Researchers in the Netherlands reported that two patientsdeveloped thyroid problems after receiving granulocyte colonymacrophage stimulating factor (GM-CSF).

According to their letter this week in The Lancet, the apparentautoimmune response was induced only in these two patientsout of 25 with either breast or soft tissue cancers whom thedoctors followed. Both required thyroxine therapy for twomonths, but their thyroid function returned to normal withineight weeks of the last dose of GM-CSF.

The two patients had pre-existing thyroid antibodies prior totheir therapy with GM-CSF, which was a recombinant human,non-glycosylated form derived from E. coli and obtained fromBehringwerke AG of Germany.

GM-CSF has previously been reported to aggravate arthritis anda platelet disorder called idiopathic thrombocytopenia, saidthe researchers, who are physicians at Free UniversityHospital in Amsterdam and Erasmus University in Rotterdam.

Last week, The Lancet published letters stating that GM-CSFappeared to exacerbate a woman's rheumatoid arthritis.

"Patients receiving GM-CSF must be screened for autoimmunityand their clinical condition carefully followed during theadministration of this cytokine," the researchers concluded.

Sandoz/Schering Plough and Genetics Institute Inc., as well asImmunex Corp., are working on GM-CSF. -- RF

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