Subpopulation of human tonsillar lymphocytes with mitochondria visible by light microscopy.

We observed a subpopulation of human tonsillar lymphocytes with cytoplasmic inclusions that stained orthochromatically blue with Wright stain. These lymphocytes represented fewer than 2% of cells in suspensions of cells from most tonsils; however, suspensions of tonsillar cells from 4 to 18 studied patients contained more than 2% (2.8%--6.4%) lymphocytes with cytoplasmic inclusions. These cells sedimented less rapidly than the modal population of lymphocytes in a previously described isokinetic gradient. Histochemical and ultrastructural studies suggested that the stained inclusions were prominent mitochondria stained by the Wright stain.