Hematopoietic Stem/Progenitor Cells and the Pathogenesis of HIV/AIDS

Prevalence trends of anemia impairment in adolescents and young adults with HIV/AIDS

BACKGROUND

Anemia is a common complication of HIV/AIDS, particularly in adolescents and young adults across various countries and regions. However, little is known about the changing prevalence trends of anemia impairment in this population over time.

METHODS

Data on anemia in adolescents and young adults with HIV/AIDS from 1990 to 2019 were collected from the Global Burden of Disease. Prevalence was calculated by gender, region, and country for individuals aged 10-24, and trends were measured using estimating annual percentage changes (EAPC).

RESULTS

Globally, the prevalence of adolescents and young adults with HIV/AIDS increased from 103.95 per 100,000 population in 1990 to 203.78 in 2019. However, anemia impairment has decreased over the past three decades, with a global percentage decreasing from 70.6% in 1990 to 34.7% in 2019, mainly presenting as mild to moderate anemia and significantly higher in females than males. The largest decreases were observed in Central Sub-Saharan Africa, North America, and Eastern Sub-Saharan Africa, with EAPCs of -2.8, -2.34, and -2.17, respectively. Tajikistan (78.76%) and Madagascar (74.65%) had the highest anemia impairment percentage in 2019, while China (16.61%) and Iceland (13.73%) had the lowest. Anemia impairment was closely related to sociodemographic index (SDI) levels, with a high proportion of impairment in low SDI regions but a stable decreasing trend (EAPC = -0.37).

CONCLUSION

Continued anemia monitoring and management are crucial for patients with HIV, especially in high-prevalence regions and among females. Public health policies and interventions can improve the quality of life and reduce morbidity and mortality.

Hematological Complications of Human Immunodeficiency Virus (HIV) Infection: An Update From an HIV-Endemic Setting

Medical professionals, particularly in regions with a high burden of human immunodeficiency virus (HIV), should be alert to the hematological complications of HIV, which may include cytopenias, malignancy, and coagulation disturbances. Patients may present with these conditions as the first manifestation of HIV infection. Hematological abnormalities are often multifactorial with opportunistic infections, drugs, malignancy, and HIV infection itself contributing to the clinical presentation, and the diagnosis should consider all these factors. Life-threatening hematological complications requiring urgent diagnosis and management include thrombotic thrombocytopenic purpura, superior mediastinal syndrome, spinal cord compression, and tumor lysis syndrome due to aggressive lymphoma. Antiretroviral therapy is the therapeutic backbone, including for patients with advanced HIV, in addition to specific therapy for the complication. This article reviews the impact of HIV on the hematological system and provides a clinical and diagnostic approach, including the role of a bone marrow biopsy, focusing on perspectives from sub-Saharan Africa.

Mechanisms and Cardiorenal Complications of Chronic Anemia in People with HIV

Chronic anemia is more prevalent in people living with HIV (PLWH) compared to the general population. The mechanisms that drive chronic anemia in HIV are multifaceted and include functional impairment of hematopoietic stem cells, dysregulation of erythropoietin production, and persistent immune activation. Chronic inflammation from HIV infection adversely affects erythropoiesis, erythrocyte lifespan, and erythropoietin response, leading to a heightened risk of co-infections such as tuberculosis, persistent severe anemia, and increased mortality. Additionally, chronic anemia exacerbates the progression of HIV-associated nephrotoxicity and contributes to cardiovascular risk through immune activation and inflammation. This review highlights the cardinal role of chronic inflammation as a link connecting persistent anemia and cardiovascular complications in PLWH, emphasizing the need for a universal understanding of these interconnected pathways for targeted interventions.

Detection of HIV-1 DNA/RNA in Peripheral Blood, Bone Marrow and Femoral Head of Patients with Osteonecrosis of the Femoral Head

Background

With the increasing life expectancy of people living with HIV (PLWH) following antiretroviral therapy (ART), there is a growing prevalence of chronic diseases such as osteonecrosis of the femoral head (ONFH). Compared with the more accessible blood, the viral infection profile in bone marrow and necrotic femoral heads in PLWH remains inadequately characterized.

Methods

Femoral head and bone marrow were collected from 15 PLWH undergoing total hip arthroplasty. For each femoral head, samples were obtained from the subchondral, necrotic, sclerotic, and normal areas. HIV DNA and HIV RNA assays were employed to evaluate disparities in viral load and reservoir between bone marrow and blood, as well as to quantify viral infection in distinct regions of the necrotic femoral head.

Results

Blood HIV RNA dropped below detectable levels in 8 patients (below 20 copies/mL). The median of bone marrow HIV RNA was 255.89 copies/mL. HIV DNA in blood and bone marrow was 296.35 and 454.31 copies/106 cells. HIV DNA in necrotic area was about half that in sclerotic area, HIV RNA was about twice that in normal area, the difference was statistically significant.

Conclusion

Despite using ART, there is still substantial active HIV and a potential reservoir in the bone marrow. Viral transcription was most active in the necrotic area of the femoral head, which may indicate that HIV itself is directly involved in ONFH.

Prevalence of Cytopenia and its Correlation with Immunosuppression in Naïve HIV-1 Infected Patients Initiating First-Line Antiretroviral Therapy: A Pilot Study

BACKGROUND

Cytopenias serve as common indicators and crucial predictive tools for evaluating disease progression and therapeutic outcomes in individuals with human immunodeficiency virus (HIV) infection. This study aimed to assess the prevalence of cytopenias and their correlation with the level of immunosuppression in treatment-naive HIV-infected participants after initiating highly active combined antiretroviral drug therapy (cART24).

MATERIALS AND METHODS

This prospective study focused on evaluating cytopenia in 44 treatment-naive HIV-infected patients who consented to initiate cART and were consecutively enrolled. The research was conducted at the Nasara HIV Treatment & Care Centre of Ahmadu Bello University Teaching Hospital (ABUTH), Zaria, Nigeria, spanning from December 2016 to January 2018. Cytopenias, including anemia, leucopenia, lymphocytopenia, and thrombocytopenia, were defined and assessed according to World Health Organization guidelines. A combination of cross-sectional and longitudinal mixed-design two-step analysis was employed to validate our findings.

RESULTS

The median time from enrollment to cART initiation was 7 days, following the universal test and treat protocol. The prevalence of cytopenia was 75% at the baseline before treatment and increased to 84% after cART24 administration. There were no statistically significant differences in the median values of immuno-hematological parameters between baseline and after cART24 initiation (P >0.05). In terms of longitudinal assessment, the prevalence of anemia, leucopenia, lymphopenia, and thrombocytopenia at baseline were 66%, 23%, 0%, and 11%, respectively, and after cART24, the rates were 66%, 29%, 5%, and 20%. Notably, the prevalence of cytopenia correlated with declining CD4+ T cell counts. Among instances of unicytopenia, 58% exhibited isolated anemia, 6% had lone leucopenia, and 6% had solitary thrombocytopenia. Additionally, 27% demonstrated bi-cytopenia, and 3% exhibited pancytopenia. Interestingly, none of the study participants presented with lymphopenia. The most common combination was anemia and thrombocytopenia. Both longitudinal and cross-sectional analytical findings were consistent.

CONCLUSION

In treatment-naive HIV-infected individuals, the prevalence of cytopenias, particularly anemia and thrombocytopenia, was substantial and correlated with the degree of immunosuppression as indicated by CD4+ T cell counts. These cytopenias persisted despite initiation of cART24, highlighting the complexity of hematological manifestations in HIV infection. Our study underscores the significant hematopathological impact of HIV and antiretroviral therapy, highlighting the necessity for preventive strategies to mitigate these adverse effects.

Anemia in HIV Patients Attending Highly Active Antiretroviral Therapy Clinic at Hoima Regional Referral Hospital: Prevalence, Morphological Classification, and Associated Factors

Purpose

To determine the prevalence of anemia, the morphological classification and to assess the factors associated with anemia among HIV patients attending Highly Active Antiretroviral Therapy (HAART) clinic at Hoima Regional Referral Hospital.

Methods

This was a cross-sectional study among 340 participants attending the HAART clinic at Hoima Regional Referral Hospital. Participants were recruited using a simple random sampling technique. A complete blood count (CBC) was performed using the Sysmex XN-550 hematology analyzer. Thick films were made and examined for malaria parasites, while thin films were examined for the morphological classification of anemia. Bivariate and multivariate logistic analyses were conducted using SPSS (version 23).

Results

Out of the 340 study participants, 255 (75%) were females, and the median age was 39 years (range: 6-76 years). The overall prevalence of anemia among the study participants was 16.8% (95% CI 13.1-21.1). Normocytic normochromic anemia was the most prevalent form of anemia (47.4%). The logistic regression at multivariate analysis showed that age groups (18-27 years, p = 0.017; 28-37 years, p = 0.005; and ≥38 years, p = 0.009), divorced marital status (p = 0.024), the presence of chronic disease (p = 0.010), a family history of anemia (p = 0.007), and the presence of malaria in the past one month (p = 0.001), presence of opportunistic infection (OR = 58, p = 0.000), use of antihelminthic drug in the past 3 months (OR = 0.10, p = 0.003) and unsuppressed viral load (OR = 10.74, p = 0.000) had a significant association with anemia.

Conclusion

Anemia is prevalent in HIV/AIDS patients who receive treatment at Hoima Regional Referral Hospital. Age, marital status, the presence of chronic illnesses, a family history of anemia, experiencing malaria in the past 3 months, the presence of opportunistic infections, the use of antihelminthic drugs in the past 3 months, and an unsuppressed viral load were significantly associated with anemia.

Recent advances in poor HIV immune reconstitution: what will the future look like?

Combination antiretroviral therapy has demonstrated proved effectiveness in suppressing viral replication and significantly recovering CD4+ T cell count in HIV type-1 (HIV-1)-infected patients, contributing to a dramatic reduction in AIDS morbidity and mortality. However, the factors affecting immune reconstitution are extremely complex. Demographic factors, co-infection, baseline CD4 cell level, abnormal immune activation, and cytokine dysregulation may all affect immune reconstitution. According to report, 10-40% of HIV-1-infected patients fail to restore the normalization of CD4+ T cell count and function. They are referred to as immunological non-responders (INRs) who fail to achieve complete immune reconstitution and have a higher mortality rate and higher risk of developing other non-AIDS diseases compared with those who achieve complete immune reconstitution. Heretofore, the mechanisms underlying incomplete immune reconstitution in HIV remain elusive, and INRs are not effectively treated or mitigated. This review discusses the recent progress of mechanisms and factors responsible for incomplete immune reconstitution in AIDS and summarizes the corresponding therapeutic strategies according to different mechanisms to improve the individual therapy.

Consequences of HIV infection in the bone marrow niche

Dysregulation of the bone marrow niche resulting from the direct and indirect effects of HIV infection contributes to haematological abnormalities observed in HIV patients. The bone marrow niche is a complex, multicellular environment which functions primarily in the maintenance of haematopoietic stem/progenitor cells (HSPCs). These adult stem cells are responsible for replacing blood and immune cells over the course of a lifetime. Cells of the bone marrow niche support HSPCs and help to orchestrate the quiescence, self-renewal and differentiation of HSPCs through chemical and molecular signals and cell-cell interactions. This narrative review discusses the HIV-associated dysregulation of the bone marrow niche, as well as the susceptibility of HSPCs to infection by HIV.

Risk factors and prognosis of thrombocytopenia in people living with HIV/AIDS

Background

Thrombocytopenia is a common hematological manifestation in people living with human immunodeficiency virus (HIV) or acquired immune deficiency syndrome (AIDS; PLWHA). Data on the prognostic relationship and associated factors of thrombocytopenia and HIV infection in China are limited.

Objectives

We assessed the prevalence of thrombocytopenia, its association with prognosis, and analyzed the associated risk factors among demographic characteristics, comorbidities, hematological and bone marrow indicators.

Design

We collected patients identified as PLWHA in Zhongnan Hospital. The patients were divided into two groups: the thrombocytopenia group and the non-thrombocytopenia group. We analyzed and compared demographic characteristics, comorbidities, peripheral blood cells, lymphocyte subpopulations, infection indicators, bone marrow cytology, and bone marrow morphology of the two groups. Then we analyzed the risk factors for thrombocytopenia and the effect of platelet (PLT) values on the prognosis of patients.

Methods

Demographic characteristics and laboratory results were obtained from medical records. In contrast to other studies, we included bone marrow cytology and morphology in this study. Data were analyzed with multivariate logistic regression analysis. The Kaplan-Meier method was used to plot 60-month survival curves for the severe, mild, and non-thrombocytopenia groups. The value p < 0.05 was taken as statistically significant.

Results

Among 618 identified PLWHA, 510 (82.5%) were male. Overall, thrombocytopenia was found in 37.7% [95% confidence interval (CI): 33.9-41.5%]. Multivariable logistic regression analysis showed that age ⩾40 years [adjusted odds ratio (AOR) 1.869, 95% CI: 1.052-3.320], combined with hepatitis B (AOR 2.004, 95% CI: 1.049-3.826), high procalcitonin (PCT) count (AOR 1.038, 95% CI: 1.000-1.078) were risk factors of thrombocytopenia in PLWHA. An increased percentage of thrombocytogenic megakaryocytes was a protective factor, with an AOR 0.949 (95% CI: 0.930-0.967). Kaplan-Meier survival curve analysis showed that the prognosis was worse in the severe than in the mild (p = 0.002) and non-thrombocytopenia groups (p = 0.008).

Conclusion

We discovered a general high pervasiveness of thrombocytopenia in PLWHA in China. Age ⩾40 years, combined with hepatitis B virus infection, high PCT, and decreased percentage of thrombocytogenic megakaryocytes indicated a higher risk for developing thrombocytopenia. A PLT count ⩽50 × 109/liter led to a worse prognosis. Therefore, early diagnosis and treatment of thrombocytopenia in these patients are useful.

Risk Factors in HIV-1 Positive Patients on the Intensive Care Unit: A Single Center Experience from a Tertiary Care Hospital

HIV-positive patients with acquired immunodeficiency syndrome (AIDS) often require treatment on intensive care units (ICUs). We aimed to present data from a German, low-incidence region cohort, and subsequently evaluate factors measured during the first 24 h of ICU stay to predict short- and long-term survival, and compare with data from high-incidence regions. We documented 62 patient courses between 2009 and 2019, treated on a non-operative ICU of a tertiary care hospital, mostly due to respiratory deterioration and co-infections. Of these, 54 patients required ventilatory support within the first 24 h with either nasal cannula/mask (n = 12), non-invasive ventilation (n = 16), or invasive ventilation (n = 26). Overall survival at day 30 was 77.4%. While ventilatory parameters (all p < 0.05), pH level (c/o 7.31, p = 0.001), and platelet count (c/o 164,000/µL, p = 0.002) were significant univariate predictors of 30-day and 60-day survival, different ICU scoring systems, such as SOFA score, APACHE II, and SAPS 2 predicted overall survival (all p < 0.001). Next to the presence or history of solid neoplasia (p = 0.026), platelet count (HR 6.7 for <164,000/µL, p = 0.020) and pH level (HR 5.8 for <7.31, p = 0.009) remained independently associated with 30-day and 60-day survival in multivariable Cox regression. However, ventilation parameters did not predict survival multivariably.

Recurrent visceral leishmaniasis relapses in HIV co-infected patients are characterized by less efficient immune responses and higher parasite load

Visceral leishmaniasis (VL) and HIV co-infection (VL/HIV) has emerged as a significant public health problem in Ethiopia, with up to 30% of patients with VL co-infected with HIV. These patients suffer from recurrent VL relapses and increased mortality. Those with a previous history of VL relapses (recurrent VL/HIV) experience increased VL relapses as compared to patients with HIV presenting with their first episode of VL (primary VL/HIV). Our aim was to identify drivers that account for the higher rate of VL relapses in patients with recurrent VL/HIV (n = 28) as compared to primary VL/HIV (n = 21). Our results show that the relapse-free survival in patients with recurrent VL/HIV was shorter, that they had higher parasite load, lower weight gain, and lower recovery of all blood cell lineages. Their poorer prognosis was characterized by lower production of IFN-gamma, lower CD4+ T cell counts, and higher expression of programmed cell death protein 1 (PD1) on T cells.

Following successful anti-leishmanial treatment, neutrophil counts, CD10 expression and phagocytic capacity remain reduced in visceral leishmaniasis patients co-infected with HIV

Visceral leishmaniasis (VL) patients co-infected with HIV (VL/HIV patients) experience frequent treatment failures, VL relapses, opportunistic infections, and higher mortality. Their immune system remains profoundly suppressed after clinical cure and they maintain higher parasite load. This is in contrast with patients with VL alone (VL patients). Since neutrophils play a critical role in the control of Leishmania replication and the regulation of immune responses, we tested the hypothesis that neutrophil activation status and effector functions are fully restored in VL, but not in VL/HIV patients. Our results show the neutrophil counts and all activation markers and effector functions tested in our study were reduced at the time of diagnosis in VL and VL/HIV patients as compared to controls. CD62L, CD63, arginase 1 expression levels and reactive oxygen species production were restored at the end of treatment in both groups. However, neutrophil counts, CD10 expression and phagocytosis remained significantly lower throughout follow-up in VL/HIV patients; suggesting that dysregulated neutrophils contribute to the impaired host defence against pathogens in VL/HIV patients.

Biological ageing with HIV infection: evaluating the geroscience hypothesis

Although people with HIV are living longer, as they age they remain disproportionately burdened with multimorbidity that is exacerbated in resource-poor settings. The geroscience hypothesis postulates that a discrete set of between five and ten hallmarks of biological ageing drive multimorbidity, but these processes have not been systematically examined in the context of people with HIV. We examine four major hallmarks of ageing (macromolecular damage, senescence, inflammation, and stem-cell dysfunction) as gerodrivers in the context of people with HIV. As a counterbalance, we introduce healthy ageing, physiological reserve, intrinsic capacity, and resilience as promoters of geroprotection that counteract gerodrivers. We discuss emerging geroscience-based diagnostic biomarkers and therapeutic strategies, and provide examples based on recent advances in cellular senescence, and other, non-pharmacological approaches. Finally, we present a conceptual model of biological ageing in the general population and in people with HIV that integrates gerodrivers and geroprotectors as modulators of homoeostatic reserves and organ function over the lifecourse.

The role of the CRISPR-Cas system in cancer drug development: Mechanisms of action and therapy

BACKGROUND

The recent emergence of gene editing using Clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR associated system (Cas) tools and advances in genomics and proteomics has revolutionized drug discovery and personalized medicine.

PURPOSE AND SCOPE

The CRISPR-Cas system has enabled gene and cell-based therapies, screening for novel drug targets, a new generation of disease models, elucidation of drug resistance mechanisms, and drug efficacy testing. Here, we summarized recent investigations and strategies involved in cancer-related drug discovery using the CRISPR-Cas system.

CONCLUSION

CRISPR-Cas-mediated gene editing has shown great potential in the development of next generation drugs for treatment of Mendelian disorders and various cancer types. In this review, we focused on the impact of the CRISPR-Cas system in drug discovery and its application to biomarker identification and validation, high-end target genes, and breakthrough anticancer cell therapies. We also highlighted the role of CRISPR-Cas in precision disease modeling and functional drug screening. This article is protected by copyright. All rights reserved.

Erythropoietin and iron for anemia in HIV-infected patients undergoing maintenance hemodialysis in China: a cross-sectional study

Background

Anemia is a common complication of chronic kidney disease (CKD) and HIV infection. The number of people living with HIV on hemodialysis (HD) is increasing. However, there is no data about anemia and related therapies in this kind of patients in China. We aim to assess the difference in hemoglobin (Hgb) and treatments like erythropoietin and iron between HIV-HD patients and HD patients in Chengdu, China.

Methods

This cross-sectional study was conducted with data collection from January 2020 to June 2020. Thirty-four HIV-infected HD patients and thirty-five non-HIV-infected HD patients were included. Age, gender, dialysis vintage, single-pool (sp) Kt/V, Hgb, the dose of erythropoietin, ferritin, use of iron preparations, and serum albumin were collected in all patients. Time since HIV diagnosis, counts of CD4 + T cells, HIV RNA, and antiretroviral therapy for HIV infection were collected in HIV-infected patients. T-test, Mann–Whitney U test, and chi-square statistics were applied in SPSS.

Results

The Hgb of HIV-HD and HD groups were 105.70 (95.93–112.08) g/L and 112.00 (93.00–126.00) g/L respectively (P = 0.064). There was a statistically significant higher erythropoietin dosage used in the HIV-HD population (222.55 ± 115.47 U/kg/week) compared to the HIV-negative HD group (161.86 ± 110.31 U/kg/week) (P = 0.029). 16/34 (47.06%) HIV-HD patients and 5/35 (14.29%) HD patients were treated with iron preparations (P = 0.003). The ferritin levels were 316.50 (117.38–589.75) ng/ml and 272.70 (205.00–434.00) ng/ml in HIV-HD and HD groups respectively.

Conclusions

A higher erythropoietin dosage and a higher probability of iron preparations may be required to maintain Hgb in HIV-HD patients compared with HD patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02693-y.

Immunological factors, but not clinical features, predict visceral leishmaniasis relapse in patients co-infected with HIV

Visceral leishmaniasis (VL) has emerged as a clinically important opportunistic infection in HIV patients, as VL/HIV co-infected patients suffer from frequent VL relapse. Here, we follow cohorts of VL patients with or without HIV in Ethiopia. By the end of the study, 78.1% of VL/HIV-but none of the VL patients-experience VL relapse. Despite a clinically defined cure, VL/HIV patients maintain higher parasite loads, lower BMI, hepatosplenomegaly, and pancytopenia. We identify three immunological markers associated with VL relapse in VL/HIV patients: (1) failure to restore antigen-specific production of IFN-γ, (2) persistently lower CD4+ T cell counts, and (3) higher expression of PD1 on CD4+ and CD8+ T cells. We show that these three markers, which can be measured in primary hospital settings in Ethiopia, combine well in predicting VL relapse. The use of our prediction model has the potential to improve disease management and patient care.

Mechanisms of immune aging in HIV

Massive CD4+ T-cell depletion as well as sustained immune activation and inflammation are hallmarks of Human Immunodeficiency Virus (HIV)-1 infection. In recent years, an emerging concept draws an intriguing parallel between HIV-1 infection and aging. Indeed, many of the alterations that affect innate and adaptive immune subsets in HIV-infected individuals are reminiscent of the process of immune aging, characteristic of old age. These changes, of which the presumed cause is the systemic immune activation established in patients, likely participate in the immuno-incompetence described with HIV progression. With the success of antiretroviral therapy (ART), HIV-seropositive patients can now live for many years despite chronic viral infection. However, acquired immunodeficiency syndrome (AIDS)-related opportunistic infections have given way to chronic diseases as the leading cause of death since HIV infection. Therefore, the comparison between HIV-1 infected patients and uninfected elderly individuals goes beyond the sole onset of immunosenescence and extends to the deterioration of several physiological functions related to inflammation and systemic aging. In light of this observation, it is interesting to understand the precise link between immune activation and aging in HIV-1 infection to figure out how to best care for people living with HIV (PLWH).

Mesenchymal Stromal Cells: a Possible Reservoir for HIV-1?

The introduction of antiretroviral therapy (ART) and highly active antiretroviral therapy (HAART) has transformed human immunodeficiency virus (HIV)-1 into a chronic, well-managed disease. However, these therapies do not eliminate all infected cells from the body despite suppressing viral load. Viral rebound is largely due to the presence of cellular reservoirs which support long-term persistence of HIV-1. A thorough understanding of the HIV-1 reservoir will facilitate the development of new strategies leading to its detection, reduction, and elimination, ultimately leading to curative therapies for HIV-1. Although immune cells derived from lymphoid and myeloid progenitors have been thoroughly studied as HIV-1 reservoirs, few studies have examined whether mesenchymal stromal/stem cells (MSCs) can assume this function. In this review, we evaluate published studies which have assessed whether MSCs contribute to the HIV-1 reservoir. MSCs have been found to express the receptors and co-receptors required for HIV-1 entry, albeit at levels of expression and receptor localisation that vary considerably between studies. Exposure to HIV-1 and HIV-1 proteins alters MSC properties in vitro, including their proliferation capacity and differentiation potential. However, in vitro and in vivo experiments investigating whether MSCs can become infected with and harbour latent integrated proviral DNA are lacking. In conclusion, MSCs appear to have the potential to contribute to the HIV-1 reservoir. However, further studies are needed using techniques such as those used to prove that cluster of differentiation (CD)4⁺ T cells constitute an HIV-1 reservoir before a reservoir function can definitively be ascribed to MSCs.

Anemia and thrombocytopenia in people living with HIV/AIDS: a narrative literature review

Hematologic changes are frequent complications in people living with HIV/AIDS (PLWHA). Anemia and thrombocytopenia are the most frequent multifactorial hematologic abnormalities and are associated with a low quality of life and high death rates. This study aims to describe the prevalence of anemia and thrombocytopenia in PLWHA and to identify the main clinical characteristics that aggravate these conditions in studies published in the last 10 y. A comprehensive search was performed on the PUBMED database, using the terms ‘HIV infection and anemia’ and ‘HIV infection and thrombocytopenia’. Additional searches were made in the reference lists of articles covering the theme. The selected studies reported an overall prevalence of anemia from 7.2% to 84% and of thrombocytopenia from 4.5% to 26.2%. The prevalence of thrombocytopenia and anemia were aggravated by a CD4⁺ T lymphocyte count of <200 cells/μL, increased viral load and coinfections or opportunistic infections. Antiviral therapy (ART) shows a beneficial effect, reducing the frequencies of thrombocytopenia and anemia, except in a zidovudine-based ART regimen, which worsens the anemic condition. Because anemia and thrombocytopenia are treatable comorbidities associated with increased mortality among PLWHA, physicians should monitor these risk factors in order to establish better interventions and reduce morbidity and mortality in PLWHA.

Platelets in HIV: A Guardian of Host Defence or Transient Reservoir of the Virus?

The immune and inflammatory responses of platelets to human immunodeficiency virus 1 (HIV-1) and its envelope proteins are of great significance to both the treatment of the infection, and to the comorbidities related to systemic inflammation. Platelets can interact with the HIV-1 virus itself, or with viral membrane proteins, or with dysregulated inflammatory molecules in circulation, ensuing from HIV-1 infection. Platelets can facilitate the inhibition of HIV-1 infection via endogenously-produced inhibitors of HIV-1 replication, or the virus can temporarily hide from the immune system inside platelets, whereby platelets act as HIV-1 reservoirs. Platelets are therefore both guardians of the host defence system, and transient reservoirs of the virus. Such reservoirs may be of particular significance during combination antiretroviral therapy (cART) interruption, as it may drive viral persistence, and result in significant implications for treatment. Both HIV-1 envelope proteins and circulating inflammatory molecules can also initiate platelet complex formation with immune cells and erythrocytes. Complex formation cause platelet hypercoagulation and may lead to an increased thrombotic risk. Ultimately, HIV-1 infection can initiate platelet depletion and thrombocytopenia. Because of their relatively short lifespan, platelets are important signalling entities, and could be targeted more directly during HIV-1 infection and cART.