Human immunodeficiency virus infection and systemic lupus erythematosus. An unusual case and a review of the literature

HIV-1 Env Does Not Enable the Development of Protective Broadly Neutralizing Antibodies in an Experimental Autoimmune Encephalomyelitis Mouse Model

Recent studies showed that immunological tolerance may restrict the development of Env-specific autoreactive broadly neutralizing antibodies. This evidence is consistent with the finding that Env immunization of a systemic lupus erythematosus (SLE) murine model produced antibodies that neutralize tier 2 HIV-1 strains. In this study, we address the possibility of eliciting neutralizing anti-Env antibodies in other autoimmune diseases such as multiple sclerosis (MS). While, as reported for SLE, we showed for the first time that a small number of HIV-1 negative, relapsing remitting MS patients exhibited antibodies with neutralizing properties, our attempts at inducing those antibodies in a EAE mouse model of MS failed. The success in eliciting Env-specific neutralizing antibodies might be related to the specific characteristics of the autoimmune disease, or it might rely in improving the vaccination design. Studies using mouse models are useful to gain insight in how HIV-specific neutralizing antibody responses are regulated in order to develop a protective HIV-1 vaccine.

HIV and systemic lupus erythematosus: where immunodeficiency meets autoimmunity

We report a case of a new diagnosis of systemic lupus erythematosus (SLE) in a patient with HIV who presented to the outpatient department with a fever, headache and lymphadenopathy. Cerebrospinal fluid analysis showed lymphocytic pleocytosis. Initial concerns were for an infectious process, and investigations for systemic and central nervous system infection were negative. Serum testing for ANA, dsDNA, nucleosome, anti-histone and ribosomal-P antibodies was positive. A magnetic brain imaging scan of the brain showed a well-circumscribed lesion in the right cerebellar peduncle on T2/FLAIR. The patient was commenced on prednisolone and rituximab, and had a good clinical response. The cerebellar lesion resolved and has not recurred with sequential imaging. SLE and HIV are both multi-systemic diseases which rarely co-occur. Autoimmune processes should be considered in HIV patients with multi-systemic symptoms and signs.

Concomitant systemic lupus erythematosus and HIV infection: A rare case report and literature review

RATIONALE

Coexisting systemic lupus erythematosus (SLE) and human immunodeficiency virus (HIV) infection cases are rare worldwide. Great challenges are posed on the diagnosis and treatment of such concurrent cases.

PATIENT CONCERN

We report the case of a 44-year-old Chinese man with edema, hematuria, and fever who presented at West China Hospital, Sichuan University, Chengdu, Sichuan, China, in 2013.

DIAGNOSES

An initial diagnosis of SLE was made from the clinical manifestations and laboratory findings based on the Systemic Lupus International Collaborating Clinics classification criteria. Immunosuppressant therapy relieved him of the edema and hematuria, but he regained the symptoms after a cold. Workup, including electrochemiluminescence immunoassay, western blot, and polymerase chain reaction analysis, revealed that he was concurrently infected with HIV after hospitalization.

INTERVENTIONS

The treatment plan included methylprednisolone and cyclophosphamide, with gastroprotective and hepatoprotective agents, simultaneously aiming to reduce urinary protein. After HIV infection confirmed, cyclophosphamide was stopped. He was referred to the local Centers for Disease Control and Prevention for combination antiretroviral therapy (ART). He was suggested to continue monitoring CD4 T-cell count for an appropriate dose of immunosuppressive drugs.

OUTCOMES

In the last follow-up in May 2017, he had been stable in terms of both SLE and HIV infection.

LESSONS

The case highlights the presence of concurrent SLE and HIV infection. Laboratory technicians and clinicians should be cautious on diagnosis, especially in eliminating the false-positive results. Attention should be paid to the dose of immunosuppressants and the ART procedure.

Immunologic characteristics of HIV-infected individuals who make broadly neutralizing antibodies

Induction of broadly neutralizing antibodies (bnAbs) capable of inhibiting infection with diverse variants of human immunodeficiency virus type 1 (HIV‐1) is a key, as‐yet‐unachieved goal of prophylactic HIV‐1 vaccine strategies. However, some HIV‐infected individuals develop bnAbs after approximately 2‐4 years of infection, enabling analysis of features of these antibodies and the immunological environment that enables their induction. Distinct subsets of CD4⁺ T cells play opposing roles in the regulation of humoral responses: T follicular helper (Tfh) cells support germinal center formation and provide help for affinity maturation and the development of memory B cells and plasma cells, while regulatory CD4⁺ (Treg) cells including T follicular regulatory (Tfr) cells inhibit the germinal center reaction to limit autoantibody production. BnAbs exhibit high somatic mutation frequencies, long third heavy‐chain complementarity determining regions, and/or autoreactivity, suggesting that bnAb generation is likely to be highly dependent on the activity of CD4⁺ Tfh cells, and may be constrained by host tolerance controls. This review discusses what is known about the immunological environment during HIV‐1 infection, in particular alterations in CD4⁺ Tfh, Treg, and Tfr populations and autoantibody generation, and how this is related to bnAb development, and considers the implications for HIV‐1 vaccine design.

Human Ig knockin mice to study the development and regulation of HIV-1 broadly neutralizing antibodies

A major challenge for HIV-1 vaccine research is developing a successful immunization approach for inducing broadly neutralizing antibodies (bnAbs). A key shortcoming in meeting this challenge has been the lack of animal models capable of identifying impediments limiting bnAb induction and ranking vaccine strategies for their ability to promote bnAb development. Since 2010, immunoglobulin knockin (KI) technology, involving inserting functional rearranged human variable exons into the mouse IgH and IgL loci has been used to express bnAbs in mice. This approach has allowed immune tolerance mechanisms limiting bnAb production to be elucidated and strategies to overcome such limitations to be evaluated. From these studies, along with the wealth of knowledge afforded by analyses of recombinant Ig-based bnAb structures, it became apparent that key functional features of bnAbs often are problematic for their elicitation in mice by classic vaccine paradigms, necessitating more iterative testing of new vaccine concepts. In this regard, bnAb KI models expressing deduced precursor V(D)J rearrangements of mature bnAbs or unrearranged germline V, D, J segments (that can be assembled into variable region exons that encode bnAb precursors), have been engineered to evaluate novel immunogens/regimens for effectiveness in driving bnAb responses. One promising approach emerging from such studies is the ability of sequentially administered, modified immunogens (designed to bind progressively more mature bnAb precursors) to initiate affinity maturation. Here, we review insights gained from bnAb KI studies regarding the regulation and induction of bnAbs, and discuss new Ig KI methodologies to manipulate the production and/or expression of bnAbs in vivo, to further facilitate vaccine-guided bnAb induction studies.

Immunological tolerance as a barrier to protective HIV humoral immunity

HIV-1 infection typically eludes antibody control by our immune system and is not yet prevented by a vaccine. While many viral features contribute to this immune evasion, broadly neutralizing antibodies (bnAbs) against HIV-1 are often autoreactive and it has been suggested that immunological tolerance may restrict a neutralizing antibody response. Indeed, recent Ig knockin mouse studies have shown that bnAb-expressing B cells are largely censored by central tolerance in the bone marrow. However, the contribution of peripheral tolerance in limiting the HIV antibody response by anergic and potentially protective B cells is poorly understood. Studies using mouse models to elucidate how anergic B cells are regulated and can be recruited into HIV-specific neutralizing antibody responses may provide insight into the development of a protective HIV-1 vaccine.

Breaching peripheral tolerance promotes the production of HIV-1-neutralizing antibodies

Schroeder et al. demonstrate that when peripheral tolerance is relaxed, tier 2 HIV-1–neutralizing antibodies can be elicited and identify new autoreactive antibody specificities against histone H2A capable of neutralizing tier 2 HIV-1.

A subset of characterized HIV-1 broadly neutralizing antibodies (bnAbs) are polyreactive with additional specificities for self-antigens and it has been proposed immunological tolerance may present a barrier to their participation in protective humoral immunity. We address this hypothesis by immunizing autoimmune-prone mice with HIV-1 Envelope (Env) and characterizing the primary antibody response for HIV-1 neutralization. We find autoimmune mice generate neutralizing antibody responses to tier 2 HIV-1 strains with alum treatment alone in the absence of Env. Importantly, experimentally breaching immunological tolerance in wild-type mice also leads to the production of tier 2 HIV-1–neutralizing antibodies, which increase in breadth and potency following Env immunization. In both genetically prone and experimentally induced mouse models of autoimmunity, increased serum levels of IgM anti-histone H2A autoantibodies significantly correlated with tier 2 HIV-1 neutralization, and anti-H2A antibody clones were found to neutralize HIV-1. These data demonstrate that breaching peripheral tolerance permits a cross-reactive HIV-1 autoantibody response able to neutralize HIV-1.

Progressive respiratory distress in a 42-year-old HIV-positive woman with systemic lupus erythematosus

Background

Identifying and treating the cause of pulmonary symptoms in HIV patients with underlying systemic lupus erythematosus (SLE) can be very challenging. Delays in diagnosing active SLE in HIV patients can lead to significant morbidity and even mortality. We report the case of an HIV-positive woman with SLE who presented with severe respiratory distress.

Case presentation

A 42-year-old HIV-positive woman presented with a 7-month history of anorexia, progressive dyspnoea, and a productive cough. She had been put on treatment for pulmonary tuberculosis and pneumocystis jiroveci pneumonia for several months by the referring hospital without any significant improvement in her symptoms. Her initial laboratory investigations showed highly elevated d-dimer test results but confirmatory investigations for pulmonary embolism proved otherwise. An autoimmune screen revealed highly positive antinuclear antibody and anti-double-stranded DNA tests, and she responded very well to SLE treatment.

Conclusions

Our case represents a situation where two diseases with antagonizing pathways of disease pathogenesis occur concurrently in the same patient. SLE is usually not among the differential diagnoses in HIV patients with respiratory distress. Management of patients with both SLE and HIV is also very challenging because improvement in one condition can lead to worsening of the other. Despite opportunistic infections being the likely cause of pulmonary symptoms in HIV patients, clinicians are encouraged to have a high index of suspicion for autoimmune interstitial lung disease in these patients.

Humanized Immunoglobulin Mice: Models for HIV Vaccine Testing and Studying the Broadly Neutralizing Antibody Problem

A vaccine that can effectively prevent HIV-1 transmission remains paramount to ending the HIV pandemic, but to do so, will likely need to induce broadly neutralizing antibody (bnAb) responses. A major technical hurdle toward achieving this goal has been a shortage of animal models with the ability to systematically pinpoint roadblocks to bnAb induction and to rank vaccine strategies based on their ability to stimulate bnAb development. Over the past 6 years, immunoglobulin (Ig) knock-in (KI) technology has been leveraged to express bnAbs in mice, an approach that has enabled elucidation of various B-cell tolerance mechanisms limiting bnAb production and evaluation of strategies to circumvent such processes. From these studies, in conjunction with the wealth of information recently obtained regarding the evolutionary pathways and paratopes/epitopes of multiple bnAbs, it has become clear that the very features of bnAbs desired for their function will be problematic to elicit by traditional vaccine paradigms, necessitating more iterative testing of new vaccine concepts. To meet this need, novel bnAb KI models have now been engineered to express either inferred prerearranged V(D)J exons (or unrearranged germline V, D, or J segments that can be assembled into functional rearranged V(D)J exons) encoding predecessors of mature bnAbs. One encouraging approach that has materialized from studies using such newer models is sequential administration of immunogens designed to bind progressively more mature bnAb predecessors. In this review, insights into the regulation and induction of bnAbs based on the use of KI models will be discussed, as will new Ig KI approaches for higher-throughput production and/or altering expression of bnAbs in vivo, so as to further enable vaccine-guided bnAb induction studies.

Targeting human immunodeficiency virus type 1 with antibodies derived from patients with connective tissue disease

During the budding process, human immunodeficiency virus (HIV) acquires several cellular proteins from the host. Thus, antibodies against self antigens found in sera patients with autoimmune disorders may cross react with host-derived or the HIV-specific proteins gp120 and gp41 on the viral envelope and probably neutralize HIV infection. To verify this hypothesis, 88 sera from HIV negative patients suffering from systemic lupus erythematosus (SLE) and other autoimmune disorders were analysed for cross reacting antibodies against HIV-1 by Western blot and FACS analysis indicating that antibodies cross-react with epitopes expressed on HIV infected or non-infected cells. Virus capture assays revealed that HIV-1IIIBwas directly recognized by 60% of sera from patients with autoimmune disorders. Sera were also tested in HIV neutralization assays with stimulated T cells. Reduction of the viral load by patient sera correlated with their reactivity in Western blot analysis. Complement further enhanced the reduction of viral titres, although no complement-mediated lysis was observed. These data suggest a possible protective role of auto-antibodies against HIV infection in lupus patients.

Characterisation of an epigenetically altered CD4(+) CD28(+) Kir(+) T cell subset in autoimmune rheumatic diseases by multiparameter flow cytometry

Objectives

Antigen-specific CD4⁺ T cells epigenetically modified with DNA methylation inhibitors overexpress genes normally suppressed by this mechanism, including CD11a, CD70, CD40L and the KIR gene family. The altered cells become autoreactive, losing restriction for nominal antigen and responding to self-class II major histocompatibility complex (MHC) molecules without added antigen, and are sufficient to cause a lupus-like disease in syngeneic mice. T cells overexpressing the same genes are found in patients with active lupus. Whether these genes are co-overexpressed on the same or different cells is unknown. The goal of this study was to determine whether these genes are overexpressed on the same or different T cells and whether this subset of CD4⁺ T cells is also present in patients with lupus and other rheumatic diseases.

Methods

Multicolour flow cytometry was used to compare CD11a, CD70, CD40L and KIR expression on CD3⁺CD4⁺CD28⁺ T cells to their expression on experimentally demethylated CD3⁺CD4⁺CD28⁺ T cells and CD3⁺CD4⁺CD28⁺ T cells from patients with active lupus and other autoimmune diseases.

Results

Experimentally demethylated CD4⁺ T cells and T cells from patients with active lupus have a CD3⁺CD4⁺CD28⁺CD11a^hiCD70⁺CD40L^hiKIR⁺ subset, and the subset size is proportional to lupus flare severity. A similar subset is found in patients with other rheumatic diseases including rheumatoid arthritis, systemic sclerosis and Sjögren's syndrome but not retroperitoneal fibrosis.

Conclusions

Patients with active autoimmune rheumatic diseases have a previously undescribed CD3⁺CD4⁺CD28⁺CD11a^hiCD70⁺CD40L^hiKIR⁺ T cell subset. This subset may play an important role in flares of lupus and related autoimmune rheumatic diseases, provide a biomarker for disease activity and serve as a novel therapeutic target for the treatment of lupus flares.

Immune System Regulation in the Induction of Broadly Neutralizing HIV-1 Antibodies

In this brief review, we discuss immune tolerance as a factor that determines the magnitude and quality of serum antibody responses to HIV-1 infection and vaccination in the context of recent work. We propose that many conserved, neutralizing epitopes of HIV-1 are weakly immunogenic because they mimic host antigens. In consequence, B cells that strongly bind these determinants are removed by the physiological process of immune tolerance. This structural mimicry may represent a significant impediment to designing protective HIV-1 vaccines, but we note that several vaccine strategies may be able to mitigate this evolutionary adaptation of HIV and other microbial pathogens.

Autoreactivity in HIV-1 broadly neutralizing antibodies: implications for their function and induction by vaccination

PURPOSE OF REVIEW

This review discusses progress in understanding the impact of immune tolerance on inducing broadly neutralizing antibodies (bnAbs), and how such knowledge can be incorporated into novel immunization approaches.

RECENT FINDINGS

Over 120 bnAbs have now been isolated, all of which bear unusual features associated with host tolerance controls, but paradoxically may also be required for their function. Evidence that poly/autoreactivity of membrane proximal external region bnAbs can invoke such controls has been demonstrated by knock-in technology, highlighting its potential for studying the impact of tolerance in the generation of bnAb lineages to distinct HIV-1 envelope targets. The requirement for extensive affinity maturation in developing neutralization breadth/potency during infection is being examined, and similar studies in the setting of immunization will be aided by testing novel vaccine approaches in knock-in models that either selectively express reverted V(D)J rearrangements, or unrearranged germline segments, from which bnAb lineages originate.

SUMMARY

It is increasingly apparent that immune tolerance, sometimes invoked by self-reactivity that overlaps with bnAb epitope specificity, adds to a formidable set of roadblocks impeding bnAb induction. The path to an effective HIV-1 vaccine may thus benefit from a deeper understanding of host controls, including categorizing those that are unique or common at distinct bnAb targets, and ranking those most feasible to overcome by immunization. Ultimately, such emerging information will be critical to incorporate into new vaccine approaches that can be tested in human trials.

An autoreactive antibody from an SLE/HIV-1 individual broadly neutralizes HIV-1

Broadly HIV-1-neutralizing antibodies (BnAbs) display one or more unusual traits, including a long heavy chain complementarity-determining region 3 (HCDR3), polyreactivity, and high levels of somatic mutations. These shared characteristics suggest that BnAb development might be limited by immune tolerance controls. It has been postulated that HIV-1-infected individuals with autoimmune disease and defective immune tolerance mechanisms may produce BnAbs more readily than those without autoimmune diseases. In this study, we identified an HIV-1-infected individual with SLE who exhibited controlled viral load (<5,000 copies/ml) in the absence of controlling HLA phenotypes and developed plasma HIV-1 neutralization breadth. We collected memory B cells from this individual and isolated a BnAb, CH98, that targets the CD4 binding site (CD4bs) of HIV-1 envelope glycoprotein 120 (gp120). CH98 bound to human antigens including dsDNA, which is specifically associated with SLE. Anti-dsDNA reactivity was also present in the patient's plasma. CH98 had a mutation frequency of 25% and 15% nt somatic mutations in the heavy and light chain variable domains, respectively, a long HCDR3, and a deletion in the light chain CDR1. The occurrence of anti-dsDNA reactivity by a HIV-1 CD4bs BnAb in an individual with SLE raises the possibility that some BnAbs and SLE-associated autoantibodies arise from similar pools of B cells.

Systemic lupus erythematosus and HIV infection: a whimsical relationship. Reports of two cases and review of the literature

Systemic lupus erythematosus (SLE) is rarely reported in association with HIV infection. We describe two unpredictable cases and provide a review of the literature. Retrospective analysis of the medical records of two HIV-infected patients diagnosed with SLE and admitted at Luigi Sacco Hospital (Milano, Italy). Search of the literature from 1981 to 2012 and review of the cases reported. Case 1: a 32-year-old HIV-infected African woman who developed a SLE flare after re-introduction of antiretroviral therapy (ART). The flare was characterized by bullous skin eruption and membranous glomerulonephritis. Case 2: a 44-year-old Caucasian woman, admitted to our hospital because of lacunar stroke: HIV infection and SLE were simultaneously diagnosed.

LITERATURE

55 cases of SLE in the setting of HIV infection were reported. Forty-five patients met the requirements of the American College of Rheumatology for the diagnosis of SLE. The diagnosis of SLE preceded HIV infection in six patients. On the contrary, in 29 patients, HIV infection was reported before SLE. Median CD4+ count at SLE diagnosis was 361 cells/μl. A SLE manifestation following ART immune recovery was documented in 18.2% of the cases. On the contrary, the progression of HIV infection paralleled with SLE remission in 22.5% of the patients. The study shows that an autoimmune disease such as SLE can occur despite the loss of immunocompetence caused by HIV infection. Moreover, SLE and HIV infection influence each other possibly through immunologic mechanisms determining awkward manifestations.

Induction of SerpinB2 and Th1/Th2 modulation by SerpinB2 during lentiviral infections in vivo

SerpinB2, also known as plasminogen activator inhibitor type 2, is a major product of activated monocytes/macrophages and is often strongly induced during infection and inflammation; however, its physiological function remains somewhat elusive. Herein we show that SerpinB2 is induced in peripheral blood mononuclear cells following infection of pigtail macaques with CCR5-utilizing (macrophage-tropic) SIVmac239, but not the rapidly pathogenic CXCR4-utilizing (T cell-tropic) SHIVmn229. To investigate the role of SerpinB2 in lentiviral infections, SerpinB2(-/-) mice were infected with EcoHIV, a chimeric HIV in which HIV gp120 has been replaced with gp80 from ecotropic murine leukemia virus. EcoHIV infected SerpinB2(-/-) mice produced significantly lower anti-gag IgG1 antibody titres than infected SerpinB2(+/+) mice, and showed slightly delayed clearance of EcoHIV. Analyses of published microarray studies showed significantly higher levels of SerpinB2 mRNA in monocytes from HIV-1 infected patients when compared with uninfected controls, as well as a significant negative correlation between SerpinB2 and T-bet mRNA levels in peripheral blood mononuclear cells. These data illustrate that SerpinB2 can be induced by lentiviral infection in vivo and support the emerging notion that a physiological role of SerpinB2 is modulation of Th1/Th2 responses.

Role of immune mechanisms in induction of HIV-1 broadly neutralizing antibodies

Although antibodies can be elicited by HIV-1 infection or immunization, those that are broadly neutralizing (bnAbs) are undetectable in most individuals, and when they do arise in HIV-1 infection, only do so years after transmission. Until recently, the reasons for difficulty in inducing such bnAbs have been obscure. Recent technological advances in isolating bnAbs from rare patients have increased our knowledge of their specificities and features, and along with gene-targeting studies, have also begun uncovering evidence of immunoregulatory roadblocks preventing their induction. One crucial avenue towards developing an effective HIV-1 vaccine is to harness this emerging information into the rational design of immunogens and formulation of adjuvants, such that structural and immunological hurdles to routinely eliciting bnAbs can be overcome.

Infections in systemic lupus erythematosus

Infections are an important cause of morbidity and mortality in systemic lupus erythematosus (SLE). Survival rates for SLE patients in developing countries are comparatively lower than those reported in industrialized countries, with early death from infection and active disease. In addition to the role of immunosuppressive agents in enhancing susceptibility to infection, infectious agents are also known to trigger lupus disease expression and activity. The endemicity of certain infections like tuberculosis further poses a special health issue in developing countries.

Pediatric patient with systemic lupus erythematosus & congenital acquired immunodeficiency syndrome: An unusual case and a review of the literature

The coexistence of systemic lupus erythematosus (SLE) in patients with congenital human immunodeficiency virus (HIV) infection is rare. This is a case report of a child diagnosed with SLE at nine years of age. She initially did well on non-steroidal anti-inflammatory agents, hydroxychloroquine, and steroids. She then discontinued her anti-lupus medications and was lost to follow-up. At 13 years of age, her lupus symptoms had resolved and she presented with intermittent fevers, cachexia, myalgias, arthralgias, and respiratory symptoms. Through subsequent investigations, the patient was ultimately diagnosed with congenitally acquired immunodeficiency syndrome (AIDS).

Characterization of gp120 hydrolysis by IgA antibodies from humans without HIV infection

Antibody hydrolysis of the superantigenic gp120 site and HIV-1 neutralization was studied as a potential anti-HIV mechanism in uninfected humans. gp120 hydrolysis by purified serum and salivary antibodies was determined by electrophoresis and peptide sequencing, the proteolytic mechanism was analyzed using electrophilic peptide analogs, and viral neutralization was studied using peripheral blood mononuclear cells as hosts. Polyclonal and monoclonal IgA but not IgG preparations selectively catalyzed the cleavage of HIV gp120 at rates sufficient to predict biologically relevant protection against the virus. The IgA hydrolytic reaction proceeded by noncovalent recognition of gp120 residues 421-433, a component of the superantigenic site of gp120, coordinated with peptide bond cleavage via a serine protease-like mechanism. The Lys-432-Ala-433 bond was one of the cleavage sites. Infection of peripheral blood mononuclear cells by a primary isolate of HIV was neutralized by the IgA but not IgG fractions. The neutralizing activity was specifically inhibited by an electrophilic inhibitor of the catalytic activity. The existence of catalytic IgAs to gp120 in uninfected humans suggests their role in resistance to HIV.

Decreased numbers of signal-joint T cell receptor excision circle-containing CD4+ and CD8+ cells in systemic lupus erythematosus patients

Systemic lupus erythematosus (SLE) patients have a decreased number of peripheral blood T cells containing signal-joint T cell receptor excision circles (Sj TRECs), which are considered an indicator of thymic output. The objective of this study was to investigate the mechanism of the decrease in such T cells. Peripheral blood T cells from SLE patients were classified into CD4+ and CD8+ cells. Sj TREC levels were measured by real-time PCR. Telomerase activity was determined by the telomeric repeat amplification protocol assay. The numbers of Sj TREC containing CD4+ and CD8+ cells were lower in the peripheral blood of SLE patients than in the controls. A correlation was found between the numbers of Sj TREC-positive CD4+ and CD8+ cells. The level of TRECs is influenced by an increase in cell division. To examine this increase, telomerase activity as an indicator of cell division was measured simultaneously; however, there was no correlation between the Sj TREC level and telomerase activity. These results suggest that decreased thymic output occurs in SLE patients.

Antibodies to the superantigenic site of HIV-1 gp120: Hydrolytic and binding activities of the light chain subunit

Antibodies (Abs) to the superantigenic determinant of HIV gp120 (gp120(SAg)) are potential protective agents against HIV infection. We report that the light chain subunits of Abs cloned from lupus patients using phage library methods bind and hydrolyze gp120(SAg) independent of the heavy chain. Unlike frequent gp120(SAg) recognition by intact Abs attributable to V(H) domain structural elements, the isolated light chains expressed this activity rarely. Four light chains capable of gp120(SAg) recognition were identified by fractionating phage displayed light chains using peptide probes containing gp120 residues 421-433, a gp120(SAg) component. Three light chains expressed non-covalent gp120(SAg) binding and one expressed gp120(SAg) hydrolyzing activity. The hydrolytic light chain was isolated by covalent phage fractionation using an electrophilic analog of residues 421-433. This light chain hydrolyzed a reporter gp120(SAg) substrate and full-length gp120. Other peptide substrates and proteins were hydrolyzed at lower rates or not at all. Consistent with the expected nucleophilic mechanism of hydrolysis, the light chain reacted selectively and covalently with the electrophilic gp120(SAg) peptide analog. The hydrolytic reaction entailed a fast initial step followed by a slower rate limiting step, suggesting rapid substrate acylation and slow deacylation. All four gp120(SAg)-recognizing light chains contained sequence diversifications relative to their germline gene counterparts. These observations indicate that in rare instances, the light chain subunit can bind and hydrolyze gp120(SAg) without the participation of the heavy chain. The pairing of such light chains with heavy chains capable of gp120(SAg) recognition represents a potential mechanism for generating protective Abs with enhanced HIV binding strength and anti-viral proteolytic activity.

Infections and SLE

Viral and bacterial infections may serve as an environmental trigger for the development or exacerbation of systemic lupus erythematosus (SLE) in the genetically predetermined individual. In addition, SLE patients are more prone to develop common (pneumonia, urinary tract infection, cellulitis, sepsis), chronic (tuberculosis), and opportunistic infections possibly due to inherit genetic and immunologic defects (complement deficiencies, mannose-binding lectin [MBL] polymorphisms, elevated Fcgamma III and GM-CSF levels, osteopontion polymorphism), but also due to the broad spectrum immunosuppressive agents that are part of therapy for severe manifestations of the disease. Hence, SLE patients are considered a high-risk population, where identification and treatment of chronic infections such as tuberculosis, hepatitis B or human immunodeficiency virus, are important prior to the institution of immunosuppression so as to prevent reactivation or exacerbation of the infection. Infections in SLE patients remain a source of morbidity and mortality. A caveat often encountered is to distinguish between a lupus flare and an acute infection; in such cases parameters including elevated CRP (and adhesion molecules) may aid in the diagnosis of infection. Recent research has provided convincing evidence that EBV infection may play a major role not only in molecular mimicry but also in aberrations of B cells and apoptosis leading to a state of perpetual heightened immune response in SLE.

Recurrent Pulmonary Thromboembolism in a Patient with Systemic Lupus Erythematosus and HIV-1 Infection Associated with the Presence of Antibodies to Prothrombin: A Case Report

BACKGROUND

The coexistence of human immunodeficiency virus (HIV) infection and systemic lupus erythematosus (SLE) is being increasingly reported and, because of the immunological disturbances demonstrated in HIV-infected patients, diagnostic and therapeutic difficulties may arise when the 2 conditions coexist. Antiphospholipid antibodies are demonstrable in patients with both conditions, but clinical manifestations of the antiphospholipid syndrome (APS) in HIV-infected patients, although reported, are uncommon.

METHODS

We describe a patient with HIV infection and SLE who manifested 4 episodes of deep vein thrombosis (DVT) complicated by pulmonary embolism. Enzyme-linked immunosorbant assay was used to test for the presence of antiphospholipid antibodies, including anticardiolipin antibodies, anti- beta 2-glycoprotein 1 antibodies, and antiprothrombin antibodies (anti-PT). Additionally, we performed a computer-assisted search of the literature (via the Medline database) to identify all reported cases of HIV infection plus SLE.

RESULTS

We document the case of 35-year-old African woman with HIV infection and SLE who developed recurrent episodes of DVT and pulmonary embolism in the presence of anti-PT and discuss in depth the pathogenic role of these antibodies and the clinical challenges posed to clinicians by the coexistence of HIV and SLE in the same patient.

CONCLUSIONS

Immunological reconstitution in HIV-infected patients contributes to the appearance of multiple autoimmune conditions, including SLE and APS. The recognition of the coexistence of these autoimmune disorders in HIV-infected patients has important implications in the treatment of and prognosis for these individuals.

Emergence of manifestations of HIV infection in a case of systemic lupus erythematosus following treatment with IV cyclophosphamide

Systemic lupus erythematosus (SLE) and infection with human immunodeficiency virus are rarely seen in the same patient. We describe a case of a 32-year-old lady, who was diagnosed with systemic lupus erythematosus (anti-dsDNA antibody positive) and was initially serologically negative for human immunodeficiency virus (HIV) infection. Following three cycles of IV cyclophosphamide, she was subsequently found to be infected with HIV, with marked depletion of peripheral CD4-positive T lymphocytes. While her SLE remained completely inactive, the course of HIV was rapidly progressive, suggesting that retroviral replication may have been enhanced by the underlying immunomodulation caused by cyclophosphamide and also by SLE per se.

Human and Nonhuman Primate Lentiviral Infection and Autoimmunity

The goal of this communication is to summarize the following-the types of autoimmune responses that have been characterized in human HIV-1 infection; the potential mechanisms that were initially thought to be the basis for such autoimmune responses; the prevalence and incidence of conventional autoimmune diseases with HIV-1 infection; the spectrum of autoimmune disorders following the institution of HAART and its associated mechanisms; the role of such autoimmunity in SIV-infected nonhuman primates; and the molecular basis for autoimmune responses, such as the role of exosomes in lentiviral disease.

Systemic lupus erythematosus in a patient with human immunodeficiency virus infection ? challenges in diagnosis and management

Systemic lupus erythematosus (SLE) is mainly a disease of young women. The problem of coexistent human immunodeficiency virus (HIV) infection is a growing problem in sub-Saharan Africa. We describe a case of active life-threatening neuropsychiatric lupus in a patient with underlying HIV infection. The challenges of interpreting physical signs and laboratory features that are common to both conditions, and the dilemma of treating active SLE with cytotoxics in the immunocompromised patient, are discussed.

Cross-clade HIV-1 neutralization by an antibody fragment from a lupus phage display library

A single-chain fragment containing antibody V domains (scFv) isolated from a lupus antibody library displayed the ability to bind gp120 and the conserved gp120 determinant composed of residues 421-436. The scFv neutralized R5 and X4-dependent HIV-1 strains from clades B, C, and D. The lupus repertoire may be useful as a source of neutralizing antibodies to HIV.

SLE and infections

Infections are common in systemic lupus erythematosus (SLE), and remain a source of mortality. The types of infections (such as pneumonia, urinary tract infection, cellulitis, and sepsis) in SLE patients are similar to the general population and include the same pathogens (Gram-positive and Gram-negative). SLE patients may also develop opportunistic infections, especially when treated with immunosuppressive agents. As a high-risk population, identification and treatment of chronic infections such as tuberculosis, hepatitis B, or human immunodeficiency virus (HIV), are important prior to the institution of immunosuppression to prevent reactivation or exacerbation of the infection. A common caveat is to distinguish between a lupus flare and an acute infection; judicious use of corticosteroids and cytotoxic drugs is critical in limiting infectious complications. The risk factors associated with susceptibility to disease include severe flares, active renal disease, treatment with moderate or high doses of corticosteroids and/or immunosuppressive agents, and others. Genetic factors (complement deficiencies, mannose-binding lectin, Fcgamma III, granulocyte macrophage colony-stimulating factor [GM-CSF], osteopontin) may predispose certain SLE patients to develop infections. Parameters including C-reactive protein (CRP) and adhesion molecules may help to differentiate an infectious disease from an exacerbation of the disease. Finally, the mechanism of molecular mimicry by specific microbial agents may play a role in the induction of SLE.

HIV and autoimmunity

The association of immune dysfunction in patients with human immunodeficiency virus (HIV) infection and AIDS and the development of autoimmune diseases is intriguing. Yet, the spectrum of reported autoimmune phenomena in these patients is increasing. An infectious trigger for immune activation is one of the postulated mechanisms and derives from molecular mimicry. During frank loss of immunocompetence, autoimmune diseases that are predominantly T cell subtype CD8 driven predominate. There is evidence for B cell stimulation and many autoantibodies are reported in HIV patients. We propose a staging of autoimmune manifestations related to HIV/AIDS manifestations and the total CD4 count and viral load that may be beneficial in identifying the type of autoimmune disease and establishing the proper therapy. In stage I there is the acute HIV infection, and the immune system is intact. In this stage, autoimmune diseases may develop. Stage II describes the quiescent period without overt manifestations of AIDS. However, there is a declining CD4 count indicative of some immunosuppression. Autoimmune diseases are not found. During stage III there is immunosuppression with a low CD4 count and the development of AIDS. CD8 T cells predominant and diseases such as psoriasis and diffuse immune lymphocytic syndrome (similar to Sjogren's syndrome) may present or even be the initial manifestation of AIDS. Also during this stage no autoimmune diseases are found. In stage IV there is restoration of immune competence following highly active anti-retroviral therapy (HAART). In this setting, there is a resurgence of autoimmune diseases. The frequency of reported rheumatological syndromes in HIV-infected patients ranges from 1 to 60%. The list of reported autoimmune diseases in HIV/AIDS include systemic lupus erythematosus, anti-phospholipid syndrome, vasculitis, primary biliary cirrhosis, polymyosits, Graves' disease, and idiopathic thrombocytopenic purpura. Also, there is an array of autoantibodies reported in HIV/AIDS patients which include anti-cardiolipin, anti-beta2 GPI, anti-DNA, anti-small nuclear ribonucleoproteins (snRNP), anti-thyroglobulin, anti-thyroid peroxidase, anti-myosin, and anti-erythropoietin antibodies. The association of autoantibodies in HIV-infected patients to clinical autoimmune disease is yet to be established. With the upsurge of HAART, the incidence of autoimmune diseases in HIV-infected patients is increasing. In this review, we describe the various autoimmune diseases that develop in HIV/AIDS patients through possible mechanisms related to immune activation.