Sheldon Horowitz

Prediction of persistent immunodeficiency in the DiGeorge anomaly

To assess the natural history of the immune defect in DiGeorge anomaly, we reviewed serial immunologic studies in 18 patients. The diagnosis was made with criteria based on the concept of the DiGeorge anomaly as a field defect. Initial or early follow-up laboratory examination suggested moderate to normal T cell function in 14 patients. None of these patients have lost T cell capability; they have never had infections characteristic of T cell deficiency. Four patients had clinical and laboratory evidence of profound immunodeficiency. A decreased number of CD4+ cells (less than 400/microliters) and a decrease in phytohemagglutinin responsiveness (stimulation index less than 10) may be useful in discriminating patients with immunodeficiency; absolute lymphocyte count and immunoglobulin values were not informative. At the time of surgery, the thymus was not found in 11 of 14 patients; however, only two of these patients had immunodeficiency. Patients with a persistently low number of CD4+ cells and decreased phytohemagglutinin response are candidates for immunologic reconstitution.

RECONSTITUTION OF B AND T LYMPHOCYTE FUNCTION IN SEVERE COMBINED IMMUNODEFICIENCY DISEASE AFTER TRANSPLANTATION WITH THYMIC EPITHELIUM

A patient with severe combined immunodeficiency has been given a transplant of thymic epithelium obtained from short-term culture of normal human thymus. 4 wk after transplantation immunoglobulin was detected and the patient now has normal levels of the three main classes. Functional antibodies of four specificities have been detected. An increase in reactivity to allogeneic cells and phytohaemagglutinin has been observed, with an increase in E rosettes; a positive delayed skin test to candida antigen is now present. The patient has shown reversal of wasting and has been free of infection for 7 months since receiving the transplant. It appears that under certain circumstances thymic epithelium reconstitutes both T and B cell functions.

Fatal Lymphoma after Transplantation of Cultured Thymus in Children with Combined Immunodeficiency Disease

A fatal, widespread, polyclonal, B-cell immunoblastic lymphoproliferative disorder developed in three children with combined immunodeficiency shortly after intra-abdominal transplantation of cultured thymus epithelium for immunoreconstitution. All three had surface immunoglobulin-bearing cells (15 to 20 per cent) in the peripheral blood before transplantation and polyclonally elevated immunoglobulins afterward. Abnormal immunoregulation was demonstrated by a lack of concanavalin A-induced suppressor-cell activity in mixed leukocyte culture in all three patients before transplantation and in two afterward. We suggest that the transplant acted as a promoter through immunostimulation or production of promoter factors, and that excessive polyclonal B-cell proliferation resulted because of inadequate immunoregulatory mechanisms. Although this complication occurred in only three of 30 patients with various forms of immunodeficiency treated with cultured thymus, these cases illustrate a potential problem in immunoreconstitution of combined immunodeficiency disorders.

The "active" rosette test in immunodeficiency diseases.

Abstract The “active” rosette test is a clinically useful test for assessing T cell function. When there is disparity between the result of the “active” and “total” rosette test, the clinical status and in vitro studies of the patient correlate better with active rosette formation. These studies also suggest that active rosette formation may serve as a marker of T cell differentiation.

CIRCULATING THYMIC-HORMONE ACTIVITY IN CONGENITAL IMMUNODEFICIENCY

Circulating thymic-hormone activity was assayed by measuring Thy 1-2 antigen induction on null lymphocytes from athymic mice incubated with human plasma or serum. Plasma from 19 normal children aged under 10 had inductive activity equivalent to 10-6-16-2 ng thymopoitin/ml. Plasma from 15 infants were severe combined immuno-deficiency, 2 of whom had appreciable immunoglobulin synthesis, and from 2 infants with DiGeorge syndrome had little or no inductive activity. Successful reconstitution with thymus or bone-marrow grafts and with red-cell infusions (if adenosine-deaminase deficiency is present) was followed by a rise in circulating thymic-hormone activity.

Thymic morphology in immunodeficiency diseases: results of thymic biopsies.

Abstract Extrapleural, transcervical thymic biopsy was performed on 19 patients with a variety of immunodeficiency diseases as part of their immunologic evaluation. Study of the thymus morphology revealed seven different patterns. Five different patterns were seen in patients with the clinical and laboratory diagnosis of combined immunodeficiency (CID), adding morphologic evidence to the concept of heterogeneity in CID. Clinicopathologic correlations are discussed. The study of thymic tissue obtained by transcervical thymic biopsy is a useful adjunct in the evaluation of patients with immunodeficiency diseases and may also be of value in planning therapy for these patients.

Selective T cell killing of human lymphocytes by ultraviolet radiation

Abstract The effects of ultraviolet radiation (uv) on human B and T lymphocytes were studied. In vitro studies showed that T lymphocytes were more sensitive to uv than B lymphocytes as assessed by eosin-dye exclusion. Following uv exposure, the viable lymphocytes responded to mitogens (PHA, PWM), and functional B lymphocytes were present at a time when no viable T cells were detected. Varying doses of uv were required to abrogate different in vitro responses (proliferative response to antigen or allogeneic cells, MIF production, and cell-mediated lympholysis). In vivo , uv was able to diminish an established cutaneous delayed hypersensitivity response. In vitro uv treatment of parental mouse spleen cells eliminated a graft-versus-host reaction in F 1 recipients as determined by the spleen index. The basis for the differential effect of uv on B and T lymphocyte viability and functional responses is unknown.

TREATMENT OF SEVERE COMBINED IMMUNODEFICIENCY WITH BONE-MARROW FROM AN UNRELATED, MIXED-LEUCOCYTE-CULTURE-NONREACTIVE DONOR

A 7-month-old boy with severe combined immunodeficiency had no relative who was a suitable bone-marrow donor as determined by mixed-leucocyte-culture (M.L.C.) testing. In the general population an M.L.C.-nonreactive, unrelated donor was found among individuals who were identical with our patient at the Four locus. Following a bone-marrow transplant this child showed signs of rapid immunological reconstitution and only a mild graft-versus-host reaction. Unfortunately, the child died 31 days post-transplantation of cytomegalovirus infection. The findings support the hypothesis that matching for lymphocyte-defined antigens among unrelated individuals will permit successful immunological reconstitution.

The in vitro induction of differentiation of putative human stem cells by thymosin and agents that affect cyclic AMP

Abstract The in vitro effect of thymosin and agents that alter intracellular cyclic nucleotides on human T-cell differentiation was investigated. In individuals with T-cell defects the number of E-rosette-forming lymphocytes was significantly increased by incubation with thymosin or dibutyryl cyclic AMP. These agents also induced increased responsiveness to PHA in a child with a significant B- and T-cell defect. In addition, putative stem cell fractions from normal peripheral blood were induced to form E-rosettes and to display T-cell functional responses (proliferation following PHA or allogeneic cell stimulation) following incubation with thymosin or agents that increase cellular cAMP.

Lymphocyte dysfunction in congenital hypoplastic anemia.

Congenital hypoplastic anemia (Diamond-Blackfan syndrome) is thought to involve the erythropoietic cell line alone. In this study, the evaluation of lymphocyte function in five patients with this syndrome revealed a number of abnormalities. Peripheral blood T lymphocyte percentages as assessed by monoclonal antibodies were decreased in three patients. T-helper/T-suppressor cell (OKT4:OKT8) ratios were almost unity in four of the five patients. We usually find a ratio of 2:1 in normal populations. Studies of lymphocyte-mediated suppression of lymphoproliferation demonstrated an inability to generate concanavalin A-induced suppressor cells in the same four patients and impaired prostaglandin-mediated suppression in two patients. Co-culture studies revealed a T lymphocyte-mediated suppression of erythropoiesis in a single patient, who also showed suppression of the mixed lymphocyte reaction. The four remaining patients showed no excessive suppressor effects either upon erythropoiesis or lymphoproliferation. These studies demonstrate that in congenital hypoplastic anemia, the cellular defect is not restricted to the erythroid progenitor cells, but extends to the lymphocytes.