Previous studies with animal tumors showed that bone marrow (BM) is a privileged site where potentially lethal tumor cells are controlled in a dormant state by the immune system. Here, we investigated BM of breast cancer patients with respect to tumor cell content, immune activation status and memory T-cell content. BM-derived cells from primary operated breast cancer patients (n = 90) were compared with those from healthy donors (n = 10) and also with cells from respective blood samples. Cytokeratin 19-positive tumor cells were detected by nested polymerase chain reaction. Three-color flow cytometry was used to identify numbers and activation state of T cells, natural killer (NK) cells, monocytes/macrophages and subsets by a panel of monoclonal antibodies (mAbs). The proportion of memory T cells among the CD4 and CD8 T cells was much higher in BM of cancer patients than in healthy donors (p < 0.001). The extent of memory T-cell increase was related to the size of the primary tumor. Patient-derived BM memory CD8 T cells could be shown to contain specific HLA-A2/Her-2/neu(369-377) tetramer binding cells. Patients with disseminated tumor cells in their BM had more memory CD4 T cells and more CD56(+) CD8(+) cells than patients with tumor cell-negative BM. Only some of the immunological changes seen in BM samples of cancer patients were also detectable in peripheral blood samples. Our hypothesis that BM is a special compartment for immunological memory and tumor dormancy is supported by the above findings. The overall results reveal that BM is a valuable additional compartment for immune diagnosis in pathological conditions and possibly for follow-up treatment strategies.

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We have studied the distribution patterns of carbohydrate terminals on the endothelial surface of the mouse liver microvasculature. For this purpose, a wide battery of FITC lectins specific to glucose, mannose, galactose, fucose, N-acetyl-neuraminic acid, N-acetyl-galactosamine and N-acetyl-glucosamine residues were incubated on liver cryostat sections or intraportally perfused under physiological conditions. All the resulting hepatic sections were examined under fluorescent microscopy and confocal laser scanning microscopy. With the exception of N-acetyl-galactosamine- and fucose-binding lectins, all the perfused lectins specifically bound to the microvascular wall as confirmed by blocking methods using their corresponding sugars. A wide range of binding was, however, observed among the lectins, and the latter were classified into four groups according to their affinities for the different segments of the hepatic microvasculature: (a) equal affinity for all segments (concanavalin A); (b) different affinities depending on acinar zone (wheat germ agglutinin, Ricinus communis toxin, phytohemagglutinin E, Erythrina cristagalli agglutinin and Pisum sativum agglutinin); (c) preferential binding to the sinusoidal network (Lathyrus odoratus, phytohemagglutinin); and (d) lectins that fail to bind to the hepatic microvasculature (N-acetyl-galactosamine- and fucose-binding lectins). Sinusoidal segment walls in acinar zone 1 expressed a higher concentration of certain lectin-binding carbohydrate residues (N-acetyl-neuraminic acid, N-acetyl-galactosamine, galactose, mannose and glucose) than in acinar zone 3. The labeling patterns obtained through the incubation of liver sections or through in vivo perfusion with the different lectins did not always coincide. Only concanavalin A, wheat germ agglutinin and phytohemagglutinin E lectins proved to be concordant (i.e., they produced identical labeling patterns in both procedures).(ABSTRACT TRUNCATED AT 250 WORDS)

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