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Biomedical subjects

A B Cosimi

Publications and source records attributed to A B Cosimi.

At least 163 records · Page 9Linked to original sources
PubMed1986

Two-color flow cytometry and functional analysis of lymphocytes cultured from human renal allografts: identification of a Leu-2+3+ subpopulation.

The phenotype of T lymphocyte subsets present in renal biopsies showing acute cellular allograft rejection in six patients on cyclosporine have been characterized in situ by immunoperoxidase staining, and after expansion in vitro in interleukin 2 (IL-2) by two-color flow cytometry, sorting, and functional analysis. After 8 to 42 days in organ culture, both Leu-3+ (CD4) and Leu-2+ (CD8) subsets were found in each culture, in a ratio that varied from 0.2 to 5.0, which was not significantly different than the results of in situ immunoperoxidase staining of the uncultured biopsy. The cultured cells were almost all Leu-4+ (CD3) T cells (89% +/- 4), which expressed the activation markers DR (82% +/- 6) and the IL 2 (CD25) receptor (15% +/- 4). The Leu-3+ cells were largely Leu-8- (90% +/- 6), whereas a minority of the Leu-2+ cells were Leu-15+ (CD11) (26% +/- 4). Only a small fraction of the Leu-2+ cells stained for Leu-7 (8% +/- 6). Functional analysis of FACS-purified Leu-2-3+ and Leu-2+3- populations indicated that both subsets proliferated in response to graft donor antigens in a mixed lymphocyte reaction (MLR) and produced IL 2. Only the Leu-2+3- population demonstrated donor-specific cytotoxic activity. A minor subpopulation in each culture were both Leu-3+ and Leu-2+ (2.0%). Leu-2+3+ cells from one biopsy were purified to homogeneity (99.8%), and were found to express the T cell antigen receptor complex Ti/CD3 (WT-31+, Leu-4+), but not the common thymocyte antigen CD1 (OKT6). The Leu-2+3+ cells neither responded in the MLR, nor showed any cytotoxic capacity. The Leu-2+3+ cells were capable of IL 2 but not interferon-gamma production. None of the purified cultures demonstrated NK activity. A subset of the purified Leu-2+3+ cells lost Leu-2+ during 1 to 3 wk in culture, and became Leu-2-3+. These studies provide evidence that the cells that infiltrate renal allografts during rejection include alloproliferative, lymphokine-producing cells of both Leu-2+ and Leu-3+ subsets. The Leu-2+3- cells are also highly cytotoxic against donor lymphocytes, indicating the presence of helper independent cytotoxic T cells. A minor population of Leu-2+3+ T cells that do not express donor specific function was also identified.

Antibodies, Monoclonal↗
PubMed1986

Monoclonal antibody therapy. Anti-idiotypic and non-anti-idiotypic antibodies to OKT3 arising despite intense immunosuppression.

The frequency, timing, and specificity of the humoral antibody response to a murine monoclonal antibody (OKT3, IgG2a) were measured in 21 consecutive renal allograft recipients. These patients received i.v. OKT3, 1-5 mg/day for 10-20 days as treatment for acute graft rejection. Maintenance immunosuppression consisted of azathioprine and corticosteroids. Using three different assays, an antibody response was detected in 75% of the 20 patients with adequate samples. The ELISA assay of the overall IgM and IgG reactivity to OKT3 revealed that IgM anti-OKT3 appeared in 65% and IgG anti-OKT3 in 50% of the patients, reaching a peak 20-33 days after the last dose of OKT3. The IgM preceeded the IgG in most cases (P less than 0.02) and in 8 cases was detected during therapy. One patient had high levels of IgM anti-OKT3 before therapy, yet responded normally to OKT3. Interference with the therapeutic effectiveness was evident in one patient who developed IgG antibodies during therapy. His serum blocked the binding of F-OKT3 to normal lymphocytes in the presence of normal BALB/c serum. The blocking assay, done by flow cytometry, measured anti-idiotypic (Id) reactivity since the sera did not affect the binding of OKT8 (another IgG2a) or anti-Leu4 (another anti-T3), and the blocking activity remained after affinity absorption with normal mouse IgG. Using this assay, 60% of the patients made an anti-Id response. One made only anti-Id, and several had anti-Id at times when other reactivities were undetectable. Antibodies to non-idiotypic, presumably isotypic, determinants represented on OKT8 occurred in only 44%, while other reactivity (OKT4; IgG2bK) was less common (12%) and weaker. While no adverse allergic reactions occurred in this group of patients, the anti-Id antibodies, which are a prominent feature of the immune response to this and probably other monoclonal antibodies, can block their therapeutic effectiveness and can arise despite intense immunosuppression. This response may require the use of different idiotypes for prolonged or repeated courses of therapy and may be the major obstacle to the use of human monoclonal antibodies.

Antibodies, Anti-Idiotypic↗
PubMed1986

Diagnosis of tubular injury in renal transplant patients by a urinary assay for a proximal tubular antigen, the adenosine-deaminase-binding protein.

Two murine monoclonal antibodies (URO-4 and URO-4a)--which detect different epitopes of a proximal tubular cell glycoprotein antigen, the adenosine-deaminase-binding protein (ABP)--have been formatted into a sandwich enzyme immunoassay for detection of ABP in the urine. Serial urine samples from 34 renal transplant patients during the first six months posttransplant were analyzed to determine the correlation of this test with clinical rejection and cyclosporin (CsA) nephrotoxicity. In 29/29 acute rejection episodes the ABP level was elevated, beginning 1-7 days prior to treatment of rejection. Eighteen patients were treated for rejection with courses of OKT3 or antithymocyte globulin: 0/6 whose ABP level fell to normal during therapy had rerejection; 10/12 whose ABP level remained elevated had rerejection within 7 days of therapy completion. Of 15 patients treated with CsA, 7 had no rejection or drug toxicity; all 7 had normal ABP levels. The remaining 8 had CsA nephrotoxicity, all in association with elevated ABP levels that rapidly fell to normal with decreased CsA dose. An additional 7 patients with creatinine elevations more than 6 months posttransplant were studied: 5 had chronic vascular changes on biopsy, no response to increased immunosuppression, and normal ABP levels; 2 had a cellular infiltrate on biopsy, response to increased immunosuppression, and elevated ABP levels. We conclude that the urinary ABP assay provides information useful in the management of renal transplant patients with acute and chronic rejection and CsA toxicity.

Adenosine Deaminase↗
PubMed1986

OKT3 monoclonal antibody plasma levels during therapy and the subsequent development of host antibodies to OKT3.

OKT3 levels and the presence of human antibodies to OKT3 were determined in the plasma of 66 patients receiving OKT3 monoclonal antibody (5 mg i.v. daily) for the treatment of acute renal allograft rejection. Plasma 24-hr trough levels of OKT3 rose over the first three days and then remained in a steady state over the remainder of the 14-day period of OKT3 therapy, with a mean level of 902 +/- 71 ng/ml (mean + SEM). On termination of OKT3 therapy plasma levels of OKT3 dropped to very low levels after 3 days. Host antibodies, usually of low titer, developed in a number of patients, usually 2-3 weeks after the start of OKT3 therapy. 37/43 patients (86%) who received OKT3 alone developed IgG anti-OKT3 antibodies; 9/23 patients (39%) who received Cytoxan in addition to OKT3 developed IgG anti-OKT3 antibodies, a significantly lower (P = 0.0002) incidence. The present regimens permitted maintenance of adequate levels of circulating OKT3 for 2 weeks, a sufficient time to reverse acute renal allograft rejection in most patients.

Antibodies, Anti-Idiotypic↗
PubMed1986

Pharmacokinetics and pharmacodynamics of atracurium during isoflurane anesthesia in normal and anephric patients.

We compared the pharmacokinetics and pharmacodynamics of atracurium in eight normal and eight anephric patients during isoflurane anesthesia. Plasma concentrations were measured by high performance liquid chromatography after a single injection of 0.5 mg/kg, and neuromuscular effects were evaluated by the single twitch method. With regard to pharmacokinetic or pharmacodynamic parameters, we found no statistically significant differences between normal and anephric patients. We conclude that during isoflurane anesthesia, anephric patients distribute and eliminate atracurium much as normal patients do.

Anesthesia, General↗
PubMed1985

Anaphylactic reaction and cardiopulmonary arrest following intravenous cyclosporine.

Cyclosporine, a new immunosuppressive agent useful in recipients of a variety of organ transplants, has been associated with a number of adverse effects, most notably nephrotoxicity. This report describes a woman about to undergo liver transplantation in whom intravenous administration of cyclosporine was associated with an apparent anaphylactic reaction resulting in cardiopulmonary arrest. Similar reactions have thus far not been reported after oral administration of cyclosporine. Intravenous cyclosporine must be administered under close supervision and should be avoided in any patients with a history of prior allergic reactions to the drug or to a component of its intravenous formulation.

Adult↗
PubMed1985

Immunogenicity of hepatitis B vaccine in renal transplant recipients.

To evaluate the immunogenicity of hepatitis B vaccine in renal transplant recipients, we administered three 40-microgram doses of vaccine to 17 patients who had previously undergone transplantation and were on immunosuppressive therapy. Life-table analysis revealed a cumulative antibody response rate of only 17.6% at 12 months, and the three responders had low titers of antibody to hepatitis B surface antigen. There were no serious adverse effects and no episodes of graft rejection in responders or nonresponders. In addition, the ratio of helper/inducer (T4) to suppressor/cytotoxic (T8) T cells in vaccinees bore no relationship to the immunogenicity of the vaccine. These data indicate that hepatitis B vaccine is weakly immunogenic in renal transplant recipients and illustrate the need for vaccination prior to transplantation for maximal protection against hepatitis B virus infection.

Adult↗
PubMed1984

Conservative surgical management of superficially invasive cutaneous melanoma.

Between 1976 and 1980, 136 patients were evaluated for primary treatment of cutaneous melanoma. Forty-nine lesions were invasive to Clark's Level II (38 patients) or III (11 patients) with a thickness of 0.3 to 1.2 mm. Conservative re-excision was advised as definitive therapy for these patients. The margin of resection was defined as the maximum excision that would allow primary closure of the wound. Pathology reports of the re-excised specimens revealed the narrowest margins to be 0.7 to 4 cm. Unexpected residual tumor was present in 2 specimens and melanocytic hyperplasia in 12 specimens. After a follow-up period of 2.5 to 7.0 years, there have been no local recurrences. One patient developed regional lymph node metastases 16 months and, then central nervous system (CNS) metastases 25 months after primary treatment. A second patient died with pulmonary metastases 4.5 years after initial therapy. Melanomas that are not deeply invasive do not require wide excision and skin grafting for local control. Occasionally these thin lesions do produce systemic metastases, emphasizing the need for long-term follow-up of even "low-risk" patients.

Adult↗
PubMed1984

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.

Antibodies, Monoclonal↗
PubMed1984

The use of local allograft irradiation following renal transplantation.

Over a 10 year period, 67 recipients of 71 renal allografts received graft irradiation following the diagnosis of rejection. The majority of kidneys were treated with a total dose of 600 rad, 150 rad per fraction, in 4 daily fractions. Fifty-three kidneys were irradiated following the failure of standard systemic immunosuppression and maximally tolerated antirejection measures (pulse high dose steroids, Actinomycin, ATG) to reverse an episode of acute rejection. Seven of these patients (13%) had greater than a 50% improvement in serum creatinine (Cr) 1 week following completion of the irradiation. Twenty-two (42%) of these allografts were noted to have stable (i.e. no deterioration) or improved function 1 month following the treatment with irradiation. Eleven (21%) of these allografts maintained function 1 year following transplantation. There were 10 patients whose allografts were irradiated because of renal dysfunction in a clinical setting which did not permit the administration of further immunosuppression, i.e., infection or hematologic dyscrasias. Three of these patients (30%) had greater than a 50% improvement in serum Cr 1 week following completion of the irradiation. Nine (90%) of these allografts had stable or improved function 1 month following the treatment with irradiation. Biopsies were obtained of 41 allografts. Of the 24 renal allografts with predominantly cellular rejection, 10 (42%) had the process reversed or stabilized at 1 month following irradiation. Five (21%) of these allografts were functioning at 1 year following irradiation. Rejection was reversed or stabilized in 6 of 17 (35%) allografts at 1 month when the histologic features of renal biopsy suggested predominantly vascular rejection. One (6%) of these allografts was functioning at 1 year following transplantation. Local graft irradiation has helped maintain a limited number of allografts in patients whose rejection has failed to respond to systemic immunosuppression. Irradiation may also benefit patients with ongoing rejection in whom further systemic immunosuppression is contra-indicated.

Adult↗
PubMed1984

Parathyroid surgery in patients with renal failure.

A subtotal parathyroidectomy was performed in 32 patients with hyperparathyroidism and renal dysfunction. Minimal long-term sequelae were observed [two patients with recurrent hyperparathyroidism (6.2%), one patient with persistent hypoparathyroidism (3.1%)]. This experience is compared with reports in the literature advocating total parathyroidectomy and autotransplantation. A subtotal parathyroidectomy remains the preferred approach at this institution. Patients with elevated alkaline phosphatase levels before surgery should be monitored carefully for early postoperative hypocalcemia. The low incidence (3.2%) of hyperparathyroidism observed in patients following successful renal transplantation indicates that hypercalcemic allograft recipients should be observed for at least 4 months before contemplating surgical intervention.

Adolescent↗
PubMed1984

Evolving use of OKT3 monoclonal antibody for treatment of renal allograft rejection.

OKT3, a monoclonal antibody reactive with a surface glycoprotein present on all postthymic T cells, was used to treat the initial acute episode of rejection in 30 recipients of cadaveric donor renal allografts. The first 16 patients received 1-5 mg daily for a period of 10-21 days during which the azathioprine and prednisone dosages were sharply reduced. Circulating T cells were eliminated within minutes after the first OKT3 infusion. T cells reactive with OKT3 remained depressed throughout the period of treatment, although a significant number of cells reactive with other T cells subset reagents became detectable after several days of OKT3 treatment. In all instances, the established rejection episode was reversed in 2-8 days without the addition of other immunosuppressive measures. Recurrent rejection occurred in 12 of 16 patients, but with further conventional immunosuppression, 50% of the renal allografts remain functional 20-44 months after transplantation. Fever, chills, and, in some instances, dyspnea following the first dose of OKT3 were the only side-effects observed. Most patients developed antiidiotypic or antimouse immunoglobulin antibodies without apparent clinical sequelae. In the subsequent 14 patients, modifications in the protocol included a steroid bolus prior to the first OKT3 infusion, limitation of therapy to 10 days, resumption of maintenance levels of azathioprine and prednisone prior to discontinuing OKT3, and addition of 3 i.v. doses of cyclophosphamide at the termination of treatment. Respiratory symptoms after the first infusion of the reagent have been eliminated. Antibody responses to OKT3 have been reduced, occurring in 38% as compared with 73% of patients treated previously. Recurrent rejection episodes observed in 8 of 14 patients have been reversible in all but one case. Allograft survival is 86% at 6-17 months posttransplantation. In the entire series of 30 OKT3-treated patients, only 4 grafts (13%) have been lost because of recurrent episodes of rejection.

Antibodies, Monoclonal↗
PubMed1984

Monoclonal antibodies for the diagnosis and treatment of transplant rejection.

Extensive experience with antibodies to lymphocytes for immunosuppression suggested the need for better means of evaluating alterations of peripheral blood lymphocytes during treatment. Improved immunosuppression was also anticipated if more precise control of selected lymphocyte populations could be achieved. The advent of monoclonal antibodies has permitted progress in both of these areas. For evaluation of the immune status of patients, the ratio between the numbers of the subclass of T lymphocytes having helper/inducer properties and those having suppressor/cytotoxic activity (OKT4+/OKT8+ cells) has been explored. Transplant rejection is more common in the presence of normal cell ratios than when ratios are reversed. In the former situation, however, when rejection occurs it is much more readily reversed than in the latter. Monoclonal antibodies have been used to treat transplant rejection in both nonhuman primates and in patients. Patient trials have so far been confined to the use of the pan-T-cell antibody OKT3. This has proved to be the most effective agent available for the reversal of acute cellular rejection in human kidney transplants. The problems of recurrent rejection activity after treatment and of antibody formation to the monoclonal antibody itself are being examined.

Animals↗
PubMed1984

Differential recovery of circulating T cell subsets after nodal irradiation for Hodgkin's disease.

To better understand the immunologic effects of lymphoid irradiation (LI), blood levels of T cell subsets were sequentially monitored in 15 patients before, during, and after irradiation treatment for Hodgkin's disease. Blood levels of all lymphocytes, T cells, and T cell subsets (defined by OKT4 and OKT8) fell dramatically and in similar proportions during early therapy, reaching levels less than 20 to 25% of control by the completion of mantle irradiation, and continuing at very depressed levels through the completion of therapy. Blood levels of OKT8-reactive (OKT8+) cells returned to pretreatment levels (402 +/- 38/mm3 vs 360 +/- 32/mm3 pretreatment) between 6 to 8 mo after LI, whereas blood levels of OKT4-reactive (OKT4+) cells returned to only 42% of previous values (242 +/- 22/mm3 vs 584 +/- 34/mm3 pretreatment) over the same period. The pre-LI ratio of OKT4+ to OKT8+ cells was 1.85 +/- 0.24 and fell to 0.65 +/- 0.05 between 6 to 8 mo after LI. During the recovery period, discrepancies of 208 +/- 32 cells/mm3 (3 to 5 months post LI) and 198 +/- 32 cells/mm3 (6 to 8 mo post LI) developed between the blood levels of OKT3+ cells and the sum of OKT4+ and OKT8+ cells. This suggests the emergence of OKT4+/OKT3-, OKT8+/OKT3-, and/or OKT4+/OKT8+ cells. In five patients, the sum of OKT4+ and OKT8+ cells was compared with the number of cells simultaneously co-stained by OKT4 and OKT8. It appeared that a significant proportion of the cells were OKT4+/OKT3- and OKT8+/OKT3- lymphocytes. We concluded that LI is similarly cytotoxic to peripheral blood T cell subpopulations. The reversed ratio after LI is a result of a slower repopulation of the peripheral blood by OKT4+ cells relative to OKT8+ cells. T cells after LI show a high degree of antigenic immaturity. It is postulated that the bone marrow that lies outside the fields of treatment and contains predominantly immature OKT8+/OKT3- cells is a major source of T cells repopulating the peripheral blood after LI.

Adult↗