Suppression of dendritic cell function in cancer patients is thought to contribute to the inhibition of immune responses and disease progression. Molecular mechanisms of this suppression remain elusive, however. Here, we show that a fraction of blood monocyte-derived myeloid dendritic cells (MDCs) express B7-H1, a member of the B7 family, on the cell surface. B7-H1 could be further upregulated by tumor environmental factors. Consistent with this finding, virtually all MDCs isolated from the tissues or draining lymph nodes of ovarian carcinomas express B7-H1. Blockade of B7-H1 enhanced MDC-mediated T-cell activation and was accompanied by downregulation of T-cell interleukin (IL)-10 and upregulation of IL-2 and interferon (IFN)-gamma. T cells conditioned with the B7-H1-blocked MDCs had a more potent ability to inhibit autologous human ovarian carcinoma growth in non-obese diabetic-severe combined immunodeficient (NOD-SCID) mice. Therefore, upregulation of B7-H1 on MDCs in the tumor microenvironment downregulates T-cell immunity. Blockade of B7-H1 represents one approach for cancer immunotherapy.

Specialized epithelia known as M cells overlying the lymphoid follicles of Peyer's patches are important in the mucosal immune system, but also provide a portal of entry for pathogens such as Salmonella typhimurium, Mycobacterium bovis, Shigella flexneri, Yersinia enterocolitica and reoviruses. Penetration of intestinal M cells and epithelial cells by Salmonella typhimurium requires the invasion genes of Salmonella Pathogenicity Island 1 (SPI1). SPI1-deficient S. typhimurium strains gain access to the spleen following oral administration and cause lethal infection in mice without invading M cells or localizing in Peyer's patches, which indicates that Salmonella uses an alternative strategy to disseminate from the gastrointestinal tract. Here we report that Salmonella is transported from the gastrointestinal tract to the bloodstream by CD18-expressing phagocytes, and that CD18-deficient mice are resistant to dissemination of Salmonella to the liver and spleen after oral administration. This CD18-dependent pathway of extraintestinal dissemination may be important for the development of systemic immunity to gastrointestinal pathogens, because oral challenge with SPI1-deficient S. typhimurium elicits a specific systemic IgG humoral immune response, despite an inability to stimulate production of specific mucosal IgA.

We conducted a retrospective chart review of human immunodeficiency virus (HIV)-infected patients who died in 1995 and in 1999-2000. We found an increase in the proportion of patients who died from an illness that was not related to acquired immunodeficiency syndrome (AIDS). Although there was a decrease in the prevalence of AIDS-defining illnesses, 185% of patients died with CD4 counts of !200 cells/mL. The leading cause of death was Pneumocystis carinii pneumonia (PCP). Nonadherence to therapy and new diagnosis of HIV infection were the leading reasons why patients were not receiving antiretroviral therapy. The leading causes of non-AIDS-related deaths in 1999-2000 were non-AIDS-defining infections and end-stage liver disease. At our hospital, PCP remains an important cause of death in the highly active antiretroviral therapy (HAART) era, possibly because 150% of HIV-infected patients who died were not receiving HAART. AIDSdefining illnesses continue to be a major cause of mortality in the HAART era in populations where access to care and adherence to HAART is limited.

No abstract

Pseudallescheria boydii is a ubiquitously occurring fungus. While rarely causing opportunistic infection in humans, it is the most common cause of fungal pneumonia in cases of near drowning, and is associated with high mortality. P. boydii typically causes cutaneous mycetomas but may invade the lungs or brain. P. boydii infections are difficult to treat due to amphotericin B resistance and frequent need for surgical resection. Zygomycetous infections, often referred to as "mucormycoses," usually occur in immunocompromised hosts, trauma or burn victims. Like P. boydii, these organisms are found on decaying vegetation and in soil. Zygomycetous infections generally require debridement and prolonged amphotericin B. We report a case of P. boydii pneumonia with a simultaneous brain lesion and cutaneous mucormycosis in a near drowning patient. The pneumonia responded to treatment with voriconazole and the brain lesion resolved without surgery. The cutaneous mucormycosis responded to surgery and amphotericin B. This is the first documented case of simultaneous invasive P. boydii and cutaneous mucormycosis successfully treated with dual systemic antifungal therapy and resection.