Circulating antibodies to endogenous erythropoietin and risk for HIV-1-related anemia

Investigating the Role of Anti-TPO Antibodies in HIV-Associated Thrombocytopenia before and after Initiation of HAART: A Case-Control Longitudinal Study

This longitudinal, case-control study aimed to investigate the role of thrombopoietin (TPO) and anti-TPO antibodies in HIV-associated thrombocytopenia, focusing on the changes seen before and after the initiation of highly active antiretroviral therapy (HAART). Patients were assessed before and at least six months after the initiation of HAART. In total, 75 PLWHIV (age/sex-matched and randomized at 2:1, according to thrombocytopenia status) were included in this study. The baseline assessment revealed significantly higher TPO levels in thrombocytopenic patients (140.45 vs. 106.8 mg/mL, p = 0.008). Furthermore, anti-TPO-positive patients displayed lower platelet counts (109,000 vs. 139,000/L, p = 0.002) and TPO levels (114.7 vs. 142.7 mg/mL, p = 0.047). Longitudinally, HAART initiation reduced the frequency of thrombocytopenia from 75.47% to 33.96% (p < 0.001) and elevated the median platelet counts from 131,000 to 199,000 (p < 0.001). No significant difference in median platelet counts was found post-HAART among the anti-TPO subgroups (p = 0.338), a result contrasting with pre-HAART findings (p = 0.043). Changes in anti-TPO status corresponded with significant platelet count alterations (p = 0.036). Notably, patients who became anti-TPO negative showed a median increase of 95,000 platelets (IQR: 43,750-199,500). These marked differences between subgroups underscore the potential role of anti-TPO antibodies in modulating the hematological response to HAART. Further research is needed to elucidate the complex interplay between HIV infection, HAART, and thrombocytopenia.

Serum anti-erythropoietin antibodies among pregnant women with Plasmodium falciparum malaria and anaemia: A case-control study in northern Ghana

BACKGROUND

Anaemia in pregnancy is common in underdeveloped countries, and malaria remains the predominant cause of the condition in Ghana. Anti-erythropoietin (anti-EPO) antibody production may be implicated in the pathogenesis of Plasmodium falciparum malaria-related anaemia in pregnancy. This study ascertained the prevalence of anti-EPO antibody production and evaluated the antibodies' relationship with Plasmodium falciparum malaria and malaria-related anaemia in pregnancy.

METHODS

This hospital-based case-control study recruited a total of 85 pregnant women (55 with Plasmodium falciparum malaria and 30 controls without malaria). Venous blood was taken from participants for thick and thin blood films for malaria parasite microscopy. Complete blood count (CBC) analyses were done using an automated haematology analyzer. Sandwich enzyme-linked immunosorbent assay (ELISA) was used to assess serum erythropoietin (EPO) levels and anti-EPO antibodies. Data were analyzed using IBM SPSS version 22.0.

RESULTS

Haemoglobin (p<0.001), RBC (p<0.001), HCT (p = 0.006) and platelet (p<0.001) were significantly lower among pregnant women infected with Plasmodium falciparum. Of the 85 participants, five (5.9%) had anti-EPO antibodies in their sera, and the prevalence of anti-EPO antibody production among the Plasmodium falciparum-infected pregnant women was 9.1%. Plasmodium falciparum-infected pregnant women with anti-EPO antibodies had lower Hb (p<0.001), RBC (p<0.001), and HCT (p<0.001), but higher EPO levels (p<0.001). Younger age (p = 0.013) and high parasite density (p = 0.004) were significantly associated with Plasmodium falciparum-related anti-EPO antibodies production in pregnancy. Also, younger age (p = 0.039) and anti-EPO antibody production (p = 0.012) related to the development of Plasmodium falciparum malaria anaemia in pregnancy.

CONCLUSION

The prevalence of anti-EPO antibodies among pregnant women with Plasmodium falciparum malaria was high. Plasmodium falciparum parasite density and younger age could stimulate the production of anti-EPO antibodies, and the antibodies may contribute to the development of malarial anaemia in pregnancy. Screening for anti-EPO antibodies should be considered in pregnant women with P. falciparum malaria.

Antierythropoietin Antibody Production Is Not Associated with Malaria and Malaria-Related Anaemia in Humans

Introduction

The pathophysiology of malaria-related anaemia is not fully understood although increased destruction of parasitized and nonparasitized erythrocytes, as well as inadequate erythropoiesis, has been proposed. Circulating antierythropoietin (anti-EPO) antibodies have also been implicated in malaria and malaria-related anaemia in mice. However, studies on this association have not been investigated in humans. This study therefore determined the prevalence of anti-EPO antibody production and assessed its association with malaria and malaria-related anaemia in humans.

Methods

A total of 86 children aged 1-10 years (57 children with malaria serving as the case group and 29 healthy children serving as control), all residents of Duayaw Nkwanta, Ghana, were recruited for this case-control study. Venous blood was collected for thick and thin films for malaria microscopy, full blood count by automated haematology analyzer, and antierythropoietin antibody and erythropoietin estimation by sandwich ELISA method.

Results

Out of the 86 participants recruited, only 3 (3.5%) were positive for anti-EPO antibody; 2.3% of the case group; and 1.2% of the control group. There was no association between the cases and the controls in the production of anti-EPO antibodies. Erythropoietin concentration was significantly higher in malaria-related anaemic subjects (p=0.032).

Conclusion

Antierythropoietin antibodies are not associated with malaria infection and malaria-related anaemia in humans. Erythropoietin concentration is associated with malaria-related anaemia.

Circulating autoantibodies to endogenous erythropoietin are associated with chronic hepatitis C virus infection-related anemia

BACKGROUND

Chronic hepatitis C virus (HCV) infection is associated with autoimmune phenomena and is often complicated by anemia. Circulating autoantibodies to endogenous erythropoietin (anti-EPO) have been detected in patients with chronic viral infections and were correlated to anemia. The present study aimed to determine anti-EPO prevalence in patients with chronic HCV infection and investigate its possible association with anemia.

METHODS

Ninety-three consecutive patients (62 males and 31 females) with chronic HCV infection, who had never received antiviral therapy or recombinant EPO, were enrolled in the study. Circulating anti-EPO were detected in the serum by using an ELISA assay. Quantitative determination of serum EPO levels was done by radioimmunoassay. HCV RNA viral load measurement and genotype sequencing were also performed.

RESULTS

Circulating anti-EPO were detected in 10.8% of HCV-infected patients and the prevalence of anti-EPO was significantly higher in patients with anemia (19.4% vs 5.3%, P=0.040) compared to that in those without anemia. Compared to anti-EPO negative cases, anti-EPO positive patients had higher frequency of anemia (70.0% vs 34.9%, P=0.030), lower EPO concentrations (median 16.35 vs 30.65 mU/mL, P=0.005), and higher HCV RNA viral load (median 891.5X10³ vs 367.5X10³ IU/mL, P=0.016). In multivariate regression analysis the presence of anti-EPO remained an independent predictor of anemia (adjusted OR: 14.303, 95% CI: 1.417-36.580, P=0.024). EPO response to anemia was less prominent among anti-EPO positive patients (P=0.001).

CONCLUSIONS

Circulating anti-EPO are detected in a significant proportion of treatment-naive HCV-infected patients and are independently associated with anemia, suggesting a further implication of autoimmunity in the pathophysiology of HCV-related anemia.

Lack of Evidence for Molecular Mimicry in HIV-Infected Subjects

Previous studies in HIV patients have reported autoantibodies to several human proteins, including erythropoietin (EPO), interferon-α (IFN-α), interleukin-2 (IL-2), and HLA-DR, as potential mediators of anemia or immunosuppression. The etiology of these autoantibodies has been attributed to molecular mimicry between HIV epitopes and self-proteins. Here, the Luciferase Immunoprecipitation System (LIPS) was used to investigate the presence of such autoantibodies in HIV-infected adults. High levels of antibodies to HIV proteins such as capsid (p24), matrix (p17), envelope (gp41), and reverse transcriptase (RT) were detected using LIPS in both untreated and anti-retroviral-treated HIV-infected individuals but not in uninfected controls. LIPS readily detected anti-EPO autoantibodies in serum samples from subjects with presumptive pure red cell aplasia but not in any of the samples from HIV-infected or uninfected individuals. Similarly, subjects with HIV lacked autoantibodies to IFN-α, IL-2, HLA-DR and the immunoglobulin lambda light chain; all purported targets of molecular mimicry. While molecular mimicry between pathogen proteins and self-proteins is a commonly proposed mechanism for autoantibody production, the findings presented here indicate such a process is not common in HIV disease.

Anti-erythropoietin antibody levels and its association with anaemia in different strains of semi-immune mice infected with Plasmodium berghei ANKA

Background

Malaria anaemia is still a major public health problem and its pathogenesis still unclear. Interestingly, the progression of anaemia is at relatively low parasitaemia with some mortality in the semi-immune individuals in the endemic areas despite adequate erythropoietin (EPO) synthesis. A recent study has shown that treatment with exogenous anti-erythropoietin (anti-EPO) antibodies (Ab) of infected mice gives protection against malaria infection, suggesting an important role for anti-EPO Ab in malaria. The objective of the study was to evaluate anti-EPO antibody levels in anaemic condition of different strains of semi-immune mice with malaria.

Methodology

Semi-immune status was attained in four mice strains (Balb/c, B6, CBA and NZW) by repeated infections with 10⁴Plasmodium berghei ANKA, and treatment with chloroquine/pyrimethamine. ELISA was used to measure anti-EPO Ab, transferrin and EPO while inflammatory cytokines measurement was done using bead-based multiplex assay kit.

Results

The mean anti-EPO Ab levels in the mice strains [Optical Density (OD) values at 450 nm: Balb/c (2.1); B6 (1.3); CBA (1.4) and NZW (1.7)] differed (p = 0.045), and were significantly higher when compared with uninfected controls, p < 0.0001, and mean anti-EPO Ab levels in the mice strains at recovery [OD values at 450 nm: Balb/c (1.8); B6 (1.1); CBA (1.5) and NZW (1.0) also differed (p = 0.0004). Interestingly, EPO levels were significantly high in NZW and low in Balb/c mice (p < 0.05), with those of B6 and CBA of intermediary values. Again, NZW were highly parasitaemic (20.7%) and the other strains (Balb/c, B6 and CBA) ranged between 2.2-2.8% (p = 0.015). Anti-EPO Ab correlated positively with extent of Hb loss (r = 0.5861; p = 0.003). Correlation of anti-EPO antibody with EPO was significant only in Balb/c mice (r = −0.83; p = 0.01). Significant levels of IL6 and IFNγ (p < 0.0001), both known to be associated with erythropoiesis suppression were observed in the Balb/c. Transferrin was significantly lower in Balb/c (p < 0.0001) when compared with the other mice strains (B6, CBA and NZW).

Conclusion

This is the first ever report in estimating endogenous anti-EPO antibodies in malaria anaemia. The data presented here suggest that anti-EPO Ab is produced at infection and is associated with Hb loss. Host factors appear to influence anti-EPO antibody levels in the different strains of mice.

Effects of human immunodeficiency virus on the erythrocyte and megakaryocyte lineages

Anaemia and thrombocytopenia are haematological disorders that can be detected in many human immunodeficiency virus (HIV)-positive patients during the development of HIV infection. The progressive decline of erythrocytes and platelets plays an important role both in HIV disease progression and in the clinical and therapeutic management of HIV-positive patients. HIV-dependent impairment of the megakaryocyte and erythrocyte lineages is multifactorial and particularly affects survival, proliferation and differentiation of bone marrow (BM) CD34+ haematopoietic progenitor cells, the activity of BM stromal cells and the regulation of cytokine networks. In this review, we analyse the major HIV-related mechanisms that are involved in the genesis and development of the anaemia and thrombocytopenia observed in HIV positive patients.

Anaemia in HIV-infected children: severity, types and effect on response to HAART

Background

HIV and anaemia are major health challenges in Africa. Anaemia in HIV-infected individuals is associated with more rapid disease progression and a poorer prognosis if not addressed appropriately. This study aimed at determining the severity and types of anaemia among HIV infected children and its effect on short term response to antiretroviral therapy (ART).

Methods

At baseline, clinical and haematological parameters of 257 HIV-infected ART-naïve children aged 3 months to 18 years were assessed to determine the prevalence, severity and types of anaemia. ART eligible patients were started on therapy according to WHO criteria, enrolled (n=88) into an observational cohort and followed up for 6 months.

Results

Anaemia was present in 148/257 (57.6%) of children, including (93/148) 62.2% with mild anaemia, 47/148 (32.0%) moderate anaemia, and 7/148 (4.8%) with severe anaemia. The mean haemoglobin (hb) was lower among children with more advanced HIV disease (p<0.0001). Microcytic-hypochromic anaemia (44.9%) was the commonest type of anaemia. Anaemia was independently associated with young age (p <0.0001), advanced HIV WHO disease stage (p = 0.034) and low CD4 percentage (p = 0.048). The proportion of children who had attained viral suppression (viral load <400 copies/ml) at 3 months was significantly lower among the anaemic children, 31/58 (53.4%) compared to the non-anaemic children 26/30 (86.7%) (p=0.002). However, the difference in clinical and immunological response between the anaemic and non-anaemic patients did not reach statistical significance.

Conclusion

Anaemia is highly prevalent among HIV-infected children in a rural Ugandan clinic and is associated with poorer virological suppression. However, the anaemia did not impact clinical and immunological response to ART among these children.

Treatment for anemia in people with AIDS

BACKGROUND

Anemia is common in persons with HIV infection and is associated with poor prognosis. There is a need to assess the effects of anemia treatments, and to determine whether these interventions are beneficial.

OBJECTIVES

To determine the efficacy and safety of treatments for anemia in people with HIV infection and AIDS.

SEARCH STRATEGY

The Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 10, 2010), MEDLINE (1980-November 25, 2010), EMBASE (1980-November 25, 2010), LlLACS (1982 to November 25, 2010), Africa Index Medicus (up to November 9, 2010), ISI Web of Knowledge (2005 to October 9, 2010), Scirus (October 9, 2010) reference lists of relevant articles. We asked the Cochrane HIV/AIDS and Pregnancy and Childbirth Groups to check their Specialised Registers. We also checked the reference lists of all trials identified by the above methods.

SELECTION CRITERIA

Randomized trials assessing the effects of treatments for anemia in people diagnosed with HIV infection. There were no age restrictions.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed relevant studies for inclusion. Data extraction and quality assessment of relevant studies was performed by two authors and checked by the other two authors.

MAIN RESULTS

Six trials with a high risk of bias, including 537 patients, met the inclusion criteria. These trials only covered recombinant Human erythropoietin alfa (rHuEPO). Two of them including adult and paediatric participants (84 participants and 4 events) comparing rHuEPO to placebo did not reduce the risk of mortality with a follow up to 12 weeks (pooled RR 0.56, 95% confidence interval (CI) 0.08 to 4.05, I(2) = 0%). Any trials that compared rHuEPO to placebo did not show any benefit on hematological values response, number of patients transfused, or number of packed red cell transfused. Two trial compared the effects of two rHuEPO dosing regimens on hemoglobin value and quality of life, but the effects are unclear. Three RCT reported high risk of attrition bias; therefore, were not included in a meta-analysis.

AUTHORS' CONCLUSIONS

This updated Cochrane review provides evidence that rHuEPO compared with placebo does not reduce mortality, does not reduce transfusion requirements, did not increase hemoglobin levels, and did not improve quality of life in HIV-infected patients with anemia. The results are based on six RCTs with high risk of bias. Therefore prescription of this intervention for treating anemia in patients with AIDS is not justified, unless new evidence from a large high quality trial alters this conclusion.

Fine epitope specificity of anti-erythropoietin antibodies reveals molecular mimicry with HIV-1 p17 protein: a pathogenetic mechanism for HIV-1-related anemia

BACKGROUND

Circulating autoantibodies to endogenous erythropoietin (anti-Epo) are detected in human immunodeficiency virus type 1 (HIV-1)-infected patients and represent a risk factor for anemia. The aim of this study was to map the B-cell epitopes on the Epo molecule.

METHODS

Serum samples from HIV-1-positive patients and healthy individuals were tested against overlapping peptides covering the entire sequence of Epo.

RESULTS

Serum samples from anti-Epo-positive patients exhibited significant binding to Epo epitopes spanning the following sequences: amino acids 1-20 (Ep1), amino acids 54-72 (Ep5), and amino acids 147-166 (Ep12). Structural analysis of erythropoietin revealed that the immunodominant epitopes, Ep1 and Ep12, comprise the interaction interface with Epo receptor (EpoR). Autoantibodies binding to this specific region are anticipated to inhibit the Epo-EpoR interaction, resulting in blunted erythropoiesis; this phenomenon is indicated by the significantly higher Epo levels and lower hemoglobin levels of anti-Ep1-positive patients compared with anti-Ep1-negative individuals. The region corresponding to the Ep1 epitope exhibited a 63% sequence homology with the ³⁴LVCASRELERFAVNPGLLE⁵² fragment of the HIV-1 p17 matrix protein.

CONCLUSIONS

These results suggest that the main body of anti-Epo is directed against a functional domain of Epo, and that the presence of anti-Epo can be considered to be a result of a molecular mimicry mechanism, which is caused by the similarity between the Ep1 region and the p17 protein.