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

Regional deficiency of secretory IgA in a patient with combined immunodeficiency of the ADA deficient type

The IgA system in a patient with SCID and ADA deficiency showed heterogeneity. Serum IgA and stool secretory IgA (SIgA) levels were normal, but with altered kappa/lambda and A1/A2 subclass ratios; IgA in saliva and urine was deficient. Amounts of secretory component were normal. Jejunal and rectal biopsies showed prominent lymphonodular hyperplasia, but no cells containing IgA. A normal serum IgA level therefore does not always predict an intact secretory IgA system.

Red cell adenosine deaminase (ADA) polymorphism in Southern Africa, with special reference to ADA deficiency among the !Kung

Studies have been carried out on polymorphism of adenosine deaminase in 36 Southern African populations comprising more than 3000 individuals. The common variant allele ADA2 has been found to attain polymorphic frequencies only in those populations descended from non-indigenous (i.e. non-Negro and non-Khoisan) groups. Its presence in certain other populations at low frequencies could be ascribed to small-scale Caucasoid admixture. A deficiency of the enzyme is found in certain members of the !Kung division of the San ('Bushman'). The low levels of enzyme activity are not associated with severe combined immunodeficiency and the gene which determines them appears to be polymorphic in the !Kung and possibly in some other San populations as well as possibly in Negro populations which have received substantial contributions of San genes.

Adenosine-adenosine deaminase modulation of histamine release from human basophils in vitro

Since extracellular adenosine is a physiologically important regulator of adenylate cyclase and cell function in various mammalian tissues, we have examined the effect of adenosine on histamine release from human basophils. Adenosine inhibited IgE-mediated histamine release by its ability to increase leukocyte cyclic AMP levels; the same concentrations of adenosine which inhibited histamine release increased the cyclic AMP level of mixed leukocytes. Inhibition of histamine release was also observed with an adenosine deaminase (ADA) inhibitor [erythro-9-(2-hydroxy-3-nonyl)-adenine: EHNA] in the presence of autologous serum. We suggest that the adenosine-ADA system normally modulates histamine release and that this contributes to the severe combined immune deficiency (SCID) associated with a lack of ADA.

Limited effect of erythrocyte and plasma infusions in adenosine deaminase deficiency

A 10-month-old child with a profound deficiency of adenosine deaminase and severe combined immunodeficiency was treated for a period of 17 months with red cell and plasma transfusions containing normal amounts of the deficient enzyme. Following each transfusion, the plasma adenosine, red cell and lymphocyte ATP, urinary adenine, and urinary deoxyadenosine decreased transiently. During this period, the absolute blood lymphocyte count rose and a limited increased in the response of the lymphocytes to PHA-P was observed. Delayed hypersensitivity skin tests remained negative during the transfusion periods. A quantitative elevation of serum immunoglobulins occurred, but specific antibody formation was not elicited. In contrast to a previous report of successful therapy of ADA deficiency with red cell and plasma infusions, this patient responded poorly to enzyme replacement therapy. The difference may be related to a more profound enzyme deficiency in our patient.

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.

Characterization of a guanine-sensitive mutant defective in adenylo-succinate synthetase activity

A contingent auxotrophic mutant of CHO-Kl cell is described. This mutant grows in minimal medium. Its growth is inhibited by the exogenous addition of guanine at levels which do not affect the wild type parent. Adenine reverses the guanine effect. This mutant does not complement ade-H (defective in adenylosuccinate synthetase) and has been denoted as ade-HG because of its guanine sensitivity. Some partial revertants of ade-H are found to be also sensitive to guanine, suggesting a close relationship between the ade-H locus and the guanine sensitivity. Studies of 14C-hypoxanthine incorporation into nucleotides indicated that ade-HG has some adenylosuccinate synthetase activity whether it is pre-exposed to guanine or not. Early de novo purine synthesis in ade-HG, however, is greatly inhibited when pre-exposed to guanine. This inhibition of purine synthesis by guanine is reversible and its recovery is facilitated by adenine.

Analysis of adenosine-mediated pyrimidine starvation using cultured wild-type and mutant mouse T-lymphoma cells

Using the S49 T-cell lymphoma system for the study of immunodeficiency diseases, we characterized several variants in purine salvage and transport pathways and studied their responses to the cytotoxic action of adenosine (5-20 micron) in the presence of adenosine deaminase (ADA) inhibitors. Both an adenosine transport deficient mutant and a mutant lacking adenosine (ado) kinase activity are resistant to the cytotoxic effects of adenosine up to 15 micron. Variants lacking hypoxanthine-guanine phosphoribosyl transferase or adenine phosphoribosyltransferase are sensitive to the killing action of adenosine. We monitored the intracellular concentrations of purine and pyrimidine nucleotides, orotate, and PPriboseP in mutant and wild-type cells following the addition of adenosine and an ADA inhibitor. We conclude that at low concentrations, adenosine must be phosphorylated to deplete the cell of pyrimidine nucleotides and PPriboseP and to promote the accumulation of orotate. These alterations account for one mechanism of adenosine toxicity.

Purine nucleoside phosphorylase from human erythrocytes: physiocochemical properties of the crystalline enzyme

The major physicochemical properties of human erythrocytic purine nucleoside phosphorylase (PNPase) have been described. The molecular weight, estimated by ultracentrifugation, molecular sieving and sucrose density gradient centrifugation, ranged from 87 000 to 92 000. Other physical constants of erythrocytic PNPase were: sedimentation coefficent (s20, w), 5.4 S obtained by sedimentation analysis and 5.5 S by the sucrose density gradient procedure; Stokes radius, 38 A; calculated diffusion coefficient (D20, w), 5.7 X 10(-7) cm2 s-1; frictional ration, 1.29; and partial specific volume calculated from amino acid analysis, 0.73 cm3 g-1. The CD spectra of the human erythrocytic and bovine spleen PNPases were almost identical and indicated a very low alpha-helical content. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate indicated that the molecular weight of the PNPase subunit is 30 000 +/- 500. These results corroborate earlier reports that the native enzyme is a homologous trimer. Comparative studies with crystalline bovine spleen PNPase confirmed that it is also a trimer but is somewhat smaller than the human erythrocytic enzyme with a molecular weight of about 86 000.

A micromethod for determining adenosine deaminase and purine nucleoside phosphorylase activity in cells from human peripheral blood

A radiochromatographic method is described for measuring adenosine deaminase and purine nucleoside phosphorylase activity in cells from human peripheral blood. The respective substrates, [8-14C]adenosine or [8-14C]inosine, are converted either to inosine and hypoxanthine or hypoxanthine, respectively. A single simple and rapid chromatographic procedure is used to isolate the products of both reactions. The mean normal activity (nmol h-1mg-1) of ADA for erythrocytes is 63 +/- 24 (+/- 1 S.D.) for leukocytes, 750 +/- 280 and for lymphocytes, 2105 +/- 1170. Corresponding activities for purine nucleoside phosphorylase are 1850 +/- 490, 3665 +/- 1170 and 5890 +/- 2030. With the described methods a further patient with severe combined immuno-deficiency and adenosine deaminase deficiency has been identified.

Adenosine deaminase (ADA) activity in lymphocytes of normal individuals and patients with chronic lymphatic leukaemia

Adenosine deaminase (adenosine aminophydrolase, ADA) activity was found to be low in lymphocytes of chronic lymphatic leukaemia (CLL) patients compared to normal lymphocytes. This was determined on 42 controls and 49 CLL patients. The mean activity in normal lymphocytes was found to be 4.35 +/- 3.34 mumol/h/10(8) cells while in CLL cells it was 2.45 +/- 2.54 mumol/h/10(8) cells.

Purine nucleoside phosphorylase deficiency associated with selective cellular immunodeficiency

We studied a 15-month-old girl who had normal T-cell and B-cell immunity at birth, after which a gradual decrease in T-cell immunity developed. This selective cellular immunodeficiency was inherited as an autosomal recessive trait: two older sisters had the same immunodeficiency. Adenosine deaminase activity was present in erythrocytes and lymphocytes of the patient, parents and a healthy brother. Purine nucleoside phosphorylase activity was not found in the patient's erythrocytes and lymphocytes (the parents and brother had intermediate values, indicating that the enzyme deficiency too was inherited as an autosomal recessive trait). Analysis of serum and urine from the patient and of serum from her two deceased sisters showed high levels of inosine and guanosine in addition to hypouricemia and hypouricosuria. The bone marrow was megaloblastic, and the blood hypochromic microcytic. The patient had spastic tetraparesis. Intoxication of the T lymphocytes after birth by metabolic products may explain the progressive cellular immunodeficiency.

Immunological aspects of purine metabolism

The development of our knowledge of the immune system has been reviewed and evidence presented of the need for a rapid rate of purine synthesis de novo for the proliferative events in this process. The mechanism of the inhibition of the immune system in a model of ADA deficiency has been studied intensively and considerable indirect evidence obtained of adenosine toxicity as a possible mediator of a reversible inhibition of proliferation of T-cells and to a slightly lesser extent B-cells. A secondary inhibition of ADA by inosine accumulation in PNP deficiency is proposed as a unifying hypothesis in which a somewhat lesser adenosine toxicity would inhibit proliferation only only of T-cells. The correction of the immune response by addition of ADA both in vitro and in vivo provides strong evidence in favor of this view. In HPRT deficiency no evidence was found of a gross impairment of the immune system; however, the HPRT enzyme is required for inhibition of the immune response by 6MP in a variety of systems using different mitogenic stimuli.

Abnormal purine metabolism and purine overproduction in a patient deficient in purine nucleoside phosphorylase

To delineate the normal function of purine nucleoside phosphorylase and to understand the pathogenesis of the immune dysfunction associated with deficiency of this enzyme, we studied purine metabolism in a patient deficient in purine nucleoside phosphorylase, her erythrocytes and cultured fibroblasts. She exhibited severe hypouricemia and hypouricosuria but excreted excessive amounts of purines in her urine, the major components of which were inosine and guanosine. Her urine also contained deoxyinosine, deoxyguanosine and uric acid 9-N riboside. The patient's erythrocytes but not her cultured fibroblasts contained increased concentrations of phosphoribosylpyrophosphate and inosine. The metabolic abnormalities resembled those in the erythrocytes of patients with the Lesch-Nyhan syndrome. Purine nucleoside phosphorylase is a necessary component of the major, if not the sole, pathway for the conversion of purine nucleosides and nucleotides to uric acid. The increased intracellular concentrations of inosine may, by inhibiting adenosine deaminase, be related to the immunologic dysfunction.

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.

Two biochemical markers in lymphocyte subpopulations

Human blood lymphocytes can be separated into two populations according to the presence of surface complement receptors. Lymphocytes containing complement receptors (CR+) were found to have a high rate of RNA synthesis or turnover accompanied by increased protein synthesis. Lymphocytes not containing complement receptors (CR-) while maintaining a low profile in RNA synthesis, had a 10-12-fold greater activity in adenosine deaminase enzyme which is believed to be related to lymphocyte-immune responses and cell-mediated immunity. These two biochemical characteristics can be useful tools for future studies in lymphocyte functions. By using these two biochemical markers, we found that CLL lymphocytes were predominantly of the CR+ type, had high active RNA synthesis, and very low adenosine deaminase level. Lymphocytes from two patients with X-linked agammaglobulinaemia showed a picture opposite to that of CLL.

The chondro-osseous dysplasia of adenosine deaminase deficiency with severe combined immunodeficiency

Three children, two of them siblings, with severe combined immunodeficiency and adenosine deaminase deficiency died within the first six months of life from the complications of acute bacterial infections. Subtle radiographic abnormalities were seen at the costochondral junctions, at the apophysis of the iliac bones, and in the vertebral bodies. At autopsy, the thymus showed evidence of early differentiation and, in one instance, aborted Hassall's corpuscles. Histologic study of the bone disclosed lack of organized cartilage columnar formation, large lacuni containing hypertrophied cells, and lack of trabecular formation with uninterrupted areas of calcified cartilage. These changes are distinctly different from those observed in the metaphyseal chondrodysplasias or in other chondrodystrophies.

Deficiency of adenosine deaminase not associated with severe combined immunodeficiency

The 12-year-old Kung (""Bushman'') boy from South West Africa who has marked deficiency of red cell adenosine deaminase has been found to have 2 to 3% of enzyme activity in red blood cells, 10 to 12% in leukocytes, and 10 to 30% in cultured fibroblasts. The enzyme has ADA 1 electrophoretic mobility: SV40 transformation of cultured fibroblasts caused a decrease of ""tissue ADA'' and an increase in ""red cell ADA'' isozymes. A battery of investigations revealed that the child has normal humoral and cellular immunity. A family study showed that a sibling had the same level of red cell ADA and the parents had intermediate levels. Studies of the Kung population from which the child comes have shown that the allele responsible for the condition, and which we designate ADA8, is polymorphic.

Characterization of a cell culture model for the study of adenosine deaminase- and purine nucleoside phosphorylase-deficient immunologic disease

The absence of erythrocytic adenosine deaminase (ADA) or purine nucleoside phosphorylase (PNP) has been associated with severe immunodeficiency disease in children. We have developed a cell culture model to study the possible relationships between purine salvage enzymes and immunologic function using an established T cell lymphosarcoma (S49) and a potent inhibitor of ADA, erythro-9(2-hydroxy-3-nonyl) adenine (EHNA). Wild-type S49 cells are killed by dexamethasone or dbc AMP, and adenosine (5 muM) in the presence of an ADA inhibitor (6 muM EHNA) also prevents the growth of and kills these S49 cells. It has been proposed that adenosine is toxic to lymphoid cells by virtue of its ability to increase the intracellular concentrations of cyclic AMP. We examined the sensitivity of three mutants of S49 cells, with distinctive defects in some component of cyclic AMP metabolism or action, to killing by adenosine and EHNA. All three mutants are resistant to killing by isoproterenol or cholera toxin and two are resistant to dbc AMP itself, but all are sensitive to killing by adenosine and EHNA. Similarly, two dexamethasone-resistant S49 mutants are as sensitive to adenosine and EHNA as are the wildtype cells. We have also simulated the purine nucleoside phosphorylase deficiency in S49 cells by adding inosine and adenosine to the growth medium. In the presence of EHNA or inosine, the toxic effects of adenosine can be partially reversed by addition of (10-20 muM) uridine, an observation suggesting that adenosine is toxic as the result of its inducing pyrimidine starvation.

Severe combined immunodeficiency with leukopenia (reticular dysgenesis) in siblings: immunologic and histopathologic findings

The hematologic and histologic features of two, nontwin, male siblings with severe combined immunodeficiency and variable granulocytopenia are compared to the four previously reported cases of reticular dysgenesis. These sibs died at 50 and 3 days of age, respectively, with Pseudomonas sepsis and congenital cytomegalovirus infection, respectively. A maternal uncle has selective IgA deficiency. Cord blood from the second sib contained a normal percentage of E-rosetting lymphocytes; however, these lymphocytes failed to respond to mitogenic stimulation in vitro. Erythrocyte and lymphocyte levels of adenosine deaminase were elevated in the father and the second sib. Serum immunoglobulin concentrations were low in both siblings.

Purine metabolism in adenosine deaminase deficiency

Purine and pyrimidine metabolites were measured in erythrocytes, plasma, and urine of a 5-month-old infant with adenosine deaminase (adenosine aminohydrolase, EC 3.5.4.4) deficiency. Adenosine and adenine were measured using newly devised ion exchange separation techniques and a sensitive fluorescence assay. Plasma adenosine levels were increased, whereas adenosine was normal in erythrocytes and not detectable in urine. Increased amounts of adenine were found in erythrocytes and urine as well as in the plasma. Erythrocyte adenosine 5'-monophosphate and adenosine diphosphate concentrations were normal, but adenosine triphosphate content was greatly elevated. Because of the possibility of pyrimidine starvation, pyrimidine nucleotides (pyrimidine coenzymes) in erythrocytes and orotic acid in urine were measured. Pyrimidine nucleotide concentrations were normal, while orotic acid was not detected. These studies suggest that the immune deficiency associated with adenosine deaminase deficiency may be related to increased amounts of adenine, adenosine, or adenine nucleotides.

Heterogeneity of lymphocyte subpopulations in severe combined immunodeficiency. Evidence against a stem cell defect

Surface markers typical of T and B lymphocytes were present on varying proportions of peripheral blood lymphocytes from three infants with severe combined immunodeficiency disease. Despite this, functions mediated by T and B cells were either absent or very minimal in all three, including cell-mediated responses in vivo; the in vitro proliferative response to mitogens, allogeneic cells, or antigens; effector cell function in lymphocyte-antibody lymphocytolytic interaction assays; and in vitro synthesis of IgG, IgA, and IgM. In contrast, mononuclear cells from one of the infants were tested and found capable of lysing both human and chicken antibody-coated erythrocyte targets normally. Co-cultivation experiments with unrelated normal control lymphocytes failed to demonstrate suppressor cell activity for immunoglobulin synthesis in these infants. Augmentations of immunoglobulin production from 310 to 560% over that expected on the basis of individual culture data were noted in co-cultures of one of the infants' cells with two different unrelated normal control cells. These findings suggest that that infant may have had a T helper cell defect or that his T cells were unable to produce soluble factors necessary for B cell differentiation. The finding of cells with differentiation markers characteristic of T and B lymphocytes in each of these patients, though in variable quantities, is further evidence for heterogeneity among patients with the clinical syndrome of severe combined immunodeficiency and argues against the concept that their immunodeficiency was due to a stem cell defect.

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.

Inhibition of maturation of human precursor lymphocytes by coformycin, an inhibitor of the enzyme adenosine deaminase

High concentrations of adenosine are known to be toxic to fibroblasts and lymphocytes under conditions of in vitro culture (1,2). Normally, accumulation of adenosine nucleotides in all mammalian cells is prevented by the presence of adenosine deaminase, an aminohydrolase which converts adenosine to inosine (3). A genetically determined deficiency of adenosine deaminase has been associated with the autosomal recessive form of severe combined immunodeficiency, a syndrome in which precursor lymphocytes fail to mature into T cells and B cells (4-7). Erythrocytes of affected infants convert exogenous adenosine to AMP and ATP at an abnormally increased rate as a consequence of the enzyme defect, and ATP at an abnormally increased rate as a consequence of the enzyme defect, and fail to form inosine from the exogenous adenosine (8). These metabolic disturbances can be mimicked in normal erythrocytes by coformycin (8), a potent competitive inhibitor of adenosine deaminase (9, 10). In this study, the effects of coformycin were examined on the in vitro function of normal lymphocytes.

Purine nucleoside metabolism in the erythrocytes of patients with adenosine deaminase deficiency and severe combined immunodeficiency

Deficiency of erythrocytic and lymphocytic adenosine deaminase (ADA) occurs in some patients with severe combined immunodeficiency disease (SCID). SCID with ADA deficiency is inherited as an autosomal recessive trait. ADA is markedly reduced or undetectable in affected patients (homozygotes), and approximately one-half normal levels are found in individuals heterozygous for ADA deficiency. The metabolism of purine nucleosides was studied in erythrocytes from normal individuals, four ADA-deficiency patients, and two heterozygous individuals. ADA deficiency in intake erythrocytes was confirmed by a very sensitive ammonia-liberation technique. Erythrocytic ADA activity in three heterozygous individuals (0.07,0.08, and 0.14 mumolar units/ml of packed cells) was between that of the four normal controls (0.20-0.37 mumol/ml) and the ADA-deficient patients (no activity). In vitro, adenosine was incorporated principally into IMP in the heterozygous and normal individuals but into the adenosine nucleotides in the ADa-deficient patients. Coformycin (3-beta-D-ribofuranosyl-6,7,8-trihydroimidazo[4,5-4] [1,3] diazepin-8 (R)-ol), a potent inhibitor of ADA, made possible incorporation of adenosine nucleotides in the ADA-deficient patients...

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.