Qualitative and quantitative studies of cytokines synthesized and secreted by non-human primate peripheral blood mononuclear cells

Non-human primates are being utilized in a variety of pre-clinical studies, including those involved with mechanisms of organ transplant rejection and those being used as models to test the efficacy of vaccines against a variety of infectious diseases, most notably AIDS. These studies clearly involve immunological effector mechanisms, which include the interaction between T cells, B cells, monocytes, and cytokines that regulate these interactions. However, there is very little known about assays and quantitation of cytokines from non-human primates. In attempts to address this issue, bioassays, commercially available EIA kits, and primer pairs and probes specific for human cytokines were evaluated for their ability to detect and quantitate the non-human primate homologues. Data suggest that although the EIA kits that were evaluated for human IL-1 alpha, IFN-gamma, and TNF-beta failed, the EIA kits for IL-1 beta, IL-2, IL-4, IL-6, and TNF-alpha, the bioassays and RT-PCR assays for each of the cytokines were successful in detection and most likely quantitation of the non-human primate cytokine homologues. These assays will greatly facilitate future studies on the role of cytokines in these non-human primate studies.

Effects of IL-7 on human lymphocytes

Interleukin-7 (IL-7) is known as a growth factor for pre B-cell and mature T-cells in human. But in leukemic cells, IL-7 effect is variously reported. To investigate the effect of IL-7 on the cells of childhood acute leukemia we used 3H-Thymidine assay. Twelve Acute lymphoblastic leukemia (ALL), seven T-ALL and three Acute myelogenous leukemia (AML) were involved in this study. Two out of twelve ALL and three out of seven T-ALL bone marrow (BM) cells were stimulated by IL-7 in 3H-Thymidine incorporation. In normal and AML BM cells, IL-7 had no stimulatory activity as in various leukemic cell lines. Two normal peripheral blood T-cells responded to IL-7 dose dependently. We have seen the effect of IL-7 to stimulate T-lineage cells but, for precise conclusion, further study using more purified samples will be needed.

Phase I study of recombinant human interleukin-2 for pediatric malignancies: feasibility of outpatient therapy. A Pediatric Oncology Group Study

Published data indicate that when recombinant interleukin-2 (rIL-2) is administered to children as a 15-min i.v. bolus, doses of 18 x 10(6) IU/m2 are poorly tolerated, requiring intensive care unit (ICU) management of IL-2-induced hypotension. We administered rIL-2 as a 1- or 2-h i.v. infusion to 11 children with malignancies refractory to conventional therapy. IL-2 was given every Monday/Wednesday/Friday for 3 weeks. Four children received 12 x 10(6) IU/m2/dose, four received 18 x 10(6) IU/m2/dose, and three received 24 x 10(6) IU/m2/dose (1 Cetus Unit = 6 IU). Fever, chills, flushing, nausea, vomiting, transient weight gain, and oliguria were observed at all three dose levels (not dose-limiting toxicities). Cardiovascular toxicity was significantly reduced compared to the bolus regimen. Mild hypotension was observed at all three dose levels; however, there was no severe dose-limiting hypotension. Because of reduced cardiovascular toxicity, IL-2 was safely administered on an outpatient basis. This regimen induced marginal transient increases in natural killer cell activity and lymphokine-activated killer cell activity. No measurable clinical tumor response was observed in any of the 11 children. The maximum-tolerated dose has not been reached. This regimen allows for a considerable cost reduction (outpatient care instead of ICU care) and safety, making further clinical trials on the use of IL-2 in children more feasible.

A phase I study of interleukin-2 in children with cancer and evaluation of clinical and immunologic status during therapy. A Pediatric Oncology Group Study

The authors performed a Phase I study to assess the toxicity and hematologic effect of recombinant human interleukin-2 (rIL-2) in seven children with advanced malignancies. The rIL-2 was given as a bolus injection of 1 or 3 X 10(6) U/m2/dose three times a week (Monday, Wednesday, and Friday) for 3 weeks. No life-threatening toxicity occurred with the dose of 1 X 10(6) U/m2 of rIL-2. At a dose of 3 X 10(6) U/m2, therapy had to be terminated due to cardiovascular toxicity in two patients. Toxic effects at low-dose rIL-2 included fever, nausea, vomiting, and mild hypotension. High-dose rIL-2 toxicity included fluid retention, increased creatinine, oliguria, elevated liver enzymes, and significant hypotension. Immunologic studies showed that rIL-2 caused a drop in the number of circulating peripheral blood mononuclear cells, T-cells, and natural killer cells which returned to pretherapy levels or above by 24 to 48 hours. The rIL-2 exerted no growth or stimulatory activity on the leukemic cell population. To the authors' knowledge, this is the first report of a Phase I study of IL-2 therapy in children.

Cyclosporine in the treatment of red cell aplasia

A 4-year-old girl was diagnosed to have pure red cell aplasia. For 5 years, she received multiple packed red cell transfusions (average 11/year). Several therapeutic maneuvers were attempted including prednisone, oxymethalone, plasmaphoresis, high dose methyl prednisolone-to no avail. Finally, cyclosporine was administered for 5 months. This increased her reticulocyte count and cured the disease. For the last 2 years she has been in excellent health and has not required any further transfusions. The possible mechanism of action of cyclosporine in this disease is discussed.

Phagocytosis of neutrophils by marrow macrophages in childhood chronic benign neutropenia

Chronic benign neutropenia of childhood is a heterogeneous disorder. This study describes two severely neutropenic children with a benign clinical course and the unique bone marrow finding of macrophage engulfment of band and segmented neutrophils. Phagocytic vacuoles in the majority of macrophages contained neutrophils in various stages of digestion at both the light and electron microscope level (with as many as four neutrophils observed in single macrophages). Ultrastructural studies demonstrated that the neutrophils were morphologically normal, and apparently viable at the time of phagocytosis. This type of neutrophil phagocytosis was not observed in five other consecutively studied children with CBN. All of these children with CBN had ultrastructurally normal neutrophils, lacked demonstrable antineutrophil antibodies or serum inhibitors to in vitro myelopoiesis, and had normal colony-forming cells and colony-stimulating activity in vitro. Thus despite many similar clinical and laboratory features in children with CBN, only a unique subgroup of these patients demonstrates abnormal neutrophil-macrophage interaction.