Genetics of the Immune Response

covered in the chapter on the phylogeny of the blood system. The origin of hematopoiesis from the invertebrates to the vertebrates is, unfortunately, not as extensively covered. A more vigorous analysis, in the field of invertebrate hematology, would have been of greater value to both the novice and the researcher of vertebrate hematology than the outline format that is presented. However, the next two chapters on the ontogeny and marrow structure are informative and well written. The use of histologic and electron micrographs allows the reader to understand easily the structure and function of the marrow. The concepts of developing regions of auxiliary cells such as fat, endothelial, and macrophage cells, along with hormonal marrow regulation and the identification of lectin receptors on marrow endothelial cells, indicate the importance of selectivity of the marrow microenvironment in allowing maturing hematopoietic cells entry into the circulation. Four extensive chapters are devoted to the regulation of the four specific blood cell compartments, their life spans, and regulation and recovery after various perturbations. An analysis of the interactions of compartments with regard to recovery after perturbation is excellently reviewed within each of the four chapters. The development of the study of hematopoiesis that has occurred in the past twenty years is well summarized in the final two chapters. The authors present data on the response of the transitional stem cell compartment which upon demand can give rise to various groups of blood cells. Although this aspect of hematopoiesis has been extensively covered in numerous volumes, it allows the reader to obtain a complete perspective of the role of the marrow in the regulation of stem cells, as well as the maturing blood cell's entry into the circulation.