Antibodies to retroviral proteins in autoimmune connective tissue disease. Relation to clinical manifestations and ribonucleoprotein autoantibodies

Positive melioidosis serology in a patient with adult onset Still's disease: a case report of a diagnostic dilemma

Background

Autoimmune disorders are known to produce false positives in serological tests for infections. Aetiological association between infections and autoimmunity, increased susceptibility to infectious and autoimmune disorders with immune dysregulation and non-specific polyclonal expansion of B cells with autoimmunity may cause confusion in diagnosis and patient management. We report a patient with Adult Onset Still’s Disease (AOSD) presenting with rising melioidosis antibody titres that caused diagnostic confusion.

Case presentation

A forty-nine-year-old female presented with prolonged fever, sore-throat, large joint arthritis, lymphadenopathy, hepatomegaly and transient rash. She had elevated inflammatory markers and a rising melioidosis antibody titre. The patient responded poorly to prolonged course of appropriate antimicrobials but showed rapid and sustained improvement with glucocorticoids.

Conclusion

Positive melioidosis serology could have been due to a co-infection or false positive antibody reaction due to non-specific B cell expansion or an indicator of true infection that triggered the immune dysregulation to develop AOSD.

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.

[A paraneoplastic Sharp syndrome reversible after resection of a benign schwannoma: a paraneoplastic syndrome?]

Paraneoplastic syndromes commonly occur in malignancies and often precede the first symptoms of the tumor. By definition, paraneoplastic syndromes are only associated with malignancies although some exceptions have been reported, occurring with benign tumors. We report a patient presenting with a clinical and serological Sharp syndrome, followed a few months later by a cervical schwannoma. Curative surgical resection of the mass resulted in a clinical and serological healing from the Sharp syndrome. To our knowledge, this is the first report of a benign schwannoma complicated by a possible paraneoplastic Sharp syndrome.

Rheumatic conditions in human immunodeficiency virus infection

Many rheumatic diseases have been observed in HIV-infected persons. We, therefore, conducted a comprehensive literature search in order to review the prevalence, presentation and pathogenesis of rheumatic manifestations in HIV-infected subjects. Articular conditions (arthralgia, arthritis and SpAs) are either caused by the HIV infection itself, triggered by adaptive changes in the immune system, or secondary to microbial infections. Muscular symptoms may result from rhabdomyolysis, myositis or from side-effects of highly active anti-retroviral therapy (HAART). Osseous complications include osteonecrosis, osteoporosis and osteomyelitis. Some conditions such as the diffuse infiltrative lymphocytosis syndrome and sarcoidosis affect multiple organ systems. SLE may be observed but may be difficult to differentiate from HIV infection. Some anti-retroviral agents can precipitate hyperuricaemia and are associated with arthralgia. When indicated, immunosuppressants and even anti-TNF-alpha agents can be used in the carefully monitored HIV patient. Thus, rheumatic diseases and asymptomatic immune phenomena remain prevalent in HIV-infected persons even after the widespread implementation of highly active anti-retroviral therapy.

Human RNA "rumor" viruses: the search for novel human retroviruses in chronic disease

Retroviruses are an important group of pathogens that cause a variety of diseases in humans and animals. Four human retroviruses are currently known, including human immunodeficiency virus type 1, which causes AIDS, and human T-lymphotropic virus type 1, which causes cancer and inflammatory disease. For many years, there have been sporadic reports of additional human retroviral infections, particularly in cancer and other chronic diseases. Unfortunately, many of these putative viruses remain unproven and controversial, and some retrovirologists have dismissed them as merely "human rumor viruses." Work in this field was last reviewed in depth in 1984, and since then, the molecular techniques available for identifying and characterizing retroviruses have improved enormously in sensitivity. The advent of PCR in particular has dramatically enhanced our ability to detect novel viral sequences in human tissues. However, DNA amplification techniques have also increased the potential for false-positive detection due to contamination. In addition, the presence of many families of human endogenous retroviruses (HERVs) within our DNA can obstruct attempts to identify and validate novel human retroviruses. Here, we aim to bring together the data on "novel" retroviral infections in humans by critically examining the evidence for those putative viruses that have been linked with disease and the likelihood that they represent genuine human infections. We provide a background to the field and a discussion of potential confounding factors along with some technical guidelines. In addition, some of the difficulties associated with obtaining formal proof of causation for common or ubiquitous agents such as HERVs are discussed.

A serological screening assay of human immunodeficiency virus type 1 antibodies based on recombinant protein p24-gp41 as a fusion protein expressed in Escherichia coli

The objective of this study was expression of a recombinant fusion protein p24-gp41 to gain a proper folding pattern of the proteins which could be recognized by specific antibodies against human immunodeficiency virus type 1 (HIV-1) for development of a reliable serodiagnostic kit. Serodiagnostic method using enzyme-linked immunosorbent assay (ELISA) with the expressed recombinant fusion protein p24-gp41 was carried out to test the sensitivity and specificity of the protein using human sera and various reference panels from Boston Biomedica Inc. (BBI). The level of the expression was determined to be 30% and the final recovery from fermentation and purification process was calculated as 80 mg/L with more than 98% purity. The developed ELISA assay was demonstrated to have 100 and 99.5% sensitivity and specificity, respectively, detecting anti-HIV-1 antibody using 900 positive and 10,000 negative human sera. The developed assay showed reliable results in comparison with other reference HIV ELISA kits using various BBI panels as well. In conclusion, the recombinant fusion protein p24-gp41 was expressed and used to develop a serodiagnostic kit for screening of the HIV-1 with high sensitivity (100%) and specificity (99.5%) which could be useful for screening large groups of blood donors.

CD14-dependent Modulation of Transcriptional Activities of Endogenous Retroviruses in the Lung after Injury

Lipopolysaccharide (LPS) plays a central role in the pathogenesis of distant organs after burn. Recent studies demonstrated the regulation of mouse endogenous retroviruses (MuERVs) in several organs after burn. In this study, the role of CD14, a LPS receptor, in burn-mediated regulation of MuERV expression in the lung was investigated. CD14 knockout (KO) and wild type (WT) mice were subjected to burn followed by RT-PCR analysis of alterations in the MuERV expression in the lung 1 day after injury. Even without injury, CD14 KO mice had a unique profile of MuERV expression compared to WT. Three bands (Lung-1, Lung-2, and Lung-3) in CD14 KO were downregulated after injury. Lung-2 and Lung-3 transcripts were almost identical to 2 previously described defective env transcripts of MuERVs, respectively. The Lung-1-1 transcript was a double spliced message generated by the env and a set of novel splicing signals, whereas the Lung-1-2 transcript was a defective env transcript. Only the Lung-1-1 transcript had a significant ORF capable of encoding a gag-pol fusion polypeptide. Putative proviral sequences of Lung-1-1 and Lung-1-2 transcripts were mapped to chromosomes 4 and 11, respectively. The results from this study suggest that the absence of CD14 expression in CD14 KO mice contributes to the transcriptional regulation of MuERVs in the lung after injury.

False-positive human immunodeficiency virus antibody test in a dialysis patient

A patient developed end-stage renal disease secondary to p-anti-neutrophil cytoplasmic antibody (p-ANCA) positive rapidly progressive glomerulonephritis. He subsequently had human immunodeficiency virus (HIV)-1 antibody screening performed as part of a pre-transplant evaluation. The HIV-1 enzyme immunoassay (EIA) antibody test was repeatedly reactive. The HIV-1 western blot was indeterminate. The western blot pattern revealed "non-specific staining obscuring bands in that region." Another sample of serum was sent and the results were identical to the first result. An HIV-1 proviral qualitative polymerase chain reaction test was then performed several months later and no HIV-1 DNA was detected. One year later, an HIV-1 RNA test was negative. Thus, the positive antibody EIA test and the indeterminate western blot represent a false-positive result, most likely due to cross-reacting antigens in the patient's serum with various HIV antibodies. Throughout this period and thereafter, the patient has exhibited no symptoms of HIV infection.

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

Systemic lupus erythematosus (SLE) and infection with the human immunodeficiency virus (HIV) are rarely seen in the same patient. Both diseases share clinical and serological features and the differential diagnosis is difficult, with renal manifestations being of special interest. To date, 29 cases of association between the two diseases have been reported, but the diagnosis was simultaneous in just two of these and only 18 fulfilled the ARA criteria for the diagnosis of SLE. Most patients experienced an improvement in their SLE after development of their HIV associated immunosuppression and a reactivation of lupus manifestations has also been noted after immunological recovery secondary to antiretroviral therapy. We present the case of a woman in whom HIV and SLE with renal involvement were diagnosed simultaneously.

The genotype of mice influences the autoimmune response to spliceosome proteins induced by cytomegalovirus gB immunization

In previous studies we have established a link between cytomegalovirus (CMV) infection and an autoimmune response to the U1-70 k protein of the spliceosome in man. This autoimmune response, generally referred to as the anti-RNP (ribonucleoprotein) antibodies, is observed in about 30% of patients with systemic lupus erythematosus (SLE). We have also found that the CMV glycoprotein B (CMV gB) when expressed in a adenovirus vector (Ad) could induce a significant anti-U1-70 k antibody response in several strains of mice, such as C3H, MRL and BALB/c. In the present study we examined the autoimmune response induced by immunization with Ad-gB in A/J and C57BL/6 (B6) mice and determined whether there was any autoimmune phenotype similar to that observed in patients with SLE. Thus groups of A/J and B6 mice were immunized with Ad/gB or with Ad alone and then observed for possible skin or kidney disease. In addition the autoantibody response to the spliceosome was measured, and the target antigens identified by immunoblot techniques. All of the A/J mice mounted a very high IgG response primarily to the U1-70 k protein of the spliceosome, with evidence of a rapid spreading of the autoantibody response to other components of the complex. In contrast, B6 mice mounted only a very low titre autoantibody response and failed to show signs or symptoms of autoimmunity. The A/J but not the B6 mice were found to have deposits of IgG in their kidneys, which were consistent with abnormal levels of blood urea nitrogen in the A/J but not B6 mice. This study demonstrates the importance of the genetic background in the susceptibility to autoimmunity.

Endogenous retroviruses in systemic lupus erythematosus: candidate lupus viruses

Although the etiology of systemic lupus erythematosus (SLE) remains unclear, there is substantial circumstantial evidence that the development of SLE is dependent on environmental, genetic, and retroviral factors. SLE patients produce high titer antibodies to various retroviral proteins, including Gag, Env, and Nef of HIV and HTLV, in the absence of overt retroviral infection. We review the factors linking HERVs to SLE and consider the various processes utilized by endogenous retroviruses in the etiopathogenesis of SLE. In particular, we consider the role of HTLV-1-related endogenous sequence (HRES-1) in SLE. We propose that molecular mimicry between HRES-1 and the small ribonucleoprotein complex initiates the production of autoantibodies, leading to immune complex formation, complement fixation, and pathological tissue deposition.

Antibody to human endogenous retrovirus peptide in urine of human immunodeficiency virus type 1-positive patients

Human endogenous retrovirus (HERV)-like sequences are normal inherited elements that constitute several hundredths of the human genome. The expression of genes located within these elements can occur as a consequence of several different events, including persistent inflammation or genotoxic events. Antibodies to endogenous retroviral gene products have been found in a number of infectious, chronic, and malignant diseases, suggesting a role in disease initiation and progression. We studied human immunodeficiency virus type 1 (HIV-1)-infected patients for evidence of urine antibody to a HERV peptide and investigated correlates with clinical and laboratory parameters. Forty-three HIV-1-infected patients in documented asymptomatic, symptomatic, or AIDS stages of disease and 21 age- and gender-matched, uninfected controls were tested for antibody to HERV-related peptide 4.1. Urine specimens were examined in a blinded fashion with the Calypte Biomedical Corp. experimental enzyme immunoassay for antibody to peptide 4.1. Results were compared with demographic data, medical history, clinical state of disease, and results of other laboratory tests. Thirty-six percent of the asymptomatic (Centers for Disease Control and Prevention [CDC] category A) and 81.3% of both the symptomatic (CDC category B) and AIDS (CDC category C) patients were positive for antibody to HERV-related peptide 4.1. None of the controls were positive. In this study, antibodies to HERV-related peptide 4.1 were found more frequently in patients with advanced stages (categories B and C) of HIV-1 disease than in those patients with an earlier stage (category A) of HIV disease. In HIV patients, severe immunosuppression, defined as having had at least one opportunistic infection, correlated with the expression of antibody to a HERV-related peptide.

Anti-HIV indeterminate western blot in dialysis patients: a long-term follow-up

In a group of 520 patients undergoing chronic hemodialysis, 23 (4. 4%) were enzyme immunoassay (EIA) positive for human immunodeficiency virus (HIV) and indeterminate by Western blot (IWB) analysis. The antibodies were mostly directed against p24 and p55 antigens. A comparison between hemodialysis patients with and without IWB showed significant differences between the two groups with respect to number of units of blood transfused, history of renal transplant rejection, and Rh status. No significant differences were observed with respect to ethnic group, nature of renal disease, duration of hemodialysis, associated diseases, and ABO blood group. The HIV IWB phenomenon may represent abnormal immune reactivity as a result of transplantation antigens and/or autoantibody formation. Five-year follow-up of the HIV EIA-positive IWB patients showed that none had seroconverted to HIV-positive status.

Antiretroviral antibodies: implications for schizophrenia, schizophrenia spectrum disorders, and bipolar disorder

BACKGROUND

Some retroviral antigens share structural homology within a group of related retroviruses. It is possible that antibodies directed against one virus may cross-react with antigens from a different virus in the group.

METHODS

Using this principle, the human immunodeficiency virus 1 (HIV-1) Western blot assay was used as an available source of human retroviral antigens to screen serum samples from an archived collection to ascertain whether there was an association between serum antiretroviral antibodies and mental illnesses.

RESULTS

A statistically significant proportion (28/54, 52%) of patients suffering from psychiatric disorders had serum antibodies that recognized at least one antigen present on the blot, culminating in indeterminate HIV-1 tests. The majority of the reactive samples were directed against the HIV-1 group antigens p24 and p17. These findings contrast with those of nonpsychiatric patients, who had 4/16 (25%) indeterminate blots.

CONCLUSIONS

The results suggest exposure to retroviral antigens related to those of HIV-1 in subpopulations of schizophrenic, schizophrenic spectrum disorder, and bipolar disorder patients.

Renal manifestations of concurrent systemic lupus erythematosus and HIV infection

Autoimmune phenomena are common in human immunodeficiency virus (HIV) infection, yet systemic lupus erythematosus (SLE) and HIV infection rarely are seen concurrently in the same patient. Many of the cases of combined HIV infection and SLE reported in the literature are patients with SLE before HIV infection and who did not undergo renal biopsy at a time when both processes were present. We report the clinical manifestations and renal biopsy findings in four subjects with concurrent HIV infection and SLE and compare them with the seven previously reported cases in the literature. Taken together, most patients were black (91%) and male (73%), and approximately half (55%) were children with perinatal HIV infection. These demographics differ markedly from those of idiopathic SLE, a disease that predominantly affects female adults. Renal presentations included proteinuria and hypocomplementemia, frequently with hematuria and renal insufficiency. Renal biopsy findings in 10 cases included all classes of lupus nephritis (class IIb in two cases, class III in one case, class IV in three cases, class V in three cases, class III and V in one case), two of which also displayed overlapping features of HIV-associated nephropathy (HIVAN). One case had isolated findings of HIVAN. This cohort provides a unique population in which to study interacting pathomechanisms between HIV infection and SLE.

Lupus erythematosus-like features in patients with cutaneous T-cell lymphoma

BACKGROUND

The development of lupus erythematosus-like (LE-like) features in patients with cutaneous T-cell lymphoma (CTCL) has not been reported previously in the literature. Both diseases, however, have been etiologically linked to retroviruses.

OBJECTIVE

Our purpose was to report four cases of patients with CTCL who developed LE-like features during the course of their disease, and to evaluate for evidence of antibodies to retroviruses in the sera of these patients.

PATIENTS

Four patients with biopsy-proven CTCL with clinical or histologic features of systemic lupus erythematosus (SLE) were evaluated for clinical and laboratory criteria for SLE. Only one patient demonstrated four American Rheumatism Association (ARA) criteria sufficient for the diagnosis of SLE. The remaining three patients demonstrated one or two criteria for SLE. In addition, the sera of these patients were examined by Western blot analysis for evidence of human immunodeficiency virus type I (HIV-I), human T-cell lymphotrophic virus type I (HTLV-I), or human intracisternal A-type particle type I (HIAP-I) retroviral proteins. Each patient demonstrated antibodies to some of the retroviral proteins examined. The sera of two patients reacted to proteins for HIAP-I, and the sera of two patients reacted to p24 gag proteins of HIV-I. No patient reacted to HTLV-I proteins.

CONCLUSIONS

Our report identifies four patients with CTCL who developed LE-like features during the course of their disease. Although the etiology of CTCL and SLE has not been well established, each has been linked to retroviruses. Evidence of antibodies to retroviral proteins was identified in each of our patients by Western blot analysis. Although the clinical and laboratory findings in these cases do not resolve the etiologic role of retroviruses in CTCL or SLE, they suggest that retroviruses may have a role in the pathogenesis of the clinical phenomenon reported in these four patients.

Reactivity of sera from systemic lupus erythematosus and Sjögren's syndrome patients with peptides derived from human immunodeficiency virus p24 capsid antigen

We have previously demonstrated that about one-third of patients with either Sjögren's syndrome (SS) or systemic lupus erythematosus (SLE) react to human immunodeficiency virus (HIV) p24 core protein antigen without any evidence of exposure to, or infection with, HIV itself. Herein, we further characterize the specificity of this reaction using enzyme-linked immunosorbent assay to peptides representing fragments of p24. Characteristic epitope-specific profiles were seen for SS and SLE patients. SS patients had significantly increased responses to peptides F (p24 amino acids 69 to 86) and H (amino acids 101 to 111) and diminished reactivity to peptides A (amino acids 1 to 16) and P (amino acids 214 to 228). SLE patients had increased reactivity to peptides E (amino acids 61 to 76), H, and P. Utilization of peptide P hyporeactivity as the criterion to select for SS patients results in a screen that is moderately sensitive (64%) and specific (79.3%). Adding hyperreactivity to one other peptide (F or H) as an additional criterion yields an expected decrease in sensitivity (to 41%) while increasing specificity (to 93.1%). All sera-reactive peptides from regions of known structure of HIV p24 were located in the apex of the p24 molecule. Thus, the specificity of the peptide reactivities described here indicates a specific pattern of a nonrandom cross-reactivity between HIV type 1 p24 and autoimmune sera which may be partially syndrome specific. The future focus of our work will be to optimize assays of the peptide as diagnostic tools.

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

A number of clinical and laboratory features of HIV infection are found in systemic lupus erythematosus (SLE). The objective of this study was to analyze the presence of circulating antibodies to small nuclear ribonucleoproteins (snRNP) in both diseases. Sera from 44 HIV-infected children, from 22 patients with childhood-onset SLE, and from 50 healthy children were studied. Anti-snRNP antibodies were detected by ELISA using recombinant and affinity-purified nuclear antigens, by counterimmunoelectrophoresis (CIE), and by immunoblotting using extractable nuclear antigens. Results included the detection of anti-snRNP antibodies by ELISA in 30 HIV-infected patients (68.1%) and 19 SLE patients (86.3%). These antibodies were directed against U1-RNP (61.3% and 77.2%, respectively), Sm (29.5% and 54.5%, respectively), 60 kDa Ro/SS-A (47.7% and 50%, respectively), and La/SS-B proteins (18.1% and 9%, respectively). None of the HIV-infected children and 11 SLE patients (50%) showed anti-snRNP antibodies by CIE. None of the HIV-infected patients showed anti-70 kDa U1-RNP or anti-D-Sm antibodies by immunoblotting. No differences between the two groups were noted on the presence of nonprecipitating anti-snRNP antibodies. No such reactivities were observed among the normal sera tested. The authors concluded that nonprecipitating anti-snRNP antibodies in HIV-infected children are as frequent as in childhood-onset SLE. The significance of these antibodies is not clear at present. Although polyreactive and low-affinity antibodies and a mechanism of molecular mimicry may explain these results, a specific stimulation of B cells by nuclear antigens could not be excluded.

Detection of antibodies to a recombinant gag protein derived from human endogenous retrovirus clone 4-1 in autoimmune diseases

To investigate whether human endogenous retroviruses (HERV) contribute to autoimmune diseases, we prepared a recombinant p30gag protein derived from clone 4-1 of the HERV family, using a baculovirus-vector system. This p30gag protein (CA41B) was approximately 30 kDa, as expected, and reacted with antibodies for p30gag purified from both murine and feline leukemia virus. This result suggested that the antigenic determinant for p30gag was well conserved in CA41B. Analysis of serum antibodies to p30gag in patients with autoimmune diseases was done by Western blotting. CA41B detected anti-p30gag antibodies in 48.3% of systemic lupus erythematosus (SLE) patients, 35.0% of Sjögren's syndrome (SS) patients, and 33.3% of mixed connective tissue disease (MCTD) patients, whereas no anti-p30gag antibodies were found in healthy subjects. This suggested that HERV p30gag or other retroviral p30gag proteins possessing the same antigenic determinant as CA41B may play a role in these diseases. Although detection of antibodies to HERV p30gag in autoimmune diseases is indirect evidence that HERV proteins are involved, this study showed that patients with autoimmune diseases have antibodies to HERV p30gag using a recombinant HERV protein rather than synthetic peptides based on HERV or retroviral proteins of other species.

An evolution-based hypothesis on the origin and mechanisms of autoimmune disease

The pathogenesis of autoimmune disease remains an enigma. Here, the condition is analysed from an evolutionary standpoint, and the thesis developed that viruses, in particular retroviruses, are important to our evolution, and that their inappropriate re-expression by repetitive (? ischaemic) cell damage in individuals of appropriate major histocompatibility type, leads to autoimmune disease. Such a view requires a slight adjustment to traditional ways of seeing Darwinian evolution, but one which makes real sense of the MHC-restricted nature of the adaptive immune response.

Different patterns of soluble adhesion molecules in systemic and cutaneous lupus erythematosus

Circulating isoforms of cellular adhesion molecules (CAMs) have been described recently, and elevated levels of certain sCAMs have been reported in various inflammatory diseases such as systemic lupus erythematosus (SLE). There are previously no reports on sCAMs in cutaneous LE. Sera from 61 patients with LE: systemic (SLE: n=24), chronic cutaneous (discoid LE, DLE: n= 19) or subacute cutaneous (SCLE: n=8), chronic biologically false positive (CBFP) reactors for syphilis (n= 10) and 32 controls were examined for sICAM-1, sVCAM-1 and sE-Selectin with specific ELISA kits. Protocol forms were reviewed. We found significantly elevated levels of sE-Selectin in patients with DLE and widespread cutaneous symptoms, and a correlation between active cutaneous disease as well as polymorphous light eruption (PLE) and elevated levels of sE-Selectin. In contrast, patients with systemic LE did not have elevated levels of sE-Selectin, but in concordance with earlier reports, sICAM-1 and sVCAM-1 levels were elevated compared to controls in SLE, as well as in SCLE patients, which has not been reported previously. Since activated endothelial cells are the only source for E-Selectin, the elevated sE-Selectin level in patients with widespread and active cutaneous disease suggests a more important role for endothelial cells in the pathogenesis of cutaneous LE than previously assumed.

Biochemical characterization of the reverse transcriptase of a human intracisternal A-type particle (HIAP)

The discovery of novel human intracisternal A-type particle (HIAP) that may be associated with the autoimmune disease Sjŏgren's syndrome has been previously reported. Although the HIAP retrovirus has been shown to be antigenically related to HIV-1, the viruses were distinguishable by different hydrodynamic mobilities through a sucrose gradient by morphology and intracellular location, and by differing divalent cation requirements for their in vitro reverse transcriptase (RT) reactions. In this report, additional biochemical characteristics are provide that further differentiate the HIAP RT from HIV-1 RT. Data are also presented that distinguish the HIAP RT from the known cellular DNA polymerases.

Retroviruses and systemic lupus erythematosus

In some animal models of autoimmune diseases the roles of exogenous and endogenous retroviruses are clearly defined. In ungulates caprine arthritis encephalitis virus, equine infectious anemia virus or Maedi-Visna virus infections cause a well-defined autoimmune disease and the appearance of seropositivity of the animals is of diagnostic value. Likewise, in MRL lpr/lpr mice insertion of a retrotransposon into the fas gene could clearly be shown to cause survival of autoreactive lymphocytes. Despite intensive research in this field over a long period of time, molecular data on retroviral involvement in either etiology or pathology of human SLE and other autoimmune rheumatic diseases remain rather scarce. However, the analysis of retroviral antibodies and antigens in human autoimmune disease is undoubtedly important with regard to the search for retroviruses as disease-causing agents.

Human endogenous retroviruses: nature, occurrence, and clinical implications in human disease

Retroviral diagnostics have become standard in human laboratory medicine. While current emphasis is placed on the human exogenous viruses (human immunodeficiency virus and human T-cell leukemia virus), evidence implicating human endogenous retroviruses (HERVs) in various human disease entities continues to mount. Literature on the occurrence of HERVs in human tissues and cells was analyzed. Substantial evidence documents that retrovirus particles were clearly demonstrable in various tissues and cells in both health and disease and were abundant in the placenta and that their occurrence could be implicated in some of the reproductive diseases. The characteristics of HERVs are summarized, mechanisms of replication and regulation are outlined, and the consistent hormonal responsiveness of HERVs is noted. Clear evidence implicating HERV gene products as participants in glomerulonephritis in some cases of systemic lupus erythematosus is adduced. Data implicating HERVs as etiologic factors in reproductive diseases, in some of the autoimmune diseases, in some forms of rheumatoid arthritis and connective tissue disease, in psoriasis, and in some of the inflammatory neurologic diseases are reviewed. The current major needs are to improve methods for HERV detection, to identify the most appropriate HERV prototypes, and to develop diagnostic reagents so that the putative biologic and pathologic roles of HERVs can be better evaluated.

Antibody reactivity to the HRES-1 endogenous retroviral element identifies a subset of patients with systemic lupus erythematosus and overlap syndromes. Correlation with antinuclear antibodies and HLA class II alleles

OBJECTIVE

To evaluate the correlation between the presence of antibodies to an endogenous retroviral element-encoded nuclear protein autoantigen, HRES-1, and the presence of other antinuclear antibodies and HLA class II alleles in patients with systemic lupus erythematosus (SLE) and overlap syndromes.

METHODS

Antibody reactivities to native and recombinant proteins and synthetic peptides were assessed by counterimmunoelectrophoresis, enzyme-linked immunosorbent assay, and Western blotting. HLA class II alleles were determined by oligonucleotide typing.

RESULTS

Forty-eight percent of the 153 patients with autoimmune disease, and 52% of the subgroup with SLE, had HRES-1 antibodies. In contrast, 3.6% of 111 normal donors, and none of 42 patients with the acquired immunodeficiency syndrome or 50 asymptomatic human immunodeficiency virus 1-infected patients, had HRES-1 antibodies. Chi-square analyses revealed a significant association between anti-HRES-1 and anti-RNP and an inverse correlation between HRES-1 and Ro/La autoantibodies in patients with SLE or overlap syndromes. Antigenic epitopes of HRES-1 and the retroviral gag-related region of the 70-kd protein component of U1 small nuclear RNP, which share 3 consecutive highly charged amino acids (Arg-Arg-Glu), an additional Arg, and functionally similar Arg/Lys residues, represent cross-reactive epitopes between the two proteins. Selective removal of HRES-1 antibodies from sera of HRES-1-seropositive/RNP-seropositive patients by absorption on recombinant HRES-1/glutathione-S-transferase-conjugated agarose beads had no effect on anti-RNP reactivities. A comparative multivariate analysis of HLA class II genes revealed a differential segregation of DQB1 alleles in HRES-1-seropositive versus HRES-1-seronegative patients (P = 0.04). While a relative increase of DQB1*0402 among HRES-1-seropositive patients was noted across ethnic groups (P = 0.02), a decrease of DQB1*0201 and DQB1*0301 was found in white HRES-1-seropositive patients (P = 0.04).

CONCLUSION

Autoantibodies to HRES-1 are detectable in a distinct subset of patients with autoimmune disease, primarily in those who do not have antibodies to Ro and La. Anti-HRES-1 and anti-RNP reactivities are mediated by cross-reactive but separate antibody molecules. HLA-DQB genes, rather than HLA-DRB or DQA genes, may have a more significant influence on generation of these antinuclear autoantibodies.

Anti-human immunodeficiency virus type 1 antibodies of noninfected subjects are not related to autoantibodies occurring in systemic diseases

Indeterminate Western blot (WB) (immunoblot) patterns for anti-human immunodeficiency virus type 1 (HIV-1) antibodies are often observed when testing serum samples from noninfected individuals. We investigated here the possible involvement of some frequently occurring autoantibodies (anti-SmB/B', U1snRNP [68 kDa, A, and C], Ro/SS-A [60 and 52 kDa], and Jo-1) in the generation of such indeterminate HIV-1 WB. In particular, the role of a reported sequence homology between p24 gag and the SmB/B' autoantigen was investigated. Serum samples were obtained from 50 healthy controls, 51 patients with systemic lupus erythematosus (SLE), 46 with systemic sclerosis, 6 with Sjögren's disease, 3 with mixed connective tissue disease, and 41 healthy subjects with persistent indeterminate HIV-1 WB. Reactivity to HIV-1 p24 gag was slightly but not significantly more frequent in patients with SLE than in controls (25.5% versus 14.0%; P > 0.1), whereas reactivity to HIV-1 p17 gag was significantly more frequent in the former subjects (23.5% versus 8.0%; P = 0.03). Simultaneous reactivity to p17 and p24 was observed in patients with SLE (11.8%; P = 0.014) or systemic sclerosis (8.7%; P = 0.049) but not in controls. There was no association found between the presence of any autoantibody and the occurrence of indeterminate HIV-1 WB nor between the presence of p24-reactive antibodies and anti-SmB/B'; this indicates that most p24-reactive antibodies are directed to epitopes other than the proline-rich sequences shared by p24 gag and SmB/B'.

Retroviruses and autoimmune rheumatic diseases

In autoimmune rheumatic diseases, retroviruses have been repeatedly discussed as important etiologic factors. However, despite a considerable amount of indirect evidence that retroviruses might indeed be involved in triggering or perpetuating autoimmune rheumatic diseases, clear cut direct evidence is still missing. Studies on arthropathies associated with HIV-1 or HTLV-1 infection as well as new experimental animal models like the Tax transgene mice and new data from the MLR/lpr mouse model might help to answer the questions how and by what mechanisms retroviral infection may lead to autoimmune rheumatic diseases. From data obtained in the MLR/lpr mouse it seems obvious that a potential link of retroviruses, apoptosis and autogenes to autoimmune diseases opens exciting new approaches to the study of rheumatic disease pathogenesis.

Binding of glycoprotein 120 and peptides from the HIV-1 envelope by autoantibodies in mice with experimentally induced systemic lupus erythematosus and in patients with the disease

Systemic lupus erythematosus (SLE) and infection with the human immunodeficiency virus type 1 (HIV) are diseases that are characterized by immune dysregulation and autoantibody production. In this article we identify and characterize IgG antibodies from mice with SLE and SLE patients that bind HIV gp120 and HIV envelope-derived peptides. SLE can be induced in susceptible mouse strains by immunization with a human monoclonal anti-DNA antibody that bears a common idiotype designated 16/6 Id. We tested sera from various strains of mice in which experimental SLE was induced by this method, as well as from 93 patients with SLE and 31 controls (17 healthy controls, 14 patients with other autoimmune diseases) for the presence of antibodies reactive to gp120 by an ELISA. Antibodies reactive with gp120 were produced by BALB/c, C3H.SW, AKR, and DBA/2 mice, all of which were 16/6 Id immunized and had experimental SLE. C57BL/6 mice, which are resistant to induction of SLE by this method, did not produce antibodies reactive with gp120 despite 16/6 immunization. Forty-three percent of SLE patients made antibodies that bound to gp120 at titers greater than 1:40, whereas 12% of healthy control sera (p < or = 0.02) and 14% of patients with other autoimmune diseases contained such antibodies (p < or = 0.05). We delineated the specificity of this antibody activity by testing for reactivity to six HIV envelope peptides. In both mice and SLE patients, sera reactive with gp120 recognized the same three envelope peptides. Removal of the anti-DNA antibodies from the sera by DNA-agarose affinity purification did not change anti-gp120 specificity.

Panel of anti-gp120 monoclonal antibodies reacts with same nuclear proteins in uninfected cells as those recognized by autoantibodies from patients with systemic lupus erythematosus

Mouse monoclonal antibodies (MAbs) directed against the HIV-1 gp120 envelope protein were screened for their reactivity with intracellular antigens expressed in normal uninfected monocytes by indirect immunofluorescence and immunoblotting. Some of these MAbs reacted with the nuclei of normal uninfected cells, producing three main staining patterns by indirect immunofluorescence. Western blot analysis showed that these monoclonal antibodies recognize peptides of various molecular weights present in nuclei preparations of normal monocytes. Reactivity with peptides of similar molecular weight was also detected in sera from both HIV-infected individuals and patients with systemic lupus erythematosus. This evidence for antigenic similarities between HIV-1 gp120 and nuclear antigens represents a novel example of molecular mimicry of self-antigens by HIV envelope proteins, which supports the involvement of mechanisms of autoimmunity in HIV disease pathogenesis through recruitment of autoimmune responses to self-structures by HIV antigens.

New method for detection of C34-T mutation in the AMPD1 gene causing myoadenylate deaminase deficiency

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Absence of an association between antibodies to retroviral proteins and anticardiolipin antibody and/or lupus anticoagulant in systemic lupus erythematosus

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Distinguishing beta 2-glycoprotein I dependent (systemic lupus erythematosus type) and independent (syphilis type) anticardiolipin antibody with Tween 20

We investigated whether or not the use of Tween 20 could help to distinguish beta 2-glycoprotein I (GPI) independent anticardiolipin antibody (aCL) (syphilis-type aCL) from GPI-dependent aCL (SLE-type aCL) in a GPI-dependent/independent aCL ELISA. aCL was positive in all 16 SLE patients and all 15 syphilis patients, who were positive for aCL in the standard ELISA, in the GPI-independent ELISA with Tween 20. GPI-dependent aCL was detected in 12/16 SLE patients by the GPI-dependent ELISA with Tween 20. aCL was not detected in any of the syphilis patients by GPI-dependent ELISAs. On the basis of these results, we recommend that Tween 20 should be used in ELISAs to distinguish GPI-dependent aCL from GPI-independent aCL.