Plasma cell depletion with bortezomib in the treatment of refractory N-methyl-d-aspartate (NMDA) receptor antibody encephalitis. Rational developments in neuroimmunological treatment.

BACKGROUND AND PURPOSE: The aim was to assess the therapeutic potential of bortezomib in the treatment of refractory N-methyl-d-aspartate receptor (NMDAR) antibody encephalitis and its potential in other immune-mediated, B-cell-driven neurological diseases. METHODS: Two cases of severe NMDAR antibody encephalitis, resistant to first and second line therapy with steroids, intravenous immunoglobulins, plasma exchange, cyclophosphamide and rituximab, were treated with four and five cycles of 1.3 mg/m2 bortezomib at 350 and 330 days following initial presentation. RESULTS: Both patients showed significant clinical improvement with reductions of NMDAR antibody titres following bortezomib treatment. This is the first case in the literature where the NMDAR antibody level was undetectable following treatment with bortezomib. CONCLUSION: Bortezomib's unique ability to target long-lived autoreactive plasma cells appears to be a useful adjunct to standard second line immunosuppressive therapy in treatment-refractory NMDAR antibody encephalitis. The drug's pharmacodynamics, cell targeting and mechanism of action are reviewed, and it is postulated that bortezomib may be useful in a host of B-cell-driven neuroimmunological diseases.

Antibodies to endothelial cells identify myocardial damage and predict development of coronary artery disease in patients with transplanted hearts.

BACKGROUND: Transplant-induced coronary artery disease is a leading cause of graft failure in cardiac allograft recipients after the first year of transplantation, but there presently is no test to identify patients at high risk for developing the disease. Our research is focused on development of a predictive test to identify patients at high risk of developing the disease. METHODS: Sixty-eight cardiac allograft recipients transplanted and followed at Methodist Hospital between 1982 and 1996 were studied. Serial annual angiograms were used to diagnose coronary artery disease, and serial endomyocardial biopsies were used to detect cellular infiltrates and microvascular disease. Biopsy-matched serum samples were used for cardiac troponin-T determinations as measures of myocardial damage, and serum antibodies to endothelial cells were determined by using flow cytometry, enzyme-linked immunosorbent assay and immunoblotting techniques. The endothelial antibody data were evaluated statistically for associations with angiographic changes, biopsy findings and biochemical evidence of myocardial damage. FINDINGS: Antibodies to endothelial cells were identified by all three techniques, and significant associations were found for the amount of antibody identified by Western immunoblotting with histological rejection grades in biopsies, which were confirmed immunocytochemically as macrophages (p<0.01) and T lymphocytes (P = 0.03). These antibodies also associated significantly with vascular antithrombin depletion (p = 0.02), biochemical evidence of myocardial damage (p = 0.005) and subsequent development of coronary artery disease (p = 0.03). INTERPRETATION: The significant association of anti-endothelial antibodies with cellular infiltrates, depletion of vascular antithrombin and myocardial damage suggests a role for antibody in the development of transplant-induced arteriopathy. The significant association of antiendothelial antibodies with the future development of coronary artery disease further suggests that assessment of these antibodies may provide a non-invasive test to predict the development of transplant-induced coronary artery disease.

Antiendothelial antibodies after heart transplantation: the accelerating factor in transplant-associated coronary artery disease?

Although the precise cause of transplant-associated coronary artery disease is unknown, immune mechanisms have been implicated. Using the techniques of SDS-PAGe and Western immunoblotting, we have previously shown that a strong positive correlation exists between the development of coronary artery disease and the presence of antiendothelial antibodies reactive with a doublet of polypeptides of approximately 60 and 62 kDa. We have now extended this study to investigate the temporal pattern of antiendothelial antibody formation after transplantation and its association with cellular rejection episodes. The original study used patients in whom coronary artery disease had developed early after transplantation, that is at 1 or 2 years. Here we investigate whether antiendothelial antibodies are also made in patients in whom the disease does not develop until 5 to 10 years after heart transplantation and whether the antibodies are found in patients with severe nontransplant atherosclerosis. We confirm the 60 to 62 kDa antigens are membrane bound, and recalculation of their molecular mass makes the doublet 56 and 57.5 kDa. The results show that antibodies specific for the doublet of endothelial antigens are rarely produced by patients other than those in whom rapidly progressing coronary artery disease develops early after transplantation. The antibodies are unrelated to cellular rejection episodes. We believe their production may be an accelerating factor for the rapid development of transplant-associated coronary artery disease.

Pre-transplant anti-epithelial cell antibodies and graft failure after single lung transplantation.

Eighty-five patients undergoing single lung transplantation have been studied to determine the presence of anti-epithelial cell antibodies (AECA) prior to transplantation using the human lung carcinoma epithelial cell line A549 in a microcytotoxicity assay. In addition, 29 healthy volunteers were also assayed for the presence of AECA. Twenty-seven of the 85 recipients exhibited AECA prior to transplantation compared to none of the 29 control subjects (p = 0.0001). Actuarial graft survival at 1 year was 78% for the AECA negative group compared to 56% for AECA positive recipients (p = 0.01). No correlation was seen between the presence of AECA and graft rejection as determined by transbronchial biopsy. However, there was an association between AECA and post-transplant infection (p = NS) where 16 (64%) of the AECA positive recipients had postoperative infection episodes compared to 25 (47%) of the negative recipients. Sodium dodecylsulphate polyacrylamide gel electrophoresis and Western blotting was also performed for 68 of the recipients and antibody reactivity was detected in 22 patients compared to 26 patients exhibiting AECA detectable by microcytotoxicity. The presence of AECA demonstrable by Western blotting did not correlate with graft survival, rejection or infection. In conclusion, AECA detectable prior to single lung transplantation are associated with a decrease in graft survival and with postoperative infections.

Anti-endothelial antibodies and coronary artery disease after cardiac transplantation.

Accelerated coronary artery disease is the most serious complication after cardiac transplantation. The disease has a multifactorial aetiology, with little agreement about the relative importance of the various risk factors. We have investigated the frequency of anti-endothelial antibodies against human umbilical vein endothelial cells by one-dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis and western blotting. Peptide-specific anti-endothelial antibodies were found in 15/21 heart transplant recipients with accelerated coronary artery disease, and 1/20 transplant patients who had not developed the disease. Positive immunofluorescence of patients' serum on frozen sections of coronary vessels confirmed the endothelial specificity of antibodies. These results provide evidence of an immune aetiology for transplant-associated coronary artery disease and could have important implications for its diagnosis and therapy.

Donor ACE gene polymorphism: a genetic risk factor for accelerated coronary sclerosis following cardiac transplantation.

AIMS: To investigate the role of angiotensin converting enzyme (ACE) (I/D) gene polymorphism in the development of coronary sclerosis after cardiac transplantation. METHODS AND RESULTS: Eighty cardiac transplant recipients (44 transplant associated coronary artery disease; 36 non-transplant associated coronary artery disease) and their donors were genotyped by polymerase chain reaction. The allele frequencies of the recipients in the transplant associated coronary artery disease and non-transplant associated coronary artery disease groups (I = 0.47 and 0.48, D = 0.53 and 0.52, respectively) did not differ significantly between the groups. However, there was a negative association between the frequency of the I allele in the donor and the development of transplant associated coronary artery disease. The D allele in the donor population of the non-transplant associated coronary artery disease group had a significantly (P < 0.01) lower frequency (0.35) than either the transplant associated coronary artery disease group (0.53) or that of the general population (0.57). Other factors analysed were recipient family history, cholesterol levels, age, sex and body mass index, donor age and acute rejection, of which the significant (P < 0.05) factors were acute rejection and sex of the recipient. CONCLUSION: These results suggest that the ACE genotype of the donor organ may be an additional risk factor for the development of coronary artery disease following cardiac transplantation and that tissue rather than circulating ACE could be implicated in the pathogenesis of this disease.