Antiribonucleoprotein antibodies in children with HIV infection: a comparative study with childhood-onset systemic lupus erythematosus

Post-Immune Antibodies in HIV-1 Infection in the Context of Vaccine Development: A Variety of Biological Functions and Catalytic Activities

Unlike many other viruses, HIV-1 is highly variable. The structure of the viral envelope changes as the infection progresses and is one of the biggest obstacles in developing an HIV-1 vaccine. HIV-1 infection can cause the production of various natural autoantibodies, including catalytic antibodies hydrolyzing DNA, myelin basic protein, histones, HIV-integrase, HIV-reverse transcriptase, β-casein, serum albumin, and some other natural substrates. Currently, there are various directions for the development of HIV-1 vaccines: stimulation of the immune response on the mucous membranes; induction of cytotoxic T cells, which lyse infected cells and hold back HIV-infection; immunization with recombinant Env proteins or vectors encoding Env; mRNA-based vaccines and some others. However, despite many attempts to develop an HIV-1 vaccine, none have been successful. Here we review the entire spectrum of antibodies found in HIV-infected patients, including neutralizing antibodies specific to various viral epitopes, as well as antibodies formed against various autoantigens, catalytic antibodies against autoantigens, and some viral proteins. We consider various promising targets for developing a vaccine that will not produce unwanted antibodies in vaccinated patients. In addition, we review common problems in the development of a vaccine against HIV-1.

ANA testing in the presence of acute and chronic infections

Autoantibody testing is performed to help diagnose patients who have clinical symptoms suggestive of possible autoimmune diseases. Antinuclear antibodies (ANA) are present in many systemic autoimmune conditions such as systemic lupus erythematosus (SLE). However, a positive ANA test may also be seen with non-autoimmune inflammatory diseases, including both acute and chronic infections. When the ANA test is used as an initial screen in patients with non-specific clinical symptoms, such as fever, joint pain, myalgias, fatigue, rash, or anemia, the likelihood of a positive result due to infection will increase, especially in children. This article identifies acute and chronic infectious diseases that are likely to produce a positive ANA result and summarizes recent literature addressing both the causes and consequences of these findings.

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.

Antiretroviral Therapy Normalizes Autoantibody Profile of HIV Patients by Decreasing CD33⁺CD11b⁺HLA-DR⁺ Cells: A Cross-Sectional Study

Autoimmune manifestations are common in human immunodeficiency virus (HIV) patients. However, the autoantibody spectrum associated with HIV infection and the impact of antiretroviral therapy (ART) remains to be determined. The plasma autoantibody spectrum for HIV patients was characterized by protein microarrays containing 83 autoantigens and confirmed by enzyme-linked immunosorbent assay (ELISA). Regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs) were analyzed by flow cytometry and their effects on autoantibodies production were determined by B cell ELISpot. Higher levels of autoantibody and higher prevalence of elevated autoantibodies were observed in ART-naive HIV patients compared to healthy subjects and HIV patients on ART. The highest frequency of CD33(+)CD11b(+)HLA-DR(+) cells was observed in ART-naive HIV patients and was associated with the quantity of elevated autoantibodies. In addition, CD33(+)CD11b(+)HLA-DR(+) cells other than Tregs or MDSCs boost the B cell response in a dose-dependent manner by in vitro assay. In summary, HIV infection leads to elevation of autoantibodies while ART suppresses the autoimmune manifestation by decreasing CD33(+)CD11b(+)HLA-DR(+) cells in vivo.The roles of CD33(+)CD11b(+)HLA-DR(+) cells on disease progression in HIV patients needs further assessment.

Altered frequency and phenotype of CD4+ forkhead box protein 3+ T cells and its association with autoantibody production in human immunodeficiency virus-infected paediatric patients

The association between immune dysfunction and the development of autoimmune pathology in patients with human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) is not clear. The frequency and phenotype of regulatory T cells, as well as the presence of autoantibodies, were evaluated in a paediatric cohort of HIV-infected patients without clinical evidence of autoimmune disease. Lower absolute counts but higher percentages of total CD4(+) forkhead box protein 3 (FoxP3)(+) T cells were recorded in children with severe immunosuppression than in those without evidence of immunosuppression. The frequencies of classical CD4(+) CD25(+) FoxP3(+) regulatory T cells were not altered, whereas CD4(+) FoxP3(+) CD25(-) T cells were found increased significantly in patients with severe immunosuppression. Like classical regulatory T cells, CD4(+) FoxP3(+) CD25(-) T cells display higher cytotoxic T-lymphocyte antigen 4 (CTLA-4) but lower CD127 expression compared with CD4(+) FoxP3(-) CD25(+) T cells. An improvement in CD4(+) T cell counts, along with a decrease in viral load, was associated with a decrease in CD4(+) FoxP3(+) CD25(-) T cells. The majority of the patients with severe immunosuppression were positive for at least one out of seven autoantibodies tested and displayed hypergammaglobulinaemia. Conversely, HIV-infected children without evidence of immunosuppression had lower levels of autoantibodies and total immunoglobulins. A decline in CD4(+) FoxP3(+) T cell numbers or a variation in their phenotype may induce a raise in antigen exposure with polyclonal B cell activation, probably contributing to the generation of autoantibodies in the absence of clinical autoimmune disease.

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.

Alterations of self-reactive antibody repertoires in HIV disease: An insight into the role of T cells in the selection of autoreactive B cells

Infection with human immunodeficiency virus (HIV) is characterized by a progressive depletion of CD4(+) T cells that parallels a dysfunction of the B cell compartment and a disturbed recognition of self-antigens. The relationship between T lymphocyte homeostasis and abnormalities in the selection of self-reactive B cells is not clear as yet. We have therefore compared repertoires of natural antibodies of healthy donors and of patients at various stages of HIV infection. The reactivity of IgM and IgG antibodies in plasma of healthy blood donors and of HIV-positive patients with high and low CD4(+) T cell counts was assessed by semi-quantitative immunoblotting using self-antigens extracted from normal human tissues. Repertoires of reactivites were compared between groups of individuals by means of multiparametric statistical analysis. We observed that repertoires of self-reactive IgM and IgG from HIV-seropositive patients exhibited significantly altered patterns of reactivity, as compared to those of healthy controls. Further, self-reactive repertoires of IgM and IgG of patients with high CD4(+) T cell counts differed significantly from those of patients with low CD4(+) T cell counts. A longitudinal analysis of self-reactive antibody repertoires of progressor and non-progressor patients suggested an influence of CD4(+) T cell counts on immunoglobulin reactivity toward self-antigens. These observations support the hypothesis that altered T cell/B cell interactions due to altered CD4(+) T cell help severely impact on the selection of self-reactive antibody repertoires and may contribute to the onset of pathological autoimmunity in HIV disease.

Simultaneous identification of various antinuclear antibodies using an automated multiparameter line immunoassay system

The objective was to determine the sensitivity and specificity of an automated multiparameter line immunoassay system compared with other techniques for the identification of autoantibodies in rheumatic diseases. We studied sera from 90 patients. Anti-U1RNP, anti-Sm, anti-Ro/SS-A, anti-La/SS-B, anti-Jo 1 and anti-Scl 70 antibodies were identified by counterimmunoelectrophoresis (CIE) techniques, enzyme-linked immunosorbent assay (ELISA), immunoblotting (IB) using extracts of rabbit thymus and human placenta, and an automated multiparameter line immunoassay system (INNO-LIA ANA UPDATE K-1090) that detects nine different antibodies simultaneously (anti-U1RNP, anti-Sm, anti-Ro/SS-A, anti-La/SS-B, anti-Scl 70, anti-Jo 1, anticentromere, antihistone, and antiribosomal P protein). The line immunoassay system equaled or surpassed the other techniques in the identification of anti-Sm, anti-La/SS-B, anti-Jo 1 and anti-Scl 70 antibodies (sensitivity 100%, specificity 94-100%) and was similarly effective in the case of anti-U1RNP (sensitivity 87.5%, specificity 93.9%) and anti-Ro/SS-A (sensitivity 91.4%, specificity 87.2%) antibodies. In addition, this technique detected more 52 and 60 kD anti-Ro/SS-A sera than IB. Nine antibodies can be detected with this method at a cost of 25.38 Euros per serum sample. In five hours, 19 sera can be studied. The approximate cost of detecting these nine antibodies with an automated ELISA system would be 28.93 Euros, which allows 10 sera to be studied in four hours. In conclusion, the automated multiparameter line immunoassay system is a valid method for the detection of autoantibodies in rheumatic diseases. Its most notable advantages are automated simultaneous detection of several autoantibodies in the same serum and its lower cost compared with ELISA techniques.

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.