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

Status of renal transplantation. A clinical perspective

Although the survival of patients on chronic dialysis has improved in recent years, the quality and status of rehabilitation remains poor. Renal transplantation must be used to complement chronic dialysis in the management of these patients. Physicians should not be biased and commit their patients to one or the other form of long-term treatment.

Importance of cytotoxic lymphocytes during cytomegalovirus infection in renal transplant recipients

Thirty renal transplant recipients were studied prospectively to evaluate the relationship of cytomegalovirus-specific cytotoxic lymphocyte responses to clinical outcome during cytomegalovirus infection. Cytomegalovirus infection developed in 20 patients; of these 20, 14 had cytomegalovirus-specific cytotoxic lymphocyte responses whereas six did not. Clinical findings (fever, leukopenia, thrombocytopenia, or elevations in serum transaminase levels) were significantly more frequent among patients without responses than among patients with responses (p less than 0.001), and prolonged viremia and complications of infection including superinfection, interstitial pneumonitis, pancreatitis, and death occurred exclusively among patients without responses. Acute allograft dysfunction during infection was experienced by four patients without responses but by only one patient with response (p = 0.02), indicating that the virus-specific cytotoxic response did not result in a renal immunopathologic condition, and may have protected against virus-induced injury to the graft. In seven of nine patients with responses who shed virus, cytotoxic responses occurred within one week of detection of activation of virus shedding. Absence of cytotoxic responses correlated with prior high-dose, intravenous methylprednisolone treatment, and apparently resulted from inhibition of cytotoxic T cell precursors. Immunosuppressive treatment to inhibit graft rejection should be minimized, and methods should be developed that do not inhibit cytomegalovirus-specific cytotoxic T cell responses.

Analysis of intragraft effector mechanisms associated with human renal allograft rejection: immunohistological studies with monoclonal antibodies

Immunohistological studies of rejecting human renal allografts show that the onset of graft rejection is accompanied by the influx of small numbers of T-cells and macrophages. Both cell types occur in focal aggregates adjacent to the Class II antigen-rich renal vasculature and glomerular Bowman's capsule. Although most of the T-cells express the OKT8+ phenotype of cytotoxic T-cells, analysis with markers for activation of T-cells suggests that the vast majority of these cells are present as functionally inactive precursor cells. Smaller numbers of OKT4+ helper T-cells, NK cells and occasional B-cells are also present. Within a few days, up to 15% of T-cells express receptors for IL-2 and other activation markers, suggesting that they are now functionally active. OKT8+ T-cells continue to predominate, but at least some OKT4+ T-cells appear active as DTH cells. A large influx of mononuclear cells, particularly macrophages, follows and these cells are found within and adjacent to the large Class I antigen-rich intertubular capillary network. Many of these intragraft macrophage express pro-coagulant function, presumably through lymphokine-induced activation, and are enmeshed in a fibrin network. Irreversible kidney damage may result from the combined onslaught of these cellular and humoral mechanisms, and examination of nephrectomy specimens suggests that this destruction is principally mediated by macrophages and polymorphs. These studies, by showing the presence of multiple functionally active cell types within rejecting grafts, provide evidence for a multiplicity of intragraft effector mechanisms. This evidence indicates that in addition to cytotoxic T-cells, DTH cells, macrophages, NK, K and B cells contribute to the rejection process. Further unravelling of the complex response and, hence, greater insights into the basis for more effective immunosuppression are likely to follow from the immunohistological application of monoclonal antibodies to rejecting grafts. However, comparison with animal models of kidney rejection already suggests that there may be important differences in both the initiation and effector phases of human kidney allograft rejection.

Antigenic polymorphism of the T4 differentiation antigen expressed on human T helper/inducer lymphocytes

The human TH lymphocyte population has been established to express a differentiation antigen (T4) which appears to function in cellular collaboration and T cell recognition of Class II MHC alloantigens. Because we observed altered immunofluorescence staining of the TH cells of some individuals using the OKT4 mAb, a systematic investigation on both the epitopic structure of the T4 glycoprotein molecule and possible polymorphism of these epitopes was undertaken. From competitive blocking assays using eight murine anti-T4 mAbs coupled with quantitative flow cytometry, at least five and possibly seven different epitopes can be recognized on the T4 molecule. Population studies showed some individuals had a reduced phenotypic expression of the OKT4 reactive determinant to one-half that of normal and others completely lacked this epitope. The OKT4 reactive epitope variations are common but have so far been racially restricted to American Blacks and do not appear related to the stage of TH cell differentiation, any identifiable immune abnormality in vitro, or a definable disease process. The OKT4 epitope cannot be unmasked by neuraminidase treatment or T cell stimulation with lectins, soluble antigens, or allogeneic lymphocytes. Coupled with a family study, the alterations in OKT4 phenotype are best explained by autosomal, codominant expression of the T4 gene product. The significance of this polymorphism on TH cell function remains unclear.

Monoclonal antibodies in the treatment of cancer

Potential uses of monoclonal antibodies in anti-cancer treatment include passive serotherapy, radioisotope conjugates, toxin-linked conjugates, and chemotherapy-monoclonal antibody conjugates. The bases for these applications have been founded in research with heterologous antisera, and in some cases with monoclonal antibodies in animal tumor models. Human trials with passive serotherapy have already begun in both hematopoietic and solid tumor malignancies. Promising results have been reported in cutaneous T cell lymphoma with anti-T cell monoclonal antibody, and in nodular lymphoma with anti-idiotype monoclonal antibody. Radioisotope conjugate work appears promising for imaging in both animals and humans, and this work will lay the foundation for possible therapeutic application of radio-immunotherapy. Toxin-linked conjugates are promising in vitro and may have application in autologous bone marrow transplantation. Research with chemotherapy conjugates is also underway. Preliminary results suggest that murine monoclonal antibodies will be well tolerated clinically except in the setting of circulating cells which bear the target antigen, where rapid infusions may be associated with intolerable side effects. In certain diseases, production of endogenous anti-mouse antibodies may also limit application. Advances in the technology for human-human hybridoma production may help solve some of these problems.

Lymphocyte subpopulations in normal and preeclampsia pregnancies

We have made an effort to determine whether or not there is any change in subpopulations of lymphocytes in normally pregnant and preeclamptic pregnancies using monoclonal antibody markers. Eleven normally pregnant and ten women with preeclampsia were studied, both during the third trimester and again two months postpartum, and compared to eleven age-matched nonpregnant women. Mononuclear cells were isolated from heparinized venous blood. One million cells were treated with each appropriate antibody (Ortho-mune OKM1, OKT3, OKT4, OKT8, OKT11, OKIa), and then reacted with FITC-antimouse IgG and examined by flow cytometry and/or fluorescence microscopy. No significant differences between these three groups were noted in the OKT3, OKT4, OKT8, OKT11, or OKIa cellular populations. The OKM1 population was significantly decreased in the third trimester of normal pregnancies but not in the preeclamptic pregnancies. No significant differences were found 2 months postpartum.

Administration of prednisolone in vivo affects the ratio of OKT4/OKT8 and the LDH-isoenzyme pattern of human T lymphocytes

Oral administration of prednisolone (in single doses of 10, 30, or 60 mg) to healthy volunteers was found to affect the T lymphocytes in the blood with regard to binding of monoclonal antibodies and lactate dehydrogenase isoenzyme pattern. The findings indicate that these effects are dependent on the dose of the drug and the time after the administration of the drug. Prednisolone induces a T lymphocytopenia in the peripheral blood that affects OKT4-positive lymphocytes more than OKT8-positive lymphocytes, resulting in a slight decrease in the ratio OKT4/OKT8. Moreover, the lactate dehydrogenase isoenzyme pattern changes, resulting in a decrease of the H/M ratio of this enzyme. The proliferative responses of peripheral blood lymphocytes are not affected after a single dose of 10 mg. However, after administration of either 30 or 60 mg of prednisolone, the proliferative responses are decreased to a different extent, depending on the stimulus used. In vitro experiments are presented showing that any effect of prednisolone on nonstimulated lymphocytes is reversible. Based on the observed changes in OKT pattern and lactate dehydrogenase isoenzyme profile of the T lymphocytes induced by administration of prednisolone, it is concluded that the drug induces a temporary depletion from the peripheral blood, preferentially of high-reactive T lymphocytes. As a consequence, the peripheral blood compartment is enriched for T lymphocytes with a low H/M ratio of lactate dehydrogenase isoenzymes, known to be less reactive to proliferative stimuli.

Lymphocyte markers in health and disease

In the 7 years since the last review of lymphocyte markers, written by Tomasi and Stobo, appeared in this journal, there has been a revolution in the diversity and sophistication of immunologic tests directly applicable to investigations of clinical disorders. The promise of such procedures and their allied genetic and monoclonal antibody probes in aiding the classification, early recognition, and therapy of hematologic malignancies, autoimmune disorders, and infectious diseases now is approaching fruition. A synopsis of those assays in vitro and in vivo, together with the primary immune cell subsets they define, is given in Table 12. A grasp of the basic mechanisms underlying them should permit their judicious use, as they are requested either through the clinical laboratory (the initial screen) or as they are complemented by more complex studies obtained through university-affiliated immunology centers (further workup). In this manner, clinically relevant information for the diagnosis and treatment of disorders of immune function will be realized.

Preincubation of donor bone marrow cells with a combination of murine monoclonal anti-T-cell antibodies without complement does not prevent graft-versus-host disease after allogeneic marrow transplantation

Protection of mice against graft-versus-host disease (GVHD) can be accomplished by incubating donor marrow with anti-T-cell antisera or with anti-Thy-1 monoclonal antibody. Incubation of donor marrow with a single anti-T-cell monoclonal antibody, however, does not prevent GVHD in humans. Therefore, we carried out a clinical trial to determine the effect of treatment of donor marrow with a combination of eight anti-T-cell antibodies in the absence of complement. The nine patients were genotypically HLA identical with their donors and received methotrexate postgrafting. Prompt engraftment occurred in eight patients. Of six patients surviving at least 40 days with sustained engraftment, three had severe (grade III or IV) GVHD. Thus, there is no evidence that treatment of donor marrow with murine anti-T-cell monoclonal antibodies as described here can prevent GVHD.

The use of monoclonal antibodies in skin basement membrane research

Recent experiments have indicated that it is possible to uncover new antigens within both the basement membrane zone and the epidermis of normal adult human skin by producing murine anti-human monoclonal antibodies following immunization with human skin preparations. Already one such monoclonal antibody has defined a biochemical defect that may be important in the pathogenesis of one of the more severe blistering skin diseases, dystrophic epidermolysis bullosa. It is likely that further attempts at hybridoma production using basement membrane extracts of skin will lead not only to the identification of other as yet unknown components of the human dermo-epidermal junction, but may also shed insight into the biochemical basis of one or more cutaneous diseases involving that region of the skin.

Analysis of T cell subsets in cancer patients treated with interferon

T cell subsets were analyzed in 33 patients with advanced cancer who were treated with either of two interferon preparations: a partially purified human leukocyte interferon (HulFN-alpha (Le] and a highly purified recombinant interferon (lFLrA). Included in the lFLrA-treated group were eight patients with immunodeficiency and Kaposi's sarcoma. The OKT4+/OKT8+ ratio was used to define the balance between helper/inducer and suppressor/cytotoxic T cell subsets. With both interferon preparations, the mean OKT4+/OKT8+ ratio decreased 24 hours after the first interferon dose. Within the HulFN-alpha (Le) group, the decrease in ratio was related to an increase in OKT8+ cells; in the lFLrA group, it was accompanied by a small decrease in the proportion of OKT4+ cells that was greater than the decrease in OKT8+ cells. Patients treated with lFLrA were followed for the first three weeks of therapy. Most patients treated with lFLrA at all dose levels, ranging from 1 X 10(6) to 54 X 10(6) units per day, had a decrease in OKT4+/OKT8+ ratio on Day 1. No substantial change in the ratio was observed on Days 7, 14, and 22. Patients with immunodeficiency and Kaposi's sarcoma had responses similar to those of patients with other cancers treated with lFLrA. In conclusion, although both HulFN-alpha (Le) and lFLrA induce immediate decreases in the OKT4+/OKT8+ ratio, the T cell subset(s) primarily responsible for the decrease varies with the source of interferon.

Functional heterogeneities among concanavalin A-activated OKT4+ and OKT8+ cells by using autologous erythrocyte rosette technique

Normal human peripheral blood T lymphocytes activated by concanavalin A (Con A) were fractionated into OKT4+ and OKT8+ populations by complement-dependent cell lysis using OKT8 and OKT4 antibodies, respectively. By using the preferential ability of some, but not all, Con A-activated T cells to form rosettes with autologous erythrocytes, each population was further divided into autorosetting cells and nonautorosetting cells, and thus Con A-activated OKT4+ autorosetting, OKT4+ nonautorosetting, OKT8+ autorosetting, and OKT8+ nonautorosetting cells were obtained. The immune regulatory function of these populations was then investigated using a pokeweed mitogen-driven B cell plaque-forming cell system. These studies demonstrated that (a) autorosetting cells can exert potent suppressor activity regardless of their phenotypes of OKT4+ and OKT8+ antigens, and fail to help B cell differentiation; suppressor function mediated by these cells is radiosensitive; moreover, receptors for autologous erythrocytes may constitute either the interleukin 2 (IL2) receptors themselves or a component of an IL2 receptor-effector complex involved in modulating the growth signal that IL2 transmits to T cells; (b) OKT4+ nonrosetting cells serve adequately as radioresistant helper cells, but are devoid of suppressor cells; and (c) OKT8+ nonrosetting cells are found to lack either suppressor or helper activity, suggesting that they may belong to a T lymphocyte subset distinct from the subsets related to immune regulation. The results lead us, therefore, to the conclusion that there may exist functional heterogeneities among both the OKT4+ and OKT8+ populations; these heterogeneities can be dissected by virtue of the autologous erythrocyte rosette technique.

Comparison of complement-dependent cytotoxicity and indirect immunofluorescence for enumeration of T-cell subpopulations in human peripheral blood

The monitoring of T-lymphocyte subsets of recipients of organ grafts enables studies on immune reconstitution (after bone-marrow transplantation) and may predict graft rejection (after kidney transplantation). Quantitation of human peripheral T-lymphocyte subsets from healthy volunteers and from recipients of a bone-marrow graft by a complement dependent cytotoxicity (CDC) assay, based on the use of propidium iodide, and by an indirect immunofluorescence (IIF) technique has been compared using the monoclonal antibodies OKT3, OKT4 and OKT8. Except for OKT3 in healthy individuals--for which no significant difference was found between CDC and IIF--CDC detected significantly more cells of each subset than IIF. Furthermore, the CDC results indicated the presence of low numbers of OKT4+8+ cells in the peripheral blood of healthy individuals and--with higher numbers--following marrow transplantation. Results of depletion experiments, obtained by fluorescence activated cell sorting (FACS) for either OKT4 or OKT8, supported this conclusion. OKT4/OKT8 ratios were calculated from enumerations by the CDC assay and by the IIF assay and found to be linearly related, both in healthy persons and in marrow-graft recipients. Thus, the CDC assay is a reliable method for monitoring T-cell subsets, allowing detection of lymphocytes carrying low densities of membrane determinants.

Right angle light scatter: a necessary parameter in flow cytofluorimetric analysis of human peripheral blood mononuclear cells

The techniques of flow cytometry are being increasingly used to classify lymphocytes according to their surface antigens. Accurate analyses depend on the exclusion of non-lymphocytic contaminant cells. Using a fluorescence-activated cell sorter (FACS IV), virtually complete separation of human lymphocytes from monocytes and granulocytes can be achieved by means of wide-angle (90 degrees) light scatter. The technique described is simple and suitable for routine use. Used in conjunction with fluorescein-labelled monoclonal antibodies and logarithmic amplification of the fluorescence signals, it improves the accuracy of lymphocyte subset analysis. Its use is particularly necessary in the study of subjects such as renal allograft recipients, who have a high or variable contaminant cell:lymphocyte ratio.

Transplantation 1983

Renal transplantation has entered a new era of optimism characterized by steady increases in our scientific appreciation of the transplant event and improving allograft survival rates. Advances in tissue typing, methods of preventing rejection including an appreciation of the blood transfusion effect and the discovery of new immunosuppressive drugs such as cyclosporin A, and methods of rejection treatment have been responsible for this new era. With renewed impetus, continued advances can only increase an optimistic approach to renal transplantation.

T-cell subsets in patients with preeclampsia

Peripheral blood mononuclear cells from patients with preeclampsia were enumerated by means of monoclonal anti-T-cell antibodies. The percentage of total T cells was significantly decreased in this group of patients, as compared with normal term pregnant women. The low proportion of T cells was due to a proportional reduction in both helper and suppressor T cells; therefore, the ratio of helper to suppressor T cells was not different from that in normal pregnant women. There was no correlation between the degree of reduction in percentage of T cells and severity of the disease. The absolute numbers of T cells were slightly, but not significantly, decreased. Our findings support previous evidence of reduced, not increased, immune reactivity in preeclampsia.

Is renin a factor in the etiology of essential hypertension?

The widespread clinical study of converting-enzyme inhibitors has shown that they are effective antihypertensive drugs even in patients who may manifest either normal or decreased plasma renin activity. This suggests either that renin in a site other than plasma may play a contributory role in essential hypertension or that the hypotensive effect is caused by increased concentrations of kinins and prostaglandins, both demonstrated consequences of converting-enzyme inhibitor administration. Specific renin inhibitors appropriate for studies in humans would aid in the resolution of this question. 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. With the purification of renin, specific polyclonal or monoclonal antibodies have become available. The former have already been used extensively in physiologic studies in intact animals. Pepstatin is an inhibitor of many acid proteases. Its in vivo application has been retarded by its relative insolubility, but recent chemical modifications, particularly the addition of charged amino acids at the carboxy terminus, have rendered it more useful. The minimal substrate for renin is an octapeptide segment of the protein substrate: His-Pro-Phe-His-Leu-Leu-Val-Tyr. Variants of this sequence have resulted in competitive inhibitors that are useful in vivo. Recently, remarkably active inhibitors have been synthesized by reducing the peptide bond that is cleaved by renin, producing what may be a transition state inhibitor.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunoregulatory T cell subsets in chronic hepatitis B virus infection: the influence of homosexuality

The purposes of this study were 2-fold: (i) To enumerate peripheral immunoregulatory T cell subsets in untreated patients with chronic hepatitis B virus (HBV) infection and (ii) to examine the relationship between disturbances in the balance of lymphocyte subsets with liver disease and the presence of homosexuality. Circulating T lymphocyte subsets were evaluated by monoclonal antibodies to the following cell antigens: OKT3 (total T cells), OKT4 (helper/inducer T cells), and OKT8 (suppressor/cytotoxic T cells). The following groups of subjects were examined: (i) 16 heterosexuals with HBV-associated chronic active hepatitis (CAHB); (ii) 10 heterosexual, healthy HBsAg carriers, and (iii) 16 male homosexuals with CAHB. Controls included 51 healthy heterosexuals and 12 healthy, noninfected male homosexuals. We were able to demonstrate that heterosexuals with CAHB had T4/T8 ratios which did not differ from those of noninfected heterosexuals. Both healthy carriers and healthy homosexuals, however, exhibited significantly lower T4/T8 ratios than did noninfected heterosexuals (p less than 0.05, p less than 0.01, respectively). In addition, homosexuals with CAHB had lower (1.5 +/- 0.1) T4/T8 ratios than did heterosexuals with CAHB (2.0 +/- 0.2). A possible mechanism for these findings is discussed. The data indicate that the presence of homosexuality may be an important factor to consider when evaluating immunoregulatory subsets in CAHB.

Lymphocytes recognize human vascular endothelial and dermal fibroblast Ia antigens induced by recombinant immune interferon

T-lymphocyte-mediated responses to the cellular components of blood vessels are important in rejection of allografts. The induction of cytolytic T lymphocytes (CTLs) depends on recognition of foreign class II major histocompatibility complex antigens (human HLA-DR, DC/DS, SB and others, collectively referred to as Ia) on the target cells whereas killing by CTLs usually depends on recognition of foreign class I antigens (HLA-A, B), although some alloreactive CTLs recognize foreign Ia instead of HLA-A, B (refs 5-8). The expression of Ia antigens has traditionally been regarded as restricted to immunological cell types, and the presence of class II antigen-bearing 'passenger' leukocytes in rodent organ grafts appears necessary for graft rejection. Recently, Ia antigens have been observed by immunofluorescence microscopy on human renal and dermal capillary endothelium. We have previously shown that human umbilical vein endothelial (HUVE) cells in standard culture conditions do not bear Ia antigens, but may be induced to do so by products of lectin- or alloantigen-activated T lymphocytes. Furthermore, we found that recombinant immune interferon (IFN-gamma), free of other lymphokines, is a potent inducer of Ia expression in HUVE cells. Here we report that IFN-gamma also induces Ia expression on human foreskin capillary endothelial (HFCE) cells, HUVE cells transformed by Simian virus 40 viral DNA (SV-HUVE cells) and human dermal fibroblast (HDF) cells in culture. Further, we present evidence that Ia present on HUVE cells and HDF cells can be functionally recognized by human T cells, resulting in a two-way interaction between T cells and mesenchymal cells that may be important in allograft rejection.

Immunological monitoring of diabetic and nondiabetic recipients of renal allografts

Peripheral blood T-lymphocyte populations were monitored sequentially in diabetic recipients of renal allografts. Unfractionated buffy coat preparations were reacted with the murine monoclonal antibodies, OKT3 (all circulating T-cells), OKT4 (helper/inducer/regulatory T-cells), and OKT8 (cytotoxic/suppressor cells). Levels of peripheral blood lymphocyte subpopulations of diabetic patients monitored prior to transplantation revealed no significant abnormalities. Following transplantation, but prior to any therapy for acute rejection, the mean percentage of OKT3, 4, and 8 reactive cells in diabetic recipients closely resembled those observed in nondiabetic recipients. After treatment for acute rejection, a marked decrease in the mean OKT4/OKT8 ratio from normal (1.90 +/- 0.7) was observed in both diabetic (1.04 +/- 0.5), and nondiabetic (1.35 +/- 0.5) allograft recipients. Eleven of thirteen diabetic recipients with long-term functioning allografts were found to have a depressed OKT4/OKT8 ratio (mean 1.03 +/- 0.6). T-cell subset monitoring of diabetics with end-stage renal failure failed to reveal any significant differences from nondiabetic, uremic patients. The high incidence (75%) of allograft rejection noted in these diabetic allograft recipients similarly suggests normal immunocompetence. Following successful completion of rejection therapy, however, reduction in the ratio of OKT4 to OKT8 reactive cells suggests that an alteration in immune responsiveness has occurred. Immunological monitoring of these long-term diabetic recipients with functioning allografts suggests that the observation of a consistently depressed OKT4/OKT8 ratio may (1) be useful in predicting continued allograft function and (2) prompt the more rapid reduction of steroid medication to maintenance dosage since this pattern may be indicative of subclinical viral infection.

Monoclonal antibodies in urology

The recent development of hybridoma technology has made it possible to obtain large quantities of antibody against a single determinant (monoclonal antibodies). This review describes the history of hybridoma technology and the method of producing monoclonal antibodies. It examines the role of such antibodies in diagnosis, tissue typing, histochemistry, developmental biology and study and treatment of diseases, including cancer, emphasizing the work being done on urological diseases.

Treatment of intractable rheumatoid arthritis with total lymphoid irradiation (TLI): immunological and clinical changes

Eleven patients with intractable rheumatoid arthritis were treated with total lymphoid irradiation in a feasibility study. The mantle and the inverted Y fields were treated successively to a cumulative dose of 2000 rads. Nine of eleven patients showed at least a 35% improvement in three of four clinical parameters by six months and continued to maintain at least this level of improvement at their last observation points (13-28 months after TLI). There was a marked decrease in the percentage of total T cells and Leu-3 cells (helper), but an increase in the percentage of Leu-2 cells (suppressor/cytotoxic), resulting in a dramatic increase in the Leu-2/Leu-3 ratio. There was also a decrease in response to PHA, Con A and MLR.

Lymphocyte subpopulations in patients with acne vulgaris

T- and B-lymphocyte subpopulations were measured in the peripheral blood of patients with varying severity of acne and in acne-free control subjects. Increased severity of acne correlated with an increased number of T lymphocytes, helper T cells and B cells, while the number of suppressor T cells remained normal and did not alter significantly. This evidence suggests that there is no lack of regulation of the immune response in acne patients.

Circadian variation of lymphocyte subpopulations: a study with monoclonal antibodies

Use of monoclonal antibodies to identify subpopulations of circulating lymphocytes in healthy adults showed pronounced circadian variations in total T cells, the two major T cell subsets, and HLA-DR+ lymphocytes. When the results for the T cell subsets were expressed as a ratio (helper:suppressor) no significant rhythmic variation was observed. Lymphocytes bearing a surface antigen identified by the HNK-1 antibody (a population containing the natural killer and antibody dependent killer activity) did not show significant rhythmic variation. There was an inverse relation between plasma cortisol concentration and numbers of T and B cells. These observations have therapeutic implications and should be considered in the course of immunological monitoring.

Detection of renal allograft rejection by computer

A computer program incorporating an adaptation of a statistical method, the multiprocess Kalman filter, was used to detect changes in trends of plasma creatinine and urea concentrations. In 28 recipients of renal allografts a definite deterioration in renal function was identified retrospectively on 32 occasions by an experienced renal physician independently of the statistical analysis. The computer identified 31 of these 32 episodes using creatinine and urea results, and 29 using creatinine alone. Dysfunction was identified by the computer significantly earlier (p less than 0.05) than by the clinician and a median of one day earlier (p less than 0.02) than treatment was actually initiated. The computer identified dysfunction on 11 out of 1259 days when the clinician did not suspect rejection. These 11 episodes may have had a pathological importance, though no clinical diagnosis was made. This computer method is useful for immediate analysis of incoming results and for timing events either prospectively or retrospectively.

Changes in T-cell subsets in patients with rheumatoid arthritis treated with total lymphoid irradiation

Patients with intractable rheumatoid arthritis (RA) were treated with total lymphoid irradiation (TLI, 2000 rads). We previously reported long-lasting clinical improvement associated with marked suppression of in vitro lymphocyte function in this group. In an attempt to better understand the mechanism of immunosuppression and clinical changes observed after TLI, we studied in greater detail changes in peripheral blood T-cell subsets identified by monoclonal antibodies. Before TLI, RA patients had a higher percentage of Leu-3 (helper subset) cells and a lower percentage of Leu-2 (suppressor/cytotoxic subset) cells than normals. Immediately after TLI, the absolute numbers of both Leu-2 and Leu-3 cells were reduced by at least 90%. Within 6-12 weeks, the number of Leu-2 cells returned to the pretreatment levels, but the levels of Leu-3 cells remained depressed for months thereafter. The lack of repopulation of Leu-3 cells resulted in a marked increase in the ratio of Leu-2 to Leu-3 cells as compared to pretreatment values (1.73 +/- 0.23 vs 0.39 +/- 0.06), and in a decrease in the percentage and absolute number of total T (Leu-1 and Leu-4) cells. The failure of Leu-3 cells (which mediate predominantly helper/inducer functions) to repopulate the peripheral blood may contribute to the prolonged clinical immunosuppression observed after TLI. Similar changes in T-cell subsets were not observed in RA patients given remittive drugs or low doses (200 rads) of radiotherapy. Thus, TLI differs from other treatment modalities with regard to its prolonged selective effect on the Leu-3 subset.

OKT4/8 ratio in the blood and in the graft during episodes of human renal allograft rejection

We have analyzed the frequency of T helper (Th) and T suppressor/killer (Ts/k) lymphocytes in the blood and in the renal allograft during episodes of rejection and during quiescence. Monoclonal OKT4 and OKT8 antibodies were used to mark the Th and Ts/k cells, respectively. Density centrifugation-separated mononuclear leukocytes and FACS IV cell sorter or the Staphylococcus aureus rosette assay were used to determine the ratio in the blood, with concordant results. Fine needle aspiration biopsy (FNAB) and the Staph. assay were used to demonstrate the lymphocyte subtypes in the graft. The mean OKT4/8 ratio in the blood was significantly lower in the transplant recipients than in healthy controls (1.1 +/- 0.7 vs 1.8 +/- 0.2, respectively, P = 0.000). The individual variation was, however, high and no correlation between the OKT4/8 ratio in the blood and the inflammatory episodes in situ was observed. During 19 of the 25 episodes of inflammation, the dominant lymphocyte subtype in the graft was the Ts/k cell. In the remaining six cases it was the Th cell. All rejection episodes of the former type were reversible, in the latter type, four out of six were irreversible.

Lymphocyte subsets in normal and pre-eclamptic pregnancies

Peripheral blood lymphocyte subsets in normal and preeclamptic pregnancies have been studied by using the monoclonal antibodies OKT3 (T cells), OKT4 (helper/inducer T cells) and OKT8 (suppressor/cytotoxic T cells). In addition the numbers of mononuclear cells bearing Ia and monocyte antigens have been assessed by using the monoclonal antibodies OKIa1 and OKM1. No significant differences were found between 10 normal pregnant and 10 non-pregnant subjects. Ten preeclamptic patients were studied and showed an increase in OKT4-positive helper cells. This was significant in terms of percentage of mononuclear cells but not the absolute numbers or the helper/suppressor (OKT4/OKT8) ratio.

The immunologic and ultrastructural characterization of the cellular infiltrate in acute cardiac allograft rejection: prevalence of cells with the natural killer (NK) phenotype

The inflammatory cell infiltrates in 15 endomyocardial biopsies serially obtained from a human cardiac allograft during a 1 1/2-year period were characterized. An indirect immunofluorescent technique with hybridoma-derived monoclonal antibodies which preferentially react with B lymphocytes (anti-Ia), mature T cells (OKT3, Leu 1), and helper (OKT4b,d) and supressor/cytotoxic (OKT8) T-cell subsets and with natural killer cells, macrophages, and granulocytes (OKM1) was used. During each of seven rejection episodes the overwhelming majority of infiltrating cells in the endomyocardial biopsy were OKM1+Ia. These cells displayed short microvilli, a moderate amount of cytoplasm, numerous mitochondria, a large amount of rough endoplasmic reticulum, Golgi, and an indented nucleus, that is, the ultrastructural features of large, granular lymphocytes. Thus, they morphologically and phenotypically resemble those lymphoid cells which have been shown to possess natural killer (NK) functions in man. Occasional Leu 1+OKT3+ cells, some of which were OKT8+, were also seen during acute rejection. In each instance following therapy and resolution of the rejection episode only rare OKM1+Ia- cells were present. At this time the majority of the cells were Leu 1+OKT3+OKT8+. Routine biopsies, performed at times without evidence of rejection, showed only reactivity for Ia antigens by the capillary endothelium. These studies demonstrate the prevalence of cells with the natural killer phenotype in this human cardiac allograft during episodes of acute graft rejection.

Some recent developments in immunocytochemistry

Immunocytochemistry has become an indispensable tool both in basic biomedical research and in diagnostic histopathology. Several recent innovations have led to improvements in the sensitivity; specificity and precision of these techniques. Numerous modifications of the original methods have been developed, many with increased sensitivity. In particular, methods using protein A or the avidin-biotin complex as second steps appear to be promising. New methods for the quantitative determination of sensitivity have become available. The introduction of monoclonal antibodies as immunocytochemical reagents appears to be a major improvement. New methods of immunochemical analysis, such as immunoblotting and immunospotting of antigens extracted from tissue specimens, allow the molecular composition of immunoreactive antigenic sites in a tissue to be analysed. The accuracy of localization in immunoelectron microscopy has been improved significantly through the use of ultracryotomy of unfixed tissue in combination with colloidal gold particles as a label. In addition, gold particles can be counted and thus allow relatively simple quantification of the immune reaction. Using flow cytometry, especially in combination with monoclonal antibodies, quantitative immunofluorescence has become feasible.

A rapid micromethod for evaluating T cell subsets in blood using monoclonal antisera

A simple accurate method is described for enumerating T cell subsets in whole blood. The method, which depends on indirect immunofluorescence using biotin-coupled monoclonal antisera and fluorescein-coupled avidin, and propidium iodide for nuclear counterstaining, was compared with the conventional method based on initial separation of lymphocytes by density flotation and exposure to monoclonal antisera. Accurate identification of mononuclear cells in whole blood by nuclear staining with propidium iodide was established. The whole blood method gave numbers for T cell subpopulations generally comparable with those obtained by the conventional method, but slightly higher numbers of Leu2a+ cells were found by the whole blood method, and shown to be higher because of selective loss of Leu2a+ plastic-adherent cells in the conventional method. The whole blood method is quicker, uses only 0.5 ml blood and is economical in use of monoclonal reagents.

Association of herpesvirus infections with T-lymphocyte-subset alterations, glomerulopathy, and opportunistic infections after renal transplantation

We studied the interrelation among herpes-virus infections, T-lymphocyte subsets, opportunistic infections, and renal histopathology in 28 recipients of renal allografts. All primary or reactivated herpesvirus infections occurring in the first three months after transplantation in recipients of cadaveric grafts accompanied persistent inversions in the ratio of OKT4 (helper/inducer) to OKT8 (cytotoxic/suppressor) lymphocytes. In the less heavily immunosuppressed recipients of organs of living related donors, these inversions were seen only in association with clinically apparent cytomegalovirus infections. Five of seven opportunistic infections occurred in patients with OKT4/OKT8 ratios of less than 1.0. Biopsy specimens from patients with renal dysfunction occurring in association with a low OKT4/OKT8 ratio frequently revealed glomerular damage rather than acute cellular rejection. Monitoring of T-lymphocyte subsets provides early evidence of herpesvirus infections and identifies patients at increased risk for opportunistic infection after renal transplantation.

Monoclonal antibodies in clinical medicine--a review

Monoclonal antibodies are produced by the cell fusion method, whereby immune murine spleen cells are fused with a murine myeloma to produce large quantities of specific homogeneous antibodies. These have obvious advantages over conventional antisera particularly for in vitro diagnostic procedures. The use of monoclonal antibodies to human T cells, leukaemias and solid tumours are reviewed. In these areas, monoclonal antibodies are now being used for the diagnosis of disease activity, for the monitoring of graft rejection, and for the in vivo treatment of leukaemia and graft rejection in man. Murine monoclonal antibodies--examples of genetic engineering--represent a new and early phase of the use of molecular biological techniques for the production of reagents of use in clinical medicine.

The effect of plasmapheresis and drug immunosuppression on T-cell subsets as defined by monoclonal antibodies

The number of total T-cells and the number of helper/inducer T-cells decreased in 27 of 31 patients with immunologic disorders treated with plasmapheresis and drug immunosuppression. The number of suppressor/cytotoxic T-cells increased in the majority of patients. The helper/inducer to suppressor/cytotoxic cell ratio, which was initially elevated in 26 of 31 patients, decreased significantly in all but 2 patients after therapy. Ten patients were already on drug immunosuppression at the time plasmapheresis was started, and all 10 showed increased helper/inducer to suppressor/cytotoxic cell ratio despite their drug therapy. The helper/inducer to suppressor/cytotoxic cell ratio decreased in all ten patients after plasma exchange. The number and the percentage of total T-cells and helper/inducer cells decreased from prepheresis levels while the number and the percentage of suppressor/cytotoxic cells increased. Plasmapheresis, in combination with drug immunosuppression, was effective in decreasing the elevated helper/inducer to suppressor/cytotoxic cell ratio in disorders of the immune system. In contrast, patients on immunosuppressive drug therapy alone had persistently high immunoregulatory ratio.