title: Screening for primary immunodeficiencies associated with purine nucleoside phosphorylase deficiency or adenosine deaminase deficiency.
abstract: A screening method has been established for PNP deficiency. This enzyme activity in dried blood absorbed on filter paper can be detected by the formation of a blue insoluble formazan with a gel containing inosine, xanthine oxidase, MTT-tetrazolium, and phenazine methosulfate. The color change is very clear and definite and no false results have been obtained in the testing of 256 enzyme-positive and 107 enzyme-negative samples. The enzyme activity in dried blood on filter paper is so stable at room temperature that samples can be mailed. A screening method for ADA deficiency was developed, also depending on the color change of MTT-tetrazolium. Although the test is slightly more expensive than that developed by Moore and Meuwissen, its accuracy is greater. A common screening method for detecting deficiencies of either PNP or ADA is described.
mesh_terms: D000243:Adenosine Deaminase / Q000172:deficiency*; D006358:Hot Temperature; D006801:Humans; D007153:Immunologic Deficiency Syndromes / Q000201:enzymology*; D066298:In Vitro Techniques; D009700:Nucleoside Deaminases / Q000172:deficiency*; D010430:Pentosyltransferases / Q000172:deficiency*; D011683:Purine-Nucleoside Phosphorylase / Q000172:deficiency*; D013056:Spectrophotometry, Ultraviolet; D013997:Time Factors
chemical_list: D010430:Pentosyltransferases; D011683:Purine-Nucleoside Phosphorylase; D009700:Nucleoside Deaminases; D000243:Adenosine Deaminase