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M R Ehrenstein

Publications and source records attributed to M R Ehrenstein.

33 records · Page 2Linked to original sources
PubMed1996

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.

Adult↗
PubMed1995

Human IgG anti-DNA antibodies deposit in kidneys and induce proteinuria in SCID mice.

We investigated the capacity of five human monoclonal IgG anti-DNA antibodies derived from lupus patients to produce glomerular immune deposits. The hybridomas secreting these antibodies were administered intraperitoneally to severe combined immunodeficiency (SCID) mice. Three of the five antibodies (B3, 35.21, 33.C9) were detected in the kidneys, but only one (33.C9) deposited exclusively in the glomeruli in the mesangium and capillary wall, whereas the other two antibodies bound to nuclei both in the kidney and in other organs. The antibodies were tested against a variety of autoantigens by ELISA, the only unique feature of 33.C9 was that it also bound strongly to histones. There were no particular amino acid motif that was related to immunoglobulin deposition in the kidney. All the mice that had immunoglobulin deposited in the kidney, either extracellularly or intranuclearly developed 2 to 3+ proteinuria, whereas the other mice had only trace amounts of proteinuria. This study demonstrates that some human monoclonal IgG anti-dsDNA antibodies are capable of binding to the glomerulus while others can penetrate cells and bind to nuclei in vivo. Although no abnormal pathology was observed, proteinuria was detected, perhaps representing an early phase of disease. These results indicate that the affinity for dsDNA is not the sole determining factor governing the biological properties of human anti-DNA antibodies in vivo.

Animals↗
PubMed1995

The occurrence, nature and distribution of flares in a cohort of patients with systemic lupus erythematosus: a rheumatological view.

This study examines the occurrence, nature and distribution of disease flares in systemic lupus erythematosus (SLE) according to organ involvement. One-hundred-and-fourteen patients were seen in the Lupus Clinic of the Bloomsbury Rheumatology Unit over a 3-yr period. At each visit a data sheet was completed to assess their disease activity in eight separate organs/systems according to the British Isles Lupus Assessment Group (BILAG) activity index. This information was entered into a computer and a score for each organ system was obtained. The record of each individual patient was examined to identify flares in the individual organs; 458 flares occurred in 107 patients. The majority of patients (69%) experienced more than one flare during the study period. Fifty-four per cent of patients had flares in more than one system simultaneously, but the majority (70%) of flares involved only one system. The most severe organ involvement (A score) was most commonly observed in the musculoskeletal system, whereas severe renal disease occurred only three times. These results indicate that although SLE is a multisystem disease, the flares that occur tend to be confined to one system at a time. Further, these results demonstrate that in our rheumatology practice the most common 'A' flare observed was severe polyarthritis (A score in musculoskeletal).

Adult↗
PubMed1994

Comparison of a monoclonal and polyclonal anti-idiotype against a human IgG anti-DNA antibody.

Over the last decade a number of idiotypes (Id) have been identified on monoclonal IgM anti-DNA antibodies which represent germ-line genes. This study describes two new idiotypes present on a monoclonal human IgG anti-DNA antibody, D5 derived from a patient with active SLE. The two idiotypes, designated D5-RId and D5-MId, are defined by a polyclonal and monoclonal anti-Id respectively. Both anti-Ids inhibited each other's binding to D5 in an ELISA and did not bind to human IgG. Using western blotting the D5-RId was located on the light chain whereas the D5-MId bound to conformational determinants; both idiotypes were close to or at the binding site for DNA. The anti-Id reagents were used in ELISAs to screen human sera and tissue samples for the presence of the D5-MId and the D5-RId. The upper limit of normal for sera in the D5-MId ELISA was much lower than the D5-RId ELISA indicating a greater degree of specificity in the former. The idiotypes were found only in the IgG fraction of the sera. About 30% of SLE patients had either the D5-MId or the D5-RId and 20% had elevated levels of both, showing a considerable overlap in the expression of the two idiotypes. This overlap was also observed in the other disease groups including patients with other autoimmune diseases, though the numbers of patients expressing the idiotypes were significantly lower than in the SLE group. The idiotypes were present on both DNA binding and non-DNA binding fractions of lupus sera. D5-MId was present in 6/10 renal lupus biopsies and only in 2/15 disease control renal biopsies in which immunoglobulin was deposited. D5-RId did not stain any sections. There is a close correlation between the presence of the D5-MId and D5-RId in SLE sera and the level of expression. It is evident that both idiotypes are associated with SLE and are markers of a population of IgG anti-DNA antibodies, the isotype associated with active disease. Since the idiotypes are not found on IgM antibodies they are likely to be generated by somatic mutation.

Animals↗
PubMed1994

Serological and genetic characterization of a human monoclonal immunoglobulin G anti-DNA idiotype.

This study analyzed the distribution of an idiotype, B3-Id, in patients with active SLE, classified according to organ involvement, normal controls, and other autoimmune rheumatic diseases. A polyclonal anti-idiotype was raised by immunizing a rabbit with a monoclonal IgG anti-double-stranded (ds) DNA antibody, B3, generated from a patient with SLE who had active arthritis. The idiotype is present on the lambda chain and is at or near the binding site for double-stranded DNA. The lambda chain, which was characterized by nucleotide sequencing, was 90% homologous to the V lambda 2.1 germline, which is known to be involved in coding for nephritogenic anti-DNA antibodies carrying the 8.12 idiotype. There were four changes to positively charged amino acids, known to be involved in DNA binding, in the complementarity determining regions of B3 lambda chain compared with a non-DNA binding, 8.12 positive antibody, PV11. Only one change to a positively charged amino acid occurs in the heavy chain of B3, which is 93.5% homologous to VH-26. The B3-Id was present on IgG antibodies in the serum of 20% of patients with SLE but was not found in the normal controls. Within the SLE group, there is a statistically significant association of B3-Id on IgG in the arthritis group (42%) compared to the other manifestations (9%) (P < 0.001). In four B3-Id-positive SLE patients tested serially, the level of B3-Id reflected the arthritis disease activity more closely than the overall disease activity (P < 0.05). The B3-Id was also present on IgM antibodies in one third of patients with rheumatoid arthritis. This idiotype is the first to be derived from a human monoclonal anti-DNA antibody of the IgG class, the isotype associated with active disease. Sequence analysis shows that positively charged amino acids on the lambda chain may contribute to DNA binding.

Adult↗
PubMed1993

Anti-DNA antibodies in the primary antiphospholipid syndrome (PAPS)

Primary antiphospholipid syndrome (PAPS) is considered a distinct entity from SLE and patients with PAPS are generally regarded as being dsDNA antibody negative. Levels of IgG and IgM ss and ds DNA antibodies were measured by ELISA in 30 patients who fulfilled the criteria for the diagnosis of PAPS. We compared these patients with 20 normal controls and seven patients with idiopathic SLE. We also examined all the sera for anti-nuclear antibodies by Hep-2 cells and for dsDNA antibodies by Crithidia. We found that 16 patients with PAPS had antibodies to ss and/or dsDNA. Only three of the 16 positive patients had both IgG and IgM anti-DNA antibodies. Twelve patients had anti-nuclear antibodies, but only two were weakly positive for dsDNA antibodies by Crithidia immunofluorescence. Eleven out of 30 patients with PAPS had IgM anti-dsDNA antibodies compared to two out of the seven SLE patients. The PAPS patients with anti-DNA antibodies were clinically indistinguishable from the PAPS patients without antibodies against DNA. Our results show that 53% of patients with PAPS had antibodies to DNA which supports the view that PAPS and SLE are probably overlapping disorders.

Antibodies, Antinuclear↗
PubMed1992

Idiopathic myositis: a rheumatological view.

Twenty five patients with idiopathic myositis attended this department for long term follow up from 1980 to 1989. Twelve patients had primary polymyositis (four men, eight women) and six had primary dermatomyositis (three men, three women); five women had an overlap syndrome. Two patients had a malignant condition associated with the myositis. The mean age at diagnosis was 40 years. All of the patients had proximal muscle weakness, 18/25 had a raised creatine kinase value (mean 2325 IU/l), 19/20 had an abnormal electromyogram, and 19/24 had positive muscle biopsy samples. Of the disease specific antibodies, anti-Jo-1 was detected in only 1/21 patients tested (three patients with fibrosing alveolitis were negative for this antibody), but the 56 kDa antibody was detected in 12/17 patients. The HLA data analysed in the white patients (17/25) showed that 6/8 of those tested were HLA-DR3 positive. All patients were treated with prednisolone and azathioprine was used for 14/25 patients. Only three deaths occurred during the eight year follow up, but there was a substantial morbidity, which may reflect the referral pattern. Muscle strength tests and creatine kinase levels were useful in recording the response to treatment in some patients. These data emphasise that careful long term follow up of patients with myositis is mandatory and that although the present treatment strategy has substantially reduced the death rate, morbidity associated with the disease remains a major problem.

Adolescent↗
PubMed1992

Production of human monoclonal antibodies to myeloperoxidase.

Two mouse-human heterohybridomas secreting human antibodies to myeloperoxidase (MPO) were derived from the peripheral blood of a patient who developed microscopic polyarteritis as the result of long-term treatment with hydralazine. Forty-five immunoglobulin-secreting lines were obtained from the fusion of patient lymphocytes with the CB-F7 heteromyeloma cell line. Of these, two antibodies, one IgG and one IgM, bound to myeloperoxidase in solid phase ELISA and gave a perinuclear staining pattern on ethanol-fixed human neutrophil cytospin preparations. The staining patterns were similar to those seen with serum from the patient. Antigen-inhibition studies revealed that the affinity of the IgG monoclonal antibody was 28 times higher (k = 1.4 x 10(-7)) than the IgM antibody (k = 5 x 10(-5)). Cross-inhibition studies further suggested that the two monoclonal antibodies recognized the same epitope on MPO. Of the other secreting cell lines, none produced antibody which reacted with the panel of autoantigens used for testing. Neither mononuclear antibody reacted with this panel indicating that they were not simply polyreactive natural autoantibodies. These are the first human monoclonal antibodies to native myeloperoxidase to be reported.

Animals↗
PubMedDate not supplied

Diversification and selection mechanisms for the production of protein repertoires: lessons from the immune system.

The physiological mechanism for producing antigen-specific antibodies is based on a two-phase neo-Darwinian process: the first phase consists of diversity generation (formation of the repertoire), and the second phase is antigen-mediated selection. In this article, we consider how the natural immunoglobulin gene-diversification processes can be exploited both in vivo and in vitro in order to allow the generation of novel antibody (and heterologous protein) repertoires.

Animals↗