James Cerilli

The Vascular Endothelial Cell Antigen System

Vascular endothelial cells (VEC) are clearly immunogenic and express antigens unique to vascular endothelial cells. The observation that peripheral blood monocytes also express this VEC antigen system made prospective testing feasible. Preformed antibody to the VEC/monocyte antigen system of the donor usually leads to graft rejection in HLA-identical combinations, but antibody directed against donor monocytes exclusively (monocyte-specific antigens) appears to be benign. Clearly the VEC antigen system is an important immunogen in HLA-identical living-related donor combinations—and, in addition, this antigen system may be equally important in the non-HLA-identical combinations. The identification of antibody directed against the VEC/monocyte antigens of the donor is frequently masked by the concurrent developmetn of anti-HLA antibody. Preliminary family segregation studies support the concept of genetic linkage between the VEC/monocyte antigen system and the major histocompatibility complex. A group of 153 consecutive, prospective monocyte crossmatches performed have yielded approximately a 7% incidence of positive monocyte crossmatches, with traditional crossmatches being negative. This frequency of patients sensitized to the VEC/monocyte antigens of the donor could conceivably account for up to 70% of the observed early graft loss in living-related donors. We think a positive monocyte crossmatch to the donor in the presence of positive reactivity to concordant VEC and monocytes remains a contraindication to transplantation.

Identification of the antibody to vascular endothelial cells in patients undergoing cardiac transplantation

Acute cardiac dysfunction occurred in four cardiac allograft recipients with negative donor-specific lymphocyte crossmatches. In two recipients the transplanted heart was removed and the patients were maintained on bypass for several hours until a second cardiac allograft was available. In these patients the second transplanted heart also underwent acute dysfunction. The lymphocyte crossmatch was again negative in both second transplants. Two of the four recipients had no detectable antibody to a panel of lymphocytes. Examination of the hearts demonstrated histologic findings consistent with hyperacute rejection. Direct immunofluorescence performed on the transplanted hearts revealed the presence of immunoglobulin and complement deposited on the vascular endothelium. Pathology data was available on 3 of the 4 patients who experienced acute cardiac dysfunction. Pretransplant sera from these four recipients were screened for the presence of antivascular endothelial cell (VEC) antibody. The sera from all four recipients were found to contain antibody against an endothelial cell panel. In addition, donor-specific aorta and vena cava were available from one of the heart donors. The recipient was found to have donor-specific antibody to VEC. Thus, antibody directed against VEC specific antigens appears to be related to hyperacute rejection of heart allografts.

Immunosuppressive metabolites of cyclosporine in the blood of renal allograft recipients.

Cyclosporine levels by radioimmunoassay (RIA) and high-performance liquid chromatography (HPLC) were monitored in serial blood samples (n = 177) from 11 renal allograft recipients. HPLC analysis revealed three primary metabolites of CsA (M17, M1, and M21) in peak and trough blood samples; M17 was the preponderant metabolite. In 4 patients on whom serial metabolite assays were performed, M17 was found in the blood at 86-2004 ng/ml; M1 and M21 were found at up to 100 ng/ml. The immunosuppressive properties of purified metabolites M1, M17, M21, and M8 (which was not detected in the blood) were compared with CsA. M17--and, to a lesser extent, M1 and M21--were found to inhibit the in vitro response of human mononuclear cells in the mixed leukocyte culture and in mitogen (phytohemagglutinin [PHA], concanavalin A [Con A], and pokeweed mitogen [PWM]) assays at 1000 ng/ml. M8 exhibited no in vitro inhibitory activity. M17 was further tested at 10-1000 ng/ml in PHA and mixed lymphocyte culture (MLC) assays. M17 had considerably less inhibitory activity (12-43%) than CsA (18-70%) in the PHA assay. However, in MLC experiments M17 blocked the proliferative response by 39-72% at 100-800 ng/ml, which approached the degree of inhibition exhibited by CsA (63-87%). In 34 of 37 (92%) patient blood samples, the level of metabolite M17 was found to exceed the parent drug level and could not be measured accurately by RIA. The observed in vitro immunosuppressive activity of metabolites (particularly M17) and their presence in the blood of renal allograft recipients suggest a possible role for these metabolites in the immunopharmacology of CsA.

Role of the vascular endothelial cell antigen system in the etiology of atherosclerosis.

An autoantibody directed against an antigen system that is expressed on the vascular endothelial cell (VEC) was recently identified in random patients with peripheral vascular disease. This VEC antigen system is also present on the peripheral blood monocyte but not on any other cell type studied to date. In a randomized study of 112 patients with peripheral vascular disease at the Albany Medical College, 46% demonstrated an autoantibody against their autologous monocytes and VEC. This autoantibody is a highly cytotoxic, complement-fixing antibody directed against VEC antigens. It does not crossreact with autologous T or B lymphocytes and appears to be highly polymorphic. It is present in only nine per cent of the age-matched controls and was never detected in young controls. This preliminary investigation suggests that immunological injury may be the initiating factor in the development of atherosclerotic lesions more frequently than currently appreciated. Whether this autoantibody to VEC is the result of or the cause of endothelial cell damage in these patients is still under study.

The significance of a donor-specific vessel crossmatch in renal transplantation.

Very early graft rejection is usually attributed to pretransplant sensitization to HLA antigens represented on the lymphocyte. However, it is possible that such rejection episodes are secondary to antibody to a transplant-relevant system that is not represented on the lymphocyte but is represented within the allograft. This study suggests that sensitization to antigens on the VEC is detrimental to allograft success and can occur in the absence of sensitization to HLA antigens on the T or B cell or monocyte. When antibody to donor VEC is not present pretransplant, almost all patients (95%) will have a very benign posttransplant clinical course. When anti VEC antibody is present, early graft rejection or severe rejection episodes occur with a very high frequency (80%) in the nondiabetic patient. These observations, therefore, suggest that the pretransplant presence of antibody to VEC is detrimental to graft survival, and that such antibody can develop in the absence of anti HLA antibody. While the presence of such antibody is not an absolute contraindication to transplantation it does appear to represent a significant risk factor for immunological graft loss.

Correlation of tissue typing, mixed lymphocyte culture, and related donor renal allograft survival.

Results of mixed lymphocyte culture reactions and tissue typing were correlated with the clinical courses of recipients of living related donor renal allografts. Forty-nine patients tested by the mixed lymphocyte culture technique were divided into two response groups: stimulation index greater than 5 and stimulation index less than 5. Seventy patients were tested by standard tissue typing methods and were categorized by the number of misstimulation in mixed lymphocyte culture than with mismatched antigens, suggesting that lymphocyte-defined histocompatibility is more important than serologically defined histocompatibility in selecting the best possible allograft donor.

The effect of combined immunosuppressive agents and cell-free antigen on xenograft survival.

SUMMARY Mice receiving rat skin grafts were treated with the immunosuppressive agents procarbazine, rabbit antimouse lymphocyte serum (RAMLS), and acriflavine, either alone or in combination with each other. Although the three drugs had different toxicities, overimmunosuppression and high mortality in the absence of drug-specific toxicity resulted when the agents were used together. In an attempt to avoid this high mortality, the three drugs were administered in varying dosages and combined with cell free antigen (CFA). The results indicate that CFA leads to more prolonged graft survival when combined with varying dosages of the three drugs. The presence of acriflavine. a known suppressant of antibody formation, appears necessary for CFA to be an effective adjuvant

An immunological study of renal allograft rejection using the direct macrophage inhibition test.

The direct macrophage inhibition test was used to evaluate the relationship between cellular immune response and graft rejection in related renal allograft recipients. Forty recipients were evaluated before and at regular intervals after transplantation while on maintenance immunosuppressive therapy. Allograft recipients were classified into four categories: 1) Non-HL-A-identical with a rejection episode (14 patients); 2) non-HL-A-identical without a rejection episode (13 patients); 3) HL-A-identical with a rejection episode (3 patients); 4) HL-A-identical without a rejection episode (10 patients). Ten HL-A-identical sibling pairs in good health were utilized as controls. Cellular immunity against donor antigen (macrophage inhibition > 20%) uniformly occurred in 16 of the 17 patients who experienced episodes of rejection in both the HL-A-identical and nonidentical graft recipient groups. Transplant recipients who did no experience any rejection episodes up to 2 years post-transplant, and members of the HL-A-identical control group had negative inhibition tests. In 5 cases changes in cellular immune response preceded rejection by several days. The two recipients with positive macrophage inhibition to their prospective donors before transplantation experienced irreversible accelerated rejection. Thus, the direct macrophage inhibition test can be used to screen prospective related donors and to monitor cellular immunity in recipients after transplantation. Preexistent cellular immunity to the donor detected before transplantation correlates with a very high incidence of rejection episodes. Graft recipients who experienced no rejection episodes failed to develop cellular immunity to their donors.

SIGNIFICANCE OF MIGRATION STIMULATORY FACTOR IN HUMAN RENAL ALLOTRANSPLANTATION

SUMMARY Seventy-four recipients of related donor renal allografts were tested for the presence of cellular immunity to specific donor lymphocyte antigens using the direct migration inhibition factor (MIF) assay. Responses on the assay fell into one of the following three statistically distinct groups: (1) greater than 20% inhibition of macrophage migration, (2) nonresponsiveness, 10% of control migration, and (3) greater than 12% stimulation of macrophage migration. Migration stimulation was shown to be reproducible and to correlate well with a very benign post-transplant clinical course. The production of migration stimulatory factor appears to be an immunological response analagous to the production of migration inhibition factor.

The incidence of infection in neuroblastoma patients receiving chemotherapy

Abstract The hospital records of 32 neuroblastoma patients diagnosed during a 6-yr period were reviewed, with special emphasis on a comparison of the incidence of infection in patients receiving chemotherapy and those not receiving the treatment. Examination of the records of the survivors and comparison of their frequency of infection both while receiving and not receiving the treatment indicate that the administration of chemotherapy may be related to an increased incidence of infection in these patients.