Lymphocyte subsets in Eastern Highlanders of Papua New Guinea.

Lymphocyte subsets were enumerated in Papua New Guinean children, adolescents and adults from the Eastern Highlands and comparative groups of age-matched expatriates living in the Goroka area. From the age group under 6 months until adolescence, the numbers and percentages of CD8-positive (suppressor/cytotoxic) T cells were higher in Papua New Guinean highlanders than in expatriates. In highland subjects over 35 years of age, both CD8-positive and CD4-positive (helper/inducer) T-cell numbers were lower than in younger subjects whereas in expatriates their numbers remained the same. Highlanders over the age of 35 years had fewer T cells (including CD8-positive T cells) than expatriates. Helper/suppressor ratios were lower in highlanders than in expatriates from the age group under 6 months to the 20-30 year age group; the lowest ratio was found at 10-15 years of age, when the mean was 0.95.