Redistribution of FOXP3-Positive Regulatory T Cells From Lymphoid Tissues to Peripheral Blood in HIV-Infected Patients

[Modern modifications of penetrating keratoplasty with complex operative incision]

The basic principle of modern keratoplasty is selectivity, i.e. the choice of whether to replace only the affected corneal layer. However, when layer-by-layer and interlayer transplantation is not indicated, the method of choice is conventional penetrating keratoplasty. An alternative can be its modifications with complex profiles of the transplant edges and the bed, which are better justified in terms of pathogenesis. The most popular among them are mushroom, zig-zag and top-hat. These surgeries combine optical benefits of penetrating keratoplasty as they do not involve dissection of the corneal optical zone and can negate - to a certain degree - its main downsides such as low trauma tolerance of the postoperative scar, significant level of postoperative astigmatism, and increased visual rehabilitation time. Mushroom-shaped incisions can be performed manually with a femtosecond laser or a microkeratome, zig-zag incision - only with a femtosecond laser. Considering the diversity of keratoplasty modifications with complex operative incisions, further research is required for evaluation of their clinical effectiveness and analysis of postoperative complications.

Microbiome Dependent Regulation of Tregs and Th17 Cells in Mucosa

Mammals co-exist with resident microbial ecosystem that is composed of an incredible number and diversity of bacteria, viruses and fungi. Owing to direct contact between resident microbes and mucosal surfaces, both parties are in continuous and complex interactions resulting in important functional consequences. These interactions govern immune homeostasis, host response to infection, vaccination and cancer, as well as predisposition to metabolic, inflammatory and neurological disorders. Here, we discuss recent studies on direct and indirect effects of resident microbiota on regulatory T cells (T_regs) and Th17 cells at the cellular and molecular level. We review mechanisms by which commensal microbes influence mucosa in the context of bioactive molecules derived from resident bacteria, immune senescence, chronic inflammation and cancer. Lastly, we discuss potential therapeutic applications of microbiota alterations and microbial derivatives, for improving resilience of mucosal immunity and combating immunopathology.

Mucosal Regulatory T Cells and T Helper 17 Cells in HIV-Associated Immune Activation

Residual mucosal inflammation along with chronic systemic immune activation is an important feature in individuals infected with human immunodeficiency virus (HIV), and has been linked to a wide range of co-morbidities, including malignancy, opportunistic infections, immunopathology, and cardiovascular complications. Although combined antiretroviral therapy (cART) can reduce plasma viral loads to undetectable levels, reservoirs of virus persist, and increased mortality is associated with immune dysbiosis in mucosal lymphoid tissues. Immune-based therapies are pursued with the goal of improving CD4(+) T-cell restoration, as well as reducing chronic immune activation in cART-treated patients. However, the majority of research on immune activation has been derived from analysis of circulating T cells. How immune cell alterations in mucosal tissues contribute to HIV immune dysregulation and the associated risk of non-infectious chronic complications is less studied. Given the significant differences between mucosal T cells and circulating T cells, and the immediate interactions of mucosal T cells with the microbiome, more attention should be devoted to mucosal immune cells and their contribution to systemic immune activation in HIV-infected individuals. Here, we will focus on mucosal immune cells with a specific emphasis on CD4(+) T lymphocytes, such as T helper 17 cells and CD4(+)Foxp3(+) regulatory T cells (Tregs), which play crucial roles in maintaining mucosal barrier integrity and preventing inflammation, respectively. We hypothesize that pro-inflammatory milieu in cART-treated patients with immune activation significantly contributes to enhanced loss of Th17 cells and increased frequency of dysregulated Tregs in the mucosa, which in turn may exacerbate immune dysfunction in HIV-infected patients. We also present initial evidence to support this hypothesis. A better comprehension of how pro-inflammatory milieu impacts these two types of cells in the mucosa will shed light on mucosal immune dysfunction and HIV reservoirs, and lead to novel ways to restore immune functions in HIV(+) patients.

In vivo intratumoral Epstein-Barr virus replication is associated with XBP1 activation and early-onset post-transplant lymphoproliferative disorders with prognostic implications

Post-transplant lymphoproliferative disorders are life-threatening complications following hematopoietic or solid organ transplantation. They represent a spectrum of mostly EBV-driven lymphoplasmacytic proliferations. While the oncogenic effect of EBV is related to latent infection, lytic infection also has a role in lymphomagenesis. In vitro, EBV replication is linked to plasma cell differentiation and XBP1 activation, although this phenomenon has never been addressed in vivo. We analyzed for the first time latent and lytic intratumoral EBV infection in a series of 35 adult patients with a diagnosis of post-transplant lymphoproliferative disorder (26M/9F, median age 54 years). A complete EBV study was performed including the analysis of the latent EBER, latent membrane protein-11, and EBV nuclear antigens as well as the immediate-early BZLF1/ZEBRA and early BMRF1/EADE31 lytic genes. XBP1 activation was assessed by nuclear protein expression. EBV infection was observed in 28 (80%) cases being latency II and III the most frequently observed 22 (79%). Intratumoral EBV replication was detected in 17 (60%) cases. Among these, XBP1 activation was observed in 11/12 evaluable cases associated with strong cytoplasmic immunoglobulin expression consistent with plasma cell differentiation. Intriguingly, the combination of latency III infection and EBV replication identified a high-risk subgroup of patients with significantly shorter survival (overall survival at 1 year 18% vs 48%) and early-onset (median of 7 vs 26 months) post-transplant lymphoproliferative disorder. Moreover, these patients appear to be more heavily immunosuppressed, so they exhibit lower rates of rejection and graft vs host disease but higher rates of cytomegalovirus reactivation. In conclusion, EBV replication is associated with plasma cell differentiation and XBP1 activation with prognostic implications. Both latency III and lytic EBV infection are related to aggressive and early-onset post-transplant lymphoproliferative disorder. These results suggest that immunohistochemical study of latent and lytic EBV genes in the clinical practice may help to select higher-risk patients to new therapies including antiviral treatments.

Immune restoration after antiretroviral therapy: the pitfalls of hasty or incomplete repairs

Antiretroviral therapy (ART) is a life-saving intervention in human immunodeficiency virus (HIV) infection. Immune restoration after ART dramatically reduces the incidence and severity of opportunistic diseases and death. On some occasions, immune restoration may be erratic, leading to acute inflammatory responses (known as immune reconstitution inflammatory syndrome) shortly after ART initiation, or incomplete, with residual inflammation despite chronic treatment, leading to non-infectious morbidity and mortality. We propose that ART may not always restore the perfect balance of innate and adaptive immunity in strategic milieus, predisposing HIV-infected persons to complications of acute or chronic inflammation. The best current strategy for fully successful immune restoration is early antiretroviral therapy, which can prevent acquired immunodeficiency syndrome (AIDS)-associated events, restrict cell subset imbalances and dysfunction, while preserving structural integrity of lymphoid tissues. Future HIV research should capitalize on innovative techniques and move beyond the static study of T-cell subsets in peripheral blood or isolated tissues. Improved targeted therapeutic strategies could stem from a better understanding of how HIV perturbs the environmental niches and the mobility and trafficking of cells that affect the dynamic cell-to-cell interactions and determine the outcome of innate and adaptive immune responses.

Cellular interplay among Th17, Th1, and Treg cells in HIV-1 subtype "C" infection

CD4 T cell depletion is central to HIV pathogenesis and disease progression. Different subsets of CD4 T cells cooperate to combat an infection. Therefore, the immune balance among Th17, Th1, and Treg cells may be critical in HIV immunopathogenesis which is not adequately defined yet. The impact of HIV-1 infection on the interplay of Th17/Th1/Treg cells in HIV-1 infected Indian individuals was examined in the present study and report that HIV-1 Gag specific peripheral blood Th17 cells were significantly depleted in late infected subjects, compared to early infected subjects and slow progressors. Although, the gradual loss of Th1 cells was also reported during HIV-1 disease progression but relative to Th17 cells, Th1 cells were found to be more resistant to HIV-1 infection. Additionally, a significant and progressive gain in Treg cellular frequency was observed as disease progress from early to late stage of HIV-1 infection. This study also indicate that slow progressors might have an intrinsic capacity to develop strong HIV-1 specific Th17 and Th1 cell responses contrasted with a faint Treg cellular performance signifies the importance of these cellular subsets in progressive versus nonprogressive HIV-1 infection. A significant gradual loss of Th17/Treg ratio was found to be associated with disease state, plasma viral load and immune activation.

Different immunological phenotypes associated with preserved CD4+ T cell counts in HIV-infected controllers and viremic long term non-progressors

BACKGROUND

HIV-infected controllers control viral replication and maintain normal CD4+ T cell counts. Long Term Non-Progressors (LTNP) also maintain normal CD4+ T cell counts, but have on-going viral replication. We hypothesized that different immunological mechanisms are responsible for preserved CD4+ T cell counts in controllers and LTNP.

METHODS

25 HIV-infected controllers and 14 LTNP were included in this cross-sectional study. For comparison, 25 progressors and 34 healthy controls were included. Production and destruction of T cells were addressed by determination of T cell receptor excision circles (TREC), recent thymic emigrants, naïve cells, immune activation, senescence and apoptosis. Furthermore, telomere length was determined, and the amount of lymphoid tissue in tonsil biopsies was quantified.

RESULTS

Controllers presented with partly preserved thymic output, preserved expression of the IL-7 receptor and IL-7 receptor density, and lower levels of destruction of cells than progressors resembling HIV-negative healthy controls. In contrast, LTNP appeared much like progressors, and different from controllers in immune activation, senescence, and apoptosis. Interestingly, CD8+ RTE, TREC and telomere length were partly preserved. Finally, both controllers and LTNP displayed decreased amounts of lymphoid tissue compared to healthy controls.

CONCLUSIONS

Controllers presented with an immunological profile different from LTNP. While controllers resembled healthy controls, LTNP were similar to progressors, suggesting different immunological mechanisms to be responsible for preserved CD4+ T cell counts in LTNP and controllers. However, both controllers and LTNP presented with reduced amounts of lymphoid tissue despite preserved CD4+ T cell counts, indicating HIV to cause damage even in non-progressors.

Therapeutic vaccines against HIV infection

Resistance to medication, adverse effects in the medium-to-long-term and cost all place important limitations on lifelong adherence to combined antiretroviral therapy (cART). In this context, new therapeutic alternatives to 'cART for life' in HIV-infected patients merit investigation. Some data suggest that strong T cell-mediated immunity to HIV can indeed limit virus replication and protect against CD4 depletion and disease progression. The combination of cART with immune therapy to restore and/or boost immune-specific responses to HIV has been proposed, the ultimate aim being to achieve a 'functional cure'. In this scenario, new, induced, HIV-specific immune responses would be able to control viral replication to undetectable levels, mimicking the situation of the minority of patients who control viral replication without treatment and do not progress to AIDS. Classical approaches such as whole inactivated virus or recombinant protein initially proved useful as therapeutic vaccines. Overall, however, the ability of these early vaccines to increase HIV-specific responses was very limited and study results were discouraging, as no consistent immunogenicity was demonstrated and there was no clear impact on viral load. Recent years have seen the development of new approaches based on more innovative vectors such as DNA, recombinant virus or dendritic cells. Most clinical trials of these new vectors have demonstrated their ability to induce HIV-specific immune responses, although they show very limited efficacy in terms of controlling viral replication. However, some preliminary results suggest that dendritic cell-based vaccines are the most promising candidates. To improve the effectiveness of these vaccines, a better understanding of the mechanisms of protection, virological control and immune deterioration is required; without this knowledge, an efficacious therapeutic vaccine will remain elusive.

Altered frequency and phenotype of CD4+ forkhead box protein 3+ T cells and its association with autoantibody production in human immunodeficiency virus-infected paediatric patients

The association between immune dysfunction and the development of autoimmune pathology in patients with human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) is not clear. The frequency and phenotype of regulatory T cells, as well as the presence of autoantibodies, were evaluated in a paediatric cohort of HIV-infected patients without clinical evidence of autoimmune disease. Lower absolute counts but higher percentages of total CD4(+) forkhead box protein 3 (FoxP3)(+) T cells were recorded in children with severe immunosuppression than in those without evidence of immunosuppression. The frequencies of classical CD4(+) CD25(+) FoxP3(+) regulatory T cells were not altered, whereas CD4(+) FoxP3(+) CD25(-) T cells were found increased significantly in patients with severe immunosuppression. Like classical regulatory T cells, CD4(+) FoxP3(+) CD25(-) T cells display higher cytotoxic T-lymphocyte antigen 4 (CTLA-4) but lower CD127 expression compared with CD4(+) FoxP3(-) CD25(+) T cells. An improvement in CD4(+) T cell counts, along with a decrease in viral load, was associated with a decrease in CD4(+) FoxP3(+) CD25(-) T cells. The majority of the patients with severe immunosuppression were positive for at least one out of seven autoantibodies tested and displayed hypergammaglobulinaemia. Conversely, HIV-infected children without evidence of immunosuppression had lower levels of autoantibodies and total immunoglobulins. A decline in CD4(+) FoxP3(+) T cell numbers or a variation in their phenotype may induce a raise in antigen exposure with polyclonal B cell activation, probably contributing to the generation of autoantibodies in the absence of clinical autoimmune disease.

Low level of regulatory T cells and maintenance of balance between regulatory T cells and TH17 cells in HIV-1-infected elite controllers

BACKGROUND

A subgroup of HIV-1-infected individuals, elite controllers, have spontaneous viral control and offer an exceptional opportunity to study virological and immunolocigal factors of possible involvement in control of HIV-1 infection.

METHODS

The frequencies of Tregs and TH17 cells was evaluated and correlated to markers of disease progression in peripheral blood mononuclear cells from 3 different groups of individuals infected with HIV-1: treatment-naive viremic individuals, individuals on successful highly active antiretroviral therapy, and elite controllers. In addition, a group of HIV-1-negative individuals were included.

RESULTS

We demonstrate that elite controllers have lower levels of Tregs compared with HIV-1-infected viremic individuals, but that the low Treg level does not differ between individuals with HIV-1 control, whether natural or therapy induced. We also show that T-cell activation and proliferation both correlate to the level of Tregs. Finally, the TH17/Treg ratio was similar in Elite Controllers and uninfected controls, whereas in viremic and treated HIV-1-infected individuals, the TH17/Treg ratio was lower compared with uninfected controls.

CONCLUSIONS

We show that one feature of spontaneous HIV-1 control is a maintained balance between regulatory T cells and TH17 cells.

Th17 cells and regulatory T cells in elite control over HIV and SIV

PURPOSE OF REVIEW

We present current findings about two subsets of CD4+ T cells that play an important part in the initial host response to infection with the HIV type 1: those producing IL-17 (Th17 cells) and those with immunosuppressive function (CD25+FoxP3+ regulatory T cells or T-reg). The role of these cells in the control of viral infection and immune activation as well as in the prevention of immune deficiency in HIV-infected elite controllers will be examined. We will also discuss the use of the simian immunodeficiency virus (SIV)-infected macaque model of AIDS to study the interplay between these cells and lentiviral infection in vivo.

RECENT FINDINGS

Study of Th17 cells in humans and nonhuman primates (NHPs) has shown that depletion of these cells is associated with the dissemination of microbial products from the infected gut, increased systemic immune activation, and disease progression. Most impressively, having a smaller Th17-cell compartment has been found to predict these outcomes. T-reg have been associated with the reduced antiviral T-cell responses but not with the suppression of generalized T cell activation. Both cell subsets influence innate immune responses and, in doing so, may shape the inflammatory milieu of the host at infection.

SUMMARY

Interactions between Th17 cells, T-reg, and cells of the innate immune system influence the course of HIV and SIV infection from its earliest stages, even before the appearance of adaptive immunity. Such interactions may be pivotal for elite control over disease progression.

Lymphoid tissue collagen deposition in HIV-infected patients correlates with the imbalance between matrix metalloproteinases and their inhibitors

We studied the lymphoid tissue biopsies of 20 patients with chronic human immunodeficiency virus (HIV) infection by analyzing collagen deposition, CD4+ cell number, and gene expression of metalloproteinases (MMPs; MMP-2, MMP-9) and tissue inhibitors of MMPs (TIMPs; TIMP-1, TIMP-2). HIV-infected patients had significantly increased collagen deposition (P = .001), fewer CD4+ T cells (P = .05), and decreased MMP-9/TIMP-1 and MMP-2/TIMP-2 ratios (P = .01), compared with HIV-negative control patients. Moreover, we found a significant negative correlation between collagen deposition and the MMP-9/TIMP-1 ratio (ρ = -0.50; P = .047). To our knowledge, this is the first time that MMP/TIMP imbalance has been correlated with lymphoid tissue collagen deposition and incomplete immune recovery in HIV-infected patients, even after long-term antiretroviral treatment.

Normalization of FoxP3(+) regulatory T cells in response to effective antiretroviral therapy

Regulatory T cells (Tregs) blunt uncontrolled immune responses. In advanced human immunodeficiency virus (HIV) infection, the total number of Tregs is decreased, but the proportion of T cells with a regulatory phenotype is highly variable. We studied CD4(+)CD25(+)FoxP3(+) T cells from patients successfully treated with combination antiretroviral therapy (ART). The proportion of CD4(+)CD25(+)FoxP3(+) cells transiently increased and then decreased from a median of 13% at baseline to 5.1% at 48 weeks, similar to values in normal subjects. These data suggest that with effective therapy, the regulatory cell numbers normalize, and that the inflammatory signals driving their production may also abate.

Factors associated with collagen deposition in lymphoid tissue in long-term treated HIV-infected patients

OBJECTIVE

The factors associated with fibrosis in lymphoid tissue in long-term treated HIV-infected patients and their correlation with immune reconstitution were assessed.

METHODS

Tonsillar biopsies were performed in seven antiretroviral-naive patients and 29 successfully treated patients (median time on treatment, 61 months). Twenty patients received protease inhibitors-sparing regimens and nine protease inhibitor-containing regimens. Five tonsillar resections of HIV-negative individuals were used as controls. Lymphoid tissue architecture, collagen deposition (fibrosis) and the mean interfollicular CD4(+) cell count per mum were assessed.

RESULTS

Naive and long-term treated HIV-infected patients had a higher proportion of fibrosis than did HIV-uninfected persons (P < 0.001). Patients with greater collagen deposition showed lower levels of CD4 cells in lymphoid tissue (P = 0.03) and smaller increase in peripheral CD4(+) T cells (r = -0.40, P = 0.05). The factors independently associated with fibrosis in lymphoid tissue were age (P < 0.0001), treated patients with detectable lymphoid tissue viral load when compared with patients with undetectable lymphoid tissue viral load (median 5 vs. 12%, respectively, P = 0.017) and patients receiving a protease inhibitor-sparing vs. a protease inhibitor-containing regimen (median 8 vs. 2.5%, respectively, P = 0.04).

CONCLUSION

Fibrosis in lymphoid tissue was associated with a poor reconstitution of CD4(+) T cells and long-term antiretroviral therapy did not reverse this abnormality. HIV infection, older age, a detectable level of lymphoid tissue viral load in treated patients and protease inhibitor-sparing regimens seem to favour fibrosis in lymphoid tissue.

HIV+ elite controllers have low HIV-specific T-cell activation yet maintain strong, polyfunctional T-cell responses

OBJECTIVE

HIV elite controllers are a unique group of rare individuals who maintain undetectable viral loads in the absence of antiretroviral therapy. We studied immune responses in these individuals to inform vaccine development, with the goal of identifying the immune correlates of protection from HIV.

METHODS

We compared markers of cellular activation, HIV-specific immune responses and regulatory T (Treg) cell frequencies in four groups of individuals: HIV-negative healthy controls, elite controllers (HIV RNA level <75 copies/ml), individuals on HAART and individuals with HIV RNA level more than 10,000 copies/ml (noncontrollers).

RESULTS

Elite controllers possessed significantly lower levels of activated HIV-specific CD8 T cells and of recently divided HIV-specific CD4 T cells than noncontrollers, whereas these differences were not seen in the respective cytomegalovirus-specific T-cell populations. Elite controllers also mounted a stronger and broader cytokine and chemokine response following HIV-specific stimulation than individuals on HAART and noncontrollers. Finally, we found that HAART-suppressed individuals had elevated Treg cell frequencies, whereas elite controllers and noncontrollers maintained normal percentages of Treg cells.

CONCLUSION

Elite controllers maintain high levels of HIV-specific immune responses with low levels of HIV-specific T-cell activation and do not have elevated Treg cell levels. Based on these data an ideal HIV vaccine would induce strong HIV-specific immune responses whereas minimizing HIV-specific T-cell activation.

Increased peripheral blood leukocyte subsets with regulatory phenotype in clinically stable long-term HIV-infected hemophilia patients on HAART may be beneficial and contribute to a decrease in autoimmunity

After initiation of highly-active antiretroviral therapy (HAART), long-term HIV-infected hemophilia patients have been shown to lose autoantibodies against CD4(+) peripheral blood leukocytes (PBL), suggesting that HAART induces autoimmunity-blocking mechanisms. We compared cytokine levels and subpopulations of lymphocytes and dendritic cells (DC) in the blood of 40 long-term HIV(+) patients with those of 13 long-term HIV(-) hemophilia patients; 23 HIV(+) patients had a detectable retroviral load. Cell subsets were determined using flow cytometry and cytokine levels were measured using ELISA. HIV(+) patients showed higher proportions of DC subpopulations with immunostimulatory phenotypes (p < 0.01), CD8(+) PBL (p < 0.001), and IL-2 (p < 0.001) and sIL-2R plasma levels (p = 0.002) than HIV(-) patients. They also exhibited increased proportions of T PBL with immunosuppressive phenotypes such as CD3(+)CD4(+)CD25(+)Foxp3(+) (p = 0.001), and CD3(+)CD8(+)CD28(-)Foxp3(+) PBL (p < 0.001), and a decreased IL-7R expression on CD3(+)CD8(+) PBL (p = 0.001) compared to HIV(-) patients. Frequencies of CD3(+)CD4(+)CD25(+) PBL producing IL-2, IL-4, IL-10, IL-12, and/or IFN-gamma, and of CD3(+)CD4(+)CD28(-) PBL secreting IL-2 and/or IL-4 were lower in HIV(+) than in HIV(-) patients (p <or= 0.02). Proportions of CD4(+) PBL coated with IgG, IgM, and C3d were similar in HIV(+) and HIV(-) patients (p = n.s.). However, the proportion of CD4(+)gp120(+) PBL was higher in HIV(+) patients (p = 0.002), and associated with low CD3(+)CD4(+)CD25(+)Foxp3(+) PBL (p = 0.012). We conclude that long-term HIV-infected hemophilia patients on HAART show an adaptive immune response, presumably against HIV, in the presence of upregulated immunosuppressive T PBL, downregulated cytokine-producing CD4(+) PBL, and downregulated IL-7R expression on CD8(+) PBL. Increased immunoregulatory T PBL might decrease autoimmunity, thereby contributing to immunological reconstitution and stabilization of long-term HIV-infected hemophilia patients on HAART.

A brief review of potential mechanisms of immune reconstitution inflammatory syndrome in HIV following antiretroviral therapy

A subset of HIV-infected individuals who receive antiretroviral therapy (ART) develop a paradoxical pathological response that significantly increases morbidity and sometimes mortality. Following the induction of highly active ART, a rapid decline in the viral load results within weeks and coincides with a steep rise in the CD4(+) T-cell counts and immune hyperactivation. Although no mechanistic pathway has been elucidated for the development of immune reconstitution inflammatory syndrome (IRIS), it is thought that change in the nature of the immune response is a predominant factor in the development of reconstitution disease. In this article, we review the current state of knowledge in this field and provide a model for the development of IRIS.

Foxp3 and Treg cells in HIV-1 infection and immuno-pathogenesis

FoxP3(+)CD4(+)CD25(+) regulatory T (Treg) cells are implicated in a number of pathologic processes including elevated levels in cancers and infectious diseases, and reduced levels in autoimmune diseases. Treg cells are activated to modulate immune responses to avoid over-reactive immunity. However, conflicting findings are reported regarding relative levels of Treg cells during HIV-1 infection and disease progression. The role of Treg cells in HIV-1 diseases (aberrant immune activation) is poorly understood due to lack of a robust model. We summarize here the regulation and function of Foxp3 in Treg cells and in modulating HIV-1 replication. Based on recent findings from SIV/monkey and HIV/humanized mouse models, a model of the dual role of Treg cells in HIV-1 infection and immuno-pathogenesis is discussed.

Autoimmune type I diabetes mellitus in a perinatally HIV infected patient with a well-preserved immune system

We report an 8 year-old girl with well-controlled perinatally acquired HIV infection who developed autoimmune type 1 diabetes mellitus (DM1A) confirmed by the presence of diabetes-related auto-antibodies. Although non-autoimmune insulin dependent diabetes mellitus (DM1B) and more frequently type 2 DM has been reported in patients affected with HIV, this is the first report of DM1A diagnosed in an HIV positive patient.

HIV-specific regulatory T cells are associated with higher CD4 cell counts in primary infection

OBJECTIVE

Expansion of regulatory T (Treg) cells has been described in chronically HIV-infected individuals. We investigated whether HIV-suppressive Treg could be detected during primary HIV infection (PHI).

METHODS

Seventeen patients diagnosed early after PHI (median: 13 days; 1-55) were studied. Median CD4 cell count was 480 cells/microl (33-1306) and plasma HIV RNA levels ranged between 3.3 and 5.7 log10 copies/ml. Suppressive capacity of blood purified CD4CD25 was evaluated in a coculture assay. Fox-p3, IL-2 and IL-10 were quantified by reverse transcriptase (RT)-PCR and intracellular staining of ex vivo and activated CD4+CD25 T cells.

RESULTS

The frequency of CD4CD127CD25 T cells among CD4 T cells was lower in patients with PHI compared with chronic patients (n = 19). They exhibited a phenotype of memory T cells and expressed constitutively FoxP3. Similar to chronic patients, Treg from patients with PHI inhibited the proliferation of purified tuberculin (PPD) and HIV p24 activated CD4CD25 T cells. CD4CD25 T cells from patients with PHI responded specifically to p24 stimulation by expressing IL-10. In untreated patients with PHI, the frequency as well as HIV-specific activity of Treg decreased during a 24-month follow-up. A positive correlation between percentages of Treg and both CD4 cell counts and the magnitude of p24-specific suppressive activity at diagnosis of PHI was found.

CONCLUSION

Our data showed that HIV drives Treg, as PHI and these cells persist throughout the course of the infection. A correlation between the frequency of Treg and CD4 T-cell counts suggest that these cells may impact on the immune activation set point at PHI diagnosis.

Preservation of FoxP3+ regulatory T cells in the peripheral blood of human immunodeficiency virus type 1-infected elite suppressors correlates with low CD4+ T-cell activation

Elite suppressors (ES) are untreated human immunodeficiency virus type 1 (HIV-1)-infected individuals who maintain normal CD4(+) T-cell counts and control viremia to levels that are below the limit of detection of current assays. The mechanisms involved in long-term control of viremia have not been fully elucidated. CD4(+) CD25(+) regulatory T cells (Tregs) downmodulate chronic inflammation by suppressing the activation and proliferation of effector lymphocytes. We found that while Tregs were functional in ES and patients on highly active antiretroviral therapy (HAART), ES maintained high levels of Tregs in peripheral blood mononuclear cells whereas patients on HAART had evidence of Treg depletion. We also demonstrated that Tregs can serve as reservoirs for HIV-1 in vivo. These data suggest that both direct infection by HIV-1 and tissue redistribution are possible explanations for declining FoxP3(+) Tregs in progressive HIV-1 infection. Furthermore, the maintenance of Tregs may be one mechanism associated with the nonprogressive nature of HIV-1 infection in ES.