Use of monoclonal antibodies to T-cell subsets for immunologic monitoring and treatment in recipients of renal allografts

The effect of immunosuppressive agents on lymphocyte subsets in rat peripheral blood

A method for monitoring circulating lymphocytes subsets in the rat on an automated flow cytometer with monoclonal antibodies was used to ascertain in vivo effects of various doses of immunosuppressive agents. The agents tested were anti-lymphocyte serum (ALS), azathioprine (AZA), cyclophosphamide (CTX), cyclosporin A (CsA) and methylprednisolone (MP). Each immunosuppressive agent varied in its capacity to induce changes in T cell subsets and B cell numbers. The rapidity of onset of action of the agents varied considerably; with ALS and MP maximal effects were seen within hours whilst the effects with CsA, cyclophosphamide (CTX) and azathioprine (AZA) took several days to develop. ALS had marked anti-T cell activity but did not selectively affect the T cell subsets. AZA and CTX both exerted their major effect upon the B cell (OX4+) subpopulation. CsA administration was associated with the appearance of many circulating lymphocytes which expressed the pan-T marker (W3/13) but neither of the T cell subset markers (W3/25, OX8). With CsA there was no significant alteration in the W3/25:OX8 ratio, although a persistent decrease in the number of all T lymphocytes was observed after administration of this drug at a dose of 45 mg/kg had ceased. MP was the only drug which had a marked selective effect on a T cell subset. The numbers of circulating Class II major histocompatibility complex (MHC) reactive lymphocytes (W3/25+) were significantly more depressed than the Class I MHC reactive subset (OX8+). This effect persisted for up to 31 days after the single injection of a depot preparation of this drug, and was found to be associated with prolonged survival of precultured endocrine xenografts.

Monoclonal antibody therapy with ciclosporin and steroids in nonmatched cadaveric renal transplants

Thirty-six ciclosporin-prednisone-treated recipients of nonmatched cadaver renal allografts were given a course of Orthoclone OKT3 monoclonal antibody for steroid-resistant cell-mediated rejection. Although side effects were common, only 2 patients had to be withdrawn from therapy and there were no deaths related to therapy. Twenty-three (63.9%) allografts were rescued with OKT3 therapy and 21 (58.3%) of the grafts have continued to function well. We conclude that OKT3 is an effective agent for the treatment of steroid-resistant cell-mediated rejection and that rebound rejection can be prevented in most patients if adequate therapy with ciclosporin-prednisone is maintained.

Effect of cyclophosphamide on leukocytic subset distributions in rats carrying the Dunning R3327-MAT-LyLu prostatic adenocarcinoma

The Dunning R3327 adenocarcinoma represents a model for studying prostate cancer in rats; early studies have indicated its utility for studying relationships between tumor growth, immunologic markers, and chemotherapy. Normal animals and those bearing the metastatic Dunning R3327 MAT-LyLu tumor were treated with 10, 30, and 100 mg/kg doses of cyclophosphamide (CTX) and their spleens assayed for leukocytic subset distributions using monoclonal antibodies. Tumor-bearing animals had significant reductions in helper T cell content as well as reduced helper/suppressor T cell ratios, compared to controls. These effects occurred rapidly following implantation and were not reversed by chemotherapy. When administered to both tumor- and non-tumor-bearing animals, CTX also depleted T cell populations. Despite reductions produced in all subsets, two administrations of CTX (30 mg/kg) were capable of retaining (in non-tumor-bearing animals) or restoring (in tumor-bearing) normal helper/suppressor T cell ratios. Such studies aid in identifying therapeutically effective dosages of cytotoxic drugs that minimize their deleterious effects on the immune system.

T-lymphocyte analysis in cardiac allograft recipients treated with cyclosporine

To assess the usefulness of circulating T-lymphocyte analysis in cardiac transplantation, T helper (Th) and T suppressor-cytotoxic (Ts-c) subsets were serially monitored in 33 cardiac allograft recipients treated with cyclosporine. The short-term prognosis of their 47 treated rejection episodes were retrospectively correlated with the changes in T-cell subpopulations. The data indicate three main findings. Reversed Th to Ts-c ratio (less than 1) was associated with a reduced incidence of rejection onset and a benign clinical course after treatment for rejection. Reversed Th:Ts-c ratio caused by antirejection therapy was associated with less chance of recurrence during the rest of hospitalization, regardless of the mode of therapy and irrespective of whether the rejection was primary or recurrent. These changes were mainly mediated by a reduction in T helper cells rather than changes in the T suppressor-cytotoxic subset or total T cells. Titration of antirejection therapy based on these T-cell dynamics may reduce either overtreatment or undertreatment. A prospective randomized study seems warranted to evaluate this approach as an alternative to a predetermined antirejection protocol.

Characterization of mononuclear cells in cyclosporin A induced gingival enlargement

Gingival biopsies from five patients with cyclosporin A (CsA) induced enlargement of the gingiva contained prominent mononuclear infiltrates beneath the epithelial basement membrane. These infiltrates and surrounding tissues were studied using monoclonal antibodies directed against lymphocytes and their subgroups (OKT 3, OKT 4, OKT 8, Leu 3 and Leu 4), monocytes (OKM 1) and the framework structure of HLA-DR antigens (OKI al). As revealed by the reactivity of these antibodies the vast majority of the mononuclear cells in two individuals consisted of monocytes and in the others of T-lymphocytes. Virtually no B-lymphocytes were observed. The ratio between T-cells bearing T 4 and T 8 antigens, in separate biopsies, varied between 6 and 0.3. Control biopsies were obtained from the gingiva of seven healthy individuals without gingivitis. These biopsies contained relatively few mononuclear cells all of which had T-lymphocyte phenotype.

Long-term humoral unresponsiveness in vivo, induced by treatment with monoclonal antibody against L3T4

mAbs directed against the L3T4 molecule administered in vivo caused a severe and long lasting helper cell depletion in mice. Regeneration of the L3T4+ subpopulation occurred gradually (2-3 mo) after a single antibody treatment. Experiments were designed to examine the humoral immunocompetence of such anti-L3T4-treated animals during and after regeneration of the L3T4+ T cell subset. The animals were injected with anti-L3T4, immunized with soluble antigen, and challenged with antigen every 2 wk. Antibody responses to two antigens, sperm whale myoglobin (SpWMb) and KLH, which differ with regard to their immunogenicity, were compared. The lack of humoral immune responsiveness to either of these two antigens shorty after anti-L3T4 treatment responsiveness to either of these two antigens shortly after anti-L3T4 treatment was probably due to clonal depletion. The anti-L3T4-induced immunosuppressive effect on antibody production seemed to be determined in part by the preexisting T cell repertoire, as was suggested by the recovery of responsiveness to the highly immunogenic antigen KLH and the transient inhibitory effect of anti-L3T4 treatment in primed animals. The regenerating L3T4+ T cell subpopulation was relatively incompetent in initiating B cell responses. More than 40% of the L3T4+ T cell compartment had to recover to provide help for the production of anti-KLH antibodies, whereas elimination of 90% of the L3T4+ helper cells did not inhibit a primary anti-KLH response. Evidence for a heterogeneous composition of the L3T4+ subset came from experiments using rIL-2 in vivo. The addition of rIL-2 during early helper cell depletion improved the recovery of the humoral responsiveness without apparently affecting the kinetics of the regeneration of L3T4+ T cells. Interestingly, humoral unresponsiveness to the weakly immunogenic antigen SpWMb persisted for at least 120 d. This long lasting unresponsiveness could not be explained by clonal depletion, and suggested as one possibility that the presence of antigen during regeneration of the L3T4+ helper cell population may have influenced the ultimate T cell repertoire.

Immunotoxin therapy of malignant melanoma

Current standard therapies for metastatic malignant melanoma are poor, and surgical excision of disease remains the cornerstone of melanoma management. Unmodified monoclonal antibodies have been used therapeutically in this, and other, malignancies, but results have been disappointing. This has led to attempts to improve the efficacy of monoclonal antibodies by using them to target therapeutic modalities to tumors. These therapeutic modalities include chemotherapeutic, radiotherapeutic and cytotoxic agents. An example of the latter is ricin A-chain, which is so potent that it has been reported that one molecule of it entering the cytosol is sufficient to cause cell death. Preclinical studies support the potential of immunotoxins as effective therapy for malignancy. A phase I-II trial of immunotoxin therapy of malignant melanoma has been completed and a trial to determine clinical efficacy has been implemented.

Serial immunologic studies in recipients of hepatic allografts

Thirty recipients of hepatic allografts had serial immunologic evaluations. Prior to transplant, patients had marked depression of lymphocyte subsets and impaired in vitro immunoglobulin synthesis, while phytohemagglutinin responsiveness was similar to that of controls. Following transplantation and introduction of cyclosporine and low-dose steroid therapy, there was a significant decline in both T cell subsets, but only the T4 population remained significantly depressed throughout the entire study period. The T4:T8 ratio in 5 patients who experienced acute rejection episodes was 1.4 +/- 0.6 prior to transplant. It increased to a mean of 2.0 +/- 0.6 by the time the diagnosis of rejection was made. By contrast, 12 subjects transplanted during a similar time period who did not demonstrate rejection had a T4:T8 ratio of 4.0 +/- 3.9 prior to transplant which fell to 1.5 +/- 0.6 (P less than 0.01) by 1 week post-transplant. In all 12 of these, the T4:T8 ratio fell in the 7 days post-transplant. The results indicate that monitoring the T4:T8 ratio in hepatic allograft recipients may be a useful marker for determining patients at risk for a rejection episode.

Fine specificity of antibodies produced in rhesus monkeys following in vivo treatment with anti-T cell murine monoclonal antibodies

The immune response of 23 rhesus monkeys against different murine monoclonal antibodies (mAb) administered in vivo as immunosuppressive agents has been analyzed. Seven mAb specific for either helper-inducer (CD4 molecules) or cytotoxic/suppressor (CD8 molecules) T cells, that cross-react with monkey lymphocytes, were administered i.v. for 10 consecutive days in rhesus monkeys. Nineteen of the animals were recipients of a skin or renal allotransplant. Nineteen out of the 23 monkeys developed a significant immune response against the injected monoclonal. This response was restricted in its specificity since unrelated murine monoclonals were not recognized by the monkeys' anti-monoclonal immunoglobulins. Fine analysis of the monkeys' sera revealed that the antibodies produced against the xenogeneic proteins selectively exhibited two major specificities i.e., anti-isotypic and anti-idiotypic. On a practical basis, these results suggest that an animal already immunized against a given mAb should still be sensitive to the therapeutic effect of another monoclonal sharing the same specificity but different idiotype.

Identification of inflammatory cells infiltrating renal allografts

Eight nephrectomies and 13 biopsies of renal allografts (living 15, cadaveric 6) were investigated on the origin of inflammatory cells in the graft tissues by the use of an immunohistologic method (ABC method). Various monoclonal antibodies and heterosera were used to identify different leukocyte subsets. In all specimens the most predominant inflammatory cells were T cells. Other cells decreased in the following order; B cells, neutrophils and monocytes, and natural killer cells. In T cell subsets Leu 2a-positive cells (suppressor/cytotoxic T cells) predominated over Leu 3a-positive cells (helper/inducer T cells) in 4 nephrectomies (living 1, cadaveric 3) and 12 biopsies (living 11, cadaveric 1). Among these 16 cases, 7 were undergoing acute rejection in various degrees, and 9 were without clinical rejection. In the former 7 cases only one was suffering from another disease. In contrast, Leu 3a-positive cells predominated over Leu 2a-positive cells in 1 biopsy (living) and 4 nephrectomies (living 2, cadaveric 2). Four of these 5 cases concurrently had other diseases in addition to acute rejection. Two cases underwent acute tubular necrosis (cadaveric graft nephrectomies) and 2 underwent chronic rejection and crescentic glomerulonephritis (living graft nephrectomies). The one remaining case was without clinical rejection.

The human immune response to the OKT3 monoclonal antibody is oligoclonal

The availability of highly specific and homogeneous antibodies to human T cells by the hybridoma technique has elicited new interest in the clinical use of antibodies to lymphocytes as immunosuppressive agents. OKT3 is the murine monoclonal antibody that has been the most widely used in clinical transplantation to induce immunosuppression. This antibody recognizes a membrane molecular complex, exclusively present on mature human T lymphocytes, which is tightly linked to the T-cell antigen receptor. The long-term therapeutic use of murine monoclonal antibodies in vivo is hampered by the intense antibody response that occurs in most human patients. Thus, when administered alone, OKT3 manifests its immunosuppressive activity only during the 10 to 15 days that precede the onset of sensitization. The results presented here show, by use of isoelectrofocusing, that the antibody response to OKT3, already reported to be restricted in its specificity (only anti-isotypic and anti-idiotypic antibodies are produced), is in addition oligoclonal. This restriction of the anti-monoclonal response may suggest that an efficient way to circumvent the sensitization problem would be to administer consecutively different monoclonal antibodies presenting the same specificity but distinct idiotypes.

Kidney transplantation

The current status of bone marrow transplantation is reviewed. The diseases that are treatable with marrow transplantation, the basic transplant procedure, and the potential complications of marrow transplantation are discussed in detail. The future application of marrow transplantation to additional disease processes is considered.

Detection of retroviral particles in hybridomas secreting monoclonal antibodies

Electronmicroscopy of hybridoma clones derived by fusing BALB/c mouse spleen cells with P3U1 mouse plasmacytoma cells to generate monoclonal antibodies against human sarcoma antigens, revealed the presence of large number of viral particles. These particles were also seen budding from the cell surfaces. The intracytoplasmic particles were intracisternal and resembled type-A oncornavirus, while the budding and extracellular forms, with a centrally located nucleoid, resembled mature type-C oncornaviruses. Cells of the parental P3U1 palsmacytoma cell line and of the NS-1 myeloma cell line contained morphologically identical viral structures. The scientific and medical communities engaged in hybridoma research should be alert to the possible presence of viruses in hybridomas and their products. The question is raised as to whether it is safe to use mouse monoclonal antibodies for clinical purposes, both diagnostic and therapeutic.

Leukocytic subset distributions of spleen cells obtained from rats bearing variants of the Dunning prostatic adenocarcinoma

Employing monoclonal antibodies, the relative frequencies of mononuclear cell types found in spleen cell populations were compared between rats bearing variants of the Dunning prostate adenocarcinoma and a series of non-tumor bearing control animals. The identification and quantitation of such subsets greatly expands our knowledge of immune status and function. The results indicate that the spleen cell populations from animals bearing either the Dunning R3327-H, G or MAT-LyLu sublines have significant decreases in their helper T cell/suppressor T cell ratios when comparisons are made to cells obtained from non-tumor bearing animals. In addition decreases in total T cell content and increases in splenic monocytes were noted. It appears that most of these deviations are the result of general Dunning tumor presence, rather than due to any particular subline characteristic. These changes may be analogous to similar alterations reported in the peripheral blood of humans bearing Stage D prostatic cancer, suggesting that the Dunning tumor may provide an appropriate model for evaluating interactions between the immune response, the tumor and therapy.

The biodistribution of radiolabeled antilymphocyte monoclonal antibody in the rat

The biodistribution of radiolabeled mouse anti-pan T monoclonal antibody (W3/13) against rat lymphocytes was examined in normal rats. Monoclonal antibody to human prostate-associated antigens (PAA) served as a control. In vitro studies demonstrated a 38% maximum binding of radiolabeled W3/13 to lymphocytes, which was significant (P less than 0.001) when compared with the control (PAA) value of 3.4%. In vivo, intravenously administered 111In labeled W3/13 and 131I labeled W3/13 exhibited similar tissue distribution patterns. The localization of W3/13 in lymphoid tissue was significantly greater than that achieved with PAA. W3/13, however, did not demonstrate significant localization in the intact thymus and accumulated to a higher degree (6-10% ID/g) than expected in bone marrow at 24 h. These findings suggest that radiolabeled anti-lymphocyte monoclonal antibodies may not be well suited for the treatment of lymphoreticular neoplasms and allograft rejection in patients.

Subpopulations of lymphocytes in connective tissue from phenytoin-induced gingival overgrowth

The presence of mononuclear cells was studied in gingival biopsies from seven children exhibiting phenytoin(PHT)-induced gingival overgrowth, three children with gingivitis and a control group consisting of three children without clinical signs of inflammation. The mononuclear cells were detected using monoclonal antibodies defining functional T-lymphocyte subpopulations, B-lymphocytes and monocytes. Gingival biopsies from the individuals in the PHT-group showed a substantial number of mononuclear cells. The distribution of mononuclear cells in separate individuals were as follows: 69-95% OKT3 +/Leu4+ cells (T-lymphocytes), 50-64% OKT4 +/Leu3+ cells (T-helper phenotype) and 29-46% OKT8+ cells (T-suppressor/cytotoxic phenotype). None of the biopsies in the PHT-group contained more than a few scattered plasma cells. The vast majority of all mononuclear cells present in the biopsies reacted with OKIa1, a monoclonal antibody defining the HLA-DR framework. In contrast, biopsies from the control group and the gingivitis group contained few mononuclear cells, the majority of which were T-cells. This suggests that immunologic reactions mediated by T-cells may play a role in the pathogenesis of the PHT-induced lesion.

Pediatric renal transplantation

This article outlines the current status of pediatric renal transplantation and emphasizes a practical approach to patient management. It discusses two areas of renal transplantation in children in which results differ significantly between children and adults. These areas are renal transplantation in the very young child and transplantation in children with renal failure secondary to urologic disease.

A randomized clinical trial of OKT3 monoclonal antibody for acute rejection of cadaveric renal transplants

Since the murine monoclonal antibody OKT3 reacts with human T cells and blocks their function, we explored its effectiveness in treating T-cell-mediated rejection of renal allografts. In a prospective randomized multicenter trial, 123 patients undergoing acute rejection of cadaveric renal transplants were treated either with OKT3 daily for a mean of 14 days, with concomitant lowering of the dosage of other immunosuppressive drugs (63 patients), or with conventional high-dose steroids (60 patients). OKT3 reversed 94 per cent of the rejections--a figure that was significantly better (P = 0.009) than the 75 per cent reversal rate obtained with conventional steroid treatment. This superior reversal rate with OKT3 was reflected in an improved one-year graft survival of 62 per cent for the OKT3-treated group, as compared with 45 per cent for the steroid-treated group (P = 0.029), in patients who were all selected by virtue of having had acute rejection. We conclude that treatment with OKT3 (with concomitant lowering of the dosage of other immunosuppressive drugs) is an effective approach for acute renal-allograft rejection.

Retrospective study of histological features of acute rejection in renal allografts and comparison with circulating T cell populations

The histological severity of acute rejection in renal allografts was determined for 39 rejection episodes in 30 renal transplant recipients. Data were compared with the peripheral blood T cell subset ratios measured before and at the onset of the rejection episode. T cell subset ratios showed no correlation with the histological severity of rejection, nor with the reversibility of the rejection episode. The grade of histological rejection on biopsy was predictive of graft survival. We conclude that renal biopsy remains the best method for determining the severity and outcome of acute allograft rejection episodes.

Neutralization of hepatitis B virus infectivity by a murine monoclonal antibody: an experimental study in the chimpanzee

Two study chimpanzees were inoculated intravenously with approximately 1,000 chimpanzee infectious doses of hepatitis B virus (HBV), one with subtype adr and one with subtype ayw, each previously incubated with 0.1 ml of a murine monoclonal antibody (IgG 1(K) class) directed against a single epitope on hepatitis B surface antigen common to most or all HBV. Two control chimpanzees received identical doses of HBV not incubated with the murine anti-HBs. Neither study chimpanzee developed HBV infection during 12 months of follow-up as judged by normal serum aminotransferase activity, normal liver biopsies, and negative serological tests for HBV-associated antigens and antibodies. In contrast, both control chimpanzees became infected by HBV as evidenced by elevated serum aminotransferase activity, liver biopsy changes characteristic of viral hepatitis, and the appearance of hepatitis B surface antigen (HBsAg) in their sera. Both study chimpanzees were shown to be fully susceptible to infection with these same HBV inocula when challenged 15 months after the initial inoculations at a time when passively administered anti-HBs was no longer detectable. Prior to challenge with HBV, one of the two study chimpanzees received a second injection of the same volume of the murine monoclonal anti-HBs. The survival of this anti-HBs in serum was reduced from six weeks (after the initial injection) to approximately two weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Graft-versus-host disease prophylaxis with anti-T-cell monoclonal antibody OKT3, prednisone and methotrexate in allogeneic bone-marrow transplantation

A new regimen for prevention of acute graft-versus-host disease (GvHD)--OKT3 (murine monoclonal anti-pan-T antibody), prednisone and methotrexate (OKT3-pred-MTX)--was compared with the Minnesota standard regimen--antithymocyte globulin, prednisone and methotrexate (ATG-pred-MTX)--for adverse effects, effect on incidence of acute GvHD, and survival at 1 year post-transplant. Twenty patients (aged 25 +/- 9 years) had bone-marrow transplantation (BMT) from their HLA-MLC identical sibling donors for treatment of aplastic anaemia (four), acute leukaemia in remission (13) or chronic myelogenous leukaemia (three). These 20 patients received (OKT3-pred-MTX) on days 8-22 post-transplant. Results of this group are compared to those of 19 concurrent patients (aged 26 +/- 12 years) who received ATG-pred-MTX on days 8-22 post-transplant. On the first day of treatment, 20/20 OKT3 patients and 18/19 ATG patients were febrile. Within 24 h of the first dose of OKT3, 6/20 patients experienced dyspnoea or chest pain and 3/20 patients developed diarrhoea. No further adverse effects were seen after the second dose of OKT3 and no late adverse effects were attributed to this drug. Time to engraftment (means 25 d) was not statistically significantly different in the two prophylactic groups. Acute GvHD was diagnosed in 14 of 20 patients who received OKT3-pred-MTX and in eight of 19 patients who received ATG-pred-MTX (P = 0.06). The incidence of hepatic or gastrointestinal GVHD (greater than or equal to grade 2) was similar in the two groups: 4/20 OKT3-pred-MTX, 6/19 ATG-pred-MTX. Characteristics of post-transplant infections were also similar for the two prophylactic groups. Survival at 1 year post-transplant was 65% for patients who received OKT3 and 44% for patients who received ATG (P = 0.13). The use of OKT3 with prednisone and methotrexate is relatively safe and is associated with a similar incidence of moderate-severe acute GvHD to that experienced in the use of ATG with prednisone and methotrexate.

Defining the physiologic and pathophysiologic roles of renin: the role of specific inhibitors

Although renin was identified as playing a role in cardiovascular homeostasis by the experiments of Goldblatt in the 1930's, neither its physiologic role in organs other than the kidney nor its contribution to the genesis of essential hypertension has been defined as yet. It is difficult to interpret studies with converting enzyme inhibitors because of their multiple pharmacologic effects. Specific inhibitors of renin appropriate for clinical investigation would help resolve many questions. Four classes of compounds have been demonstrated to be renin inhibitors of high potency: specific antibody, general peptide inhibitors of acid proteases, analogs of angiotensinogens, and peptides that are related to the amino-terminal sequence of prorenin. Of these, it is likely that angiotensinogen analogs will be the first applied in human studies. The minimal substrate for renin has the sequence: His-Pro-Phe-His-Leu-Leu-Val-Tyr. Variants of this sequence have yielded competitive inhibitors. Recently, remarkably active compounds have been synthesized by reducing the peptide bond that is cleaved by renin, or by incorporating the amino acid statine, found in pepstatin. These compounds have been shown now to be effective in dogs, rats, and monkeys, and most recently, preliminary studies have reported their efficacy in humans. Recent studies with one of these inhibitors, RIP, raise questions concerning both its specificity and site of action.

Systemic lupus erythematosus: delineation of subpopulations by clinical, serologic, and T cell subset analysis

Patients with systemic lupus erythematosus (SLE) (n = 194) were analyzed for correlation of clinical features. In addition, the proportions of the two major T cell subsets were determined in 87 subjects. Two patient subgroups were discerned: one in which severe renal disease, leukopenia, and thrombocytopenia predominated, and a second in which sicca syndrome and involvement of the central nervous system, lungs and muscle occurred. The ratio of T helper/inducer to T suppressor/cytotoxic cells was reduced in the first group and increased in the second. We conclude that SLE does not comprise a single disease entity, but rather represents a number of syndromes with overlapping clinical features. The correlation of clinical symptoms with the proportions of circulating T cell subsets suggests that several immunologic mechanisms may underlie the various types of SLE.

Heart transplant pathology: the British experience

An account of human heart transplantation as seen by the histopathologists involved at the two UK transplant centres is presented. Between January 1979 and July 1984 179 patients received 186 hearts and 124 are still alive up to four years after operation. Cyclosporin A based immunosuppression has been used in the last 120 patients. Four patients developed neoplastic lesions. The commonest reason for transplantation was ischaemic heart disease (63%), followed by congestive cardiomyopathy (35%). The seven retransplants were for acute or chronic rejection. The monitoring of rejection by endomyocardial biopsies is described, and the causes of death and necropsy findings are presented.

Clinical applications of monoclonal antibodies

This review highlights the properties, problems, and potentials of monoclonal antibodies as diagnostic and therapeutic agents. The most extensive experience has been obtained with antibodies specific for functionally distinct subsets of lymphocytes. They have been used to monitor the immunosuppression of organ-graft recipients and to attempt to elucidate the disturbance of immunologic function in a variety of conditions. Current therapeutic applications under trial include immunosuppression to treat organ-graft rejection and to eliminate cells responsible for graft-vs-host disease from the bone marrow. Applications to cancer diagnosis and treatment have been hampered by the difficulty of identifying truly tumor-specific antigens. Successes have, however, been obtained in the location of metastases and in the extracorporeal treatment of autologous marrow to purge it of malignant cells, and, more rarely, with the direct administration of monoclonal antibodies in vivo. The conjugation of cell-type specific monoclonal antibodies with cytotoxic agents should overcome a number of limitations.

Successful treatment of autoimmunity in NZB/NZW F1 mice with monoclonal antibody to L3T4

Autoimmune NZB/NZW mice were treated with weekly injections of monoclonal antibody (mAb) to L3T4, an antigen expressed on a distinct subpopulation of T cells that respond to class II major histocompatibility antigens. Treatment with anti-L3T4 depleted circulating target cells, reduced autoantibody production, retarded renal disease, and prolonged life relative to control mice treated either with saline or with purified nonimmune rat IgG. These findings establish that autoimmune disease in NZB/NZW mice is regulated by T cells. In contrast to mice treated with nonimmune rat IgG, mice treated with rat anti-L3T4 mAb developed little or no antibody to rat Ig. Thus, the benefits of treatment with anti-L3T4 were achieved while minimizing the risks associated with a host immune response to therapy. This study raises the possibility that treatment with mAb against Leu-3/T4, the human homologue for L3T4 might be effective in the treatment of certain autoimmune diseases in people.

Normal values for the different classes of venous blood mononuclear cells defined by monoclonal antibodies

We present the data obtained from routine quantitation of normal venous blood mononuclear cells using 19 monoclonal antibodies against defined mononuclear cell surface antigens. The results indicate different values for percentage and absolute numbers of T lymphocytes and of T lymphocyte subsets depending on the monoclonal antibodies used to quantify these populations. In most instances the total number of identified cells was significantly less than the total number of recovered blood mononuclear cells, which suggests the existence in blood of a null cell population. Evidence is advanced to support previous observations that at least a proportion of this population is of B cell lineage, expressing cytoplasmic immunoglobulin but lacking other class or lineage specific markers. The value of a diverse monoclonal panel in routine quantitation of peripheral blood mononuclear cells is discussed.

Lymphocyte subpopulations in patients with breast cancer after postoperative radiotherapy

The effects of radiotherapy on the immune competence of patients with mammary cancer was studied using enumeration of the various lymphocyte subpopulations as detected by monoclonal OKT antisera, lymphocyte proliferative responses to phytohemagglutinin, concanavalin A, purified protein derivative to tuberculin (PPD), and serum immunoglobulin levels. The tests were carried out in nine patients with newly diagnosed and operated mammary cancer before and after the radiation therapy, and 6 months later, and in ten patients whose mammary cancer had been diagnosed and treated at least 3 years earlier and who had remained tumor-free. The number of lymphocytes in the peripheral blood and the various T-cell subpopulations as well as the OKIa1 cells mostly representing B-cells decreased. The only population increasing were the OKM1-positive cells, mostly representing monocytes and null cells. As also described earlier, the responses to mitogens decreased because of the radiotherapy but recovered, except for the responses to PPD which remained low.

CAPD--a risk factor in renal transplantation?

Theoretical considerations suggest that patients undergoing continuous ambulatory peritoneal dialysis (CAPD) may fare less well after renal transplantation than their haemodialysed (HD) counterparts. Review of 121 consecutive cadaveric renal allografts performed in this centre indicate this to be the case with graft survival rates at 1 year of 63.5 per cent in the HD group compared with 35.5 per cent in the CAPD-treated patients. This difference appeared to be independent of the duration of dialysis and, although a significant blood transfusion effect was seen in the HD group, no such trend was evident in the CAPD group. Studies of T cell subsets (using monoclonal antibodies) in the two groups suggests that, in part at least, the differences in graft survival rates may be attributable to the maintenance or restoration of immunological integrity in the CAPD group.

Analysis of immune status of hemodialyzed adults: association with prior transfusions

Peripheral blood leukocytes of 29 hemodialyzed adults, 19 transfused and 10 nontransfused, were studied using immunofluorescent staining with monoclonal antibodies and in vitro measurement of natural killer (NK) cell activity. When compared with control subjects, the absolute number of leukocytes in transfused hemodialyzed patients was significantly reduced (P less than 0.01), as were the absolute numbers of OKT11+ cells (P less than 0.01), and OKT4+ cells (P less than 0.0001). The percent representation of OKT11+ and OKT4+ cells was also significantly lower among transfused hemodialyzed patients (P less than 0.01 and 0.001, respectively), and this loss of OKT4+ cells resulted in a decrease in the ratio of OKT4+/OKT8+ cells (P less than 0.01). The absolute number of Leu-7+ cells was also decreased in the transfused group (P less than 0.05). A decrease in in vitro NK cell activity was present in both transfused and nontransfused hemodialyzed subjects. Whether these differences in peripheral blood lymphocytes were induced by the erythrocyte transfusions could not be determined; however, if they reflect changes in central lymphoid tissues, then these results may help explain the prolonged survival of renal allografts in transfused individuals.

Unusually restricted anti-isotype human immune response to OKT3 monoclonal antibody

The unusual anti-mouse immunoglobulin (Ig) sensitization of a renal allograft recipient who was treated prophylactically with the anti-T cell monoclonal antibody OKT3 (IgG2a) is reported. Whereas in most patients, the injection of OKT3 (5 mg/day, i.v. for 13 days) induces the rapid appearance of neutralizing anti-OKT3 antibodies, the patient reported here did not show the signs of conventional anti-OKT3 sensitization. High levels of circulating OKT3 persisted and no OKT3+ lymphocytes reappeared during the whole treatment period. Moreover, no IgG or IgM anti-OKT3 antibodies were detected at any time, using a specific enzyme-linked immunosorbent assay. However, an atypical anti-isotype response was evidenced in this subject whose Ig were shown by indirect fluorescence to bind to normal T cells coated with OKT3 or with other anti-T cell murine monoclonal antibodies carrying the IgG2a isotype (no reactivity was observed with IgG1 or IgG2b molecules). The patient's Ig did not bind to normal T cells coated with F(ab')2 fragments of OKT3 and did not inhibit the binding of OKT3 to its target antigen indicating that they reacted with the Fc fragment of the OKT3 molecule. Additionally, and probably explained by this unusual anti-OKT3 response, the patient's Ig were shown to inhibit the phytohemagglutinin-induced proliferation of normal lymphocytes, to bind under selected in vitro conditions to normal T cells and lastly to enhance the antigenic modulation induced in vitro by OKT3 on its membrane receptor.

A quantitative comparison of T-cell subsets in Hodgkin's disease and reactive hyperplasia. Frozen section immunohistochemistry

Cryostat sections of lymph nodes from patients with Hodgkin's disease were stained with monoclonal antibodies reactive with T-cells including T-cell subsets. Lymph nodes showing reactive hyperplasia were used as controls. Using an eyepiece grid, the stained cells were counted and subset ratios determined. The ratio of helper T-cells to cytotoxic/suppressor T-cells, i.e., (formula; see text) in Hodgkin's disease was found to be significantly different from ratios obtained from reactive nodes. This difference may be explained by a relative increase in cytotoxic/suppressor T-cells and/or a decrease in helper T-cells. This finding may relate to the previously reported increase in suppressor cell activity in patients with Hodgkin's disease and may also correlate with diminished delayed-type hypersensitivity in such patients.

Immunopathology of polymorphous light eruption. T lymphocytes in blood and skin

Polymorphous light eruption (PLE; actinic prurigo) is a relatively common dermatologic disease. People suffering from it have a pruritic skin eruption on exposed areas. PLE may be an immunologically mediated disease. Sixteen patients with PLE were studied. T lymphocytes and the helper and suppressor-cytotoxic subsets were assessed in peripheral blood by an indirect immunofluorescent method with the use of monoclonal antibodies. Total T lymphocytes were significantly increased as compared to controls. By an indirect immunoperoxidase technic with the use of monoclonal antibodies, characterization of the dermal cell infiltrate was done. Predominance of T total, T helper, and cells marked with Ia antigen were found. These findings suggest that an abnormal immune response is responsible for the tissue damage in PLE.

Serial monitoring of T-cell subset ratios with monoclonal antibodies in steroid- and antithymocyte globulin-treated patients with renal allotransplants

Sequential changes in T-cell subsets or their ratios were employed to predict severity of rejection crises and to identify those patients who might require future antirejection therapy. Forty-two percent of the transplant recipients had a pretransplant OKT4:8 ratio in the range of 1.3 +/- 0.5. By contrast, only 11% had a OKT4:8 ratio of 2.9 or greater. Examination of the entire study group demonstrated that the mean OKT4:8 ratios fell (P less than 0.01) in the first week following the transplant procedure. All patients had at least one episode of acute rejection. There was a marked increase (P less than 0.05) in the OKT4:8 ratio between the first week value and the value immediately preceding (within 3 days) the start of the rejection episode which was 2.64 +/- 0.27. The mean OKT4:8 ratio in the 15 patients leaving the hospital with a functioning transplant was 1.18 +/- 0.35. Three months post-transplant, the OKT4:8 ratio was 1.98 +/- 0.39 in the 12 patients with functioning allografts. This value was not different from those patients' initial pretransplant values. Clinically, the rejection episodes could be divided into two groups based on their response to intravenous methylprednisolone therapy. The first group (n = 9) had milder rejection crises which responded rapidly to administration of one course of methylprednisolone. The second group of patients (n = 9) were also treated initially with methylprednisolone, to which they did not respond, and subsequently received antithymocyte globulin in an attempt to control their ongoing rejection crises. Following the transplant procedure, the OKT4:8 ratio decreased in patients who were destined to have steroid-responsive rejection episodes (P less than 0.01). The OKT4:8 ratio however, failed to fall in those who required ATG for control of their transplant rejection episodes. The onset of rejection episodes was associated with an increase in OKT4:8 ratio in both groups. Following steroid administration, two patterns of OKT4:8 cell responses were observed. Those in whom renal function improved demonstrated a decline in OKT4:8 ratio from 2.4 +/- 0.4 to 1.4 +/- 0.4 (P less than 0.05). However, no change occurred in the OKT4:8 ratios with steroid therapy (2.6 to 2.4 +/- 0.33, P greater than 0.05) in individuals in whom the serum creatinine concentration failed to decline. The patients who failed to respond to steroid therapy were treated with antithymocyte globulin (ATG).(ABSTRACT TRUNCATED AT 400 WORDS)

Comparison of delayed type hypersensitivity and T subsets in random and homosexual populations in western Australia

Random and homosexual populations were tested for delayed type hypersensitivity (DTH) (Multitest) reactivity and T cell subsets. In the random population DTH reactivity was stronger in males irrespective of age. Reactivity in the homosexuals was generally even stronger especially with respect to tuberculin. As a group, male homosexuals had low OKT 4/8 ratios when compared with sex and age matched controls. Analysis of DTH and T cell subset results in the random group showed an association between anergy and low OKT 4/8 ratios. It is concluded that homosexuals demonstrate some alteration of cell mediated immunity and therefore may be at risk of various infections.

The influence of common variables on T cell subset analysis by monoclonal antibodies

Normal values for T cell subsets as defined by the most commonly used monoclonal antibodies of the OKT series were determined in a group of 142 unrelated normal individuals. In most age classes females had significantly greater portions of OKT3 and OKT4 antigen bearing lymphocytes and accordingly a higher T4/T8 index. The range of individual normal values within the control population was remarkably wide. Intra-individual differences between the T subset composition remained rather constant over a period of 2 months. Time of day, food absorption and physical exercise had no influence on the results of subset analyses. Storage of the blood sample and freezing of isolated lymphocytes can result in significantly reduced OKT3 and OKT4 positive cell numbers. If lymphocytes were isolated soon after the blood was taken and resuspended in a stabilization medium they exhibited only minimal change.