An updated review on phenocopies of primary immunodeficiency diseases.

Primary immunodeficiency diseases (PIDs) refer to a heterogenous group of disorders characterized clinically by increased susceptibility to infections, autoimmunity and increased risk of malignancies. These group of disorders present with clinical manifestations similar to PIDs with known genetic defects but have either no genetic defect or have a somatic mutation and thus have been labelled as "Phenocopies of PIDs". These diseases have been further subdivided into those associated with somatic mutations and those associated with presence of auto-antibodies against various cytokines. In this review, we provide an update on clinical manifestations, diagnosis and management of these diseases.