Memory B cells and pneumococcal antibody after splenectomy.

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.

Pilot study investigating the age-related decline in ovarian function of regularly menstruating normal women.

OBJECTIVE: To use a pilot study to investigate markers of the age-related decline in ovarian function of regularly menstruating normal women. DESIGN: Prospective. SETTING: Tertiary research center. PATIENT(S): Healthy volunteers (n = 42) aged 18 to 50 years who had regular ovulatory menstrual cycles and a prior pregnancy. INTERVENTION(S): A single 300-IU dose of human recombinant FSH on day 3 of the menstrual cycle. MAIN OUTCOME MEASURE(S): Antral follicle count by transvaginal ultrasound and basal and FSH-stimulated serum markers. RESULT(S): Age correlated most strongly with FSH-stimulated inhibin B (r = -0.660), followed by antral follicle count (r = -0.578), basal FSH (r = 0.509), basal Müllerian inhibiting substance (MIS; r = -0.468), and basal inhibin B (r = -0.358). Total antral follicle count correlated most strongly with basal MIS level (r = 0.642). CONCLUSION(S): Of the parameters tested, FSH-stimulated serum inhibin B level had the strongest correlation with age. Basal serum MIS level had the strongest correlation with total antral follicle count. We confirm a previous report that in normal women, the antral follicle count as determined by transvaginal ultrasound examination correlates better with age than do basal FSH and basal inhibin B levels.