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Query: UMLS:C0024312 (lymphopenia)
 4,859 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Acute extrinsic allergic alveolitis was experimentally induced in rabbits using horseradish peroxidase (HRP) as antigen. Broncho-alveolar lavage was performed on the excised lungs and total and differential cellular yields determined, and correlated with the histopathological changes in the lungs as well as the total and differential white blood cell counts. After a single parenteral immunization with HRP without adjuvants, and weekly aerosol challenges with nebulized HRP solution for 3 consecutive weeks, a 3-fold increase in the total cell count as well as a very pronounced rise in the percentage of lymphocytes was noticed. Histopathologically, the bronchi-associated lymphoid tissue (BALT) became more prominent, an increase in the number of foreign body giant cells was noticed and a focal interstitial and intra-alveolar accumulation of lymphocytes, granulocytes and macrophages could be demonstrated, as well as a mild hyperplasia of type 2 alveolar epithelial cells. Intramuscular injections of methylprednisolone acetate (Depo-Medrol) every 72 hours induced a pronounced peripheral lymphopenia, thymic involution and an almost complete disappearance of the BALT in both the control and HRP-challenged rabbits. Similarly, a marked decrease in the total cell count and percentage of lymphocytes was noticed in the broncho-alveolar fluid of the animals with hypersensitivity pneumonitis. No signs of interstitial or intra-alveolar reactions were seen in the lungs of the experimental animals after 3 weeks of aerosol antigen challenge when treated with steroids. Collectively, these data suggest that the development of hypersensitivity pneumonitis was, at least in part, due to a cell-mediated immunological reaction in the lung. This animal model in which steroid suppression of experimental allergic alveolitis has been demonstrated, may be employed to elucidate the cellular pathogenesis of this disease process.
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PMID:[The effect of steroid therapy on cytological and histopathological changes during experimental extrinsic allergic alveolitis (hypersensitivity pneumonitis)]. 725 58

Glucocorticoids are commonly prescribed in the post transplant period as a component of combination immunosuppressive regimens. However, the daily 24-hour pattern of helper lymphocytes (CD4+) and suppressor cells (CD8+) during chronic methylprednisolone therapy has not been examined in renal transplant recipients in relation to glucocorticoid exposure and time post-transplant. The response of total lymphocytes, CD4+ and CD8+ lymphocytes was examined in 23 stable renal transplant recipients who received methylprednisolone for at least 8 months post-transplant. The patient's prescribed oral methylprednisolone dose (mean daily dose = 9.7 +/- 2.6 mg) was given intravenously and whole blood was sampled periodically over 24 h for lymphocyte counts and methylprednisolone concentrations. A complete blood count with differential was determined via an automated hemocytometer with CD4+ and CD8+ lymphocytes determined using flow cytometry. Methylprednisolone area under the concentration versus time curve (AUC) was determined and normalized for each patient's respective dose. A general lymphopenia resulted in all patients with a mean decrease of 61 +/- 15% and an average nadir time occurring at 6 h. The decline from baseline was 76 +/- 17% for absolute number of CD4+ and 59 +/- 18% for CD8+ lymphocytes with an average nadir time at 6 h. Twelve patients exhibited a baseline CD4+ count to be less than 688 cells/mm3 (the low end of the reference range) and the lymphocyte count of all the patients fell below this value at the nadir. Six patients had a CD8+ lymphocyte count below 380 cells/mm3 (low end of the reference range) at baseline with 21 of the 23 patients exhibiting less than 380 cells/mm3 at the nadir time. At the time of nadir, the mean CD4+ and CD8+ counts were 156 +/- 105 cells/mm3 and 256 +/- 270 cells/mm3, respectively. In 17 of the 23 patients, the CD4+ count was below 200 cells/mm3 at the time of nadir. The dose-normalized AUC of methylprednisolone ranged from 22.6 to 113.5 ng.h/ml with 48% of patients exhibiting morning cortisol concentrations greater than 60 ng/ml. No correlation was noted between daily methylprednisolone exposure and the extent of lymphocyte decline. Lymphocyte response patterns are not clinically recognized in renal transplant recipients, as a means of monitoring immunosuppression. The absolute CD4+ and CD8+ lymphocyte count and the timing of these sample collections post-steroid administration, may have clinical relevance when serially assessed as is done in other immunologic diseases. Prospective evaluation of lymphocyte subset patterns and correlation with susceptibility to overimmunosuppressive (i.e. opportunistic infections) is necessary to help determine if these complications can be minimized by more individualized steroid dose modification.
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PMID:24-hour immunologic assessment of CD4+ and CD8+ lymphocytes in renal transplant recipients receiving chronic methylprednisolone. 860 8