BACKGROUND Some workers employed by the aviation industry are exposed to large pressure amplitude and low frequency (LPALF) noise (> or =90 dB SPL, < or = 500 Hz) and have developed vibroacoustic disease (VAD), a whole-body noise-induced pathology. Since VAD patients have an increased prevalence of respiratory and skin infections, we investigated whether these individuals had any quantitative changes in the number of peripheral blood cell populations. Also, we investigated whether different types of noise environments are related to cell quantification. METHODS Quantification of peripheral blood cell populations was performed in venous blood samples of 34 VAD-diagnosed patients, and 41 controls. Leukocytes, monocytes, granulocytes, and surface phenotypes of CD8+ and CD4+ T lymphocytes were considered. RESULTS We found that VAD patients showed a statistically significant elevation in the number of circulating CD8+ and CD4+ T lymphocytes when compared with the control population, but not when compared among different noise-environments. Monocyte and granulocyte populations did not register significant differences. CONCLUSIONS VAD patients present enhancement in the number of circulating cytotoxic T lymphocytes (CD8+ and CD4+ T cells) thus indicating that this environmental disease is associated with quantitative changes in immune cells.