Seronegative HIV-1 infection: a review of the literature

Seronegative HIV-1 infection in a Japanese man presenting with Pneumocystis pneumonia: Analysis of long-term antibody response and literature review

Seronegative human immunodeficiency virus (HIV) infection, where an HIV-specific antibody response is lacking even in chronic or late-stage HIV infections, is extremely rare. Here, we report the case of a 50-year-old Japanese man presenting with Pneumocystis pneumonia who did not produce antibodies against HIV-1 until the initiation of antiretroviral therapy (ART). Fourth-generation antigen-antibody testing temporarily reverted from weakly positive to negative soon after initiating ART, likely due to a reduction in viral load (assessed by p24 antigen levels). His HIV-1 antibody titers remained low or indeterminate even after four years of ART. A literature review suggested that the absence of HIV-1-specific antibody production may be associated with unimpeded HIV replication and rapid CD4+ T cell decline. Seronegative HIV infection can lead to deferred diagnosis and treatment, thereby increasing the risk of transmitting the virus to others or developing opportunistic illnesses. It is important to combine multiple tests for diagnosis, depending on the medical condition. Further studies are required to investigate the host factors involved in the production of HIV-1-specific antibodies.

Repeated false-negative HIV rapid test results in a patient presenting to care with advanced HIV disease: A case report

Severe immunosuppression has been reported as one of the causes of a false-negative HIV rapid test result. Guidelines on what tests should be performed in adult patients presenting with severe immunosuppression despite a negative HIV rapid test result are lacking. This is the second case report of a false-negative HIV rapid test results in a patient presenting with advanced HIV disease in Tanzania.

Streamlining Laboratory Tests for HIV Detection

HIV is a retrovirus that primarily infects CD4 presenting cells of the human immune system, such as macrophages and dendritic cells. People die of AIDS because the disease remains undetected for long periods of time. HIV diagnostic testing has come a long way since it was introduced in the early 1980s. Early diagnosis is key to successful treatment of HIV. Assay selection is based on initial screening results and clinical information provided by the physician, both of which are essential for the laboratory’s ability to make accurate diagnoses. Detecting HIV with high specificity and sensitivity in the early stages of infection requires simple, accurate and economical methods. In this chapter we have described the indications & criteria’s for HIV testing, HIV diagnosis by utilizing variety of immunological and molecular methods, like ELISA, rapid diagnostics, Western blotting, indirect immunoassays, and nucleic acid-based tests. Diagnostic laboratories must use testing algorithms to ensure the accuracy of results and the optimal use of lab resources. Participation in laboratory quality assurance programs are also essential to ensure that diagnostic laboratories provide accurate, timely and clinically relevant test results. HIV testing is the first step in maintaining a healthy life and preventing HIV transmission.

Influence of Combination Antiretroviral Therapy on HIV-1 Serological Responses and Their Implications: A Systematic Review and Meta-Analysis

We aimed to analyze HIV-1 seroreversion caused by combination antiretroviral therapy (cART) and to explore antibody levels of anti-HIV-1 as an alternative biomarker of HIV-1 reservoir. We searched PubMed, Embase, the Cochrane Library, and Web of Science up to August 2021 for publications about the performance of HIV-1 serological assays or the association between antibody responses against HIV-1 and HIV-1 reservoirs. Potential sources of heterogeneity were explored by meta-regression analysis, including the year of publication, country, pretreatment viral load, sample size, the timing of treatment, time on cART, and principle or type of serological assay. Twenty-eight eligible studies with a total population of 1,883 were included in the meta-analysis. The pooled frequency of HIV-1 seronegativity is 38.0% (95% CI: 28.0%–49.0%) among children with vertical HIV-1 infection and cART initiation at the age of less than 6 months, while the percentage of HIV-1 seronegativity declined to 1.0% (95% CI: 0%–3.0%) when cART was initiated at the age of >6 months. For adult patients, 16.0% (95% CI: 9.0%–24.0%) of them were serologically negative when cART was initiated at acute/early infection of HIV-1, but the seronegative reaction was rarely detected when cART was started at chronic HIV-1 infection. Substantial heterogeneity was observed among the studies to estimate the frequency of HIV-1 seronegativity in the early-cART population (I² ≥ 70%, p < 0.05 and all), while mild heterogeneity existed for the deferred-cART subjects. Moreover, anti-HIV-1 antibody response positively correlates with HIV-1 reservoir size with a pooled rho of 0.43 (95% CI: 0.28–0.55), suggesting that anti-HIV antibody level may be a feasible biomarker of HIV-1 reservoir size.

A human immunodeficiency virus-seronegative acquired immunodeficiency syndrome patient with opportunistic infections: A case report

BACKGROUND

In rare cases, people living with chronic human immunodeficiency virus (HIV) infection do not develop antibodies despite demonstrable infection. Delayed or missed diagnosis of HIV infection leads to a lack of timely therapy, resulting in rapid disease progression with opportunistic infections or malignancies.

CASE REPORT

A 44-year-old Chinese man presented with sore throat, oral leukoplakia, fever, dyspnoea and diffuse ground glass-like lesions in both lungs. Serum cytomegalovirus DNA was detectable, and CD4⁺ T-cell count was low. The patient was suspected of being a person living with HIV despite of the repeatedly negative HIV antibody tests using enzyme-linked immunsorbent assay and Western blot. Subsequently, high-plasma HIV RNA viral load was found on two repeated tests, while HIV DNA was also positive. Thus, the patient was confirmed as presenting with HIV-seronegative acquired immunodeficiency syndrome (AIDS). The symptoms improved in response to effective anti-fungal and anti-retroviral therapy after diagnosis.

CONCLUSION

This is the third reported case of an HIV-seronegative AIDS patient in China, which are also rarely reported globally. HIV nucleic acid testing is important to screen out HIV infection, especially in those who present with severe immunodeficiency but remain HIV serogenative.

Brief Report: Association Between Low HIV-1 DNA and Western Blot Reactivity to HIV-1 Pol in Chronically Infected Individuals

BACKGROUND

The aim of the study was to evaluate whether negative HIV-1 pol on Western blot (WB) was associated with low HIV-DNA in adults with chronic HIV-1 infection and suppressive antiretroviral therapy.

METHODS

Cross-sectional parent study of the APACHE trial, conducted in subjects with chronic infection, HIV-1 RNA <50 copies/mL for ≥10 years, no residual viremia for ≥5 years and CD4 >500 cells/µL screened for HIV-1 DNA. HIV-1 DNA was quantified in peripheral blood mononuclear cells (PBMCs) by real-time polymerase chain reaction and HIV-1 serostatus was tested by HIV Blot 2.2 WB assay. Multivariate logistic regression was used to determine factors associated with low HIV-1 DNA.

RESULTS

We evaluated 96 patients: 78 (81%) and 18 (19%) subjects with HIV-1 DNA ≥100 copies/10 PBMCs and with HIV-1 DNA <100 copies/10 PBMCs, respectively. Median age was 32.5 (25.3-38.9), and 61 (64%) were men; moreover, we reported that nadir CD4 was 253 (167-339) cells/µL and HIV-RNA <50 copies/mL for 11.7 (10.6-14.0) years. At multivariate analysis, higher nadir CD4 [adjusted odds ratio (AOR) [95% confidence interval (CI) 1.35 (95% CI: 1.03 to 1.76), P = 0.029], longer years of HIV-1 RNA <50 copies/mL [AOR (95% CI) 2.98 (95% CI: 1.25 to 7.10), P = 0.014], a R5-tropic virus [AOR (R5 vs. non-R5) 0.20 (95% CI: 0.04 to 0.96), P = 0.044], and negative HIV-1 pol [AOR 6.59 (95% CI: 1.47 to 29.54), P = 0.014] were associated with low HIV-1 DNA.

CONCLUSIONS

In patients with chronic HIV-1 infection and suppressive antiretroviral therapy, negative HIV-1 pol on WB was associated with low HIV-1 DNA as well as higher nadir CD4, longer years of HIV-1 RNA <50 copies/mL, and a R5-tropic virus.

A rare case of an HIV-seronegative AIDS patient with Pneumocystis jirovecii pneumonia

Background

As technology progresses, several highly sensitive human immunodeficiency virus (HIV) screening kits are being researched and developed to quickly and efficiently identify serum HIV antibodies within the non-window period. In individuals who are HIV-seronegative, HIV infections that are not within a window period are rare. In such cases, all antibody detection methods will fail, and misdiagnosing these patients will have catastrophic consequences.

Case presentation

A 22-year-old male Chinese patient with diffuse exudative lesions in both lungs and initial symptoms of cough and dyspnoea was diagnosed with Pneumocystis jirovecii pneumonia (PJP) by aetiological examination, and the patient’s plasma CD4⁺ T-cell count was extremely low. In China, PJP is prevalent in HIV-infected individuals. Pneumocystis jirovecii (P. jirovecii) has a high colonisation rate in patients with HIV infections. This patient was naturally suspected of being an HIV patient; however, serum HIV antibody tests were negative using both an enzyme-linked immunosorbent assay (ELISA) and a latex agglutination assay, and HIV was not detected by western blotting. Subsequently, the plasma HIV viral load was found to be extremely high on two repeated plasma HIV RNA tests, thus confirming HIV-seronegative acquired immunodeficiency syndrome (AIDS) in this patient. With administration of effective anti-P. jirovecii treatment and highly active antiretroviral therapy (HAART) after diagnosis, the patient’s disease condition was rapidly controlled.

Conclusion

This is the second reported case in China of an HIV-seronegative AIDS patient. Such cases are also rare worldwide. Although HIV-seronegative HIV infections are rare, AIDS should be considered in immunodeficient patients with opportunistic infections, even if the test results are HIV-seronegative. Plasma HIV RNA testing is important for such patients.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-4143-8) contains supplementary material, which is available to authorized users.

HIV-1 envelope glycoproteins isolated from Viremic Non-Progressor individuals are fully functional and cytopathic

In untreated HIV-1-infected individuals, viremia is positively associated with disease progression. However, some viremic non progressors (VNPs) individuals show paradoxical high CD4⁺ T cell counts. HIV-1 envelope glycoprotein complex (Env) is a major cytopathic determinant in viral replication; therefore, we have deeply characterized Env function in this rare clinical phenotype. Full-length Env clones isolated from individuals with Viral Load (VL) > 10,000 copies/mL classified as VNPs (n = 15) or rapid progressors (RPs, n = 17) were geno- and phenotypically analyzed by determining diversity, expression, CD4 binding/signaling, fusogenicity, infectivity and autophagy induction. Selected Env clones from VNPs and RPs (n = 32) showed similar expression, fusion and infection abilities. Env clones from both groups showed similar affinity for CD4 during cell-to-cell transmission and consistently induced similar levels of CD4 signaling, measured by α-tubulin acetylation. Moreover, we demonstrate for the first time that primary Env clones from VNP and RP induce autophagy in uninfected cells and that this feature correlated with fusogenic capacity but was unrelated to disease progression. In conclusion, our data suggest that Env clones from VNP individuals are fully functional. Therefore, the paradoxical CD4⁺ T cell count stability coexisting with high levels of viral replication is unrelated to Env function.

Lack of evidence of seronegative infection in an endemic area of Chagas disease

The diagnosis of Chagas disease is based on the detection of Trypanosoma cruzi (T. cruzi)-specific antibodies. Nonetheless, there is concern about the sensitivity of current serological assays due to reports of T. cruzi PCR positivity among seronegative individuals. The aim of this study was to evaluate if T. cruzi seronegative infections occur in endemic areas. We recruited 2,157 individuals that were identified as having Chagas disease in a public health system database of an endemic region in Brazil. All participants were interviewed and 2,091 had a sample collected for serological and PCR testing. From these, 149 (7.1%) had negative serological results. PCR was positive in 610 samples (31.4%) of the 1,942 seropositive samples but in none of the 149 samples from seronegative participants. True T. cruzi seronegative infections seem to be rare (95% CI 0-3.7) and should not be a concern for blood supply, which relies on antibody screening.

Cryptococcal meningitis: an unusual presentation of primary HIV infection

Acute HIV infection presenting as severe opportunistic disease is a very uncommon event associated with more rapid HIV progression and higher mortality. We describe the case of a patient with cryptococcal meningitis in the setting of primary HIV infection.

Fatal pulmonary Kaposi sarcoma in an HIV seronegative AIDS patient

INTRODUCTION

Although HIV antibody tests have been widely accepted in clinical diagnosis of HIV infection, they may not be sufficient to diagnose all subjects with HIV infection. Except negative result of antibody test in the well-known" acute window phase", in rare cases, patients do not develop HIV antibodies despite demonstrable infection. Primary pulmonary Kaposi sarcoma (KS) without mucocutaneous involvement accounts for only 0-15% of all AIDS-related KS. KS is rare among Chinese subjects, especially in persons of Han descent.

METHODS

A case of seronegative AIDS with primary pulmonary Kaposi sarcoma (KS) was reported. It's a 46-year-old Chinese man presented with sore throat, hemoptysis, fever, dyspnea and multiple lung nodules. The lung lesions grew over a 5-month period so as the symptoms worsened. The possibility of AIDS was discounted by his physicians because of the repeatedly negative HIV antibodies tests despite the ELISA tests or Western blot tests. Histopathologic diagnosis of fine needle lung biopsy in local hospital was undetermined. After admission, HIV infection was eventually confirmed by plasma HIV RNA testing. Histopathologic diagnosis of Lung Kaposi sarcoma was made through repeated fine needle aspiration biopsy as well as the review of former one. Multiple antibiotics and chemotherapy were administrated with no clinical effect due to advanced stage and the patient passed away soon after diagnosis.

RESULTS

This is the first case of seronegative HIV-1 infection with presentation of primary pulmonary KS.

CONCLUSION

This case underscores the importance of plasma RNA test in conjunction with HIV antibody test for some rare patients with HIV infection who present with severe immunodeficiency and opportunistic infections or malignancy.

A Case of Long-Term Seronegative Human Immunodeficiency Virus (HIV) Infection: The Importance of the Humoral Response to HIV

Background. Seronegative human immunodeficiency virus (HIV) infections are exceedingly rare but might inform HIV-host physiology.

Methods. We investigate the cause and consequences of a patient infected with HIV who did not mount a humoral response to HIV for 4 years.

Results. The patient was confirmed HIV-uninfected by nucleic acid testing 4 months before rapidly progressing to acquired immune deficiency syndrome. The patient's humoral deficit was specific to HIV: he mounted robust humoral responses to all challenge vaccines including influenza A(H1N1)pdm09 and all T cell-dependent and -independent serotypes in the 23-valent pneumococcal polysaccharide vaccine. The virus had similar gp120 antigenicity to HIV-positive control serum as NL4-3 and YU2 prototype strains. Two human leukocyte antigen alleles associated with rapid progression were identified (B*08 and B*35), and a cytotoxic T-lymphocyte epitope site variant was noted: E277K. Viral decay (t_1/2 ≈ 39 weeks) suggested that relatively long-lived cells were the source of ongoing viremia. Human immunodeficiency virus viremia was not suppressed until after the patient developed a humoral immune response, despite therapeutic antiretroviral levels. No resistance was detected by virtual phenotyping of virus obtained from serum or from gastrointestinal biopsies despite considerable antiretroviral selection pressure.

Conclusions. Ineffective antibody production may be associated with a subgroup of extremely rapid HIV progressors. Although antiretroviral therapy may be sufficient to slow propagation of infection, it appears to be ineffective for HIV viral clearance in the absence of a humoral response.

A cluster of rapid disease progressors upon primary HIV-1 infection shared a novel variant with mutations in the p6gag/pol and pol/vif genes

Few studies have described the etiologic factors associated with rapid AIDS onset during primary HIV-1 infection. Our molecular epidemiological study identified a cluster of individuals infected with HIV-1 variants characterized by novel mutations in the p6 and pol/vif genes during 2011 and 2013 in Osaka, Japan. Individuals positive for the novel HIV-1 variant showed rapid disease progression, suggesting a role of viral mutations in the fostering of the clinical course of HIV-1 infection.

Infections and arthritis

Bacteria, viruses, fungi, and parasites can all cause arthritis of either acute or chronic nature, which can be divided into infective/septic, reactive, or inflammatory. Considerable advances have occurred in diagnostic techniques in the recent decades resulting in better treatment outcomes in patients with infective arthritis. Detection of emerging arthritogenic viruses has changed the epidemiology of infection-related arthritis. The role of viruses in the pathogenesis of chronic inflammatory arthritides such as rheumatoid arthritis is increasingly being recognized. We discuss the various causative agents of infective arthritis and emphasize on the approach to each type of arthritis, highlighting the diagnostic tests, along with their statistical accuracy. Various investigations including newer methods such as nucleic acid amplification using polymerase chain reaction are discussed along with the pitfalls in interpreting the tests.

Rapid HIV progression during acute HIV-1 subtype C infection in a Mozambican patient with atypical seroconversion

Acute human immunodeficiency virus (HIV) infection (AHI) refers to the period between viral transmission and development of an adaptive immune response to HIV antigens (seroconversion) usually lasting 6-8 weeks. Rare cases have been described in which HIV-infected patients fail to seroconvert and instead, develop rapid HIV-mediated clinical decline. We report the case of a Mozambican woman with AHI and malaria coinfection who showed atypical seroconversion and experienced rapid deterioration and death within 14 weeks of diagnosis with AHI. Atypical seroconversion may be associated with rapid progression. Fourth generation rapid tests could lead to earlier identification and intervention for this vulnerable subgroup.

Human immunodeficiency virus testing pitfalls and clinical suspicion

Universal human immunodeficiency virus (HIV) screening was recommended in 2012, and major improvements in HIV testing have occurred in the past decade, but identification of HIV infected individuals remains inadequate in the United States. We report the case of a seronegative HIV-infected man who despite clinical and laboratory findings of acquired immunodeficiency syndrome,repeatedly tested nonreactive to third-generation HIV enzyme immunoassays (EIAs) and Western blot testing. Serologic diagnosis in this case required fourth-generation EIA testing due to the seronegativity of standard testing. The fourth-generation HIV EIA was positive presumably because it detects p24 HIV antigen as well as antibodies, unlike rapid HIV tests and third-generation HIV EIAs.This case highlights not only the importance of frontline providers to understand the different testing methodologies for HIV screening and their limitations but the importance of clinical suspicion as well.

How can HIV-type-1-Env immunogenicity be improved to facilitate antibody-based vaccine development?

No vaccine candidate has induced antibodies (Abs) that efficiently neutralize multiple primary isolates of HIV-1. Preexisting high titers of neutralizing antibodies (NAbs) are essential, because the virus establishes infection before anamnestic responses could take effect. HIV-1 infection elicits Abs against Env, Gag, and other viral proteins, but of these only a subset of the anti-Env Abs can neutralize the virus. Whereas the corresponding proteins from other viruses form the basis of successful vaccines, multiple large doses of HIV-1 Env elicit low, transient titers of Abs that are not protective in humans. The inaccessibility of neutralization epitopes hinders NAb induction, but Env may also subvert the immune response by interacting with receptors on T cells, B cells, monocytes, macrophages, and dendritic cells. Here, we discuss evidence from immunizations of different species with various modified Env constructs. We also suggest how the divergent Ab responses to Gag and Env during infection may reflect differences in B cell regulation. Drawing on these analyses, we outline strategies for improving Env as a component of a vaccine aimed at inducing strong and sustained NAb responses.

A cell-to-cell HIV transfer assay identifies humoral responses with broad neutralization activity

BACKGROUND

Cell-to-cell HIV spread through virological synapses proceeds in two steps, first HIV particles are rapidly transferred to target cells in a CD4-dependent manner and then coreceptor-dependent events allow for infection or death of single target cells and cell-to-cell fusion.

METHODS

293T or MOLT cells producing HIV particles were cocultured with primary CD4 T-cells or reporter cell lines. The extent of HIV transfer, cell fusion and target cell death was assessed. Inhibition by sera from 19 HIV-infected patients was evaluated and compared with cell-free HIV neutralization using different envelopes from clades A, B, C and E.

RESULTS

Sera showed different abilities to protect CD4 T-cells from cell-to-cell transfer, fusion or death when cocultured with HIV producing 293T cells. Some sera were able to block all parameters (a property of IgGb12), while other showed lower activity against HIV transfer despite being able to block fusion and death (a property of antibodies blocking post-CD4 binding steps). Neutralization of cell-to-cell HIV transfer strongly correlated with IgG binding to native Env. Interestingly, sera that efficiently blocked HIV transfer showed broader neutralizing response, as they neutralized a higher percentage of the viruses tested compared with sera showing low CD4 binding site responses (P=0.01). Similar results were observed in a model of T cell-T cell HIV transmission, although this experimental model showed lower capacity to discriminate broadly neutralizing responses.

CONCLUSION

Cell-to-cell HIV transfer assays identify sera with broadly neutralizing capacity and may help to characterize anti-HIV humoral responses.