Induction of lupus inclusions by sera from patients with systemic lupus erythematosus

Association between type I interferon pathway activation and clinical outcomes in rheumatic and musculoskeletal diseases: a systematic literature review informing EULAR points to consider

BACKGROUND

Type I interferons (IFN-I) contribute to a broad range of rheumatic and musculoskeletal diseases (RMDs). Compelling evidence suggests that the measurement of IFN-I pathway activation may have clinical value. Although several IFN-I pathway assays have been proposed, the exact clinical applications are unclear. We summarise the evidence on the potential clinical utility of assays measuring IFN-I pathway activation.

METHODS

A systematic literature review was conducted across three databases to evaluate the use of IFN-I assays in diagnosis and monitor disease activity, prognosis, response to treatment and responsiveness to change in several RMDs.

RESULTS

Of 366 screened, 276 studies were selected that reported the use of assays reflecting IFN-I pathway activation for disease diagnosis (n=188), assessment of disease activity (n=122), prognosis (n=20), response to treatment (n=23) and assay responsiveness (n=59). Immunoassays, quantitative PCR (qPCR) and microarrays were reported most frequently, while systemic lupus erythematosus (SLE), rheumatoid arthritis, myositis, systemic sclerosis and primary Sjögren's syndrome were the most studied RMDs. The literature demonstrated significant heterogeneity in techniques, analytical conditions, risk of bias and application in diseases. Inadequate study designs and technical heterogeneity were the main limitations. IFN-I pathway activation was associated with disease activity and flare occurrence in SLE, but their incremental value was uncertain. IFN-I pathway activation may predict response to IFN-I targeting therapies and may predict response to different treatments.

CONCLUSIONS

Evidence indicates potential clinical value of assays measuring IFN-I pathway activation in several RMDs, but assay harmonisation and clinical validation are urged. This review informs the EULAR points to consider for the measurement and reporting of IFN-I pathway assays.

The importance of tubuloreticular inclusions in lupus nephritis

Tubuloreticular inclusions (TRI) are distinctive cytoplasmic structures of unknown origin that typically associate with autoimmune and viral diseases. We investigated the clinical and prognostic relevance of TRI detection in patients with lupus nephritis (LN). We conducted a single centre study of patients (n=84) with biopsy evidence of LN. Clinical variables included demographics, SLEDAI score, and autoantibody profiling; while histological evaluation included TRI presence, International Society of Nephrology/Renal Pathology Society (ISN/RPS) classification with NIH activity and chronicity indices, immunofluorescence, and other EM findings. Patients with and without TRI were compared by non-parametric statistical methods and survival analysis for the endpoints of death and renal failure. TRI were detected in 37 patients (44%) that were younger (28.4 vs 34.3 years, p=0.02) and more often from Asian background (37.8% vs 19.1%, p=0.04) compared to patients without TRI. SLEDAI score (11 vs 12 units, p=0.36) and amount of proteinuria (370 vs 340 mg/mmol, p=0.71) were similar in both groups; however, TRI positive patients had increased frequency of anti-SSB antibodies (16% vs 2%, p=0.02), 'full house' immune complex deposition (85% vs 58%, p=0.04) and subendothelial electron dense deposits (83% vs 65%, p=0.07), but were less often anti-dsDNA Ab positive (62% vs 85%, p=0.02). Patient and renal survival were not influenced by TRI status. TRI were observed in nearly half of all LN patients and TRI positive patients more often carried anti-SSB antibodies. However, TRI had little bearing on disease presentation or outcome in LN.

Type I Interferons in Autoimmune Disease

Type I interferons, which make up the first cytokine family to be described and are the essential mediators of antivirus host defense, have emerged as central elements in the immunopathology of systemic autoimmune diseases, with systemic lupus erythematosus as the prototype. Lessons from investigation of interferon regulation following virus infection can be applied to lupus, with the conclusion that sustained production of type I interferon shifts nearly all components of the immune system toward pathologic functions that result in tissue damage and disease. We review recent data, mainly from studies of patients with systemic lupus erythematosus, that provide new insights into the mechanisms of induction and the immunologic consequences of chronic activation of the type I interferon pathway. Current concepts implicate endogenous nucleic acids, driving both cytosolic sensors and endosomal Toll-like receptors, in interferon pathway activation and suggest targets for development of novel therapeutics that may restore the immune system to health.

Ultrastructural Modifications in one Case of Hairy Cell Leukemia during Alpha-Interferon Therapy

There are many reports concerning the morphology of hairy cell leukemia (HCL), but, to our knowledge, there are no data on the ultrastructural modifications of HCL during interferon therapy. The ultrastructural modifications of neoplastic cells In peripheral blood in a case of HCL were investigated before and 2 and 4 months after beginning treatment with human lymphoblastoid alpha-interferon. Before therapy, hairy cells displayed the typical cytoplasmic projections, and 4 % contained ribosome-lamellae complexes (RLC) (the cells contained up to 7 RLC). Two months from the beginning of therapy, hairy cells had shorter projections, RLC had disappeared, and tubuloreticular structures (TRS) had appeared in 2.2 % of the elements. Four months from the beginning of therapy, TRS persisted in 2.3 % of hairy cells, cylindrical confronting cisternae (CCC) appeared in 6.8 % of the cells, and uncommon RLC, in close contact with the rough endoplasmic reticulum and nuclear membrane, were found in 1.5 % of the elements. The cells contained up to 3 RLC. Our data confirm that interferon stimulates the synthesis of TRS and CCC, whereas the reappearance of uncommon forms of RLC could reflect their neosynthesis, possibly related to the interferon therapy. The frequent findings of a close contact between RLC and nuclear membrane support the view that RLC are derived not only from rough endoplasmic reticulum, but also from the nuclear membrane.

Cutaneous histopathological findings of Aicardi-Goutières syndrome, overlap with chilblain lupus

We report a 2-year-old girl with developmental delay who, from the age of 1 year, developed perniotic lesions of the hands and feet initially diagnosed as chilblain lupus. Histological examination showed features of epidermal necrosis with intraepidermal bulla formation, interface dermatitis, lymphocytic vasculitis with fibrinoid necrosis and thrombi formation, both superficial and deep dermal lymphocytic infiltrate, lymphocytic eccrine hidradenitis and absence of marked dermal edema. Subsequent investigations suggested a clinical diagnosis of Aicardi-Goutières syndrome (AGS), a rare genetic leukoencephalopathy. Recently, both AGS and familial chilblain lupus, an autosomal dominant form of systemic lupus erythematosus (SLE), have been shown to be allelic thus suggesting a common pathogenic basis. In addition, a phenotypic overlap is apparent between SLE and AGS. To our knowledge, this is the first comprehensive dermatopathological report of the cutaneous lesions seen in AGS, and our paper highlights the importance of considering AGS in the differential diagnosis of perniosis and chilblain lupus.

Mutations in the gene encoding the 3′-5′ DNA exonuclease TREX1 cause Aicardi-Goutières syndrome at the AGS1 locus

Aicardi-Goutières syndrome (AGS) presents as a severe neurological brain disease and is a genetic mimic of the sequelae of transplacentally acquired viral infection. Evidence exists for a perturbation of innate immunity as a primary pathogenic event in the disease phenotype. Here, we show that TREX1, encoding the major mammalian 3' --> 5' DNA exonuclease, is the AGS1 gene, and AGS-causing mutations result in abrogation of TREX1 enzyme activity. Similar loss of function in the Trex1(-/-) mouse leads to an inflammatory phenotype. Our findings suggest an unanticipated role for TREX1 in processing or clearing anomalous DNA structures, failure of which results in the triggering of an abnormal innate immune response.

Interferon-α/β-mediated innate immune mechanisms in dermatomyositis

Dermatomyositis has been modeled as an autoimmune disease largely mediated by the adaptive immune system, including a local humorally mediated response with B and T helper cell muscle infiltration, antibody and complement-mediated injury of capillaries, and perifascicular atrophy of muscle fibers caused by ischemia. To further understand the pathophysiology of dermatomyositis, we used microarrays, computational methods, immunohistochemistry and electron microscopy to study muscle specimens from 67 patients, 54 with inflammatory myopathies, 14 with dermatomyositis. In dermatomyositis, genes induced by interferon-alpha/beta were highly overexpressed, and immunohistochemistry for the interferon-alpha/beta inducible protein MxA showed dense staining of perifascicular, and, sometimes all myofibers in 8/14 patients and on capillaries in 13/14 patients. Of 36 patients with other inflammatory myopathies, 1 patient had faint MxA staining of myofibers and 3 of capillaries. Plasmacytoid dendritic cells, potent CD4+ cellular sources of interferon-alpha, are present in substantial numbers in dermatomyositis and may account for most of the cells previously identified as T helper cells. In addition to an adaptive immune response, an innate immune response characterized by plasmacytoid dendritic cell infiltration and interferon-alpha/beta inducible gene and protein expression may be an important part of the pathogenesis of dermatomyositis, as it appears to be in systemic lupus erythematosus.

Degos' disease: a distinctive pattern of disease, chiefly of lupus erythematosus, and not a specific disease per se

Degos' disease, known confusingly as malignant strophic papularis, is an uncommon condition of unknown cause characterized by distinctive infarctive lesions in the skin, gastrointestinal tract, and central nervous system; the lesions at the two latter sites often result in death. We deem Degos' disease to be analogous to lupus erythematosus in the sense that each is fundamentally a systemic pathologic process involving several organs, among them the skin, but, moreover, we regard Degos' disease, in most instances, to be an actual manifestation of lupus erythematosus. Histopathologically, the findings in sections of tissue of skin lesions of Degos' disease are indistinguishable from those of one expression of cutaneous lupus erythematosus; immunopathologically, some patients with morphologic findings stereotypical of Degos' disease display signs characteristic of lupus erythematosus. For these reasons, we consider Degos' disease to be a distinctive pattern of disease, rather than a specific disease per se, just as are erythema multiforme, erythema nodosum, leukocytoclastic vasculitis, Sweet's syndrome, and pyoderma gangrenosum, to name but five of scores of them. The singular pattern that is designated Degos' disease usually is an expression of lupus erythematosus, but, episodically, of conditions like dermatomyositis and rheumatoid arthritis.

Interferon-alpha-induced human lupus inclusions and p36 protein in cancer and AIDS

Previous work showed that IFN-alpha induced the autoimmune-associated lupus inclusions (LI) in all 16 umbilical cord mononuclear cell samples from healthy mothers. In contrast, IFN-alpha induced LI and the LI-associated protein, p36, in only 2 of 16 human B lymphoblastoid cell lines. Resistance of these 14 cell lines to form LI and p36 may be due to their stage of development or differentiation or their transformed state. We sought to determine whether aging, neoplastic transformation, and HIV infection affected the observed IFN-alpha induction of LI in cord blood mononuclear cells. Expression of LI and p36 was investigated in PBMC on IFN-alpha chemotherapy and on culturing IFN-alpha with PBMC samples prepared from healthy adults and AIDS patients. The IFN-alpha induction of LI (detected by electron microscopy) or p36 (detected by two-dimensional gels) in all of the PBMC samples from these individuals was indistinguishable from the cord blood mononuclear cell response. Furthermore, induction of p36 and LI was not a good indicator of effective IFN-alpha chemotherapy. It may be consequential for autoimmunity induced by IFN-alpha in cancer, AIDS, and systemic lupus erythematosus (SLE). An essential biologic role for p36 and LI is suggested by a highly homologous p36 gene in the invertebrate Caenorhabditis elegans.

Ultrastructural features and prevalence of tubuloreticular structures in the ocular vasculature of patients with AIDS: a study of 23 cases

BACKGROUND

Tubuloreticular structures (TRS) are subcellular inclusions that are most commonly found in endothelial cells and lymphocytes of patients with autoimmune or collagen vascular disorders. In AIDS, TRS have been described in various tissues throughout the body including the lung, kidney, liver, muscle, and skin.

METHODS

Ocular tissues from 23 patients with AIDS were examined by electron microscopy. These included 17 postmortem eyes in addition to three chorioretinal and three conjunctival biopsy specimens.

RESULTS

The overall prevalence of TRS in the ocular and conjunctival endothelial cells was found to be 83% (19/23).

CONCLUSIONS

This is the first documented study of the prevalence of these structures in the ocular structures of patients with AIDS. Given the high frequency of their occurrence in AIDS, it is recommended that the presence of TRS in ocular or conjunctival tissues be an indication for obtaining an HIV antibody titre. Additionally, a rheumatological examination for HIV seronegative patients is suggested.

Purification, microsequencing, and immunolocalization of p36, a new interferon-alpha-induced protein that is associated with human lupus inclusions

The trace interferon-alpha-induced protein, p36, was induced in Raji cells in association with lupus inclusions. It was solubilized in a nonionic detergent buffer, enriched by differential centrifugation and by preparative isoelectric focusing, and purified to homogeneity on two-dimensional protein gels. Failure to obtain N-terminal amino acid sequence, however, suggested a blocked alpha-amino group. Sequences of six tryptic peptides, 13-19 amino acids in length, were obtained after digestion, microbore-high performance liquid chromotography purification, and chemical sequence analysis. None of the six sequences, which represented approximately 25% of the entire protein, shared any meaningful homologies with entries in protein sequence repositories. Raji-cell p36 was shown in Western blots with antipeptide antibodies to be induced at least 400-fold and by immunofluorescence microscopy to co-localize with the endoplasmic reticulum resident protein, protein disulfide isomerase. These results show that p36 is a new interferon-alpha-induced protein that localizes in the endoplasmic reticulum, the cell region in which the lupus inclusions form, and that p36 is probably physically associated with the lupus inclusions.

De novo synthesis and secretion of a 36-kD protein by cells that form lupus inclusions in response to alpha-interferon

In response to the pure recombinant human alpha-IFN, IFLrA, Raji and Daudi were the only two cell lines among 19 human lymphoblastoid cell lines tested that formed the human lupus inclusions (LI) to a high frequency. Raji, Daudi, and five other cell lines were examined for protein changes that might accompany LI formation. Their selection was based upon T or B origin, association with Epstein-Barr virus, and ability to form LI. A trace protein of an estimated molecular mass of 36 kD (p36) and an isoelectric point of 5.6 was detected on two-dimensional gels only of alpha-IFN-treated Raji and Daudi cells. Gamma-IFN did not induce p36 or LI in any of these seven cell lines. In Daudi cells p36 and LI formed simultaneously in response to IFLrA, and persisted until the alpha-IFN-induced death of the culture. In Raji cells, p36 and LI appearance and disappearance coincided with the addition and removal of alpha-IFN. Fractionation of Raji cells with nonionic-detergent buffer placed p36 with the inclusions in the cytoplasmic supernatant. With detergent-free buffer p36 and LI were distributed evenly between the nuclear and cytoplasmic fractions. Pulse-chase experiments revealed that p36 was secreted. The de novo synthesis of p36 with alpha-IFN treatment was shown by labeling the cell proteins with [35S] methionine before and after the addition of alpha-IFN. These results along with previous results on the de novo synthesis of LI in the endoplasmic reticulum (which is involved in the processing and secretion of proteins) suggest a role for LI in the synthesis and secretion of p36.

Significance of tubuloreticular structures forming in Daudi cells cultured with sera from mothers bearing infants with neonatal lupus erythematosus

It is known that infants with neonatal lupus erythematosus (NLE) may be born to mothers whose sera are positive for the anti-Ro/SSA antibody. However, women who have this antibody do not always give birth to children with NLE. We have demonstrated tubuloreticular structures in vascular endothelial cells in the skin lesions of infants with NLE. Tubuloreticular structures could no longer be detected at the site of the lesions once the annular erythema had resolved, and the anti-Ro/SSA antibody test had become negative. The probability of a child being born with NLE was assessed by observing whether tubuloreticular structures were formed in Daudi cells cultured with sera from eight mothers who were anti-Ro/SSA antibody positive. Tubuloreticular structures formed in Daudi cells cultured with sera from four mothers who bore infants with NLE, but not in Daudi cells cultured with sera from four other mothers who bore normal infants. These results suggest that women who are positive for the anti-Ro/SSA antibody have a higher risk of bearing infants with NLE if tubuloreticular structures are formed in Daudi cells cultured with sera from these women, whereas this risk is lower if tubuloreticular structures do not develop in Daudi cells.

Localization of interferon-induced lupus inclusions demonstrated by computer image reconstruction of monensin-treated Daudi cells

A structural analysis of cells that contained the interferon-alpha-induced lupus inclusions (LI) was performed using a high-voltage electron microscope to determine the exact cellular location of LI and their association with normal cell organelles. LI were induced in the human B lymphoblastoid cell line, Daudi, by culturing with the pure recombinant human leukocyte interferon, IFLrA. Just prior to harvesting, a portion of the cells was treated with monensin to selectively swell the Golgi apparatus, and thereby simplify their identification using the electron microscope. Organellar associations between LI and the outer nuclear envelope and Golgi apparatus were identified in stereopairs of 1-micron sections prepared from both cells that were not treated with monensin and those that were treated with monensin. Serial 0.25-micron sections of the monensin-treated cells were prepared, and seven arbitrarily chosen cells were examined. Each of these cells contained a single LI, and it formed throughout an endoplasmic-reticulum region that made contact with both the outer nuclear envelope and the Golgi vesicles. Reconstruction of a cell by computer from the digitized negatives of serial sections clearly illustrated these relationships. This study reports the first determination of the association between LI and the Golgi apparatus. It also identifies the presence of only one LI in every cell, and the routine association of the LI with both the outer nuclear envelope and the Golgi apparatus. The unique cell location of LI formation suggests their functioning in membrane biogenesis, the trafficking of proteins to the plasma membrane or to cytoplasmic vesicles, or the processing of proteins for secretion.

Induction of tubuloreticular structures in cultured human endothelial cells by recombinant interferon alfa and beta

Tubuloreticular structures were induced in human umbilical vein endothelial cells cultured in media containing recombinant interferon alfa and beta but not in media containing recombinant interferon gamma or other agents that induce interferon, such as 5-bromodeoxyuridine or polyinosinicpolycytidylic acid. Recombinant interferon beta induced tubuloreticular structures in endothelial cells at a lower concentration and in a greater percentage of cell sections than recombinant interferon alfa. This report of tubuloreticular structures being induced in vitro in nonlymphoid cells provides evidence that interferon is the substance that causes the formation of tubuloreticular structures in endothelial cells in vivo.

Human lupus-type inclusions in umbilical cord blood mononuclear cells

Mononuclear cells purified from umbilical cord blood activated oligoadenylate synthetase and formed human lupus-type inclusions (LI) when cultured with the purified recombinant human leukocyte interferon, IFLrA. LI frequencies increased from 0% to a low of 0.75% and a high of 6.25% in 4-day cultures with IFLrA (100 units/ml). These interferon-induced responses in the mononuclear cells of neonates indicate that LI are solely an intrinsic product of normal cells, and not an exogenous virus or some other environmental agent.

Neonatal lupus syndrome and microtubular structure

A female infant, at 6 weeks old, with the clinical manifestation of annular erythemas on the trunk and face, was positive for anti-SS-A and anti-SS-B antibodies. The annular erythema disappeared spontaneously at the age of 7 months when anti-SS-A and anti-SS-B antibodies were negative. Electron microscopic observation of the vascular endothelial cells on the annular erythema revealed microtubular structures. Later microtubular structures were found absent from the vascular endothelial cells of the area where the annular erythema had disappeared. The patient's mother is suffering from Sjögren's syndrome; she has no clinical symptoms but anti-SS-A and anti-SS-B antibodies are positive and a biopsy of small salivary glands of the lip demonstrated a marked periductal mononuclear cell infiltration. Microtubular structures were observed in her vascular endothelial cells in the small salivary gland region. These findings suggest that disappearance of microtubular structure may have some relationship with anti-SS-A and anti-SS-B antibodies.

Induction of cylindrical confronting cisternae (AIDS inclusions) in Daudi lymphoblastoid cells by recombinant alpha-interferon

Cylindrical confronting cisternae (CCC), also known as test-tube and ring-shaped forms, are frequently present in the cytoplasm of lymphocytes and occasionally in other cells from patients with acquired immunodeficiency syndrome (AIDS). Recent data indicate that the presence of these cisternae and tubuloreticular structures (TRS) in lymphocytes from patients at risk for AIDS is predictive of the development of this syndrome. CCC are formed by an alteration of the membranes of the rough endoplasmic reticulum, but the mechanism by which they are formed or demonstration of their induction by specific agents has not been previously reported. We cultured Daudi lymphoblastoid cells in medium containing recombinant alpha-interferon and induced the formation of both TRS and CCC. The number of CCC formed in Daudi cells was directly proportional to the concentration of interferon used and the length of culture. CCC were in direct continuity with TRS, which were induced in cells by interferon at an earlier time. The percentage of cell sections containing TRS stayed the same or decreased somewhat after 72 hours of culture, whereas the number of CCC increased. Our results indicate that CCC could be present in various cells from patients with AIDS and other diseases as a result of elevated interferon levels in these conditions.