state mRNA ratios of TNF-alpha, IL-4, and IL-10 were significantly increased in patients with highly replicative HIV-infection. Furthermore, elevated IL-4:IFN-gamma ratios were related to both high viral load and loss of CD4 cells.

DISCUSSION

Determination of steady-state mRNA ratios by semiquantitative RT-PCR represents a sensitive method to analyze cytokines in peripheral blood of HIV-infected patients under nonstimulated conditions. The data obtained with this technique provide further evidence for a T(H)1 to T(H)2 cytokine shift with progressive HIV disease.

Atopy, anergic status, and cytokine expression in HIV-infected subjects

BACKGROUND

In HIV infection T-cell dysfunction resulting in anergy and hypersensitivity reactions precedes T-cell depletion. A shift in the cytokine profile from a type 1 to a type 2 response has been postulated.

OBJECTIVE

We sought to examine the cytokine expression patterns in HIV infection and the relationship to allergy, stage of HIV disease, and other laboratory parameters.

METHODS

A cross-sectional analysis of IL-2, IL-4, IL-5, IL-6, IL-10, IL-12p35, IL-13, and IFN-gamma mRNA expression in PBMCs by noncompetitive dot-blot PCR was performed on blood obtained from 18 HIV-infected subjects. Delayed-type hypersensitivity multitests to detect anergy, skin prick testing and in vitro assay for specific IgE antibodies, assay for total IgE, and enumeration of eosinophils, CD4(+), and CD8(+) T cells were also performed on all subjects.

RESULTS

We found evidence of a decline in type 1 cytokines (IL-2, IL-12p35, and IFN-gamma) associated with AIDS, CD4(+) T cells less than 200/microL, anergy, and atopy, although this only reached statistical significance in anergy. There was no associated significant alteration in type 2 cytokines.

CONCLUSIONS

This is the first report of an association between low constitutive in vivo expression of IL-12 mRNA and anergy, which supports earlier data from in vitro stimulation studies. The presence of atopy was associated with a more global reduction in cytokine expression. Because the decline in type 1 cytokines was not accompanied by a similar decline in type 2 cytokines, this does suggest a shift in the type 1/type 2 balance.