Prednisone-induced alterations of circulating human lymphocyte subsets.

Area of Science:

• Immunology
• Pharmacology

Background:

• Glucocorticoids, like prednisone, are known to cause peripheral lymphopenia in humans.
• The specific T cell subsets affected by glucocorticoid administration require further elucidation.

Purpose of the Study:

• To investigate the effects of prednisone on peripheral T cell subsets (OKT4+ and OKT8+) in healthy subjects.
• To determine the dose-dependency and mechanism of prednisone-induced lymphopenia.

Main Methods:

• Four healthy subjects ingested 20 mg of prednisone.
• Peripheral blood T cell subsets (OKT11+, OKT4+, OKT8+) were quantified using monoclonal antibodies before and after prednisone administration.
• In vitro exposure of lymphocytes to methylprednisolone was performed.
• Prednisone's effect was assessed in a splenectomized subject.

Main Results:

• Prednisone administration led to a decline in circulating T cells, with a disproportionate decrease in the OKT4+ (helper-inducer) subset.
• The ratio of OKT4+ to OKT8+ cells decreased significantly post-prednisone.
• No significant lympholysis or alteration in T cell subset proportions was observed with in vitro methylprednisolone exposure.
• Prednisone-induced lymphopenia was observed in both splenectomized and non-splenectomized subjects.
• B cell counts remained unaffected.

Conclusions:

• Prednisone-induced lymphopenia primarily affects the OKT4+ T cell subset more than the OKT8+ subset.
• The mechanism is not attributed to direct lympholysis or splenic redistribution of lymphocytes.
• The findings highlight the immunomodulatory effects of prednisone on specific T cell populations.