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Immunotherapy of gram-negative infections in oncological patients
1Department of Internal Medicine, University Medical Center, Lausanne, Switzerland.
Abstract:
While it is widely recognized that gram-negative bacteria (GNB) are a leading cause of morbidity and mortality among patients whose immune defenses are compromised both by their underlying malignancy as well as by its treatment, efforts to prevent or to treat such infections by immunological means have been hampered for several reasons. First, the natural anatomical barriers are often disrupted either by the tumor itself, by the chemotherapeutic agents, or, as recognized more recently, by viral (herpetic) or fungal infections, so that entrance of the gram-negative flora into the host tissue and blood stream is greatly facilitated. Efforts to diminish the bacterial load by means of oral decontamination, be it selective or not, to prevent such ingress have brought limited success. Second, active immunization is not likely to elicit a useful response in these patients, so that mainly passive immunotherapy has been considered and studied. However, since the most immunocompromised cancer patients are very often leucopenic, the opsono-phagocytic function of passively administered antibodies is not likely to help the patients to get rid of the invading gram-negative bacteria. This latter observation has been particularly well established in the case of Pseudomonas aeruginosa infections in leukemic patients (Young LS, Stevens P, Ingram J. J Clin Invest 1975, 56, 850-861).
Insights
Gram-negative bacteria infections pose significant risks for immunocompromised cancer patients. Current immunotherapies, including passive antibody treatments, are often ineffective due to patient leukopenia, limiting their ability to clear infections.
Area of Science:
- Oncology
- Infectious Diseases
- Immunology
Background:
- Gram-negative bacteria (GNB) are a major cause of illness and death in cancer patients with weakened immune systems.
- Disruption of anatomical barriers by tumors, chemotherapy, or infections facilitates GNB entry into the bloodstream.
- Previous attempts at oral decontamination to reduce GNB load have yielded limited success.
Purpose of the Study:
- To review the challenges in preventing and treating Gram-negative bacterial infections in immunocompromised cancer patients.
- To evaluate the limitations of active and passive immunotherapy in this patient population.
Main Methods:
- Review of existing literature on Gram-negative bacterial infections in immunocompromised hosts.
- Analysis of the efficacy of immunotherapeutic strategies, particularly passive immunotherapy.
Main Results:
- Immunocompromised cancer patients face increased risk of GNB infections due to compromised barriers.
- Active immunization is generally ineffective in these patients.
- Passive immunotherapy's effectiveness is limited by leukopenia, impairing antibody opsono-phagocytic function, especially against Pseudomonas aeruginosa.
Conclusions:
- Existing immunotherapeutic approaches for Gram-negative bacterial infections in immunocompromised cancer patients have significant limitations.
- The compromised immune status, particularly leukopenia, hinders the effectiveness of antibody-based treatments.
- Further research is needed to develop effective strategies against these life-threatening infections.