title: Primary/Congenital Immunodeficiency: 2015 SH/EAHP Workshop Report-Part 5.
abstract: OBJECTIVE
  The 2015 Workshop of the Society for Hematopathology/European Association for Haematopathology aimed to review primary immunodeficiency and related lymphoproliferations.
  
  
  METHODS
  Primary immunodeficiencies were divided into immune dysregulation, DNA repair defects, low immunoglobulins, and combined immunodeficiencies.
  
  
  RESULTS
  Autoimmune lymphoproliferative syndrome (ALPS) is a prototypical immune dysregulation-type immunodeficiency, with defects in T-cell signaling or apoptosis, expansion of T-cell subsets, and predisposition to hemophagocytic lymphohistiocytosis. DNA repair defects directly predispose to malignancy. Low immunoglobulin immunodeficiencies such as common variable immunodeficiency (CVID) have underlying T-cell repertoire abnormalities predisposing to autoimmunity and B-cell lymphoproliferations. The full spectrum of B-cell lymphoproliferative disorders occurs in primary immunodeficiency.
  
  
  CONCLUSIONS
  Lymphoproliferations in primary immunodeficiency mirror those in other immunodeficiency settings, with monomorphic B- and sometimes T lymphoproliferative disorders enriched in DNA repair defects. Distinctive T-cell subset expansions in ALPS, CVID, and related entities can mimic lymphoma, and recognition of double-negative T-cell or cytotoxic T-cell expansions is key to avoid overdiagnosis.
authors.affiliation: From the Stanford University School of Medicine, Stanford, CA.
authors.forename: Dita
authors.initials: D
authors.lastname: Gratzinger
authors.affiliation: National Institutes of Health, Bethesda, MD.
authors.forename: Elaine S
authors.initials: ES
authors.lastname: Jaffe
authors.affiliation: Weill Medical College of Cornell University, New York, NY.
authors.forename: Amy
authors.initials: A
authors.lastname: Chadburn
authors.affiliation: Queen Elizabeth Hospital, Kowloon, Hong Kong.
authors.forename: John K C
authors.initials: JK
authors.lastname: Chan
authors.affiliation: VU University Medical Center, Amsterdam, the Netherlands.
authors.forename: Daphne
authors.initials: D
authors.lastname: de Jong
authors.affiliation: University of Leeds, United Kingdom.
authors.forename: John R
authors.initials: JR
authors.lastname: Goodlad
authors.affiliation: University of California Los Angeles Medical Center, Los Angeles.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Said
authors.affiliation: From the Stanford University School of Medicine, Stanford, CA.
authors.forename: Yasodha
authors.initials: Y
authors.lastname: Natkunam
mesh_terms: D004493:Education; D005260:Female; D006801:Humans; D007153:Immunologic Deficiency Syndromes / Q000150:complications* / Q000276:immunology; D008232:Lymphoproliferative Disorders / Q000175:diagnosis* / Q000209:etiology* / Q000473:pathology*; D008297:Male
keywords: Autoimmune lymphoproliferative syndrome; Common variable immunodeficiency; Double negative T cells; Primary immunodeficiency; T-cell lymphoma