title: Memory B cells and pneumococcal antibody after splenectomy.
abstract: Splenectomized patients are susceptible to bloodstream infections with encapsulated bacteria, potentially due to loss of blood filtering but also defective production of anticarbohydrate Ab. Recent studies propose that a lack of Ab is related to reduced numbers of IgM(+) CD27(+) memory B cells found after splenectomy. To test this, we analyzed CD27(+) memory B cell subsets, IgG, and IgM pneumococcal Ab responses in 26 vaccinated splenectomized subjects in comparison to memory B cell subsets and Ab responses in healthy controls. As shown previously, the splenectomized autoimmune subjects had fewer total, isotype switched, and IgM(+) CD27(+) memory B cells as compared with controls, but there was no difference in memory B cells subsets between controls and splenectomized subjects with spherocytosis. There was no difference between the geometric mean IgG Ab response between normal controls and splenectomized subjects (p = 0.51; p = 0.81). Control subjects produced more IgM Ab than splenectomized autoimmune subjects (p = 0.01) but the same levels as subjects with spherocytosis (p = 0.15.) There was no correlation between memory B cell subsets and IgG or IgM Ab responses for controls or splenectomized subjects. These data suggest that splenectomy alone may not be the sole reason for loss of memory B cells and reduced IgM antipneumococcal Ab. Because subjects with autoimmunity had splenectomy at a significantly older age than participants with spherocytosis, these data suggest that an age-related loss of extra splenic sites necessary for the maintenance or function of memory B cells may lead to impaired immunity in these subjects.
authors: Departments of Medicine, Pediatrics and the Immunology Institute, Mount Sinai Medical Center, New York City, NY 10029, USA.
authors: Heather
authors: H
authors: Wasserstrom
authors: James
authors: J
authors: Bussel
authors: Lony C-L
authors: LC
authors: Lim
authors: Charlotte
authors: C
authors: Cunningham-Rundles
mesh_terms: D000367:Age Factors; D000907:Antibodies, Bacterial / Q000097:blood*; D001327:Autoimmune Diseases; D016175:B-Lymphocyte Subsets / Q000166:cytology*; D006801:Humans; D007156:Immunologic Memory; D018655:Lymphocyte Count; D013103:Spherocytosis, Hereditary; D013156:Splenectomy; D013296:Streptococcus pneumoniae / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial