Immunomodulating effects of a short-term oral treatment with C 1821 in untreated cancer patients: a controlled study

C 1821 is a purified glycoprotein extract from Klebsiella pneumoniae serotype 2 with a molecular weight of about 350,000. It enhances immune responses in animals when given orally and the oral route of administration is devoided of any toxicity even in humans. The present controlled trial showed that C 1821 given per os at the single daily dose of 4 mg for 14 days in untreated cancer patients (mostly lymphomas) significantly enhanced delayed cutaneous hypersensitivity to recall antigens using the Multitest system (7 antigens). It also increased basal levels of lymphocyte cAMP and particularly of cGMP which were decreased in these patients. When incubated in vitro with lymphocytes from either normal controls or patients, C 1821 showed a dose-dependent stimulation of cAMP synthesis which was more pronounced in patients than in controls.