Psittacosis with increased gammadelta T cells in bronchoalveolar lavage fluid.

Experience with two cases of psittacosis is described here in which the number of gammadelta T cell receptor-positive T lymphocytes (gammadelta T cell) in the bronchoalveolar lavage fluid was markedly increased (25.1 and 66.9%) and CD8+ T cells were also increased with reversal of the CD4/CD8 ratio. These values improved to the normal range along with recovery of their radiographical findings. The present findings suggest that gammadelta T cells may play an important role in protection from lung injury caused by Chlamydia psittaci infection.