Primary immunodeficiencies Diagnosis approach in emergent countries

Primary immunodeficiencies (PIDs) correspond to various genetic diseases characterized by a heterogeneous clinical expression in children and a frequent revelation in adults Faced to clinical suspicion of an immune deficiency, the existence of syndrome features may evoke defined PID entities that need specific immunological analysis Otherwise, the diagnostic approach of PID requires four steps the first one is to rule out an acquired immune deficiency mainly HIV infection The second step is based on elementary biological investigations cell blood count, measure of G, A, and M immunoglobulins combined or not to protein electrophoresis, and an assessment of total hemolytic complement This line of analysis permit to discriminate cellular, humoral, phagocytic or complement deficiencies which can be further illustrated using specialized immunological investigations such as lymphocyte subpopulations phenotyping, quantification of immunoglobulin subclasses, detection of specific antibodies, T lymphocytes proliferation assay, nitroblue tetrazolium reduction (NBT) test, CD18 phenotyping, measure of C3 and C4 complement components The last step needs collaboration with genetic research laboratories in order to establish the genotype of the immunodeficiency (C) 2010 Elsevier Masson SAS All rights reserved