Experimental models to investigate the function of dendritic cell subsets: challenges and implications.

The dendritic cell (DC) lineage is remarkably heterogeneous. It has been postulated that specialized DC subsets have evolved in order to select and support the multitude of possible T cell differentiation pathways. However, defining the function of individual DC subsets has proven remarkably difficult, and DC subset control of key T cell fates such as tolerance, T helper cell commitment and regulatory T cell induction is still not well understood. While the difficulty in assigning unique functions to particular DC subsets may be due to sharing of functions, it may also reflect a lack of appropriate physiological in-vivo models for studying DC function. In this paper we review the limitations associated with many of the current DC models and highlight some of the underlying difficulties involved in studying the function of murine DC subsets.

Hematological findings among workers exposed to benzene at a coke oven by-product recovery facility.

Hematological findings on a population of 70 male workers exposed to benzene revealed no significant differences when compared statistically to a control group on the basis of estimated cumulative doses using analysis of variance (ANOVA) and Dunnett's t statistic procedure. The hematological data evaluated included the following parameters: red blood cell counts, white blood cell counts, and hemoglobin levels. Cumulative benzene exposure indices for each employee were estimated utilizing available personal monitoring and general air sampling data, as well as the professional judgment of local environmental health engineers familiar with the operations. Although the accuracy of these exposure estimates is unknown, the results provide no evidence that the present OSHA standard (10 ppm) is inadequate with respect to the non-leukemogenic, hematotoxic effects of chronic benzene exposure.