Background
Primary immunodeficiency diseases are underdiagnosed in developing countries. The aim of this study was to identify primary B- and T-cell immune defects in Egyptian infants and children with clinical criteria indicating primary immunodeficiency disease.
Material and Method
We enrolled 100 consecutive infants and children clinically suspected to have primary immunodeficiency disease. Subjects were evaluated with respect to immunodeficiency-related score, complete blood count, erythrocyte sedimentation rate, serum immunoglobulin (Ig) A and tetanus IgG antibody estimation, and Candida and tuberculin intradermal testing. Subjects showing IgA deficiency underwent serum total IgG, IgM, and IgE measurement, and lymphopenic patients underwent lymphocyte subset counting by flow cytometry.
Results
Thirty-five subjects showed laboratory evidence of T- and/or B-cell immunodeficiency and showed significantly higher immunodeficiency-related scores, a greater frequency of hospitalization, and were more likely to have no bacillus Calmette-Guérin scar and a negative Candida skin test. Laboratory evaluation revealed evidence of predominant B-cell defects in 19 subjects, T-cell defects in 8, and combined immunodeficiency in 8. An immunodeficiency-related score of > or =6 was associated with 71% of the immune defects, and a score > or =8 was predictive of significant immune derangement. The most helpful screening tests for B-cell defects were those for serum IgA and antitetanus IgG, whereas those for T-cell immunodeficiency were peripheral blood lymphocyte count and Candida sensitivity skin test.
Conclusions
Our screening procedures allowed for identification of most of the subjects requiring further evaluation of primary immunodeficiency disease in this study. Widescale screening of neonates and older children for primary immunodeficiency disease is indicated.

Keywords: Immunologic Deficiency Syndromes - immunology, Immunoglobulins - blood, Egypt, Child, Preschool, Child, B-Lymphocytes - immunology, Adolescent, Lymphocyte Subsets, T-Lymphocytes - immunology