EFFECT OF STORAGE TIME ON THE ANALYSIS OF LYMPHOCYTE SUBPOPULATIONS IN PLEURAL EFFUSIONS

It is not known how long cell surface antigens can be detected on lymp hocytes in pleural effusions. Therefore, the lymphocyte subpopulations of 15 native pleural effusions were analyzed after different storage times, at either 4-degrees-C or room temperature, using the peroxidase -antiperoxidase adhesive slide assay. No significant differences in th e lymphocyte subpopulations were observed after one day of storage und er both conditions, although the immunoreactivity with CD4 was poor in the majority of cases stored at 4-degrees-C and in two cases stored a t room temperature. After three days of storage at 4-degrees-C and aft er four days of storage at room temperature, a marked decrease in lymp hocytes attached to the slides was observed. Immunoreactivity with CD8 , CD20, CD45 and HLA-1 was well preserved, also, after one week of sto rage. Reactivity with CD3 was weak or poor after three days of storage in some cases. It is important to recognize that the preservation of the immunoreactivity of lymphocytes is dependent not only on the nutri tive quality of pleural fluids but also on the cell preparation method .