David Isenberg

The role of antibodies to DNA in systemic lupus erythematosus— A review and introduction to an international workshop on DNA antibodies held in London, May 1996

The term ’lupus erythematosus’ was first used approximately 150 y ago and its potential systemic involvement has been widely acknowledged during the past 100 y. In contrast the major serological marker of systemic lupus erythematosus (SLE), antibodies to DNA, were distinguished by four different groups as late as 1957.1--4 During the next 20 y a large panoply of antibodies were identified in the serum of lupus patients (see Table 1 and Reference

Correlation of 9G4 idiotope with disease activity in patients with systemic lupus erythematosus

OBJECTIVE To compare the levels of the 9G4 idiotope (9G4 Id) in systemic lupus erythematosus (SLE) patients with a detailed disease activity index, the British Isles Lupus Assessment Group (BILAG) index, and serological parameters of disease activity by ds DNA antibody levels and serum C3 concentrations. METHODS In a cross sectional analysis serum samples from 190 patients with SLE were studied and a further 55 serial bleeds from 14 patients. An enzyme linked immunosorbent assay was used to measure the 9G4 Id, and anti dsDNA and anti-myeloperoxidase (MPO) antibodies. The C3 levels were measured by laser nephelometer. RESULTS Seventy six of 190 (40%) of the patients tested had raised 9G4 Id levels. In the cross sectional study 9G4 Id levels were found to correlate with disease activity in the BILAG cardiovascular/respiratory renal, and haematological systems and with global BILAG score (p<0.01). In the serial bleeds 9G4 Id levels correlated with anti-dsDNA antibody and C3 levels, but not with anti-MPO antibodies. No correlations were found with treatment. In six cases the 9G4 Id levels correlated well with global BILAG scores and dsDNA antibody levels. In four cases the BILAG global and 9G4 Id levels alone correlated well. CONCLUSIONS Raised levels of the 9G4 Id are present in a substantial proportion of serum samples from patients with lupus, correlate with various aspects of disease activity in SLE. The Id is detectable on anti-dsDNA antibodies, though it must also be present on other immunoglobulins whose specificities remain unknown.

Disturbances in peripheral blood B cell subpopulations in autoimmune patients.

A variety of cell surface markers are being used to identify B cell subpopulations in peripheral blood. Currently at least eight subpopulationshave been identified. Analyses of healthy individuals indicate that in general the various B cell subpopulations exist in relatively similar ratios in unrelated individuals. It has been demonstrated that B lymphocyte homeostasis is disturbed during infection and autoimmune disease. In this review we compare the distribution of B cell subpopulations in the peripheral blood of patients with systemic lupus erythematosus, rheumatoid arthritis and primary Sjogrens syndrome with each other, and with healthy individuals. The different autoimmune diseases have distinct changes in the B cell subpopulations. Understanding the nature of these B subpopulation signatures will potentially impact understanding the mechanisms of disease, diagnosis and therapy.

Analysis of three new idiotypes on human monoclonal autoantibodies.

We have identified and characterised three new idiotypes on human IgM McAbs generated from the splenocytes of a SLE patient with active disease. RT-6, which binds H1 and Sm/RNP, expresses essentially a private Id. Its expression is limited to a small number of human McAbs and the sera from patients with infectious diseases. In contrast RT-72Id and RT-84Id, expressed on McAbs which are polyreactive for two or more antigens, have a public distribution. RT-72Id and RT-84Id are found on McAbs from murine and human adult, and foetal tissues. In sera, significant numbers of SLE, RA and patients with other autoimmune diseases are positive for both Ids. RT-84Id is also elevated in SLE relatives and spouses, and in patients with Klebsiella infection. No correlation with disease activity, IgM or IgG levels was observed with either Id. However, RT-72Id was significantly associated with anti-ssDNA antibodies and RhF. RT-6Id and RT-72Id are located on the framework regions of the μ heavy chain, whereas RT-84Id is present on the kappa light chain, within the binding site. The McAbs are encoded by mainly germline genes: heavy chains of RT-6, RT-72 and RT-84 are encoded by the genes VH26, VH4.22 and VH4.21, respectively, and the light chain sequences of RT- 6 and RT-72 are derived from DPL11 and HK102. Immunofluorescent staining revealed the presence of RT-72Id and RT-84Id positive immunoglobulin deposits in 18% and 45%, respectively, of the lupus renal sections compared with none in the disease control group, suggesting that these Ids may contribute to the pathology of the disease.

Review: Heat Shock Proteins and Systemic Lupus Erythematosus

This review briefly defines the heat shock proteins (hsps), their classification and their functions. The hypothesis that links hsps to the development of autoimmunity is explored, together with the rationale for investigation of the relationship between hsps and systemic lupus erythematosus (SLE). Thus, published work on this subject falls into three main categories: the overexpression of hsps in SLE, the development of autoantibodies to hsps in SLE, and the surface expression of hsps in peripheral blood mononuclear cells in SLE. This work is reviewed in detail. In conclusion, we describe areas for further study and outline ways in which this is being approached.

Analysis of immunoglobulin variable region genes of a human IgM anti-myeloperoxidase antibody derived from a patient with vasculitis

Circulating antibodies to myeloperoxidase (MPO) are associated primarily with pauci‐immune glomerulonephritis and systemic vasculitis. Anti‐MPO antibodies belong to a group of autoantibodies, anti‐neutrophil cytoplasmic antibodies, that may play a pathogenic role in vasculitis. We have generated a human monoclonal anti‐MPO antibody (E3‐MPO) using peripheral blood lymphocytes from a patient with microscopic polyarteritis. Variable region gene analysis of E3‐MPO showed that the VH region had 90% homology with the germ line gene VH4‐21. E3‐MPO was also shown to carry the 9G4 idiotope, which so far has been associated only with human antibodies that utilize the VH4‐21 gene. The 9G4 idiotope was also expressed on anti‐MPO antibodies in sera from the donor patient and from 4/7 additional patients with active, untreated vasculitis. The nucleotide sequences of both the variable heavy and light chains of E3‐MPO showed evidence of an antigen‐driven response.

The Expression of Heat Shock Proteins in Systemic Lupus Erythematosus

The heat shock response (HSR) was discovered in Drosophila buksii over 30 years ago [Ritossa 1962], and subsequently characterized by Tissieres et al [1974] who showed that it consisted of the rapid synthesis of a small number of new proteins - the heat shock proteins (hsps) - against a background of repressed general protein synthesis, upon exposure of organisms to a variety of insults. These include hypoxia, glucose deprivation or supplementation, amino acid analogues, oxygen free radicals, cytokines, heavy metals, calcium ionophores, ethanol and many infectious pathogens [Linquist 1986]. The common denominator appears to be the accumulation of unfolded or malfolded proteins in the cell [Gething and Sambrook 1992]. The HSR has been observed in all cell systems, tissues and organisms studied. There is a high degree of homology of hsps phylogenetically. They thus appear to have an important role to play in cell survival. This is borne out by the fact that both the protein-coding and the regulatory sequences of some heat shock genes have been very highly conserved throughout evolution. However, while the HSR is ubiquitous, it is also finely tuned and versatile.