Editor's note: This article was originally published in Dutch in DIAGNED, the quarterly magazine of the Dutch Association of Diagnostics Manufacturers. DPC Nederland, a member of the Association, arranged for the writing and publication of the article, and provided the English translation below, with permission of DIAGNED.

The IMMULITE^® IL-8 assay shows promise as a tool for routine clinical use in the management of cancer patients. The assay is run in the same manner as other IMMULITE assays and provides results in about an hour.

Bacterial infections threaten chemotherapy patients
The prevention of bacterial infection is a constant concern in the management of cancer patients undergoing chemotherapy. Bacterial infections can lead to sepsis in such patients, whose white blood cell counts plummet following chemotherapy. Neutropenic patients at home between treatments who develop a high temperature are rehospitalized and immediately receive intravenous administration of antibiotics for several days. Physicians typically intervene in this way without waiting to verify bacterial infection because of the need to treat sepsis as early as possible and the lack of rapid testing. Yet, in as many as 60 percent of such cases, the blood cultures remain negative, and it is not known whether the fevers are the result of bacterial infection or other causes such as viral infection, a blood transfusion, or even the chemotherapy itself. The efforts of two physicians in The Netherlands have resulted in a preliminary study and a larger follow-up study which seek to verify that testing for the cytokine IL-8 can help identify patients without bacterial infection who do not need hospitalization or antibiotic treatment.

Needless hospitalization takes toll
Notwithstanding the need for early intervention in true sepsis patients, the standard policy has several obvious drawbacks. Needless hospitalization presents an additional difficulty for cancer patients whose lives are already very disrupted. Also, indiscriminate use of antibiotics encourages the emergence of antibiotic-resistant bacterial strains. Finally, unnecessary treatment in the hospital is a financial burden to the healthcare system and possibly to the patient as well. The standard policy of treating all cancer patients with fever as sepsis patients costs about $400,000 (US) per year at the university hospital in Groningen (AZG), The Netherlands.

IL-8 test can help identify septicemia risk
In hopes of finding a suitable marker of bacterial infection, Dr. Eveline de Bont, pediatric oncologist at the AZG, examined cytokine levels in the blood of 70 cancer patients with high temperatures. She found that IL-8 was elevated in patients with bacterial infections. Moreover, the IL-8 test could define a group of cancer patients (28%, confidence interval: 15 to 40%) with fever who were at low risk of septicemia. IL-8 is released by leukocytes near the infection site and elicits the migration of additional leukocytes to the area to fight infection.

IMMULITE assay can give patients more time at home
Dr. de Bont's next concern was whether a more rapid IL-8 test than the current one-day test was available. At the time, results from a patient presenting with a high temperature at noon on Saturday would not be available until Monday-too long to wait to initiate treatment. After she learned from Dr. Joost Swaanenburg, clinical chemist at the hospital, of DPC's IMMULITE^® IL-8, a one-hour test designed to be run on the IMMULITE immunoassay analyzer which was already in use in the clinical chemistry laboratory, the test was introduced in the hospital.

A preliminary study using the IMMULITE IL-8 assay has been completed, and a large-scale follow-up study is now under way. It has the support of the AZG's hematologists, pneumonologists, oncologists and pediatric oncologists, and is being subsidized by the national health council. All cancer patients with a high temperature can request the IL-8 test (which they do unanimously) and, if the result does not suggest the presence of bacterial infection, return home. There they remain in contact with their doctor by telephone. No one has been sent home inappropriately, thanks to the competence of the laboratorians, physicians and nursing staff. The interim analyses are promising and show that some feverish cancer patients can be sent home appropriately.

An official report on the study, apparently unlike any conducted to date in Europe, will be released in 2001. Dr. de Bont is hopeful that the report will lead to widespread acceptance of this new use of the IL-8 test in The Netherlands. It could mean more time at home for patients, more effective patient management, and better use of healthcare resources.

Additional benefits may evolve from the study. Heart surgeons at the AZG are also interested in IL-8 as a marker of infection in open-heart surgery patients. An early marker could allow early intervention to prevent the serious complications that can result from infection in such patients.