The immunomodulatory effects of liposomal amphotericin B (LAMB), amphotericin B lipid complex (ABLC), and amphotericin B colloidal dispersion (ABCD) on mRNA and protein profiles of five cytokines and chemokines expressed by human monocyte-enriched mononuclear leukocytes (MNCs) were comprehensively evaluated by semiquantitative reverse transcription-PCR and enzyme-linked immunosorbent assays; they were compared to those of deoxycholate amphotericin B (DAMB). mRNAs of interleukin-1 (IL-1), IL-1 receptor antagonist (IL-1ra), tumor necrosis factor alpha (TNF-␣), monocyte chemotactic protein 1 (MCP-1), and macrophage inflammatory protein 1 (MIP-1) were assessed after treatment of MNCs with each drug for 0.5, 2, 6, and 22 h. The cytokine protein profiles were obtained after incubation of MNCs with the drugs for 2 h (TNF-␣) or 6 h (all the others). In the mRNA studies, DAMB resulted in an early increase of inflammatory cytokines or chemokines IL-1, TNF-␣, MCP-1, and MIP-1 (2 to 6 h) and in a late increase of antiinflammatory IL-1ra (22 h). ABCD showed a general similar trend of inflammatory gene up-regulation. LAMB and ABLC decreased or did not affect IL-1 and TNF-␣, whereas ABLC additionally decreased MIP-1. In protein measurement studies, DAMB and ABCD up-regulated production of IL-1 (P < 0.05), decreased the IL-1ra/IL-1 ratio, and up-regulated the production of MCP-1 and MIP-1. In comparison, LAMB and ABLC down-regulated or did not affect the production of these cytokines/chemokines compared to untreated MNCs; furthermore, ABLC tended to increase the IL-1ra/IL-1 ratio. These studies demonstrate that amphotericin B formulations differentially affect gene expression and release of an array of proinflammatory and antiinflammatory cytokines that potentially may explain the differences in infusion-related reactions and dosedependent nephrotoxicity as well as modulation of the host immune response to invasive fungal infections.Historically, deoxycholate amphotericin B (DAMB) has been considered the "gold standard" of antifungal therapy, and it remains the drug with the broadest antifungal spectrum (21, 25). However, DAMB causes adverse infusion-related reactions and dose-dependent nephrotoxicity, which are clearly associated with increased morbidity in immunocompromised patients (1,13,19). The lipid-based amphotericin B formulations liposomal amphotericin B (LAMB), amphotericin B lipid complex (ABLC), and amphotericin B colloidal dispersion (ABCD) have been developed with the goal to decrease toxicity and improve drug tolerance and thus efficacy (17, 38). Patients with neutropenia and invasive fungal infections developed infusion-related adverse reactions less frequently with LAMB than with ABLC and ABCD, whereas nephrotoxic tolerability was improved with all three lipid formulations compared to with DAMB (8,17,22,41).In vivo, amphotericin B-related toxicity has been previously correlated with increased levels in plasma of interleukin-1 (IL-1), tumor necrosis factor alpha (TNF-␣), and IL-1 receptor antagonis...