Selective severe cellular immunodeficiency. Effect of thymus transplantation and transfer factor administration

Purine Nucleoside Phosphorylase Deficient Severe Combined Immunodeficiencies: A Case Report and Systematic Review (1975-2022)

Purine nucleoside phosphorylase deficient severe combined immunodeficiency (PNP SCID) is one of the rare autosomal recessive primary immunodeficiency disease, and the data on epidemiology and outcome are limited. We report the successful management of a child with PNP SCID and present a systematic literature review of published case reports, case series, and cohort studies on PNP SCID listed in PubMed, Web of Science, and Scopus from 1975 until March 2022. Forty-one articles were included from the 2432 articles retrieved and included 100 PNP SCID patients worldwide. Most patients presented with recurrent infections, hypogammaglobulinaemia, autoimmune manifestations, and neurological deficits. There were six reported cases of associated malignancies, mainly lymphomas. Twenty-two patients had undergone allogeneic hematopoietic stem cell transplantation with full donor chimerism seen mainly in those receiving matched sibling donors and/or conditioning chemotherapy before the transplant. This research provides a contemporary, comprehensive overview on clinical manifestations, epidemiology, genotype mutations, and transplant outcome of PNP SCID. These data highlight the importance of screening for PNP SCID in cases presented with recurrent infections, hypogammaglobulinaemia, and neurological deficits.

The First Purine Nucleoside Phosphorylase Deficiency Patient Resembling IgA Deficiency and a Review of the Literature

Purine nucleoside phosphorylase (PNP) deficiency is a rare autosomal recessive primary immunodeficiency disorder characterized by decreased numbers of T-cells, variable B-cell abnormalities, decreased amount of serum uric acid and PNP enzyme activity. The affected patients usually present with recurrent infections, neurological dysfunction and autoimmune phenomena. In this study, whole-exome sequencing was used to detect mutation in the case suspected of having primary immunodeficiency. We found a homozygous mutation in PNP gene in a girl who is the third case from the national Iranian registry. She had combined immunodeficiency, autoimmune hemolytic anemia and a history of recurrent infections. She developed no neurological dysfunction. She died at the age of 11 after a severe chicken pox infection. PNP deficiency should be considered in late-onset children with recurrent infections, autoimmune disorders without typical neurologic impairment.

Purine nucleoside phosphorylase deficiency: a new case report and identification of two novel mutations (Gly156A1a and Val217Ile), only one of which (Gly156A1a) is deleterious

Purine nucleoside phosphorylase (PNP) deficiency results in an autosomal recessive immunodeficiency disease characterized by initial involvement of cellular immunity and neurological manifestations with subsequent abnormalities of humoral immunity. The initial presentation and clinical course has varied widely in the relatively few published cases. The molecular basis has been reported in only 10 patients, precluding evaluation of phenotype-genotype relationships. We now report clinical, immunologic, and molecular findings in a new case of relatively early onset that emphasizes hypotonia and developmental delay as early manifestations. The patient carried two novel missense mutations (Gly56A1a and Val217Ile) on the same allele in apparent homozygosity. Expression of each of the mutant enzymes in vitro demonstrated that the Gly156A1a mutation abolished enzyme activity while the Val217Ile mutation was without obvious effect and is therefore a normal variant. Such "normal" polymorphisms might be associated with a variable response to the immunosuppressive PNP inhibitors currently in clinical trials.

Human purine nucleoside phosphorylase cDNA sequence and genomic clone characterization

The isolation of a cDNA clone containing the complete coding region for human purine nucleoside phosphorylase (PNP) has been described previously. In this report we present the nucleotide sequence of this cDNA clone and compare the derived amino acid sequence, encoding a protein of 32 kilodaltons, with the published amino acid composition. Using a fragment of the cDNA clone as a probe, human PNP genomic clones from a bacteriophage lambda library have been isolated and the structural organization of the wild type PNP gene determined.

Therapy in adenosine deaminase and purine nucleoside phosphorylase deficient patients

The discovery of the causal association of adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) deficiency with some forms of primary immunodeficiency disease had led to new approaches to therapy, such as enzyme replacement. In ADA deficiency, bone marrow transplantation remains the primary method of choice. If no suitable bone marrow donor is available, enzyme replacement with irradiated erythrocyte transfusions should be considered. The latter therapy may be sustained by treatment with thymic factors. In ADA deficiency, bone marrow transplantation and, in about 50% of the cases, also enzyme replacement, may result in clinical and neurological improvement with concurrent (partial) restoration of immune function and (partial) disappearance of the metabolic abnormalities present before treatment. In PNP deficiency, enzyme replacement has been evaluated carefully in only two patients. The results disclose profound changes in the purine excretion patterns after each transfusion, and a slow but partial restoration of in vitro T cell function. Treatment of ADA and PNP deficiency with continued enzyme replacement by erythrocyte transfusions has certain risks which hopefully can be overcome in the near future by loading the patient's own blood cells with the missing enzyme.

Purine nucleoside phosphorylase deficiency associated with a fatal lymphoproliferative disorder

A 2 1/2-year-old boy presented with an illness resembling glandular fever. He was found to have T-cell deficiency with lack of red and white cell purine nucleoside phosphorylase enzyme activity. A spastic tetraparesis was noted. The patient subsequently died of a malignant lymphoma of the B-immunoblastic type.

Erythrocyte metabolism in purine nucleoside phosphorylase deficiency after enzyme replacement therapy by infusion of erythrocytes

Purine nucleoside phosphorylase deficiency is associated with a severely defective T-cell immunity. A patient with purine nucleoside phosphorylase deficiency was treated with transfusions of irradiated erythrocytes and plasma. This resulted in a remarkable correction of the metabolic disturbances in the patient. The urinary excretion of inosine, deoxyinosine, guanosine, and deoxyguanosine decreased, whereas uric acid excretion as well as serum uric acid concentration increased. It could be shown that the enzyme activity of the circulating erythrocytes correlated inversely with the urinary excretion of nucleosides and directly with the excretion of uric acid. As a consequence of the therapy, several glycolytic intermediates of the erythrocytes were increased, especially 2,3-diphosphoglycerate. The high 2,3-diphosphoglycerate level caused a shift to the right of the oxygen dissociation curve (P50 = 32.9 mm Hg). The immunological status of the patient showed definite improvement after the enzyme replacement therapy.

Congenital ichthyosis: concurrent immunodeficiency and atypical T cells

A patient with congenital ichthyosis and progressive neurologic anomalies showed disturbances in the specific humoral and cellular defense as well as the presence of atypical lymphoid cells in skin and lymph node. The latter resembled the atypical T cells found in mycosis fungoides and Sézary syndrome. The possibility of the presence of either a cutaneous T cell lymphoma or unregulated T cell stimulation leading to concurrent immunodeficiency in this patient is discussed.

Cellular immune deficiency with autoimmune hemolytic anemia in purine nucleoside phosphorylase deficiency

Immunologic and metabolic abnormalities were studied in a five year old boy with 0.07 per cent of normal erythrocyte purine nucleoside phosphorylase activity. The clinical course is characterized by severe autoimmune hemolytic anemia, a transient neurologic disorder with tremor and ataxia, and minor infectious illnesses. There is severe lymphopenia with decreased absolute numbers of T and B lymphocytes. Mitogen-stimulated blastogenesis is reduced, but response to allogeneic lymphocytes is normal. A monoclonal IgG protein is present. There is hypouricemia, elevated plasma inosine level, hypouricosuria and an increase in the urinary concentration of inosine and guanosine. The pattern of heterozygote distribution in the patient's family is compatible with an autosomal recessive trait in which heterozygotes are identifiable. In addition, the unusual laboratory and clinical manifestations of this patient illustrate the heterogeneity of the clinical syndrome associated with purine nucleoside phosphorylase deficiency.

Purine nucleoside phosphorylase deficiency: biochemical properties and heterogeneity in two families

The biochemical features of two families with purine nucleoside phosphorylase deficiency are compared. Laboratory studies and an evaluation of kinetic and physical properties of erythrocyte purine nucleoside phosphorylase give evidence that a) the degree of abnormality in uric acid and nucleoside concentrations in plasma and urine reflect the severity of the enzymatic deficiency and b) structural alterations of the mutant enzymes result from structural gene mutations and demonstrate genetic heterogeneity in the disease purine nucleoside phosphorylase deficiency.

Agammaglobulinaemia associated with the occurrence of a monoclonal immunoglobulin

A patient is described with a monoclonal immunoglobulin of the IgG class in the serum and no detectable IgM and IgA. Extensive immunological investigations showed the absence of B-lymphocytes in bone marrow and peripheral blood. Moreover, plasma cells were not present in the bone marrow. The monoclonal IgG was synthesized in the gastrointestinal tract. The cellular immune-status of the patient was synthesized in the gastrointestinal tract. The cellular immune-status of the patient was normal. Clinically the patient suffered from gastrointestinal and severe respiratory tract infections. It was concluded that the findings are consistent with the diagnosis congenital agammaglobulinaemia with concurrence of monoclonal IgG. It was postulated that the cell clone in the gastrointestinal tract resulted from an escape of a pre-B cell clone from the recongized arrest of pre-B cells in congenital agammaglobulinaemia.

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.

A patient with purine nucleoside phosphorylase deficiency: enzymological and metabolic aspects

1. Enzymological and metabolic data in a patient with nucleoside phosphorylase (NP) deficiency are described. 2. Incubation of intact NP-deficient red cells with [14C]adenosine showed a rapid uptake and conversion to inosine. Almost no radioactivity was incorporated in the adenosine nucleotides and no hypoxanthine labeling could be detected. 3. Incubation with [14C]inosine resulted in a rapid conversion to IMP in the normal intact red cells but in an accumulation of inosine in the medium with the erythrocytes of the patient, proving again that a NP deficiency is present. 4. The high PRPP level found may result from impaired consumption due to lack of substrates for the salvage enzyme HGPRT. 5. Incubation with [14C]hypoxanthine and [14C]adenine showed that normal HGPRT and APRT activities were present in the NP-deficient red cells. 6. In serum and urine of the patient the levels of inosine and guanosine were considerably increased, while the serum and urinary levels of uric acid were very low. In the two deceased sisters NP deficiency was also strongly suggested by analyses of the serum purines, of stored deep frozen samples.