Biology and therapeutic uses of myeloid hematopoietic growth factors and interferons

Long term administration of granulocyte-macrophage colony stimulating factor decreases development of 1-2 dimethylhydrazine-induced colon cancer in rats

BACKGROUND AND OBJECTIVES

The antitumoral activities of granulocyte-macrophage colony stimulating factor (GM-CSF) were shown earlier. In this study, the effects of GM-CSF were investigated on colon cancer induced by 18 weeks of 1-2 dimethylhydrazine (DMH) administration in rats.

METHODS

Four groups received subcutaneous saline (n = 20), 15 mg/kg DMH (n = 30), DMH +6 microg/kg GM-CSF (n = 30), and DMH +12 microg/kg (n = 30) GM-CSF.

RESULTS

The average number of tumors (2.8 vs. 1.5) and mean tumor volume (179 +/- 36 vs. 27 +/- 9 mm(3); means +/- SEM) were reduced in DMH + GM-CSF groups as compared to the DMH group (n = 30, P < 0.01). DMH-induced enhancement of free radicals and lipid peroxidation were decreased in DMH + GM-CSF group (n = 8-12, P < 0.05). The magnitude of DMH-induced alterations in superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities was lowered in the DMH + GM-CSF group (n = 12-16, P < 0.05). DMH-induced increases in the total nitrite/nitrate levels and the nitric oxide synthase (NOS) activity (n = 10-12, P < 0.05) were also reduced in the DMH + GM-CSF group (n = 8-9, P < 0.05).

CONCLUSIONS

The results indicate that GM-CSF inhibits the development of DMH-induced colon cancer in rats and suggest that inhibition of oxidative stress and NO pathway are involved in the observed antitumoral effects.

The role of immune reconstitution in cytomegalovirus infection

Cytomegalovirus (CMV) causes high morbidity and mortality in immunocompromised patients. The host immune response to CMV comprises specific and nonspecific cellular and humoral responses, but current knowledge supports a protective role only for cell-mediated immune responses. Although complete CMV eradication is unusual even in immunocompetent hosts, its morbidity can be limited by CMV-specific CD8+ cytotoxic lymphocytes supported by CD4+-mediated T lymphocyte helper activity. In patients with congenital or acquired deficiencies of cell-mediated immunity, recovery of CD4+ lymphocyte numbers and/or function coincides with cessation of CMV-associated morbidity. However, an immunological test that can predict protection against CMV disease across different types of high-risk patients is not yet available. In recent years, the introduction of antivirals active against CMV has improved the outcome of CMV disease. In addition, there is a continuous effort to develop CMV-specific immune-based therapies including vaccines and immune modulators such as cytokines, which may be of supplemental benefit in the control of CMV disease.

Use of myeloid colony-stimulating factors in neonates with septicemia

Bacterial sepsis is a major cause of neonatal morbidity and mortality. Successful management of neonatal sepsis requires early diagnosis, appropriate antimicrobial treatment, and aggressive intensive care. However, even when steps are taken appropriately, mortality rates can be high, particularly among certain subgroups, such as extremely preterm neonates and neonates with neutropenia. Multiple factors contribute to the increased susceptibility of neonates to infection, including developmental quantitative and qualitative neutrophil defects. Studies of infected animal and human neonates suggest that the use of recombinant human granulocyte colony stimulating factor (rhG-CSF) or recombinant human granulocyte macrophage colony stimulating factor (rhGM-CSF) can partially counterbalance these defects and thereby reduce morbidity and mortality. However, the body of clinical evidence is currently not sufficient to recommend rhG-CSF or rhGM-CSF administration confidently as routine adjunctive treatment for neonates with sepsis.

Detection of granulocyte-macrophage colony-stimulating factor in patients with pulmonary alveolar proteinosis

Pulmonary alveolar proteinosis (PAP) is an idiopathic lung disease in which the alveolar spaces are filled with surfactant. Recently, it has been proposed that PAP is caused by deficiency of granulocyte-macrophage colony-stimulating factor (GM-CSF) because GM-CSF-knockout mice develop the disease. To examine this possibility, we tested the two hypotheses that lung GM-CSF levels are low and that alveolar macrophages (AM) do not respond to GM-CSF in patients with PAP. Data from 10 adult patients with PAP who underwent therapeutic whole-lung lavage were compared with those of 10 healthy volunteers who underwent bronchoalveolar lavage (BAL) by fiberoptic bronchoscopy. Bronchoalveolar lavage fluid (BALF) and plasma were collected and analyzed for total protein and levels of GM-CSF, interleukin-3, and tumor necrosis factor (TNF)-alpha. Isolated AM were cultured with or without lipopolysaccharide (LPS) or GM-CSF, and production of GM-CSF and TNF-alpha was measured after 24 h. GM-CSF in BALF and plasma was higher in PAP than in control subjects (p </= 0.05), and was detectable under both reducing and nonreducing conditions as a 28-kD protein in BALF from the PAP patients. GM-CSF release by unstimulated AM from PAP patients was higher than in cells from control subjects, but the responses to LPS were similar. Mean TNF-alpha release by AM in response to GM-CSF was higher in control subjects than in PAP patients due to a low response in three patients. In conclusion, unbound immunoreactive GM-CSF is detectable in BALF and plasma of PAP patients. Most PAP patients also had intact AM responses to GM-CSF, although some may have had defects in GM-CSF receptor or signal-transduction mechanisms. Although these data exclude lack of GM-CSF production as a common etiology of human PAP, defects in GM-CSF function in PAP are under investigation.

Relationships of cytokine (GM-CSF) serum concentration to blood cell count and the inflammatory parameters in children with malignant diseases

This study examined both the endogenous and exogenous (therapy-related) pharmacokinetics of the cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF) in neutropenic children with solid and systemic malignancies. The daily endogenous GM-CSF serum concentration before application was 29 pg/mL. During the 10 days of examination, the concentration rose to an average value of 1351 pg/mL 8 h after application. A significant stimulation of the neutrophils, monocytes, and eosinophils in peripheral blood was documented. No significant correlation between the GM-CSF concentration and peripheral blood cell counts could be documented. Paraclinically, there was no evidence for functional disturbance of either the liver or the kidneys, i.e., under the cytokine therapy. The therapy was well tolerated by all the children involved in the study.

Interferons in dermatology. Present-day standard

Since the first clinical trials in the early 1980s with recombinant interferon, it was possible to show for a variety of indications that cytokines, especially interferons, at certain doses and at respective intervals, when applied in combination with other pharmaceutical compounds open new powerful therapeutic possibilities. Worldwide, recombinant interferon is licensed, especially in dermato-oncology, for the indication of HIV-associated Kaposi's sarcoma, cutaneous T-cell lymphoma, and recently for adjuvant therapy of high-risk malignant melanoma. Recombinant interferon is at present not licensed for dermatologic indication (septic granulomatosis). At the end of our century the indication spectrum for interferons as monotherapy and as combination therapy will undoubtedly be extended. Larger and controlled studies will prove the importance of interferons in dermato-oncology as well as in inflammatory and infectious dermatoses. The combination of interferons with standard therapies will surely be of the utmost importance in dermatotherapy.