Abstract: The objective was to study the peripheral lymphocyte in patients with severe acute respiratory syndrome(SARS).The lymphocyte in peripheral blood at different stage of SARS was investigated retrospectively.Results:In the mild group,lymphopenia was found in the first two weeks of onset,and a recovery from the third week.In the severe group,lymphopenia was sustained for four weeks,and recovering was not found in four weeks.At onset,exacerbating and recovering stage,comparisons of the lymphocyte between mild/severe,mild/dead,severe/dead had no significant difference.According to the state of the illness,patients were divided into four groups including the onset stage,X-ray exacerbating stage,first period of absorption,last period of absorption.The lymphocyte was significantly different between the onset stage and lost period of obsorption,X-ray exacerbating stage and last period of absorption.The lymphocyte decreased remarkably with mild dosage(160～500mg/d),and large dosage(>500～1000mg/d)of glucocorticoid.The lymphopenia in peripheral blood can be considerd as a criterion of SARS in the earlier stage diagnosis.The recovery of lymphocyte count in peripheral blood may indicate the improvement of illness.The lymphocyte decreases remarkebly by glucocorticoid(dose of>160mg/d).

Key words: lymphocyte, severe acute respiratory syndrome