Alternate-day prednisone therapy and human lymphocyte subpopulations

The mechanisms and kinetics of the immunosuppressive effects of alternate-day prednisone were investigated in a group of patients with a variety of inflammatory diseases receiving a range of alternate-day prednisone doses from 5 to 120 mg. Total circulating lymphocyte and monocyte counts, as well as proportions of lymphocyte subpopulations defined both by surface markers and by in vitro functional capacities, were studied. At 8 a. m. of the day on prednisone, just before drug administration, lymphocyte and monocyte counts, proportions of lymphocyte subpopulations, as well as in vitro lymphocyte blastogenic responses to various mitogenic and antigenic stimuli were normal. 4 h after the administration of prednisone, there was a profound lymphocytopenia and monocytopenia, with a differential depletion of thymus-derived lymphocytes as well as various functionally defined lymphocyte subpopulations. Lymphocyte kinetic studies using a radioactive chromium-labeled autologous lymphocytes showed that the lymphocytopenia was due predominantly to a transient depletion of the recirculating portion of the intravascular lymphocytepool. All these parameters returned to normal by 8 a.m. of the following day (off prednisone) and remained normal throughout the day. This very transient lymphocytopenia and monocytopenia after prednisone, with normal cell numbers, proportions, and functions throughout the remainder of the 2-day cycle, was associated with suppression of disease activity, yet did not affect cutaneous delayed hypersensitivity in these patients nor increase the likelihood of infectious complications. This drug-associated cyclic and transient monocytopenia and selective lymphocytopenia is best explained by a redistribution of recirculating lymphocytes to other body compartments, particularly the bone marrow.

Renal biopsy pathology in Wegener's granulomatosis

Eighteen renal biopsies from 10 patients with active generalized Wegener's granulomatosis (GWG), with GWG in remission on therapy, and with active localized Wegener's granulomatosis (LWG) have been examined by light and electron microscopy. In all 9 patients with active GWG, light microscopy revealed focal and segmental glomerulonephritis. Electron microscopy revealed subepithelial basement membrane densities resembling immune complex deposits in two biopsies from patients with active GWG. In biopsies from patients on cytotoxic therapy, there was no active inflammatory process, but focal glomercular obsolescence and segmental tuft sclerosis provided evidence of prior focal and segmental glomercular disease. Discrete zones of basement membrane crimping and increased mesangial material along the capillary wall were observed in some patients with apparent LWG, as well as proven GWG, possibly representing foci of previous glomerular injury. The appearance of dense deposits on the epithelial side of the basement membrane suggests that immune complex deposition in the glomeruli may be at least partially responsible for the renal injury in Wegener's granulomatosis.

The effect of in vivo hydrocortisone on subpopulations of human lymphocytes

This study was designed to determine the effect of in vivo hydrocortisone on subpopulations of lymphoid cells in normal humans. Subjects received a single intravenous dose of either 100 mg or 400 mg of hydrocortisone, and blood was drawn at hourly intervals for 6 h, and then again at 10 and 24 h after injection. Profound decreases in absolute numbers of circulating lymphocytes and monocytes occurred at 4-6 h after both 100 mg and 400 mg of hydrocortisone. Counts returned to normal by 24 h. The relative proportion of circulating thymus-derived lymphocytes as measured by the sheep red blood cell rosette assay decreased maximally by 4 h and returned to base line 24 h after hydrocortisone. There was a selective depletion of functional subpopulations of lymphocytes as represented by differential effects on in vitro stimulation with various mitogens and antigens. Phytohaemagglutinin response was relatively unaffected, while responses to concanavalin A were significantly diminished. Responses to pokeweed mitogen were unaffected by 100 mg of hydrocortisone, but greatly diminished by 400 mg of hydrocortisone. In vitro responses to the antigens streptokinase-streptodornase and tetanus toxoid were markedly diminished by in vivo hydrocortisone. Reconstitution of monocyte-depleted cultures with autologous monocytes partially corrected the diminished response to antigens. This transient selective depletion of monocytes and subsets of human lymphocytes by a single dose of hydrocortisone is most compatible with a redistribution of these cells out of the circulation into other body compartments.