BACKGROUND: Milky spots in the greater omentum of some animals are well organized perivascular infiltrates of leucocytes, and are considered to have characteristics of secondary lymphoid tissue. To determine whether milky spots in the human greater omentum can also be regarded as secondary lymphoid tissue, we studied milky spots in an unstimulated state. METHODS: Patients were selected on the basis of absence of disease in the peritoneal cavity that might influence the state of the milky spots. Using monoclonal antibodies against macrophages, B-lymphocytes and T-lymphocytes, and immunoperoxidase labeling, the number of these cells and their location in milky spots were studied by light microscopy. However, the stromal components of the greater omentum, especially those within the milky spots, were studied by electron microscopy. RESULTS: Milky spots in the human greater omentum are relatively uniform vascularized accumulations of mononuclear cells comprising macrophages (67.9% +/- 9.4, mean +/- standard deviation), B-cells (10.1% +/- 3.4), T-cells (10.2% +/- 3.7), and mast cells. However, no special B-cell and T-cell areas could be distinguished. On the ultrastructural level it was demonstrated that macrophages are present in different stages of maturation and can enter or leave the milky spots. Furthermore, no cells characteristic of secondary lymphoid organs, such as interdigitating cells or follicular dendritic cells, were seen. CONCLUSIONS: These data indicate that unstimulated milky spots in the human greater omentum are to a great extent just a preformed specific accumulation of primarily macrophages within the stroma of the greater omentum, and therefore, cannot be regarded as true secondary lymphoid tissue. Milky spots could serve as a gateway for, as well as a provider of peritoneal macrophages when the intra-abdominal status so requires. Finally, the data from this study are compared with the data of other studies of human milky spots and those in animals.
BACKGROUND: Milky spots in the greater omentum of some animals are well organized perivascular infiltrates of leucocytes, and are considered to have characteristics of secondary lymphoid tissue. To determine whether milky spots in the human greater omentum can also be regarded as secondary lymphoid tissue, we studied milky spots in an unstimulated state. METHODS:Patients were selected on the basis of absence of disease in the peritoneal cavity that might influence the state of the milky spots. Using monoclonal antibodies against macrophages, B-lymphocytes and T-lymphocytes, and immunoperoxidase labeling, the number of these cells and their location in milky spots were studied by light microscopy. However, the stromal components of the greater omentum, especially those within the milky spots, were studied by electron microscopy. RESULTS: Milky spots in the human greater omentum are relatively uniform vascularized accumulations of mononuclear cells comprising macrophages (67.9% +/- 9.4, mean +/- standard deviation), B-cells (10.1% +/- 3.4), T-cells (10.2% +/- 3.7), and mast cells. However, no special B-cell and T-cell areas could be distinguished. On the ultrastructural level it was demonstrated that macrophages are present in different stages of maturation and can enter or leave the milky spots. Furthermore, no cells characteristic of secondary lymphoid organs, such as interdigitating cells or follicular dendritic cells, were seen. CONCLUSIONS: These data indicate that unstimulated milky spots in the human greater omentum are to a great extent just a preformed specific accumulation of primarily macrophages within the stroma of the greater omentum, and therefore, cannot be regarded as true secondary lymphoid tissue. Milky spots could serve as a gateway for, as well as a provider of peritoneal macrophages when the intra-abdominal status so requires. Finally, the data from this study are compared with the data of other studies of human milky spots and those in animals.
Authors: Daniel B Harmon; Prasad Srikakulapu; Jennifer L Kaplan; Stephanie N Oldham; Chantel McSkimming; James C Garmey; Heather M Perry; Jennifer L Kirby; Thomas A Prohaska; Ayelet Gonen; Peter Hallowell; Bruce Schirmer; Sotirios Tsimikas; Angela M Taylor; Joseph L Witztum; Coleen A McNamara Journal: Arterioscler Thromb Vasc Biol Date: 2016-02-11 Impact factor: 8.311
Authors: Javier Rangel-Moreno; Juan E Moyron-Quiroz; Damian M Carragher; Kim Kusser; Louise Hartson; Amy Moquin; Troy D Randall Journal: Immunity Date: 2009-05-07 Impact factor: 31.745
Authors: Scott A Gerber; Viktoriya Y Rybalko; Chad E Bigelow; Amit A Lugade; Thomas H Foster; John G Frelinger; Edith M Lord Journal: Am J Pathol Date: 2006-11 Impact factor: 4.307
Authors: Emily K Mader; Yoshihiro Maeyama; Yi Lin; Greg W Butler; Holly M Russell; Evanthia Galanis; Stephen J Russell; Allan B Dietz; Kah-Whye Peng Journal: Clin Cancer Res Date: 2009-11-24 Impact factor: 12.531