The 81st Annual Meeting of the American Association of Physical Anthropologists (2012)


Reductions in helper T-cells and increases in natural killer cells are associated with poorer growth in an indigenous Amazonian population

AARON D. BLACKWELL1, IVAN MALDONADO SUAREZ2, JONATHAN STIEGLITZ3, MICHAEL GURVEN1 and HILLARD KAPLAN3.

1Integrative Anthroplogical Sciences, University of California, Santa Barbara, 2Proyecto Tsimane' de Salud y Antropología, San Borja, Bolivia, 3Department of Anthropology, University of New Mexico, Albuquerque, NM

Saturday 9:45-10:00, Parlors Add to calendar

The relative proportion of different lymphocyte subsets varies between populations, yet data relating this variation to broader life-history patterns is limited. We address this lack by testing for trade-offs between growth and lymphocyte subset counts in the Tsimane, a population of forager-horticulturalists with high infectious exposure. Using flow cytometry, we identified T-cells (CD4+, CD8+), B-cells (CD19+), NK-cells (CD56+), and naïve T-cells (CD45RA+) in 540 blood samples. We tested for trade-offs using change in age standardized height (ΔHR) from the previous year. Total lymphocyte count (β = 1.46 cm/1000 cells/yr (CKY), p < 0.01), CD4 count (β = 6.86 CKY, p < 0.01), and percent naïve CD4 cells (β = 12.90 cm/100%/yr, p = 0.07) were all associated with positive ΔHR, while NK-cell count (β = -5.93 CKY, p = 0.07) and CD8 cell count (β = -6.01 CKY, p = 0.01) were associated with negative changes in ΔHR. Overall Tsimane had lower CD4/CD8 ratios, CD4 counts, and naïve CD4 proportions, and higher NK-cell counts than most age-matched populations in North America, Europe, and Africa. These results suggest the Tsimane pathogenic environment may deplete CD4 cells and reduce available naïve cells, and increase production of NK-cells, and that these effects are related to poorer relative growth scores.

Supported by NIH/NIA grants R01AG024119-06 and 2P01AG022500-06A1

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