One intraperitoneal dose of Candida albicans (10(8) CFU) caused a chronic (longer than 2 months), significant elevation of plasma fibrinogen levels (Clauss method) in mice of strain C3H/HeN. Even a small dose (10(6) CFU) resulted in a significant increase in fibrinogen level for 5 days following injection, whereas other blood parameters (leukocytes, erythrocytes, platelets, hematocrit, hemoglobin, blood urea nitrogen, aspartate aminotransferase, albumin, alkaline phosphatase, antithrombin III, glucose, calcium, and total protein) measured by standard methods were normal. Blood taken during this period was negative for C. albicans. The role of tumor necrosis factor (TNF) in C. albicans infections was investigated by measuring the fibrinogen response after the administration of C. albicans or recombinant mouse TNF-alpha. Both challenges resulted in an elevated fibrinogen level. When polyclonal antibodies to mouse TNF-alpha were given prior to challenge with C. albicans or mouse TNF-alpha, the fibrinogen increase was significantly inhibited. C. albicans injections were found to significantly elevate endogenous TNF levels in mice (enzyme-linked immunosorbent assay). It was concluded that C. albicans induces TNF in the mouse. Furthermore, these data give evidence which supports a relationship between TNF and the fibrinogen increase induced by C. albicans.