Human natural killer (NK) cells originate from CD34(+) hematopoietic progenitor cells, but the discrete stages of NK cell differentiation in vivo have not been elucidated. We identify and functionally characterize, from human lymph nodes and tonsils, four NK cell developmental intermediates spanning the continuum of differentiation from a CD34(+) NK cell progenitor to a functionally mature NK cell. Analyses of each intermediate stage for CD34, CD117, and CD94 cell surface expression, lineage differentiation potentials, capacity for cytokine production and natural cytotoxicity, and ETS-1, GATA-3, and T-BET expression provide evidence for a new model of human NK cell differentiation in secondary lymphoid tissues.

In humans, T cells differentiate in thymus and B cells develop in bone marrow (BM), but the natural killer (NK) precursor cell(s) and site(s) of NK development are unclear. The CD56bright NK subset predominates in lymph nodes (LN) and produces abundant cytokines compared to the cytolytic CD56dim NK cell that predominates in blood. Here, we identify a novel CD34dimCD45RA(+) hematopoietic precursor cell (HPC) that is integrin alpha4beta7bright. CD34dimCD45RA(+)beta7bright HPCs constitute <1% of BM CD34(+) HPCs and approximately 6% of blood CD34(+) HPCs, but >95% of LN CD34(+) HPCs. They reside in the parafollicular T cell regions of LN with CD56bright NK cells, and when stimulated by IL-15, IL-2, or activated LN T cells, they become CD56bright NK cells. The data identify a new NK precursor and support a model of human NK development in which BM-derived CD34dimCD45RA(+)beta7bright HPCs reside in LN where endogenous cytokines drive their differentiation to CD56bright NK cells in vivo.

Background: Depression predicts morbidity and mortality among individuals who have coronary heart disease (CHD), and there is increasing evidence that depression may also act as an antecedent to CHD. The studies that have reported a relationship between depression and CHD incidence or mortality either were restricted to men only or analyzed women and men together. The present investigation was conducted to evaluate the differential effect depression may have on CHD incidence and mortality in women and men.

Purpose To determine the impact of longer periods between biopsy-confirmed breast cancer diagnosis and the initiation of treatment (Dx2Tx) on survival. Patients and Methods This study was a noninterventional, retrospective analysis of adult female North Carolina Medicaid enrollees diagnosed with breast cancer from January 1, 2000, through December, 31, 2002, in the linked North Carolina Central Cancer Registry–Medicaid Claims database. Follow-up data were available through July 31, 2006. Cox proportional hazards regression models were constructed to evaluate the impact on survival of delaying treatment ≥ 60 days after a confirmed diagnosis of breast cancer. Results The study cohort consisted of 1,786 low-income, adult women with a mean age of 61.6 years. A large proportion of the patients (44.3%) were racial minorities. Median time from biopsy-confirmed diagnosis to treatment initiation was 22 days. Adjusted Cox proportional hazards regression showed that although Dx2Tx length did not affect survival among those diagnosed at early stage, among late-stage patients, intervals between diagnosis and first treatment ≥ 60 days were associated with significantly worse overall survival (hazard ratio [HR], 1.66; 95% CI, 1.00 to 2.77; P = .05) and breast cancer–specific survival (HR, 1.85; 95% CI, 1.04 to 3.27; P = .04). Conclusion One in 10 women waited ≥ 60 days to initiate treatment after a diagnosis of breast cancer. Waiting ≥ 60 days to initiate treatment was associated with a significant 66% and 85% increased risk of overall and breast cancer–related death, respectively, among late-stage patients. Interventions designed to increase the timeliness of receiving breast cancer treatments should target late-stage patients, and clinicians should strive to promptly triage and initiate treatment for patients diagnosed at late stage.