Propagation of alloreactive lymphocytes from histologically negative endomyocardial biopsies from heart transplant patients. Association with subsequent histological evidence of allograft rejection

Endomyocardial biopsies from heart transplant patients were cultured in vitro in the presence of Interleukin-2 and irradiated feeder cells to propagate graft-infiltrating lymphocytes. A correlation was seen between the frequency of lymphocyte growth and the degree of cellular infiltration of the biopsies. In this study, 43 of 113 (38%) histologically negative biopsies obtained from 55 patients during the first month post-transplant yielded lymphocyte cultures. The cumulative incidence of subsequent histological rejection was considerably higher in patients with such "grower" biopsies than in patients with "nongrower" biopsies. In the grower group, we were able to obtain data on alloreactivity of 32 lymphocyte cultures assayed by primed lymphocyte testing (PLT). The presence of donor-specific PLT reactivity in the cultured lymphocytes was associated with an additional risk for subsequent histological rejection. These findings suggest that the in vitro culturing of histologically negative endomyocardial biopsies will identify patients at increased risk for developing heart transplant rejection.

Adherence of alloreactive lymphocytes to human arterial endothelial cell monolayers

Early events of cellular infiltration during allograft rejection involve interactions between alloreactive lymphocytes and vascular endothelium. These interactions have been studied in an in vitro model of lymphocyte adherence to human arterial endothelial cell (HAEC) monolayers. Alloreactive lymphocytes primed against donor HLA antigens (DPL) or unrelated HLA antigens from a third party (TPL) were studied for their adherence to HAEC derived from organ transplant donors. DPL exhibited a degree of adherence to donor HAEC which was nearly twice that of the TPL population and developed a morphologically blastoid appearance. DPL adherence was dependent on the recognition of donor HLA antigens expressed on the HAEC surface and investigation of DPL and TPL adherence at various lymphocyte concentrations showed that the binding of DPL and TPL to HAEC was saturable. Monoclonal antibody (MoAb) directed against HLA class I antigens showed inhibition of only DPL adherence to HAEC monolayers expressing donor class I HLA antigens, whereas MoAb directed against other HAEC surface antigens failed to inhibit either the DPL or TPL populations. The results of this study suggest that in a transplant situation, lymphocyte activation and adherence to the graft endothelium is increased in the context of allorecognition.

Suitability of liquid-stored donor platelets in platelet compatibility testing

Current platelet crossmatch procedures to select compatible donors for alloimmunized thrombocytopenic patients are hampered by the lack of a convenient platelet storage method. This study examined the feasibility of using washed apheresis donor platelets stored for up to 1 year in a modified Hank's buffer solution at 4 degrees C as crossmatch reagents in an indirect IgG-enzyme immunoassay. Pooled and monospecific HLA and PlA1 antisera were used to determine the antigenic reactivity of donor platelets in relation to duration of storage. There were no significant differences between mean HLA and PlA1 antigen expression in fresh and stored platelets. HLA reactivity was detected on 12 of 13 donor platelet samples stored for 3 to 9 months and on 14 of 17 platelets stored for 12 to 14 months. PlA1 reactivity was maintained at 12 to 14 months for all 12 donor platelet samples tested. In addition, incompatibility remained in 23 of 24 paired fresh and stored platelet crossmatches using individual alloimmunized patient plasmas. These data indicate that both HLA and platelet-specific PlA1 antigen reactivity can be maintained adequately in liquid storage at 4 degrees C for up to 1 year. The availability of a convenient platelet storage method should facilitate the general application of platelet crossmatching procedures for alloimmunized patients.

Lymphocyte growth from cardiac allograft biopsy specimens with no or minimal cellular infiltrates: association with subsequent rejection episode

Histologic features of endomyocardial biopsy specimens are essential in the monitoring of heart transplant patients. Significant cellular infiltrates accompanied by myocyte damage are diagnostic of transplant rejection, whereas no or minimal infiltrates (grades 0 and 1) suggest absence of rejection. Biopsy specimens were cultured on the basis of the principle that the allograft is infiltrated by activated lymphocytes, which can be expanded in the presence of interleukin-2, a lymphokine that induces proliferation of activated T cells. Although frequency of cell cultures was proportional to histologic rejection grade, 39% of biopsy specimens with grades 0 and 1 cultured during the first month posttransplantation yielded lymphocyte growth. Cell growth was observed in 28% of biopsy specimens with grades 0 and 1 obtained during the first 10 days posttransplantation. In this group (growers) 73% showed clinical rejection after 9.8 +/- 5.0 days. In contrast, 55% of nongrowers were treated for rejection after 19.1 +/- 13.8 days. For biopsy specimens obtained 11 to 20 days posttransplantation, subsequent rejection episodes were observed in 61% of growers, but in only 33% of nongrowers. For biopsy specimens obtained 21 to 30 days posttransplantation the incidence of clinical rejection was 60% versus 14%, respectively. A sequential analysis of biopsy specimens obtained during the first month posttransplantation enabled us to identify 16 persistent nongrowers; only 6 (37%) experienced clinical rejection during the first 3 months posttransplantation. Most of the persistent nongrowers were found among patients on the immunoprophylactic rabbit antithymocyte globulin protocol. These data suggest that in vitro cultures of biopsy specimens with no detectable or minimal cellular infiltration may be useful in identifying patients at risk of developing rejection.

Intraoperative blood transfusions in highly alloimmunized patients undergoing orthotopic liver transplantation

Intraoperative blood requirements were analyzed in patients undergoing primary orthotopic liver transplantation and divided into two groups on the basis of panel reactive antibody of pretransplant serum measured by lymphocytotoxicity testing. One group of highly sensitized patients (n = 25) had PRA values of over 70% and the second group of patients (n = 26) had 0% PRA values and were considered nonsensitized. During the transplant procedure, the 70% PRA group received considerably greater quantities of blood products than the 0% PRA group--namely, red blood cells: 21.1 +/- 3.7 vs. 9.8 +/- 0.8 units (P = 0.002), and platelets: 17.7 +/- 3.2 vs. 7.5 +/- 1.5 units (P = 0.003). Similar differences were observed for fresh frozen plasma and cryoprecipitate. Despite the larger infusion of platelets, the blood platelet counts in the 70% PRA group were lower postoperatively than preoperatively. Twenty patients in the 70% PRA group received platelet transfusions, and their mean platelet count dropped from 95,050 +/- 11,537 preoperatively to 67,750 +/- 8,228 postoperatively (P = 0.028). In contrast, nearly identical preoperative (84,058 +/- 17,297) and postoperative (85,647 +/- 12,445) platelet counts were observed in the 17 0% PRA patients who were transfused intraoperatively with platelets. Prothrombin time, activated partial thromboplastin time, and fibrinogen levels showed no significant differences between both groups. These data demonstrate that lymphocytotoxic antibody screening of liver transplant candidates is useful in identifying patients with increased risk of bleeding problems and who will require large quantities of blood during the transplant operation.

HLA antigen expression on cultured human arterial endothelial cells

Flow cytometric analysis and cellular assays were used to determine constitutive and induced expression of class I HLA antigens and class II antigens encoded by the HLA-DR, -DQ and -DP subregions on cultured human arterial endothelial cells (HAEC) derived from transplant donors. Class I but no or minimal quantities of class II HLA antigens were found on HAEC. Prior incubation of HAEC with gamma-IFN increased class I HLA antigen expression and induced class II HLA antigen expression on HAEC. The induced expression of HLA-DQ was lower than that of HLA-DR, but both were significantly reduced in comparison to the frequency of these antigens on EBV transformed lymphoblastoid cell lines derived from the same donor. In addition, supernatants from class I and class II alloreactive clones were shown to induce class II antigen expression on HAEC. By PLT analysis, it was shown that these antigens are functionally capable of generating a lymphocyte response. In this regard, HAEC have proved to be a helpful tool in designing in vitro lymphocyte-endothelial cell studies.

Immunologically mediated disease of the airways after pulmonary transplantation

Obliterative bronchiolitis has occurred in eleven of 30 recipients of cardiopulmonary allografts who survived at least 4 months after transplantation, has caused significant morbidity, and has been associated with four of eleven late deaths in this series. Although some improvement, or at least stability, of pulmonary function has followed augmented immune suppression, it appears that once the process is recognized clinically, much of the damage to the airways is irreversible. The histopathology, response to therapy, and, most important, the response of donor specific alloreactivity in the lymphocytes from the lung (bronchoalveolar lavage and peripheral blood) suggest immune- mediated basis for bronchiolitis obliterans. The presence of donor specific alloreactivity detected by primed lymphocyte testing predicted obliterative bronchiolitis in five of six recipients (83% sensitivity, 91% specificity) was absent in ten of eleven recipients who have not as yet developed the process (negative predicted value of 91%). Currently, the presence of a positive primed lymphocyte test in the bronchoalveolar lavage of the cardiopulmonary recipient is an indication for early treatment by augmented immune suppression.

Histocompatibility and liver transplant outcome. Does HLA exert a dualistic effect?

An analysis of more than 500 liver transplants has demonstrated that HLA compatibility is associated with diminished allograft survival. Liver transplants with zero mismatches for class I and/or class II HLA antigens have shown significantly lower actuarial survival rates than transplants with one or more mismatches for these loci. In a group of 119 failed liver allografts from patients undergoing retransplantation, a higher incidence of failure due to rejection correlated with a lower degree of HLA compatibility especially for HLA-DR. In contrast, the incidence of liver transplant failures due to primary nonfunction was relatively higher with HLA-DR compatible transplants. Considering the role of HLA as a restriction element in cellular interactions during the immune response, these findings suggest that HLA compatibility may have a dualistic effect on liver transplant outcome. On one hand, HLA compatibility reduced transplant rejection--and on the other hand, it may enhance other immunological mechanisms leading to allograft dysfunction, particularly in patients at risk of developing recurrent autoimmune diseases or infection.

Unexpectedly high incidence of Pneumocystis carinii infection after lung-heart transplantation. Implications for lung defense and allograft survival

Pneumonia due to Pneumocystis carinii (PCP) is regularly encountered in organ allograft recipients who are immunosuppressed to prevent rejection. Recipients of lung/heart allografts may be particularly prone to pulmonary infection due to systemic immunosuppression and the fact that defense mechanisms in the transplanted lung may be further impaired through tissue incompatibility and the effects of surgery. In this study, we monitored 16 lung transplant recipients for infection with Pneumocystis carinii using serial bronchoalveolar lavage (BAL) and found the prevalence of Pneumocystis infection of the lung to be 88%. Six episodes were associated with the usual symptoms of pneumonia, whereas 10 episodes were associated with minimal or no symptoms. In 3 of the 6 symptomatic episodes, a concurrent bacterial infection was also found. The total number of cells recovered from the lung by BAL, the proportion of T-lymphocytes, and the number of cytotoxic/suppressor and helper/inducer cells were elevated during infection with Pneumocystis compared to before and after. Spontaneous and interleukin-2-induced proliferation of BAL cells in vitro was also higher during infection, suggesting that there was an increased number of activated T-lymphocytes in the airspaces of the infected allograft. BAL cells cultured with irradiated spleen cells from the donor proliferated at higher levels when obtained after Pneumocystis infection than when obtained before or during infection even for subclinical infections. These results indicate that in the absence of prophylaxis, the prevalence of Pneumocystis infestation is very high after lung/heart transplantation. Impaired defense of the transplanted lung does not seem to stem from the inability of activated T-lymphocytes to accumulate in the allograft.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunological factors influencing liver graft survival

Donor-recipient ABO blood group mismatching is associated with a decreased graft survival rate in liver transplantation. We have been unable to demonstrate an effect of high levels of panel reactive antibody or a positive donor-specific cytotoxic antibody cross-match on graft survival. A limited analysis of HLA-matching for the A, B, and DR loci suggests a paradoxical effect, but much more experience is needed before the true effect of HLA matching on graft outcome can be reliably evaluated.

Adult rheumatoid arthritis is associated with MC1, a new HLA-D encoded determinant

We evaluated the association of a new HLA-D encoded determinant, MC1, with adult rheumatoid arthritis (RA). This determinant associates with DR1 and DR4 and can be defined by serological typing. We found MC1 in 83% of 80 patients with RA vs 43% of controls. Although the frequencies of DR1 and DR4 were both significantly increased in patients with RA compared with controls, MC1 had the highest relative risk (6.2) of any HLA-DR antigen tested. MC1 negative and positive populations were not significantly different in any of a variety of clinical and laboratory variables including age, sex, disease duration, age at onset, hours of morning stiffness, functional class, joint count, presence of subcutaneous nodules or bony erosions, frequency of side effects to gold or D-penicillamine, sedimentation rate, and antinuclear antibody.

Clonal dominance among T-lymphocyte infiltrates in arthritis

Synovial membranes in patients with rheumatoid arthritis as well as other types of chronic destructive inflammatory arthritis contain infiltrates of activated T lymphocytes that probably contribute to the pathogenesis of the disease. In an effort to elucidate the nature of these infiltrates, interleukin 2 (IL-2)-responsive T lymphocytes were grown out of synovial fragments from 14 patients undergoing surgery for advanced destructive inflammatory joint disease. Eleven of the samples examined were from patients with classical rheumatoid arthritis, while three others were obtained from individuals with clinical osteoarthritis. Southern blot analysis of T-cell receptor (TCR) beta-chain genes in 13 of 14 cultures showed distinct rearrangements, indicating that each culture was characterized by the predominance of a limited number of clones. T-cell populations from peripheral blood stimulated with a variety of activators and expanded with IL-2 did not demonstrate evidence of similar clonality in long-term culture. These results suggest that a limited number of activated T-cell clones predominate at the site of tissue injury in rheumatoid synovial membranes as well as in other types of destructive inflammatory joint disease. Further characterization of these T-cell clones may aid our understanding of the pathogenesis of these rheumatic disorders.

Progress report on the ASHI/CAP Histocompatibility Survey Program, 1981-1986

Two histocompatibility testing surveys were conducted over a five-year period by the American Society for Histocompatibility and Immunogenetics and the College of American Pathologists. More than 200 laboratories participated in the HS survey, which consisted of four shipments of cells and serum samples to be tested for ABO type, HLA-A and -B types, antibody identification, and lymphocytotoxicity crossmatching. About 100 laboratories participated in the DR survey, which consisted of four annual shipments to be tested for HLA-DR and -DQ types, antibody identification, and crossmatching. The results of the analysis of the HLA-typing results showed high consistency (generally greater than 90%) among laboratories in the definition of most recognized HLA antigens. In contrast, the HLA antibody screening was generally less consistent between laboratories. On the basis of 90% or greater consensus among participants, it was possible to develop a performance grading system.

High-dose intravenous gamma globulin improves responses to single-donor platelets in patients refractory to platelet transfusion

Ten patients, with bone marrow failure or malignant disorders, became refractory to platelet transfusions using random, as well as partial or fully HLA-matched, single-donor platelets. To determine its effect on platelet refractoriness, intravenous gamma globulin (IV IgG) was administered at 400 or 800 mg/kg/d for five days, and postinfusion platelet responses were monitored. Platelet transfusion responses following intravenous gamma globulin (IV IgG) were graded as follows: Excellent, 48-hour posttransfusion count greater than 50,000/microL; good, 48-hour count greater than 20,000 but less than 50,000/microL; Fair, increased increment, 48-hour count less than 20,000; and failed, no increased increment. Six of ten patients (60%) had improved responses to selected single-donor platelets (two were excellent, three were good, and one was fair). The time to achieve a platelet transfusion count greater than 25,000/microL ranged from one to nine days of IgG therapy. One individual had sustained benefit (greater than 1 year); the remaining responses persisted for 6 to 8 weeks. These results suggest that IV IgG may be useful in the management of platelet refractoriness, especially in patients receiving single-donor platelets.