T-dependent immunity in aged humans. I. Evaluation of T-cell subpopulations before and after short term administration of a thymic extract.

T lymphocytes, T lymphocyte subpopulations and delayed hypersensitivity reactions to recall antigens were studied in 20 aged subjects clinically unaffected by disorders of the immune system. T-cells evaluated by the sheep rosette test and absolute T-cell number were within normal range. T-cell subsets were studied by the high affinity rosetting test and by the sheep rosette test after pre-incubation with theophylline; such methods have been shown by others to discriminate between T-cells with helper or suppressor activity.

Improvement of natural killer activity and of T cells after thymopoietin pentapeptide therapy in a patient with severe combined immunodeficiency.

The case of an 18-month-old child, affected by malnutrition, severe interstitial pneumonia and immunological abnormalities is reported. Since the age of 10 months, the infant suffered from severe recurrent infections and failure to thrive. Immunological studies revealed a striking decrease of T lymphocytes and of natural killer (NK) function.

Imbalances of T cell subpopulations in primary immunodeficiencies and systemic lupus erythematosus.

In the present report we describe a recently proposed technique for the enumeration of T lymphocyte subpopulations. The study was performed on peripheral blood lymphocytes (PBL) of 21 patients with primary immunodeficiencies and 10 with systemic lupus erythematosus (SLE). With this methodology, sheep rosettes are evaluated before and after preincubation with theophylline.

Mouse rosette forming cells and surface immunoglobulins in human lymphoid cells.

Peripheral blood lymphocytes from normal subjects were studied for mouse rosette-forming cells (MRFC) and their relationship to surface immunoglobulins (SIg). The majority of MRFC expressed both SIgM and SIgD, although some dissociation between population showing SIgM+/MRFC- and SIgM-/MRFC+ could be seen. A similar pattern of association was found in human derived cultured cells of B lineage, but no simple correlation and the number of SIgM+ cells could be established.