Pathologic findings in adenosine deaminase deficient-severe combined immunodeficiency. II. Thymus, spleen, lymph node, and gastrointestinal tract lymphoid tissue alterations.

Eight autopsies of patients with adenosine deaminase deficient-severe combined immunodeficiency disease (ADA-SCID) were reviewed with special emphasis on the lymphoid tissues. The thymus histology in five cases was remarkably uniform, whether or not prior ADA enzyme replacement or immunologic reconstitution therapy had been administered. Lymph nodes and spleens in all cases examined showed a residual nonlymphoid architectural framework corresponding to usual T and B cell zones found in normals. The development of an extranodal, monoclonal IgA lambda B cell immunoblastic lymphoma as a terminal event in one patient after several years of successful ADA enzyme replacement therapy through multiple red blood cell transfusions is described. In another patient with long-term ADA enzyme replacement, a terminal autoimmune hemolytic anemia developed. Autopsy revealed severe deposits of iron in the B cell zones of the lymph nodes, which is an unusual location. In addition, iron deposits outlined the splenic trabeculae, as well as the ring fibers and bridging fibers of the splenic sinuses.     

Varicella pneumonia in a bone marrow-transplanted,immune-reconstituted adenosine deaminase-deficient patient with severe combined immunodeficiency disease

Bone marrow transplantation provides an important modality for enzyme replacement and the immune reconstitution of patients with adenosine deaminase (ADA) deficiency and severe combined immunodeficiency disease. We report a patient with ADA deficiency who develops severe varicella pneumonia 6 years after successful bone marrow transplantation and immune reconstitution. Marked abnormalities in T-cell mitogen responsiveness and pokeweed mitogen-induced polyclonal immunoglobulin synthesis occurred. Coculture experiments suggested the presence of increased suppressor activity. T-cell phenotyping showed decreased T3 and T4 subsets. These abnormalities slowly resolved over several months as the patient recovered from the varicella infection. ADA enzyme levels and metabolite concentrations in urine and erythrocytes remained unchanged. These findings, together with the chromosome and immune studies, suggested that the bone marrow graft remained intact. These studies indicate that immunologically reconstituted ADA-deficient patients may be at higher risk for complications related to varicella infection and suggest that the institution of preventive measures is important.     

Hematopoietic stem cell gene therapy for adenosine deaminase-deficient severe combined immunodeficiency leads to long-term immunological recovery and metabolic correction

Genetic defects in the purine salvage enzyme adenosine deaminase (ADA) lead to severe combined immunodeficiency (SCID) with profound depletion of T, B, and natural killer cell lineages. Human leukocyte antigen-matched allogeneic hematopoietic stem cell transplantation (HSCT) offers a successful treatment option. However, individuals who lack a matched donor must receive mismatched transplants, which are associated with considerable morbidity and mortality. Enzyme replacement therapy (ERT) for ADA-SCID is available, but the associated suboptimal correction of immunological defects leaves patients susceptible to infection. Here, six children were treated with autologous CD34-positive hematopoietic bone marrow stem and progenitor cells transduced with a conventional gammaretroviral vector encoding the human ADA gene. All patients stopped ERT and received mild chemotherapy before infusion of gene-modified cells. All patients survived, with a median follow-up of 43 months (range, 24 to 84 months). Four of the six patients recovered immune function as a result of engraftment of gene-corrected cells. In two patients, treatment failed because of disease-specific and technical reasons: Both restarted ERT and remain well. Of the four reconstituted patients, three remained off enzyme replacement. Moreover, three of these four patients discontinued immunoglobulin replacement, and all showed effective metabolic detoxification. All patients remained free of infection, and two cleared problematic persistent cytomegalovirus infection. There were no adverse leukemic side effects. Thus, gene therapy for ADA-SCID is safe, with effective immunological and metabolic correction, and may offer a viable alternative to conventional unrelated donor HSCT.     

Donor type natural killer cells after haploidentical T cell-depleted bone marrow stem cell transplantation in a patient with adenosine deaminase-deficient severe combined immunodeficiency.

T cell-depleted haploidentical (parental) bone marrow stem cell transplants are given to most infants with the syndrome of severe combined immunodeficiency (SCID) because they have no available HLA-identical sibling potential donors. Since they usually do not undergo cytoreduction prior to transplantation, these children later demonstrate mixed hematopoietic chimerism. Most often, T cells (but usually not B lymphocytes, macrophages, or other hematopoietic cells) can be shown to be of donor type. The origin of natural killer (NK) cells in such chimeras has not been reported. Two lymphocyte lines derived from the CD16+ fraction of an adenosine deaminase (ADA)-deficient male SCID's blood mononuclear cells (MNC) 13 months following maternal marrow stem cell transplantation demonstrated typical phenotypic and functional characteristics of NK cells after expansion. Karyotyping showed both lines to be XX. Thus, NK cell engraftment can occur in SCID infants who have not been conditioned, even when significant NK cell function is present before transplantation.     

Pathomorphologic findings in severe combined immunodeficiency and reticular dysgenesia

Summary Pathomorphologic findings in an 11 month old boy with severe combined immunodeficiency (case 1) and in a 4 month old boy with reticular dysgenesia (case 2) are reported. Case 1: The bone marrow exhibited regular granule-, erythro- and thrombopoiesis. The hypoplastic thymus consisted exclusively of epithelial reticulum cells. The spleen and lymph nodes showed considerable depletion of lymphocytes in both the T- and B-cell areas. There was a complete lack of all lymphatic structures in the gastrointestinal tract and aplasia of the tonsils. Death resulted from Candida sepsis in conjunction with giant cell pneumonia closely resembling Hecht's pneumonia in measles. Case 2: The bone marrow showed a total lack of granulopoiesis. The strongly dysplastic thymus weighed only 1 g. The spleen, the lymph nodes and the gastrointestinal tract exhibited a very strange histologie structure resulting from a complete absence of lymphocytes and plasma cells. The tonsils were aplastic, the parathyroid glands as well as the other endocrine glands were normally developed. The cause of death was Klebsiella sepsis and Pneumocystis pneumonia, the latter without the characteristic interstitial plasma cell infiltration. The importance of the immune system for activation of the nonspecific mechanisms of defense is discussed with respect to the two types of immunodeficiency states described here.This paper was presented in part at the 6th Fall Meeting of the German Society for Pathology in Vienna, Oct. 11, 1975.     

Pathologic findings in the adrenal glands of autopsied patients with acquired immunodeficiency syndrome

A morphologic evaluation was carried out on adrenal glands from 128 autopsied patients with the acquired immunodeficiency syndrome (AIDS). The adrenal gland was compromised in 99.2% of the cases, with distinct pathological features and infectious agents. Inflammatory infiltrates were observed in 99.2% of the cases with a predominance of mononuclear cells in 97.4%, affecting mainly the medulla. Necrosis, fibrosis, hemorrhages and neoplasias were observed. We also described 3 (2.3%) cases of calcification located in the adrenal gland central vein (AGCV). This is seldom mentioned in the literature. Cytomegalovirus was the most frequent infectious agent, observed in 48.4% of cases. Balamuthia mandrillaris, a free living ameba, was found in one case affecting the entire gland. We also found a nest of Trypanosoma cruzi in the musculature of the AGCV. The presence of the nest of T cruzi in AGCV may play a role in the reactivation of this infection in immunosuppressed individuals. Pathologic processes and opportunistic infections may contribute to the alterations in the adrenal gland that lead to multiple organ failure observed in terminal AIDS patients.     

Heterogeneity of biochemical, clinical and immunological parameters in severe combined immunodeficiency due to adenosine deaminase deficiency.

There was considerable heterogeneity of the biochemical, clinical and immunological findings in 12 patients and two fetuses from 16 kindreds affected by severe combined immunodeficiency (SCID) due to a complete deficiency of the enzyme adenosine deaminase (ADA). Despite this heterogeneity a consistent pattern was observed, in which levels of abnormal purine metabolites paralleled the severity of the immunodeficiency. A high level of urinary deoxyadenosine was a universal finding for homozygous ADA deficiency. ATP depletion, in association with raised deoxy-ATP (dATP) levels, was found in the erythrocytes of nine infants with profound cellular and humoral immunodeficiency. There was no erythrocyte ATP depletion in two patients with some residual immunity, who presented later, but adenosine accumulated in their plasma and urine. This finding, together with the presence of some T and normal B-lymphocytes in less severely affected patients, suggests that adenosine is relatively non-toxic. The other results are consistent with the hypothesis that the sequence of deoxyadenosine accumulation, dATP formation and ATP depletion represents the major mechanism of toxicity to the immune system. Low numbers of T lymphocytes and dATP accumulation were also found in the blood of affected fetuses at 18 weeks gestation. Since extreme instability of erythrocyte ADA was demonstrated in some heterozygotes, and heterozygote ADA levels were detected in one infant with SCID, simultaneous immunological and biochemical analysis of fetal blood are important for precise antenatal diagnosis.     

Severe combined immunodeficiency disease, adenosine deaminase deficiency and gene therapy.

Patients with severe combined immunodeficiency disease represent a model for the first clinical applications of gene therapy. Present attempts use insertion of the human adenosine deaminase gene into the peripheral blood T lymphocytes of patients who lack this gene. The ultimate treatment, however, will require insertion of the normal human adenosine deaminase gene into pluripotent stem cells and expression of the gene in their progeny.     

Effect of red cell transfusions, thymic hormone and deoxycytidine in severe combined immunodeficiency due to adenosine deaminase deficiency

A child with severe combined immunodeficiency due to adenosine deaminase deficiency was treated with thymic hormone (TP1) alone, thymic hormone with red cell transfusions and finally with a combination of these and parenteral deoxycytidine. TP1 alone produced no benefit while the addition of red cell transfusions resulted in only partial immunological restoration despite improvement in clinical and biochemical findings. Deoxycytidine given subcutaneously produced no additional benefit in any of the parameters measured.     

Circulating thymic hormone levels in severe combined immunodeficiency.

Twenty-three patients with severe combined immunodeficiency disease were studied for circulating thymic hormone levels (facteur thymique serique, FTS), 21 prior to treatment by transplantation of bone marrow, thymus or fetal liver. Thirteen showed undetectable FTS activity. Only two had normal levels of this hormone. In serial determinations of FTS activity prior to and after transplantation, patients given bone marrow transplants developed sustained increments of serum FTS activity early in the course of their immunological reconstitution. However, patients given transplants of fetal liver alone or fetal liver plus thymus from fetuses of less than 12 weeks gestation generally did not show an increment of FTS activity during the period of observation. Transplantation of irradiated thymus derived from fetuses of more than 14 weeks gestation produced sustained increases of thymic hormone activity. These observations suggest that a cell of haematopoietic origin provides a stimulus necessary for differentiation or maturation of thymic secretory activity and that this cell(s) is present in post-natal marrow, but is either undeveloped or immature in the early fetal liver or fails to migrate to the thymus of an allogeneic host.     

Heterogeneity of stem cells in severe combined immunodeficiency.

Two patients with severe combined immunodeficiency disease (SCID) having variable B-cell development have been shown to have marrow precursors of lymphoid cells which can be induced in vitro by thymic factors to express certain T-cell surface characteristics (HTLA+ phenotypes). Their marrow cells could not, however, be induced by these same factors to develop the E-rosette marker or functional activities of T lymphocytes. The marrow of these children also showed, when compared to that of normal adults, a different distribution of cellular elements on density gradient fractionation. The findings support the view that the disorder under study has a different pathogenesis from other forms of SCID previously analysed.     

Persistent cryptosporidiosis in horses with severe combined immunodeficiency.

Cryptosporidial infections were established in five young foals with severe combined immunodeficiency following oral administration of 10(8) Cryptosporidium parvum oocysts. All foals shed oocysts (average of 8 x 10(6) to 2 x 10(8)/g of feces) until death. Inflammation and C. parvum organisms were observed in the common bile duct, duodenum, jejunum, and ileum. Since foals with severe combined immunodeficiency lack functional T and B lymphocytes and are incapable of antigen-specific immune responses, they are well suited for evaluating the pathogenesis and treatment of persistent cryptosporidiosis.