Lymphocyte subsets in relation to immunosuppression in Mycoplasma pneumoniae pneumonia

Abstract

Lymphocyte proliferative response to mitogens and skin testing for delayed hypersensitivity to tuberculin were diminished during acute phase of Mycoplasma pneumoniae pneumonia. We analyzed peripheral blood lymphocytes from patients in the acute phase of illness, convalescent phase of illness and after recovery using monoclonal antibodies Bl, OKT3, OKT11, OKT4, OKT8, OKIA1, Leu7 and Leull. In the acute phase of illness a peripheral lymphocytopenia was found. The percentage of OKT3 positive lymphocytes and the absolute number of Bl, OKT11, OKT3, OKT4 and OKT8 positive lymphocytes were decreased in the acute phase of illness. In the convalescent phase of illness, tuberculin test and the absolute number of lymphocytes, OKT11, OKT3 and OKT4 positive lymphocytes returned to normal. The absolute number of OKT8 positive lymphocytes were still decreased. As a result, helper-suppressor ratio (OKT4/OKT8) was increased during convalescence. After recovery, lymphocyte proliferative response to mitogens and lymphocyte subsets became normal. These results demonstrate that the transient immunosuppression in the acute phase of Mycoplasma pneumoniae pneumonia is probably caused by peripheral lymphocytopenia, T lymphocytopenia and reduction of helper/inducer lymphocytes.