Advances in clinical immunology in the past year included the report of practice parameters for the diagnosis and management of primary immunodeficiencies to guide the clinician in the approach to these relatively uncommon disorders. We have learned of new gene defects causing immunodeficiency and of new phenotypes expanding the spectrum of conditions caused by genetic mutations such as a specific regulator of telomere elongation (RTEL1) mutation causing isolated natural killer cell deficiency and mutations in ras-associated RAB (RAB27) resulting in immunodeficiency without albinism. Advances in diagnosis included the increasing use of whole-exome sequencing to identify gene defects and the measurement of serum free light chains to identify secondary hypogammaglobulinemias. For several primary immunodeficiencies, improved outcomes have been reported after definitive therapy with hematopoietic stem cell transplantation and gene therapy.