Long-term Outcomes of Patients With HIV and Pneumocystis jirovecii Pneumonia in the Antiretroviral Therapy Era

Background

Pneumocystis jirovecii pneumonia (PCP) is one of the most frequent opportunistic infections in people with HIV (PWH). However, there are limited data on long-term outcomes of PCP in the antiretroviral therapy (ART) era.

Methods

We conducted a secondary analysis of 2 prospective studies on 307 PWH, 81 with prior PCP, with a median follow-up of 96 weeks. Laboratory data were measured at protocol-defined intervals. We reviewed clinically indicated chest computerized tomography imaging in 63 patients with prior PCP at a median of 58 weeks after PCP diagnosis and pulmonary function tests (PFTs) of patients with (n = 10) and without (n = 14) prior PCP at a median of 18 weeks after ART initiation.

Results

After 96 weeks of ART, PWH with prior PCP showed no significant differences in laboratory measurements, including CD4 count, when compared with those without prior PCP. Survival rates following ART initiation were similar. However, PWH with prior PCP had increased evidence of restrictive lung pathology and diffusion impairment in PFTs. Furthermore, on chest imaging, 13% of patients had bronchiectasis and 11% had subpleural cysts. Treatment with corticosteroids was associated with an increased incidence of cytomegalovirus disease (odds ratio, 2.62; P = .014).

Conclusions

PCP remains an important opportunistic infection in the ART era. While it did not negatively affect CD4 reconstitution, it could pose an increased risk for incident cytomegalovirus disease with corticosteroid treatment and may cause residual pulmonary sequelae. These findings suggest that PCP and its treatment may contribute to long-term morbidity in PWH, even in the ART era.

Reappraisal of Idiopathic CD4 Lymphocytopenia at 30 Years

BACKGROUND

Idiopathic CD4 lymphocytopenia (ICL) is a clinical syndrome that is defined by CD4 lymphopenia of less than 300 cells per cubic millimeter in the absence of any primary or acquired cause of immunodeficiency. Some 30 years after its original identification, ICL has remained a disease of obscure cause, with limited evidence with respect to its prognosis or management, despite diagnostic and therapeutic innovations.

METHODS

We evaluated the clinical, genetic, immunologic, and prognostic characteristics of 108 patients who were enrolled during an 11-year period. We performed whole-exome and targeted gene sequencing to identify genetic causes of lymphopenia. We also performed longitudinal linear mixed-model analyses of T-cell count trajectories and evaluated predictors of clinical events, the response to immunization against coronavirus disease 2019 (Covid-19), and mortality.

RESULTS

After the exclusion of patients with genetic and acquired causes of CD4 lymphopenia, the study population included 91 patients with ICL during 374 person-years of follow-up. The median CD4+ T-cell count among the patients was 80 cells per cubic millimeter. The most prevalent opportunistic infections were diseases related to human papillomavirus (in 29%), cryptococcosis (in 24%), molluscum contagiosum (in 9%), and nontuberculous mycobacterial diseases (in 5%). A reduced CD4 count (<100 cells per cubic millimeter), as compared with a CD4 count of 101 to 300 cells, was associated with a higher risk of opportunistic infection (odds ratio, 5.3; 95% confidence interval [CI], 2.8 to 10.7) and invasive cancer (odds ratio, 2.1; 95% CI, 1.1 to 4.3) and a lower risk of autoimmunity (odds ratio, 0.5; 95% CI, 0.2 to 0.9). The risk of death was similar to that in the age- and sex-adjusted general population, but the prevalence of cancer was higher.

CONCLUSIONS

Among the study patients, ICL continued to be associated with increased susceptibility to viral, encapsulated fungal, and mycobacterial diseases, as well as with a reduced response to novel antigens and an increased risk of cancer. (Funded by the National Institute of Allergy and Infectious Diseases and the National Cancer Institute; ClinicalTrials.gov number, NCT00867269.).

Polyfunctional Antigen Specific CD4+ T cell Responses in Patients With Human Immunodeficiency Virus/AIDS and Histoplasmosis Immune Reconstitution Inflammatory Syndrome

In the combination antiretroviral era, there are limited data regarding the pathogenesis of histoplasmosis immune reconstitution inflammatory syndrome (IRIS) in people with human immunodeficiency virus (HIV). We immunologically characterized 10 cases of histoplasmosis, 4 of whom developed histoplasmosis IRIS. CD4+ T cells in histoplasmosis IRIS demonstrated a significant polyfunctional cytokine response to histoplasma antigen.

Severe Mycobacterial Immune Reconstitution Inflammatory Syndrome (IRIS) in Advanced Human Immunodeficiency Virus (HIV) Has Features of Hemophagocytic Lymphohistiocytosis and Requires Prolonged Immune Suppression

BACKGROUND

People with HIV and mycobacterial infections can develop immune reconstitution inflammatory syndrome (IRIS) after starting antiretroviral therapy (ART). Severe mycobacterial IRIS has an overlapping clinical phenotype with hemophagocytic lymphohistiocytosis (HLH). We evaluated the pathophysiologic similarities between mycobacterial IRIS and HLH to identify clinical and immune predictors of mycobacterial IRIS severity.

METHODS

HLH criteria were applied to a longitudinal cohort of 80 patients with HIV (CD4 <100 cells/µL) and mycobacterial infections. Participants were subdivided into IRIS meeting HLH criteria (HLH-IRIS), IRIS without HLH (IRIS), and those without IRIS (non-IRIS). Clinical outcomes were evaluated by regression analyses. Soluble biomarkers and T-cell subsets were assessed at baseline and IRIS-equivalent time points.

RESULTS

HLH-IRIS patients required corticosteroids more frequently (OR: 21.5; 95%CI: 5.6-114.8) and for longer duration (21.2; 95%CI: 10.7-31.7 weeks) than those not meeting HLH criteria. Utilizing decision tree analyses, hemoglobin <9.2 g/dL was the best predictor of HLH-IRIS before ART, whereas ferritin, CXCL9 and sCD25 were most diagnostic for HLH at IRIS onset. At the IRIS timepoint, but not baseline, HLH-IRIS patients had lower regulatory and higher activated T cells along with greater production of IFNγ-IL-18 axis biomarkers compared with both IRIS and non-IRIS groups. Principal component analysis corroborated the distinct clustering of HLH-IRIS patients.

CONCLUSIONS

Severe mycobacterial IRIS and HLH have an overlapping pathogenesis involving IFNγ and unopposed T-cell activation causing severe inflammatory disease clinically distinguished by hyperferritinemia (hyperferritinemic IRIS [FIRIS]). Hemoglobin, ferritin, CXCL9, and sCD25 identify high-risk patients and may improve risk stratification and therapeutic strategies for mycobacterial IRIS.

Association between severe anaemia and inflammation, risk of IRIS and death in persons with HIV: A multinational cohort study

BACKGROUND

After initiating antiretroviral therapy (ART), approximately 25% of people with HIV (PWH) may develop Immune Reconstitution Inflammatory Syndrome (IRIS), which is associated with increased morbidity and mortality. Several reports have demonstrated that low haemoglobin (Hb) levels are a risk factor for IRIS. To what extent the severity of anaemia contributes to the risk of IRIS and/or death is still insufficiently explored.

METHODS

We investigated both the presence and severity of anaemia in PWH in a multinational cohort of ART-naïve patients. A large panel of plasma biomarkers was measured pre-ART and patients were followed up for 6 months. IRIS or deaths during this period were considered as outcomes. We performed multidimensional analyses, logistic regression, and survival curves to delineate associations.

FINDINGS

Patients with severe anaemia (SA) presented a distinct systemic inflammatory profile, characterized by higher TNF, IL-6, and IL-27 levels. SA was independently associated with IRIS, with a higher risk of both early IRIS onset and death. Among IRIS patients, those with SA had a higher risk of mycobacterial IRIS.

INTERPRETATION

PWH with SA display a more pronounced inflammatory profile, with an elevated risk of developing IRIS earlier and a statistically significant higher risk of death.

FUNDING

Intramural Research Program of National Institute of Allergy and Infectious Diseases/National Institutes of Health (NIAID/NIH). Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Finance code: 001) and the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Brazil.

High prevalence of gastrointestinal manifestations among Cytomegalovirus end-organ disease in the combination antiretroviral era

Background

Cytomegalovirus (CMV) end-organ disease (EOD) continues to pose a significant risk to patients with advanced HIV disease despite decreased incidence with combination anti-retroviral therapy (ART) and lower mortality with effective anti-CMV therapy. Subclinical CMV shedding may also contribute to ongoing inflammation and non-infectious comorbidities.

Methods

We examined the occurrence of CMV EOD and CMV shedding in a cohort of patients participating in a prospective observational study of severely immunosuppressed (CD4 ≤100 cells/μl), ART-naïve, HIV-1 infected adult participants.

Results

We studied 206 participants, of whom 193 (93.7%) were CMV IgG positive. Twenty-five participants (12.1%) developed confirmed CMV EOD. At baseline, 47 (22.8%) had CMV viremia detectable by PCR in the absence of clinical disease (CMV viremia). The remaining 134 (65%) had neither CMV EOD nor CMV viremia detected at baseline. Five participants with CMV EOD (2.4% of total cohort, 20% of CMV EOD) met AIDS Clinical Trials Group criteria for CMV immune reconstitution inflammatory syndrome (IRIS). Only one-third of CMV EOD patients had retinitis, while two-thirds presented with histologically confirmed gastrointestinal illness. CMV viremia was associated with higher percentages of activated CD8⁺ T cells even after HIV suppression.

Conclusion

The manifestations of CMV EOD in advanced HIV disease before and after initiation of ART may be more diverse than previously described, with high incidence of gastrointestinal illness. Recognition and treatment of unusual clinical presentations of CMV infection remains important in reducing morbidity and mortality from HIV co-infections.

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Cytomegalovirus end organ disease (CMV EOD) remains an important complication in HIV/AIDS patients.

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We found that gastrointestinal disease was the most common presentation of CMV EOD.

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In addition, subclinical CMV viremia was associated with increased immune activation.

Clinical and Immunologic Predictors of Mycobacterium avium Complex Immune Reconstitution Inflammatory Syndrome in a Contemporary Cohort of Patients With Human Immunodeficiency Virus

BACKGROUND

People with human immunodeficiency virus (HIV) can present with new or worsening symptoms associated with Mycobacterium avium complex (MAC) infection shortly after antiretroviral therapy (ART) initiation as MAC immune reconstitution inflammatory syndrome (MAC-IRIS). In this study, we assessed the utility of several laboratory tests as predictors of MAC-IRIS.

METHODS

People with HIV with clinical and histologic and/or microbiologic evidence of MAC-IRIS were identified and followed up to 96 weeks post-ART initiation within a prospective study of 206 ART-naive patients with CD4 <100 cells/µL.

RESULTS

Fifteen (7.3%) patients presented with MAC-IRIS within a median interval of 26 days after ART initiation. Patients who developed MAC-IRIS had lower body mass index, lower hemoglobin levels, higher alkaline phosphatase (ALP), and increased CD38 frequency and mean fluorescence intensity on CD8+ T cells at the time of ART initiation compared with non-MAC IRIS patients. A decision tree inference model revealed that stratifying patients based on levels of ALP and D-dimer could predict the likelihood of MAC-IRIS. A binary logistic regression demonstrated that higher levels of ALP at baseline were associated with increased risk of MAC-IRIS development.

CONCLUSIONS

High ALP levels and increased CD8+ T-cell activation with low CD4 counts at ART initiation should warrant suspicion for subsequent development of MAC-IRIS.

To Induce Immune Reconstitution Inflammatory Syndrome or Suppress It: The Spectrum of Mycobacterium genavense in the Antiretroviral Era

Mycobacterium  genavense is a challenging opportunistic pathogen to diagnose and manage in patients with human immunodeficiency virus (HIV). Persistent immunosuppression or protracted immune reconstitution inflammatory syndrome can lead to complicated clinical courses. We describe 3 cases of M. genavense in patients with HIV representing the spectrum between disease burden and strength of immune response.

Prevalence and pathogenicity of autoantibodies in patients with idiopathic CD4 lymphopenia

BACKGROUNDIdiopathic CD4 lymphopenia (ICL) is defined by persistently low CD4+ cell counts (<300 cells/μL) in the absence of a causal infection or immune deficiency and can manifest with opportunistic infections. Approximately 30% of ICL patients develop autoimmune disease. The prevalence and breadth of their autoantibodies, however, and their potential contribution to pathogenesis of ICL remain unclear.METHODSWe hybridized 34 and 51 ICL patients' sera to a 9,000-human-proteome array and to a 128-known-autoantigen array, respectively. Using a flow-based method, we characterized the presence of anti-lymphocyte Abs in the whole cohort of 72 patients, as well as the Ab functional capability of inducing Ab-dependent cell-mediated cytotoxicity (ADCC), complement deposition, and complement-dependent cytotoxicity (CDC). We tested ex vivo the activation of the classical complement pathway on ICL CD4+ T cells.RESULTSAll ICL patients had a multitude of autoantibodies mostly directed against private (not shared) targets and unrelated quantitatively or qualitatively to the patients' autoimmune disease status. The targets included lymphocyte intracellular and membrane antigens, confirmed by the detection by flow of IgM and IgG (mostly IgG1 and IgG4) anti-CD4+ cell Abs in 50% of the patients, with half of these cases triggering lysis of CD4+ T cells. We also detected in vivo classical complement activation on CD4+ T cells in 14% of the whole cohort.CONCLUSIONOur data demonstrate that a high prevalence of autoantibodies in ICL, some of which are specific for CD4+ T cells, may contribute to pathogenesis, and may represent a potentially novel therapeutic target.TRIAL REGISTRATIONClinicalTrials.gov NCT00867269.FUNDINGNIAID and National Institute of Arthritis and Musculoskeletal and Skin Diseases of the NIH.

An Inflammatory Composite Score Predicts Mycobacterial Immune Reconstitution Inflammatory Syndrome in People with Advanced HIV: A Prospective International Cohort Study

BACKGROUND

Immune reconstitution inflammatory syndrome (IRIS) is a common cause of morbidity among people with human immunodeficiency virus (PWH) who initiate antiretroviral therapy (ART) with severe lymphopenia. Easily accessible tools that reliably predict emergence and elucidate pathogenesis of IRIS are needed to facilitate improved clinical management.

METHODS

Plasma levels of biomarkers were measured before ART initiation in a large multinational cohort of ART-naive PWH with severe immunosuppression (CD4+ count <100 cells/mm3) in United States, Kenya, and Thailand. We performed a series of multiparametric analyses of inflammatory and clinical biomarkers and developed a composite score merging relevant biomarkers for use in a prediction model.

RESULTS

We identified a distinct baseline inflammatory profile and changes in inflammatory networks among biomarkers in participants who subsequently developed mycobacterial or viral IRIS. We also developed a composite score incorporating biomarkers associated with IRIS (interleukin-6 [IL-6], IL-10, IL-27, sCD14, interferon-γ, tumor necrosis factor-α, hyaluronic acid, D-dimer, body mass index, and hemoglobin) that accurately predicted mycobacterial IRIS and death in this cohort.

CONCLUSIONS

Systemic inflammatory profiles in PWH with severe immunosuppression are predictive of IRIS. Composite scores for the prediction of mycobacterial IRIS and death could be useful for risk stratification in PWH and lymphopenia initiating ART.

CLINICAL TRIALS REGISTRATION

NCT00286767.

Prospective International Study of Incidence and Predictors of Immune Reconstitution Inflammatory Syndrome and Death in People Living With Human Immunodeficiency Virus and Severe Lymphopenia

BACKGROUND

Patients living with human immunodeficiency virus (PLWH) with low CD4 counts are at high risk for immune reconstitution inflammatory syndrome (IRIS) and death at antiretroviral therapy (ART) initiation.

METHODS

We investigated the clinical impact of IRIS in PLWH and CD4 counts <100 cells/μL starting ART in an international, prospective study in the United States, Thailand, and Kenya. An independent review committee adjudicated IRIS events. We assessed associations between baseline biomarkers, IRIS, immune recovery at week 48, and death by week 48 with Cox models.

RESULTS

We enrolled 506 participants (39.3% were women). Median age was 37 years, and CD4 count was 29 cells/μL. Within 6 months of ART, 97 (19.2%) participants developed IRIS and 31 (6.5%) died. Participants with lower hemoglobin at baseline were at higher IRIS risk (hazard ratio [HR], 1.2; P = .004). IRIS was independently associated with increased risk of death after adjustment for known risk factors (HR, 3.2; P = .031). Being female (P = .004) and having a lower body mass index (BMI; P = .003), higher white blood cell count (P = .005), and higher D-dimer levels (P = .044) were also significantly associated with increased risk of death. Decision-tree analysis identified hemoglobin <8.5 g/dL as predictive of IRIS and C-reactive protein (CRP) >106 μg/mL and BMI <15.6 kg/m2 as predictive of death.

CONCLUSIONS

For PLWH with severe immunosuppression initiating ART, baseline low BMI and hemoglobin and high CRP and D-dimer levels may be clinically useful predictors of IRIS and death risk.

373. Immune Reconstitution Inflammatory Syndrome in Patients with HIV/AIDS and Histoplasmosis: A Case Series

Background

Immune Reconstitution Inflammatory Syndrome (IRIS) in HIV infection is the unexpected clinical deterioration due to worsening (paradoxical) or uncovering (unmasking) of an infection or malignancy upon initiation of antiretroviral therapy (ART). Histoplasma capsulatum (H. capsulatum) is the most common endemic mycosis in patients with AIDS, usually manifesting as disseminated disease at CD4 counts < 150 cells/μl. In the ART era, histoplasmosis IRIS has been described in case reports, but there has been a limited description regarding clinical presentations and pathogenesis in the United States.

Methods

ART-naive HIV+ patients with a CD4⁺ T-cell count < 100 cells/µL enrolled in prospective studies at the National Institutes of Health (NIH) (NCT00286767, NCT02147405) were evaluated to identify those with histoplasmosis and followed after ART initiation to identify those who would eventually develop IRIS.

Results

From a total of 271 patients, we identified 9 patients with histoplasmosis. The median age, CD4+ count and HIV VL of these 9 patients was 36 years, 40 cells/mm³ and 193,184 copies/mL, respectively. Two patients developed IRIS only to histoplasmosis (1 unmasking and 1 paradoxical), 2 patients developed IRIS to both histoplasmosis and nontuberculous mycobacteria (NTM) and 3 patients developed IRIS to other infections (1 VZV, and 2 NTM). The manifestations of histoplasmosis IRIS in our cohort ranged from worsening lymphadenopathy to small bowel obstruction and worsening pulmonary symptoms.

Conclusion

Histoplasma-related IRIS can present with worsening lymphadenopathy, small bowel obstruction, and worsening pulmonary symptoms. The emergence of IRIS appears to be very common in people with HIV and disseminated histoplasmosis but the underlying trigger may be histoplasma, other co-infections or both.

Disclosures

All authors: No reported disclosures.

1381. M.genavense in the ART Era: From Persistent Disseminated Disease to Severe Disease

Background

Mycobacterium genavense is an opportunistic pathogen in HIV patients that is difficult to culture and difficult to manage clinically. Here we describe three cases of HIV patients with Mycobacterium genavense with courses representing the spectrum of M.genavense presentations in the current ART era complicated by differing divergent immune responses.

Methods

Two patients were in a longitudinal study at NIAID enrolling patients with HIV and suspected IRIS (PANDORA) (NCT02147405) and one was seen at St. James’s hospital in Dublin. Frozen peripheral blood mononuclear cells were collected at the time of presentation and were used for in vitro stimulation with irradiated M. genavenese in cases 1 and 2 to detect production of cytokines by CD4 T cells.

Results

Pt 1: 27-year old male with M. genavense presenting as diarrhea, abdominal pain, skin nodules, hepatosplenomegaly, and lymphadenopathy (LAN) that persisted on one year of anti-mycobacterial therapy and ART. No CD4 T-cell cytokine response to M. genevense genavense was detected (Fig 1). He received interferon-g and optimization of his antimycobacterial regimen with improvement of symptoms and decreased pathogen burden on repeated biopsies. Pt 2: 55-year old female with M. genavense IRIS manifesting as fevers and abdominal pain that persisted for 10 months on ART (CD4 109 cells/µmL) requiring intermittent corticosteroid use complicated by adrenal insufficiency. She had evidence of CD4 T-cell response to M. genavense in vitro and improved with optimization of her anti-mycobacterial and corticosteroid regimen. Pt 3: 39-year-old male with M. genavense IRIS presenting as fevers, LAN, pleuritic chest pain, and abdominal pain on ART (CD4 19 c/mµL) persisting despite immunologic response to ARV therapy (CD4 recovery to 419 c/mL), appropriate anti-mycobacterial therapy and corticosteroids. He required 4 doses of infliximab (5 mg/kg IV) that facilitated tapering of prednisone.

Conclusion

The clinical presentation of Mycobacterium genavense in HIV patients in the ARV era range from disseminated disease with poor immune reconstitution to persistent or severe IRIS requiring immune suppression. Effective clinical outcomes relied on appropriate anti-mycobacterial and either immune-boosting or immune-suppressive therapies.

Disclosures

All authors: No reported disclosures.

Humanized mouse models reveal an immunologic classification of idiopathic CD4 lymphocytopenia subtypes

Idiopathic CD4 lymphocytopenia (ICL) is a clinically heterogeneous immunodeficiency disorder defined by low numbers of circulating CD4+ T cells and increased susceptibility to opportunistic infections. CD8+ T cells, NK, and/or B cells may also be deficient in some patients. To delineate possible pathogenic cellular mechanisms in ICL, we compared immune system development and function in NOD-RAGKO-γcKO (NRG) mice transplanted with hematopoietic stem cells from patients with ICL or healthy controls. CD34+ hematopoietic stem cells from healthy controls and patients with ICL reconstituted NRG mice equally well. In contrast, PBMC transfers into NRG mice identified 2 ICL engraftment phenotypes, reconstituting and nonreconstituting (NR), based on the absence or presence of donor lymphopenia. For patients in the NR group, the distribution of lymphocyte subsets was similar in the peripheral blood of both the patient and the corresponding humanized mice. The NR-ICL group could be further divided into individuals whose CD3+ T cells had defects in proliferation or survival. Thus, ICL cellular pathogenesis might be classified by humanized mouse models into 3 distinct subtypes: (a) T cell extrinsic, (b) T cell intrinsic affecting proliferation, and (c) T cell intrinsic affecting survival. Humanized mouse models of ICL help to delineate etiology and ultimately to guide development of individualized therapeutic strategies.

Increased Metabolic Activity on 18F-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography in Human Immunodeficiency Virus-Associated Immune Reconstitution Inflammatory Syndrome

Background

Immune reconstitution inflammatory syndrome (IRIS) represents an unexpected inflammatory response shortly after initiation of antiretroviral therapy (ART) in some human immunodeficiency virus (HIV)-infected patients with underlying neoplasia or opportunistic infections, including tuberculosis. We hypothesized that IRIS is associated with increased glycolysis and that 18F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) could help identify high-risk subjects.

Methods

In this prospective cohort study, 30 HIV-infected patients (CD4+ count <100 cells/µL) underwent FDG-PET/CT scans at baseline and 4-8 weeks after ART initiation. Ten patients developed IRIS (6 mycobacterial).

Results

At baseline, total glycolytic activity, total lesion volume, and maximum standardized uptake values (SUVs) of pathologic FDG uptake (reflective of opportunistic disease burden) were significantly higher in IRIS vs non-IRIS (P = .010, .017, and .029, respectively) and significantly correlated with soluble inflammatory biomarkers (interferon-γ, myeloperoxidase, tumor necrosis factor, interleukin 6, soluble CD14). Baseline bone marrow (BM) and spleen FDG uptake was higher in mycobacterial IRIS specifically. After ART initiation, BM and spleen mean SUV decreased in non-IRIS (P = .004, .013) but not IRIS subjects. Our results were supported by significantly higher glucose transporter 1 (Glut-1) expression of CD4+ cells and monocytes after ART initiation in IRIS/mycobacterial IRIS compared with non-IRIS patients.

Conclusions

We conclude that increased pathologic metabolic activity on FDG-PET/CT prior to ART initiation is associated with IRIS development and correlates with inflammatory biomarkers. Abnormally elevated BM and spleen metabolism is associated with mycobacterial IRIS, HIV viremia, and Glut-1 expression on CD4+ cells and monocytes.

Clinical Trials Registration

NCT02147405.

Emergence of Kaposi's Sarcoma Herpesvirus-Associated Complications Following Corticosteroid Use in TB-IRIS

Corticosteroid use was associated with development of Kaposi's sarcoma or multicentric Castleman disease in 3 patients with mycobacterial immune reconstitution inflammatory syndrome (IRIS) treated with corticosteroids. Monitoring for development of Kaposi's sarcoma and alternative treatment may be beneficial for patients with IRIS, especially in the presence of preexisting co-infection with Kaposi's sarcoma-associated herpesvirus.

A Paradoxical Treatment for a Paradoxical Condition: Infliximab Use in Three Cases of Mycobacterial IRIS

The management of corticosteroid refractory immune reconstitution inflammatory syndrome (IRIS) is currently unclear. Infliximab administration was associated with clinical improvement without significant adverse events in 3 patients with mycobacterial IRIS. Immunologic and virologic responses to antiretroviral therapy were unaffected. Tumor necrosis factor blockade may be beneficial for IRIS and warrants further study in clinical trials.

Clinically Indicated Corticosteroids Do Not Affect Bone Turnover During Immune Restoration of Severely Lymphopenic HIV-Infected Patients

Lymphopenia, corticosteroids, antiretroviral therapy (ART), and inflammation negatively impact bone turnover and decrease bone mineral density, but their combined effect has not been evaluated. We examined the association between corticosteroids on bone turnover markers in severely lymphopenic HIV-infected patients initiating ART. Levels of osteocalcin (bone formation marker) and C-terminal telopeptide (CTX; bone resorption marker) were measured at baseline, weeks 4, 12, and 48 of ART in individuals with severe lymphopenia and opportunistic infection (OI) who received (n=28) or did not receive corticosteroids (n=30) during the first year of ART, and in a control group with CD4 >200 (n=15). Wilcoxon tests were used to compare median values of variables between groups. Correlations between plasma interleukin (IL)-6 and tumor necrosis factor (TNF) levels with bone turnover marker levels were performed using Spearman's coefficient. Individuals given corticosteroids received a median of 21 days at a 35 mg prednisone-equivalent daily dose. Individuals with severe lymphopenia had lower osteocalcin levels at baseline and week 4 and higher CTX levels at ART initiation vs.

CONTROLS

Bone turnover markers did not differ in severely lymphopenic persons according to corticosteroid receipt. In those with severe lymphopenia, higher IL-6 was associated with higher CTX levels at ART initiation only. HIV-infected patients with severe lymphopenia and OI had lower levels of bone formation and higher levels of bone resorption than those initiating ART at higher CD4. Corticosteroid use, as prescribed during OI, was not associated with bone turnover. In contrast, higher markers of systemic inflammation prior to ART were associated with greater bone resorption.

T-Cell Depletion in the Colonic Mucosa of Patients With Idiopathic CD4+ Lymphopenia

Idiopathic CD4(+) lymphopenia (ICL) is a rare syndrome characterized by low peripheral CD4(+) T-cell counts that can lead to serious opportunistic infections. The pathogenesis of ICL remains unclear, and whether effector sites are also lymphopenic is unknown. In this study, rectosigmoid mucosal biopsy specimens from patients with ICL and healthy controls were evaluated. Significant T-cell lymphopenia was observed in the mucosal tissue of patients with ICL by flow cytometry and immunohistochemistry, compared with healthy controls. Functional capacity of T cells, assessed by production of interferon γ and interleukin 17, was preserved in the mucosa of patients with ICL. In contrast to T lymphocytes, the frequency of myeloid cells (neutrophils and macrophages) was elevated in the colonic mucosa of patients with ICL. Despite the observed mucosal abnormalities, plasma levels of intestinal fatty acid binding protein, a marker of enterocyte turnover and other inflammatory biomarkers, including interleukin 6, C-reactive protein, and tumor necrosis factor, were not elevated in patients with ICL, compared with healthy controls, whereas soluble CD14 levels were minimally elevated. These data suggest that patients with ICL, despite gut mucosal lymphopenia and local tissue inflammation, have preserved enterocyte turnover and T-helper type 17 cells with minimal systemic inflammation. These observations highlight differences from patients with human immunodeficiency virus infection, with or without AIDS, and may partially explain their distinct clinical prognosis.

Evidence of T cell lymphopenia in the colonic mucosa in idiopathic CD4 lymphocytopenia patients (HEM4P.250)

Idiopathic CD4 lymphocytopenia (ICL) is a syndrome of unknown etiology characterized by low peripheral CD4 T cell counts and susceptibility to opportunistic infections. One hypothesis for its etiology is trapping of T cells in effector sites. 11 ICL patients and 16 healthy controls (HC) underwent colonic biopsies for CD3, CD4, and CD8 T cell enumeration by flow cytometry (FC) and immunohistochemistry (IHC) in lamia propria (LP). Mucosal IL17+ CD4 T cells were assessed after PMA/ionomycin stimulation. Plasma levels of LPS (for microbial translocation), I-FABP (for gut epithelial integrity), sCD14 (for monocyte activation), D-dimer (for coagulation) and CRP, IL-6 and TNFalpha (for inflammation) were tested in 33 ICL patients and 44 HC. ICL patients had fewer CD3 (2.84-fold, P=0.0080), CD4 (3.04-fold, P=0.013) and CD8 (2.28-fold, P=0.043) T cells in the colonic mucosa compared to HC by FC and fewer CD3 (2.31-fold, P=0.036) and CD4 (3.81-fold, P=0.0003) T cells in LP by IHC. The proportion of IL-17+ CD4 T cells was higher in ICL compared to HC (6.04 vs 3.35%, P=0.013). Levels of sCD14 levels were slightly higher in ICL than in HC (1.42 vs 1.21 µg/ml, P=0.003). Levels of LPS, I-FABP, IL-6, TNFalpha, D-Dimer, and CRP levels were not significantly different between ICL and HC (all P&gt;0.05). These data suggest that colonic mucosal lymphopenia accompanies peripheral T cell lymphopenia in ICL, albeit with preserved gut epithelial integrity and a lack of systemic inflammation.

The HIV-1 envelope protein gp120 impairs B cell proliferation by inducing TGF-β1 production and FcRL4 expression

The humoral immune response after acute infection with HIV-1 is delayed and ineffective. The HIV-1 envelope protein gp120 binds to and signals through integrin α4β7 on T cells. We found that gp120 also bound to and signaled through α4β7 on naive B cells, which resulted in an abortive proliferative response. In primary B cells, signaling by gp120 through α4β7 resulted in increased expression of the immunosuppressive cytokine TGF-β1 and FcRL4, an inhibitory receptor expressed on B cells. Coculture of B cells with HIV-1-infected autologous CD4(+) T cells also increased the expression of FcRL4 by B cells. Our findings indicated that in addition to mediating chronic activation of the immune system, viral proteins contributed directly to HIV-1-associated B cell dysfunction. Our studies identify a mechanism whereby the virus may subvert the early HIV-1-specific humoral immune response.

Prevalence of Strongyloides stercoralis in an urban US AIDS cohort

OBJECTIVES

We examined the prevalence of Strongyloides stercoralis (Ss) infection in a cohort of AIDS patients from a US urban centre. We monitored our cohort for possible cases of dissemination or immune reconstitution inflammatory syndrome after antiretroviral therapy (ART) initiation.

METHODS

One hundred and three HIV-infected participants were prospectively sampled from a cohort observational study of ART-naive HIV-1-infected patients with CD4 ≤100 T cells/μl. Clinical symptoms, corticosteroid therapy, eosinophilia, CD4 count, and plasma HIV-RNA were reviewed. Sera were tested by an enzyme-linked immunosorbent assay (CrAg-ELISA) to crude Ss extract or to an Ss-specific recombinant protein (NIE) and by luciferase immunoprecipitation system assay (LIPS) for Ss-specific antibodies.

RESULTS

Twenty-five per cent of study participants were Strongyloides seropositive by CrAg-ELISA and 62% had emigrated from Strongyloides-endemic areas. The remaining 38% of the seropositives were US born and tested negative by NIE and LIPS. CrAg-ELISA-positive participants had a median CD4 count of 22 T cells/μl and a median HIV-RNA of 4·87 log(10) copies/ml. They presented with diarrhea (27%), abdominal pain (23%), and skin manifestations (35%) that did not differ from seronegative patients. Peripheral blood eosinophilia was common among seropositive patients (prevalence of 62% compared to 29% in seronegatives, P = 0·004). Seropositive patients were treated with ivermectin. There were no cases of hyperinfection syndrome.

DISCUSSION

Strongyloidiasis may be prevalent in AIDS patients in the USA who emigrated from Ss-endemic countries, but serology can be inconclusive, suggesting that empiric ivermectin therapy is a reasonable approach in AIDS patients originating from Strongyloides endemic areas.

The CD8+ HLA-DR+ T cells expanded in HIV-1 infection are qualitatively identical to those from healthy controls

HIV-induced immune activation leads to expansion of a subset of human CD8(+) T cells expressing HLA-DR antigens. Expansion of CD8(+) HLA-DR(+) T cells can be also observed in non-HIV settings including several autoimmune diseases and aging. Although these cells are felt to represent "immune exhaustion" and/or to be anergic, their precise role in host defense has remained unclear. Here, we report that this subset of cells exhibits a restricted repertoire, shows evidence of multiple rounds of division, but lacks markers of recent TCR engagement. Detailed cell cycle analysis revealed that compared with their CD8(+) HLA-DR(-) counterpart, the CD8(+) HLA-DR(+) T-cell pool contained an increased fraction of cells in S-phase with elevated levels of the G2/M regulators: cyclin A2, CDC25C, Cdc2 (CDK1), indicating that these cells are not truly anergic but rather experiencing proliferation in vivo. Together, these data support a hypothesis that antigen stimulation leads to the initial expansion of a CD8(+) pool of cells in vivo that undergo further expansion independent of ongoing TCR engagement. No qualitative differences were noted between CD8(+) HLA-DR(+) cells from HIV(+) and HIV(-) donors, indicating that the generation of CD8(+) HLA-DR(+) T cells is a part of normal immune regulation that is exaggerated in the setting of HIV-1 infection.

Attenuation of HIV-associated human B cell exhaustion by siRNA downregulation of inhibitory receptors

Chronic immune activation in HIV-infected individuals leads to accumulation of exhausted tissue-like memory B cells. Exhausted lymphocytes display increased expression of multiple inhibitory receptors, which may contribute to the inefficiency of HIV-specific antibody responses. Here, we show that downregulation of B cell inhibitory receptors in primary human B cells led to increased tissue-like memory B cell proliferation and responsiveness against HIV. In human B cells, siRNA knockdown of 9 known and putative B cell inhibitory receptors led to enhanced B cell receptor-mediated (BCR-mediated) proliferation of tissue-like memory but not other B cell subpopulations. The strongest effects were observed with the putative inhibitory receptors Fc receptor-like-4 (FCRL4) and sialic acid-binding Ig-like lectin 6 (Siglec-6). Inhibitory receptor downregulation also led to increased levels of HIV-specific antibody-secreting cells and B cell-associated chemokines and cytokines. The absence of known ligands for FCRL4 and Siglec-6 suggests these receptors may regulate BCR signaling through their own constitutive or tonic signaling. Furthermore, the extent of FCLR4 knockdown effects on BCR-mediated proliferation varied depending on the costimulatory ligand, suggesting that inhibitory receptors may engage specific pathways in inhibiting B cell proliferation. These findings on HIV-associated B cell exhaustion define potential targets for reversing the deleterious effect of inhibitory receptors on immune responses against persistent viral infections.

CD8-EOMEShigh T cells define a subpopulation of CD8 memory cells that restore CD127high expression after cART treatment in HIV infected patients. (105.27)

After acute viral infection a small population of effector CD8 T cells upregulate CD127 expression and develop into long lived resting memory T cells. During chronic infections, such as HIV, there is an accumulation of CD8 T cells with effector/memory-like phenotype. These observations led to the hypothesis that there is a developmental impairment in the long lived resting memory T cells within that setting. The transcription factors RUNX3 and Eomesodermin (EOMES) are important in the development of long lived memory CD8 T cells. We studied the dynamics of CD127 expression, RUNX3 and EOMES in patients with HIV infection and different levels of viremia. Consistent with other reports, CD127 expression was decreased in the memory CD8 T cell subset. The CD8 memory CD127low T cells showed increased expression of RUNX3 and EOMES mRNA, as well as effector molecules perforin and granzyme B. In patients with suppressed viremia, we could identify two populations of CD8 T cells expressing EOMEShigh and EOMESint. The EOMESint cells showed a short-lived effector phenotype (perforin+, granzyme B+, CD127low) and the EOMEShigh cells showed a memory-like phenotype (perforin-, CD127high). These results suggest that in human CD8 T cells, EOMES is necessary for the maintenance of long lived memory CD8 T cells and its expression was influenced by HIV-RNA levels and the associated inflammatory environment (R=0.4, p=0.01). These findings provide new insights into the pathogenesis of HIV infection.

CD4 and CD8 T cell immune activation during chronic HIV infection: roles of homeostasis, HIV, type I IFN, and IL-7

Immune activation plays an important role in the pathogenesis of HIV disease. Although the causes are not fully understood, the forces that lead to immune dysfunction differ for CD4 and CD8 T cells. In this study, we report that the molecular pathways that drive immune activation during chronic HIV infection are influenced by differences in the homeostatic regulation of the CD4 and CD8 T cell pools. Proliferation of CD4 T cells is controlled more tightly by CD4 T cell numbers than is CD8 T cell proliferation. This difference reflects the importance of maintaining a polyclonal CD4 T cell pool in host surveillance. Both pools of T cells were found to be driven by viral load and its associated state of inflammation. In the setting of HIV-induced lymphopenia, naive CD4 T cells were recruited mainly into the proliferating pool in response to CD4 T cell depletion, whereas naive CD8 T cell proliferation was driven mainly by levels of HIV RNA. RNA analysis revealed increased expression of genes associated with type I IFN and common γ chain cytokine signaling in CD4 T cell subsets and only type I IFN-associated genes in CD8 T cell subsets. In vitro studies demonstrated enhanced STAT1 phosphorylation in response to IFN-α and increased expression of the IFNAR1 transcripts in naive and memory CD4 T cells compared with that observed in CD8 T cells. CD4 T cell subsets also showed enhanced STAT1 phosphorylation in response to exogenous IL-7.

Elevated frequencies of highly activated CD4+ T cells in HIV+ patients developing immune reconstitution inflammatory syndrome

Immune reconstitution inflammatory syndrome (IRIS) is a considerable problem in the treatment of HIV-infected patients. To identify immunologic correlates of IRIS, we characterized T-cell phenotypic markers and serum cytokine levels in HIV patients with a range of different AIDS-defining illnesses, before and at regular time points after initiation of antiretroviral therapy. Patients developing IRIS episodes displayed higher frequencies of effector memory, PD-1(+), HLA-DR(+), and Ki67(+) CD4(+) T cells than patients without IRIS. Moreover, PD-1(+) CD4(+) T cells in IRIS patients expressed increased levels of LAG-3, CTLA-4, and ICOS and had a Th1/Th17 skewed cytokine profile upon polyclonal stimulation. Elevated PD-1 and Ki67 expression was also seen in regulatory T cells of IRIS patients. Furthermore, IRIS patients displayed higher serum interferon-γ, compared with non-IRIS patients, near the time of their IRIS events and higher serum interleukin-7 levels, suggesting that the T-cell populations are also exposed to augmented homeostatic signals. In conclusion, our findings indicate that IRIS appears to be a predominantly CD4-mediated phenomenon with reconstituting effector and regulatory T cells showing evidence of increased activation from antigenic exposure. These studies are registered online at http://clinicaltrials.gov as NCT00557570 and NCT00286767.

d-Dimer and CRP levels are elevated prior to antiretroviral treatment in patients who develop IRIS

Biomarkers could be useful in evaluating immune reconstitution inflammatory syndrome (IRIS). A cohort of 45 HIV-1-infected, antiretroviral treatment (ART)-naive patients with baseline CD4 T cell counts <or=100 cells/microL who were started on ART, suppressed HIV-RNA to <50 copies/mL, and seen every 1-3 months for 1 year were retrospectively evaluated for suspected or confirmed IRIS. d-Dimer, C-reactive protein (CRP), and selected autoantibodies were analyzed at baseline, 1 and 3 months post-ART in cryopreserved plasma. Median differences between cases and controls were compared with Mann-Whitney and Fisher's exact tests. Sixteen patients (35.6%) developed IRIS (median of 35 days post-ART initiation): unmasking=8, paradoxical=7, autoimmune=1. Pre-ART d-dimer and CRP were higher in IRIS cases versus controls (d-dimer: 0.89 mg/L versus 0.66 mg /L, p=0.037; CRP: 0.74 mg/L versus 0.39 mg/L, p=0.022), while d-dimer was higher in unmasking cases at IRIS onset (2.04 mg/L versus 0.36 mg /L, p=0.05). These biomarkers may be useful in identifying patients at risk for IRIS.

Defective plasmacytoid dendritic cell-NK cell cross-talk in HIV infection

HIV viremia is associated with a wide range of immune dysfunctions that contribute to the immunocompromised state. HIV viremia has been shown to have a broad effect on several immune cell types and/or their interactions that are vital for mounting an effective immune response. In this study, we investigated the integrity of plasmacytoid dendritic cell (pDC)-NK cell interactions among HIV viremic, aviremic, and seronegative individuals. We describe a critical defect in the ability of pDCs from HIV-infected individuals to secrete IFN-alpha and TNF and subsequently activate NK cells. We also describe an inherent defect on NK cells from HIV-infected individuals to respond to pDC-secreted cytokines. Furthermore, we were able to demonstrate a direct effect of HIV trimeric gp120 on NK cells in vitro similar to that described ex vivo. Finally, we were able to establish that the HIV gp120-mediated suppressive effect on NK cells was a result of its binding to the integrin alpha(4)beta(7) expressed on NK cells. These findings suggest a novel mechanism by which HIV is capable of suppressing an innate immune function in infected individuals.

A comparison of adherence assessment methods utilized in the United States: perspectives of researchers, HIV-infected children, and their caregivers

This study sought to elucidate methodological issues in adherence research by comparing multiple methods of assessing adherence to antiretroviral medication. From 2003 to 2004, 24 youths with vertically infected HIV disease (mean age = 14.0 years; range, 8-18) and their caregivers participated in a 6-month study. These children were all on highly active antiretroviral therapy (HAART) and were relatively healthy (mean CD4 absolute count = 711.8 +/- 604.5). Adherence was assessed with the Medication Event Monitoring System (MEMS), pill counts, and interviews. Patients and caregivers completed the Perceptions of Adherence Study Participation (PASP) questionnaire. MEMS provided the most detailed adherence information, and good reliability was indicated by significant correlations with medical markers. Pill counts provided similar adherence rates, while patients and caregivers reported nearly perfect adherence in interviews. Problems were experienced with each method: MEMS were expensive, had cap malfunctions, and lack a consistent guiding principle for data interpretation. With pill counts, families forgot to bring all medication bottles to clinic, and interviews were compromised by social desirability and difficulty reaching families by telephone. Most patients and caregivers believed study participation improved the child's adherence, although PASP ratings were unrelated to adherence at the study endpoint. While MEMS may be most reliable, pill counts offer comparable data and are less costly, while interviews seemed least accurate in this study. Most participants reported positive perceptions of their research experience. A consensus among researchers is needed for defining and measuring adherence, and specific recommendations are offered for achieving this goal.

Human immunodeficiency virus and hepatitis C infections induce distinct immunologic imprints in peripheral mononuclear cells

Coinfection with hepatitis C virus (HCV) is present in one-third of all human immunodeficiency virus (HIV)-infected individuals in the United States and is associated with rapid progression of liver fibrosis and poor response to pegylated interferon (IFN) and ribavirin. In this study we examined gene expression profiles in peripheral blood mononuclear cells (PBMCs) from different groups of individuals who are monoinfected or coinfected with HIV and HCV. Data showed that HIV and HCV viremia up-regulate genes associated with immune activation and immunoregulatory pathways. HCV viremia is also associated with abnormalities in all peripheral immune cells, suggesting a global effect of HCV on the immune system. Interferon-alpha-induced genes were expressed at a higher level in PBMCs from HIV-infected individuals. HCV and HIV infections leave distinct profiles or gene expression of immune activation in PBMCs. HIV viremia induces an immune activated state; by comparison, HCV infection induces immunoregulatory and proinflammatory pathways that may contribute to progression of liver fibrosis.

CONCLUSION

An aberrant type-I IFN response seen exclusively in HIV-infected individuals could be responsible for the poor therapeutic response experienced by HIV/HCV coinfected individuals receiving interferon-alpha-based current standard of care.

Lytic granule loading of CD8+ T cells is required for HIV-infected cell elimination associated with immune control

Virus-specific CD8+ T cells probably mediate control over HIV replication in rare individuals, termed long-term nonprogressors (LTNPs) or elite controllers. Despite extensive investigation, the mechanisms responsible for this control remain incompletely understood. We observed that HIV-specific CD8+ T cells of LTNPs persisted at higher frequencies than those of treated progressors with equally low amounts of HIV. Measured on a per-cell basis, HIV-specific CD8+ T cells of LTNPs efficiently eliminated primary autologous HIV-infected CD4+ T cells. This function required lytic granule loading of effectors and delivery of granzyme B to target cells. Defective cytotoxicity of progressor effectors could be restored after treatment with phorbol ester and calcium ionophore. These results establish an effector function and mechanism that clearly segregate with immunologic control of HIV. They also demonstrate that lytic granule contents of memory cells are a critical determinant of cytotoxicity that must be induced for maximal per-cell killing capacity.

CpG oligonucleotides enhance proliferative and effector responses of B Cells in HIV-infected individuals

Stimulation through TLR represents a new therapeutic approach for enhancing Ab responses to vaccination. Considering that Ab responses are decreased in HIV disease and that B cells express TLR9 and respond to TLR9 agonists, we investigated the responsiveness of B cell subpopulations from HIV-infected and uninfected individuals to the TLR9 agonist CpG oligonucleotide type B (CpG-B) in the presence and absence of BCR ligation and T cell help (CD40L). CpG-B was equally effective in stimulating the proliferation of naive B cells of HIV-infected individuals and HIV-negative individuals, and, when combined with BCR and CD40 ligation, cytokine secretion by naive B cells was also comparable in HIV-infected and uninfected individuals. In contrast, CD27(+) memory/activated B cells of HIV-infected individuals with active disease were less responsive to CpG-B in terms of proliferation and cytokine secretion when compared with CD27(+) B cells of HIV-negative and HIV-infected individuals whose viremia was controlled by antiretroviral therapy. These findings suggest that despite abnormalities in memory B cells of HIV-infected individuals with active disease, naive B cells of HIV-infected individuals, irrespective of disease status, can respond to TLR9 agonists and that the incorporation of such agents in vaccine formulations may enhance their Ab responses to vaccination.

Evidence for HIV-associated B cell exhaustion in a dysfunctional memory B cell compartment in HIV-infected viremic individuals

Human immunodeficiency virus (HIV) disease leads to impaired B cell and antibody responses through mechanisms that remain poorly defined. A unique memory B cell subpopulation (CD20^hi/CD27^lo/CD21^lo) in human tonsillar tissues was recently defined by the expression of the inhibitory receptor Fc-receptor-like-4 (FCRL4). In this study, we describe a similar B cell subpopulation in the blood of HIV-viremic individuals. FCRL4 expression was increased on B cells of HIV-viremic compared with HIV-aviremic and HIV-negative individuals. It was enriched on B cells with a tissuelike memory phenotype (CD20^hi/CD27⁻/CD21^lo) when compared with B cells with a classical memory (CD27⁺) or naive (CD27⁻/CD21^hi) B cell phenotype. Tissuelike memory B cells expressed patterns of homing and inhibitory receptors similar to those described for antigen-specific T cell exhaustion. The tissuelike memory B cells proliferated poorly in response to B cell stimuli, which is consistent with high-level expression of multiple inhibitory receptors. Immunoglobulin diversities and replication histories were lower in tissuelike, compared with classical, memory B cells, which is consistent with premature exhaustion. Strikingly, HIV-specific responses were enriched in these exhausted tissuelike memory B cells, whereas total immunoglobulin and influenza-specific responses were enriched in classical memory B cells. These data suggest that HIV-associated premature exhaustion of B cells may contribute to poor antibody responses against HIV in infected individuals.

Persistence of HIV in gut-associated lymphoid tissue despite long-term antiretroviral therapy

Human immunodeficiency virus (HIV) persists in peripheral blood mononuclear cells despite sustained, undetectable plasma viremia resulting from long-term antiretroviral therapy. However, the source of persistent HIV in such infected individuals remains unclear. Given recent data suggesting high levels of viral replication and profound depletion of CD4(+) T cells in gut-associated lymphoid tissue (GALT) of animals infected with simian immunodeficiency virus and HIV-infected humans, we sought to determine the level of CD4(+) T cell depletion as well as the degree and extent of HIV persistence in the GALT of infected individuals who had been receiving effective antiviral therapy for prolonged periods of time. We demonstrate incomplete recoveries of CD4(+) T cells in the GALT of aviremic, HIV-infected individuals who had received up to 9.9 years of effective antiretroviral therapy. In addition, we demonstrate higher frequencies of HIV infection in GALT, compared with PBMCs, in these aviremic individuals and provide evidence for cross-infection between these 2 cellular compartments. Together, these data provide a possible mechanism for the maintenance of viral reservoirs revolving around the GALT of HIV-infected individuals despite long-term viral suppression and suggest that the GALT may play a major role in the persistence of HIV in such individuals.

Normalization of B cell counts and subpopulations after antiretroviral therapy in chronic HIV disease

BACKGROUND

Untreated human immunodeficiency virus (HIV) disease leads to abnormalities in all major lymphocyte populations, including CD4(+) T cells, CD8(+) T cells, and B cells. However, little is known regarding the effect of antiretroviral therapy (ART)-induced decrease in HIV viremia on B cell numbers and subpopulations.

METHODS

We conducted a longitudinal study to evaluate changes in B cell numbers and subpopulations that occur during the course of 12 months of effective ART in a group of individuals with chronic HIV infection.

RESULTS

ART-induced decrease in HIV viremia was associated with a significant increase in B cell counts, similar to increases in CD4(+) T cell counts yet distinct from the lack of increase in CD8(+) T cells. The increase in B cell counts was accompanied by a significant decrease in the frequency of apoptosis-prone B cell subpopulations, namely mature activated and immature transitional B cells, which are overrepresented in untreated HIV disease. The increase in B cell counts was reflected by a significant increase in naive and resting memory B cells, both of which represent populations that are essential for generating adequate humoral immunity.

CONCLUSIONS

Normalization of B cell counts and subpopulations may help to explain the improvement in humoral immunity reported to occur after an ART-induced decrease in HIV viremia.

The Antiretroviral Regimen Complexity Index. A novel method of quantifying regimen complexity

BACKGROUND

Individuals with HIV disease often must adhere to complex medication regimens. To date, regimen complexity has not been examined in the literature using standardized procedures incorporating all important elements of antiretroviral (ARV) regimens.

OBJECTIVE

This article presents a novel method of quantifying regimen complexity using objective criteria addressing the factors that may complicate adherence to ARV regimens.

METHODS

Part 1 of this article describes the development of the Antiretroviral Regimen Complexity (ARC) Index scoring system. Based on input from pediatric and adult patients, caregivers of pediatric patients, and health care professionals, this comprehensive system includes the number of medications, dosing schedules, administration methods, special instructions, and required preparations associated with ARV regimens. Weights are applied for each of these factors to produce an overall score representing the regimen's level of complexity. Part 2 of this article presents reliability and validity data for the system.

RESULTS

The ARC Index demonstrates excellent test-retest and interrater reliability as well as strong construct and discriminant validity. An on-line version of this system minimizes computation errors.

CONCLUSIONS

Although modifications may be necessary for patients requiring nonstandard dosing instructions, preliminary evidence supports the utility of this measure as a reliable and valid indicator of the complexity of antiretroviral treatment regimens.

Innate Immunity in HIV Infection

In the present study, we performed DNA microarray analyses and phenotypic and functional analyses in an effort to elucidate the mechanisms by which ongoing HIV replication affects the physiologic function of natural killer (NK) cells. Functional assays confirmed an increased propensity of NK cells from HIV-infected viremic individuals to undergo Fas-mediated apoptosis but not CD16- or NKG2D-mediated apoptosis. Serum levels of sFasL and expression of Ki67 on NK cells were markedly elevated in HIV-infected viremic individuals when compared with those of HIV-infected aviremic and HIV-seronegative individuals. Our data demonstrate that ongoing HIV replication results in profound NK-cell abnormalities that are likely to be attributable to the effects of virus-induced immune activation. Of note is an increased susceptibility to cell death mediated by CD95-sFasL interactions. In addition, these NK cells, particularly the CD56(dim) CD16(bright) subset, undergo enhanced cell turnover in vivo, as demonstrated by intracellular Ki67 expression.

Impact of HIV on cell survival and antiviral activity of plasmacytoid dendritic cells

Plasmacytoid dendritic cells (pDCs) are important mediators of innate immunity that act mainly through secretion of interferon (IFN)-α. Previous studies have found that these cells can suppress HIV in vitro; additionally, pDCs have been shown to be severely reduced in the peripheral blood of HIV-infected individuals. In the present study, we sought to determine the ability of pDCs to directly suppress viral replication ex vivo and to delineate the potential mechanisms whereby pDCs are depleted in HIV-infected individuals. We demonstrate that activated pDCs strongly suppress HIV replication in autologous CD4⁺ T cells via a mechanism involving IFN-α as well as other antiviral factors. Of note, unstimulated pDCs from infected individuals who maintain low levels of plasma viremia without antiretroviral therapy were able to suppress HIV ex vivo via a mechanism requiring cell-to-cell contact. Our data also demonstrate that death of pDCs by both apoptosis and necrosis is induced by fusion of HIV with pDCs. Taken together, our data suggest that pDCs play an important role in the control of HIV replication and that high levels of viral replication in vivo are associated with pDC cell death via apoptosis and necrosis. Elucidation of the mechanism by which pDCs suppress HIV replication in vivo may have clinically relevant implications for future therapeutic strategies.

CD25+ regulatory T cells isolated from HIV-infected individuals suppress the cytolytic and nonlytic antiviral activity of HIV-specific CD8+ T cells in vitro

HIV infection is characterized by CD4(+) T cell depletion and progressive immune dysfunction; particularly impacted are HIV-specific T cell responses. An important component of immune-mediated control of HIV replication, killing of infected cells, appears to be impaired, in part due to poor cytolytic activity of HIV-specific cytotoxic T cells (CTL). In vitro, several functions of HIV-specific T cells, such as cytokine production, can be enhanced by the depletion of the immunosuppressive CD25(+) FoxP3(+) CD4(+) regulatory (Treg) cell subset. However, the effect of CD25(+) Treg cells on virus-specific cytolytic activity in the context of HIV or any human viral infection has not been investigated. The present study demonstrates that CD25(+) Treg cells isolated from the peripheral blood of HIV-infected subjects significantly suppress HIV Gag-specific cytolytic activity in vitro. In addition, CD25(+) Treg cells suppress effector function (coexpression of TNF-alpha and IFN-gamma) of HIV-specific CD8(+) T cells that proliferate in response to HIV antigen. Finally, the secretion of HIV-inhibitory CC-chemokines by HIV-specific and nonspecific CD8(+) T cells is significantly reduced in the presence of CD25(+) Treg cells. These data suggest that CD25(+) Treg-mediated suppression of the antiviral activity of HIV-specific CD8(+) T cells could impact the ability of HIV-infected individuals to control HIV replication in vivo.

Suppression of HIV-specific T cell activity by lymph node CD25+ regulatory T cells from HIV-infected individuals

CD25(+) CD4(+) FoxP3(+) regulatory T (Treg) cells isolated from the peripheral blood of asymptomatic HIV-infected individuals have been demonstrated to significantly suppress HIV-specific immune responses in vitro. CD25(+) Treg cell suppressor activity in the peripheral blood seems to diminish with progression of HIV disease, and it has been suggested that loss of Treg cells contributes to aberrant immune activation and disease progression. However, phenotypic studies suggest that Treg cells may migrate to, and be maintained or even expanded in, tissue sites of HIV replication. Currently, it is not known whether tissue-associated Treg cells maintain suppressive activity in the context of HIV infection, particularly in individuals with advanced disease. The present study demonstrates that CD25(+) Treg cells isolated from lymph nodes and peripheral blood of HIV(+) subjects, even those with high viral loads and/or low CD4(+) T cell counts, maintain potent suppressive activity against HIV-specific cytolytic T cell function. This activity was better in lymph node as compared with peripheral blood, particularly in patients with high levels of plasma viremia. In addition, the expression of certain CD25(+) Treg-associated markers on CD4(+) T cells isolated from lymph nodes differed significantly from those on CD4(+) T cell subsets isolated from the peripheral blood. These data suggest that CD25(+) Treg cell-mediated suppression of HIV-specific responses continues throughout the course of HIV disease and, because of their particularly potent suppression of HIV-specific CTL activity in lymphoid tissue, may considerably impact the ability to control HIV replication in vivo.

Patient, caregiver and regimen characteristics associated with adherence to highly active antiretroviral therapy among HIV-infected children and adolescents

BACKGROUND

This study assesses the relationship between child and caregiver perceptions of medication responsibility, disease knowledge, regimen complexity and adherence to highly active antiretroviral therapy among HIV-positive children. We also examine the association of adherence to child and caregiver demographic characteristics and surrogate markers of HIV disease.

METHODS

For this 6-month longitudinal study, 24 HIV-positive children (mean age = 14.0 years) being treated with highly active antiretroviral therapy and their caregivers completed measures of medication responsibility and disease knowledge. Medication Event Monitoring System caps calculated adherence across months 1 through 3 (time 1) and 4 through 6 (time 2).

RESULTS

Medication Event Monitoring System data revealed adherence rates of 81% at time 1 and 79% at time 2. Only 8% (n = 2) of child-caregiver pairs reported complete agreement regarding who held responsibility for medication-related tasks. Patients' responsibility for medication was correlated with age based on child (r = .51) and caregiver (r = .57; Ps < 0.05) perceptions, although their regimen knowledge was not. Greater regimen knowledge among caregivers and fewer child-caregiver discrepancies about medication responsibility predicted better adherence (adjusted R = .45). Finally, adherence was correlated with CD4 percentages at time 1 (r = .50) and viral load at time 1 (r = -.56) and time 2 (r= -.68; Ps < 0.05).

CONCLUSIONS

Medication adherence among HIV-infected children is lower than required for optimal viral suppression. Adherence is related to surrogate markers of HIV disease but not to child or caregiver demographic variables. Responsibilities for medication-related tasks should be clarified among family members, regimen knowledge should be emphasized and caregivers should avoid assigning treatment responsibility to a child prematurely.

Could human papillomaviruses be spread through blood?

The human papillomaviruses (HPVs) are epitheliotropic viruses that require the environment of a differentiating squamous epithelium for their life cycle. HPV infection through abrasion of the skin or sexual intercourse causes benign warts and sometimes cancer. HPV DNA detected in the blood has been interpreted as having originated from metastasized cancer cells. The present study examined HPV DNA in banked, frozen peripheral blood mononuclear cells (PBMCs) from 57 U.S. human immunodeficiency virus (HIV)-infected pediatric patients collected between 1987 and 1996 and in fresh PBMCs from 19 healthy blood donors collected in 2002 to 2003. Eight patients and three blood donors were positive mostly for two subgroups of the HPV type 16 genome. The HPV genome detected in all 11 PBMC samples existed as an episomal form, albeit at a low DNA copy number. Among the eight patients, seven acquired HIV from transfusion (three associated with hemophilia) and one acquired HIV through vertical transmission; this patient also had received a transfusion before sampling. Our data suggest that PBMCs may be HPV carriers and might spread the virus through blood.

Exstrophy of bladder associated with unilateral renal agenesis and bicornuate uterus: a case report

Upper urinary tract anomalies are rare in patients with classic exstrophy of the urinary bladder. We report a case of bladder exstrophy associated with unilateral renal agenesis and bicornuate uterus in a female patient. The embryological basis for this rarity and its management are discussed.