Thymus transplantation. Permanent reconstitution of cellular immunity in a patient with sex-linked combined immunodeficiency

New perspectives on use of thymic factors in immune deficiency

Current knowledge on the role of thymic factors in the immune response is inadequate and remains relatively primitive when compared with present technical possibilities for assessing lymphocyte subsets or cytokine interaction. New studies support the potential importance of thymic factors as regulators of immune interactions. Indirect evidence supports the concept that thymic factors may work at the level of IL-2. The functional identity of cells responsive to thymic factors and the relation of observed effects to cytokine network interactions need to be established. The use of thymic factors in the future will depend on the development of criteria to identify appropriate settings in which to use such factors and the implementation of appropriate measures of immune functional response.

Effect of partial testosterone replacement or thymosin on anti-DNA in castrated (NZB X NZW)F1 males

Castration of young (3-week-old) but not older (3-month-old) male (NZB X NZW)F1 mice was associated with autoantibody production similar to that of untreated female littermates. The castration-induced disease provided a unique model for the evaluation of therapeutic modalities during the first 9 months of life. Castrated male (NZB X NZW)F1 mice were treated with either long-term thymosin (fraction 5) or testosterone for different periods of time. Continuous testosterone replacement abolished the autoimmune disease-accelerating effects of castration at 3 weeks. Brief treatment during either the early or the later periods of life of castrated (NZB X NZW)F1 males was insufficient to prevent accelerated anti-DNA production. Thymosin treatment, when started at the time of castration and continued through life, abolished the rise in anti-DNA. These studies suggest that androgens work throughout the first 7 months of life of the mouse to suppress anti-DNA and that lack of androgens for a relatively brief period allows anti-DNA production to be initiated. Once initiated it cannot be completely suppressed. The cellular basis of the fixed aspect of this process is unknown. A possible role of the thymus is suggested by the ability of thymosin to suppress anti-DNA.

Immunodeficiency syndromes and the gut

The gastrointestinal tract in immunodeficiency disorders is involved with diseases similar to those seen in the immune competent. However, in some immune deficient states the incidence of gastrointestinal disease is high whereas in others it is no different than in the general population. This review clarifies the unique and specific abnormalities seen in immune deficient states and stresses the newest recognised abnormalities. It highlights the fact that the most frequent and severe abnormalities occur in patients with combined immune deficient states.

Maturational impairment of thymic lymphocytes in streptozotocin-induced diabetes in rats

Streptozotocin (STZ)-induced diabetes in rats was associated with marked decreases in thymus weight and the number of thymic lymphocytes. Histologically, the cortical lymphocytes which were present near the cortico-medullary junction in the thymus seemed to be reduced selectively in the STZ-induced diabetes. Rosette-forming cells, which bind to guinea pig erythrocytes in the presence of fetal calf serum, were also significantly decreased. Insulin treatment allayed these intrathymic changes. Preincubation of thymic lymphocytes from diabetic rats with thymosin fraction 5 significantly enhanced the percentage of rosette-forming cells to near the control level. These results suggest that a maturational impairment of thymus cortical lymphocytes may be caused in STZ-induced diabetes with hypoinsulinemia and it may be intimately related to reductions in thymus weight and the number of thymic lymphocytes.

Graft-versus-host reaction following blood product transfusion

The observation of graft-versus-host (GVH) reaction after platelet transfusion in a patient with Hodgkin's disease led us to analyze 38 reported cases in the literature, to outline prognostic factors and to characterize patients at risk. Overall mortality was 68 percent. It was higher among children (76 percent) than among adults (62 percent), and among patients with Hodgkin's disease and immune deficiency syndromes (88 percent) than among those with leukemias (23 percent, p less than 0.005). Following blood transfusions from normal donors, mortality was higher (88 percent) than after transfusions from donors with chronic myelocytic leukemia (25 percent, p less than 0.05). Minimal lymphocyte doses necessary to cause GVH reaction are in excess of 10(7)/kg. Adults seem more resistant to homografts than do children, and the host's cellular immune status is of major prognostic importance. Lymphocytes from donors with chronic myelocytic leukemia may be deficient, and after a threshold dose, the number of lymphocytes transfused does not correlate with clinical outcome. Effective prophylactic measures do exist for this complication but satisfactory therapy does not.

Thymosin therapy in the DiGeorge syndrome

Reconstruction of the T-cell immune defect in patients with the DiGeorge syndrome has been accomplished in the past by fetal thymus transplantation. Because of the risk of fatal graft-versus-host reaction with fetal thymus transplantation in patients with abnormal T-cell immunity, we have examined the effects of a thymus tissue extract, thymosin fraction 5, on the in vitro and in vivo immune function in children with the DiGeorge syndrome. T-cell numbers were increased with thymosin F5 in vitro in three of five patients. T-cell number and function was improved in three of four patients treated with thymosin F5 in vivo. Spontaneous improvement in the immune function of these patients cannot be excluded. These results suggest, however, that further trials with thymosin F5 therapy may be indicated in patients with the DiGeorge syndrome.

Transplantation of lymphoid cells in patients with severe combined immunodeficiency (SCID)

The effects of bone marrow or fetal lymphoid organ transplants in 15 patients with severe combined immunodeficiency disease are reported. The benefits and dangers inherent to the various transplantation strategies are discussed. Our studies indicate that, even in the group of patients with B cells, bone marrow transplantation may be the best procedure to obtain the reconstitution of cellular and humoral functions.

Selective defect of precursor T cells associated with apparently normal B lymphocytes in severe combined immunodeficiency disease

Two patients, one with an autosomal and the other a sex-linked form of severe combined immunodeficiency, had more than 95% B cells in their peripheral blood. Despite an increased absolute number of B lymphocytes, the patients were unable to produce serum antibodies. In each patient, geno- or pheno-identical bone marrow transplantation was followed by the visualization of a thymus shadow and the appearance of both cellular and humoral functions. Chromosome of allotype studies showed that the T cell originated from the donor whereas serum immunoglobulins were synthesized by host B cells. In these patients the pathogenesis appears to be a selective defect of bone marrow precursor T cells without concomitant intrinsic B cell defect. The successful outcome of the graft in these two patients, who are now, respectively, 5 years and 11 months of age and free of infections, indicates that the preferred form of therapy in such patients is transplantation of bone marrow stem cells, which populate the thymus and mature slowly into T cells that cooperate fully with host B cells in synthesis of antibody.

Successful restoration of immunity in the DiGeorge syndrome with fetal thymic epithelial transplant

A 13-month-old girl presented with right upper lobe pneumonia and hypocalcaemic seizures: investigations showed hypoparathyroidism and impaired cell-mediated immune responses. Other features of the DiGeorge syndrome included hypertelorism, short philtrum of the lip, right-sided aortic arch, and aberrant origin of the left subclavian artery. Successful restoration of the immunodeficiency was achieved by transplantation of fetal thymic epithelium.

Fatal histiocytic lymphoma of the brain associated with hyperimmunoglobulinemia-E and recurrent infections

A 10-year-old girl with eczema, asthma, recurrent abscesses, middle ear infections and pneumonias developed a histiocytic lymphoma of the brain. Immunologic evaluation revealed hyperimmunoglobulinemia E, depressed neutrophil chemotaxis, absent delayed hypersensitivity skin test tests, low T-lymphocyte numbers and depressed in vitro lymphocyte responses. The occurrence in this patient of a histiocytic lymphoma, which is commonly associated with more classic immunodeficiency syndromes or immunosuppression for transplantation, suggests that individuals with hyperimmunoglobulinemia E and recurrent infections may also be at increased risk for developing unusual malignancies.

Thymosin reconstitution of T cell deficits in vitro in cancer patients

Thymosin, a soluble extract of fetal calf thymus, has increased cellular immunity in children with thymic deficiency. Prior to therapy, an increase in thymus-dependent lymphocyte (T cell) levels in vitro after incubation with thymosin correlated with a rise in peripheral blood T cell levels and improvement in other parameters of cellular immunity. These correlations constituted the basis for a study of the effects of thymosin on T cell levels in vitro in cancer patients. Groups studied were 350 untreated patients with local-regional solid malignancies, 157 patients cured of these tumors, 340 patients studied at 523 intervals during radiation therapy, 80 patients receiving chemotherapy for disseminated solid malignancies, and 427 normal volunteers. Although there were significant differences among the groups in mean leukocyte, lymphocyte and T cell levels, among those with low T cell levels in each group there was a significant inverse relation between T cell levels after incubation with thymosin in vitro and initial T cell levels, with the exception of patients receiving chemotherapy. In patients receiving chemotherapy, T cell levels increased independently of initial T cell levels. These in vitro observations are consistent with evidence that a major effect of thymosin is maturation of T cell precursors; however, the effect is that of reconstitution at low T cell levels, and not of elevation to levels significantly above normal. The results provide a rationale for clinical trials with thymosin to maintain immune competence during radiation therapy and chemotherapy, and for a two-phase approach to immunotherapy of cancer utilizing thymosin for reconstitution of cellular defects followed by administration of agents that potentiate cellular immunity.

Enzyme replacement therapy for adenosine deaminase deficiency and severe combined immunodeficiency

To evaluate their role as a form of replacement therapy, frozen irradiated red blood cells were administered to a child with adenosine deaminase deficiency associated with severe combined immunodeficiency disease. In vitro lymphocyte responses to mitogens and allogeneic cells were restored. Subsequently, a "thymus shadow" appeared, and immunoglobulin synthesis was demonstrated. Frozen irradiated plasma, which alone had no effect on lymphocytes numbers or responses, promoted lymphocytosis when given with frozen irradiated red blood cells. The patient received the transfusions with or without irradiated plasma at four-week intervals and remained free of infection for 17 months. The patient's lymphocyte adenosine triphosphate levels were elevated before therapy, which consistently reduced them without altering the lymphocyte adenosine deaminase activity. Enzyme replacement therapy may provide a way to treat patients with adenosine deaminase deficiency associated with severe combined immunodeficiency disease who do not have histocompatible bone-marrow donors.

Correction of severe combined immunodeficiency by fetal liver cells

As an alternative to bone-marrow transplantation, two infants with severe combined immunodeficiency who had no histocompatible donors were given intraperitoneal infusions of fresh liver cells from fetuses of eight and nine to 10 weeks. Transient graft-versus-host disease began at 42 and 52 days, respectively. Both infants had rises in T cells and declines in B cells by three months. No functional immunologic improvement occurred in the first infant, who died of pulmonary disease 10 months later. Clinical and functional immunologic improvement occurred in the other, who is now 19 months after transplantation. Lymphocyte responses to phytohemagglutinin and pokeweed mitogen were noted by three months, to concanavalin A by five months, and to allogeneic cells by eight months. Delayed cutaneous responsiveness to candida developed and IgM became norma. IgA and IgG remained low. Chimerism was demonstrated by a donor marker chromosome in metaphases from recipient lymphocytes. Fetal liver cells therefore reversed the immunodeficiency.

Chronic cytomegalovirus infection, immunodeficiency, and monoclonal gammopathy-antigen-driven malignancy?

An infant with severe combined immunodeficiency had normal numbers of lymphocytes which bore E rosette and surface Ig markers in an appropriate distribution. However, only minimal responsivity to in vitro stimulation by mitogens and allogenic cells, and none to antigens could be elicited; functional antibody responses were also nil, except to cytomegalovirus. Intrauterine-acquired cytomegalovirus may have caused his immune dysfunction, although the possibility of a postnatal infection cannot be excluded. Therapy with transfer factor and thymus transplantation was unsucessful in restoring immunity and may have aggravated a pre-existing monoclonal gammopathy. It is possible that the monoclonal protein was derived from B-cells transplacentally received from the patients mother.

Demonstration of an intrathymic defect in a case of severe combined immunodeficiency disease

An in vitro system has been developed to elucidate the nature of the cellular defect in primary immunodeficiency diseases. Incubation, on human thymic epithelial monolayer cultures, of peripheral blood lymphocytes and bone-marrow cells from a child with documented severe combined immunodeficiency disease resulted in the appearance of a population of cells that formed rosettes with sheep erythrocytes. The same cell preparation permitted the synthesis of antigen-specific, complement-dependent antibodies after in vitro education, as demonstrated in a plaque assay system. In addition, thymic tissue from the same child gave morphologic and functional evidence of maturation when cultured in vitro. The experimental results suggest that in this case, lymphoid precursor cells were present in the bone marrow but failed to differentiate to functional maturity due to a defect in maturation of thymic tissue.

Elevated IGA in carcinoma of the nasopharynx

Fourteen patients with nasopharyngeal carcinoma were evaluated immunologically prior to standard radiotion therapy. All had elevations of serum IgA, ranging from 300 mg/100 ml to 1000 mg/100 ml, with a mean value of 549 mg/100 ml. Seven patients demonstrated depression of cell-mediated immunity as measured by delayed hypersensitivity skin tests, total lymphocyte count, in vitro stimulation with PHA, and T-cell rosette formation. Elevation of serum IgA associated with depression of cell mediated immunity may be characteristic of patients with nasopharyngeal carcinoma.

Combined immunodeficiency disease associated with adenosine deaminase deficiency. Report on a workshop held in Albany, New York, October 1, 1973

Fifty-five children with CID and known ADA status were studies at a workshop held in Albany, New York. Erythrocyte ADA determinations were performed in 22 of the 55 patients, 13 of whom were ADA negative. The ADA defect appears to be transmitted as an autosomal recessive trait. Some patients with CID and ADA deficiency have characteristic radiologic abnormalities of the skeleton, which are not found in other illnesses. The thymus glands of all patients with CID and ADA deficiency who could be examined have evidence of thymic involution manifested by presence of Hassall's corpuscles and differentiated germinal epithelium; this is in contrast to "classic" thymus findings in CID with normal ADA. Adenosine deaminase probably plays an important, although as yet undefined, role in lymphocyte development and/or function. The deficiency of ADA in CID is the first enzyme defect observed in a deficiency disease of specific immunity.

Thymosin activity in patients with cellular immunodeficiency

An extract of calf thymus, thymosin, induces an increase in percentage of T-cell rosettes when incubated in vitro with sheep erythrocytes and lymphocytes from patients with primary immunodeficiency diseases or viral illness. Precursor lymphocytes are required for this increase to occur. The percentage of T-cell rosettes, when they are normal, is not increased further upon incubation with thymosin. A patient with thymic hypoplasia and immunoglobulin synthesis was selected to receive thymosin in vivo when her T-cell rosettes had increased from 15 to 48 per cent after in vitro incubation with thymosin. During therapy, she clinically improved, the percentage of T-cell rosettes gradually increased to normal, and positive delayed hypersensitivity skin tests developed. Thymosin may be useful clinically for partial reconstitution of cellular immunity. An increased percentage of T-cell rosettes after incubation with thymosin in vitro may predict which patients will respond to thymosin therapy in vivo.

Incomplete restoration of the bursa-dependent immune system after transplantation of allogeneic stem cells into immunodeficient chicks

Transplantation of allogeneic cells from bursa of Fabricius into cyclophosphamide-treated, immunodeficient chicks resulted in immunological tolerance to donor line skin grafts; graft-versus-host disease did not occur. Allogeneic bursal stem cells taken from 3-day-old donors induced restoration of bursal morphology, of antibody formation to Brucella abortus and of occurrence of pyroninophilic cells and immunoglobulin-bearing cells in the peripheral lymphoid tissues. Secondary response to sheep red blood cells and production of germinal centers were not restored. Transplantation of histocompatible bursal stem cells resulted in a complete reconstitution of the bursa-dependent lymphoid system, both in function and in morphology. Allogeneic postbursal stem cells taken from the bursa of 10-week-old donors had a reconstitutive effect only on the production of antibodies to Brucella. Transplanted stem cells maintained their functional potential in the allogeneic environment, since, when transferred back to histocompatible hosts, they displayed normal function. These findings indicate that a complete functional and morphological restoration of the bursa-dependent immune system cannot be achieved without identity of the donor and recipient at loci near to or identical with those determining the major histocompatibility antigens, even though graft-versus-host disease is avoided. This identity permits a full cooperation of the donor and host cells.