Immunosuppressive treatment for kidney transplantation.

Immunosuppressive treatment minimizes unwanted immune reactivity, but it also leads to complications such as metabolic disorders, cardiovascular diseases and malignant tumours. In this paper we summarise the recent developments in action mechanisms of available immunosuppressive drugs and their usage for renal transplantation. These drugs act at various levels of lymphocytic activation and proliferation, and they may have additive or synergic effects when combined. In the majority of patients, the immunosuppressive protocol includes a calcineurin inhibitor (tacrolimus or cyclosporin), an antimetabolite (mycophenolate mofetil or mycophenolic acid) and a corticosteroid. Most patients also receive induction with monoclonal or polyclonal antilymphocytic antibodies. These immunosuppressive drugs allow a one-year survival of renal allografts in over 90% of cases and an incidence of acute rejection episodes below 15%. In most cases, acute cell-mediated rejection can be reversed with pulse doses of methylprednisolone; less often antilymphocytic antibodies must be applied. Acute humoral rejection can be suppressed with high doses of intravenous immunoglobulines or low doses of cytomegalovirus hyperimmune globuline, in combination with plasmapheresis, to obtain a satisfactory reduction of anti-donor antibodies. This treatment also allows renal transplantation for sensitised recipients, or transplantation against a positive cross match or AB0 incompatibility. Less often, immunoadsorption, alemtuzumab, rituximab or splenectomy are applied. New immunosuppressive drugs and protocols are currently under investigation. Immunosuppressive agents and methods targeting the induction of immune tolerance to the donor organ are especially promising.

Anti-p53 antibodies in serum: relationship to tumor biology and prognosis of breast cancer patients.

The aim of this study was to analyze the concentration of anti-p53 antibodies in the serum of breast cancer patients and to correlate these results with various clinical, pathological and biochemical parameters. We also wanted to assess the prognostic significance of these antibodies in our patients. Sera from 61 patients with breast cancer and 20 individuals without malignancies were analyzed using enzyme-linked immunoadsorbent assay. High levels of anti-p53 antibodies were detected in twenty-one (35%) breast cancer patients and one control (5%). The difference was statistically significant. We observed an inverse relationship between the anti-p53 antibodies and the age of the patients. We found significant association of anti-p53 antibodies with tumor size, histological grade of the tumors and the number of axillary lymph nodes involved. The levels of anti-p53 antibodies were higher in patients with negative estrogen and progesterone receptors in comparison with patients with positive steroid receptors, but the difference was not statistically significant. No relation was observed between anti-p53 antibodies neither with the Cathepsin D levels in the cytosol nor with the HER-2/neu extracellular domain in the serum. Patients with primary tumors and higher levels of anti-p53 antibodies had shorter 5-year survival than patients with lower levels of anti-p53 antibodies. Our results support the role of anti-p53 antibodies as a biomarker of less favorable phenotype as well as a prognostic factor for patients with breast cancer.

Amino acid control of asparagine synthetase: relation to asparaginase resistance in human leukemia cells.

Complete amino acid deprivation in mammalian cells causes a significant enhancement in gene expression for a number of important cellular activities; among these is asparagine synthetase (AS). The data presented demonstrate that, in both nonleukemic (rat Fao hepatoma cells) and human leukemia cells (MOLT-4, NALL-1, and BALL-1), AS mRNA levels, protein content, and enzymatic activity are induced after incubation in an otherwise complete tissue culture medium that is deficient in a single amino acid or in medium that has been depleted of the amino acid asparagine by the addition of asparaginase. Complete amino acid deprivation results in a concerted increase in AS mRNA, protein, and enzymatic activity, which, in conjunction with previously published research, suggests that the mechanism of this cellular response involves transcriptional control of the AS gene. Asparaginase treatment is a standard component of acute lymphoblastic leukemia therapy for which the effectiveness is related to the inability of these cells to upregulate AS activity to a sufficient level. With regard to the asparaginase sensitivity of the three human leukemia cell lines, there was a trend toward an inverse relation to the degree of AS expression. Selection for asparaginase-resistant MOLT-4 sublines resulted in enhanced AS mRNA and protein content regardless of whether the cells had been selected by asparaginase treatment directly or asparagine was removed from the culture medium. Collectively, the data illustrate that further advances in asparaginase therapy will require additional knowledge of amino acid-dependent regulation of AS gene expression and, conversely, that asparaginase resistance represents a model system for investigating metabolite control in a clinically relevant setting.