4A01.12

ICD-11 MMS 2026-01

Major histocompatibility complex class II deficiency

Description

Immunodeficiency by defective expression of HLA class II is an autosomal recessive primary immune deficiency, manifesting by recurrent viral and bacterial infections, often leading to chronic diarrhoea and growth retardation.

Index terms

  • Major histocompatibility complex class II deficiency
  • Bare lymphocyte syndrome type 2
  • HLA class 2-negative severe combined immunodeficiency
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  • Immunodeficiency by defective expression of HLA class 2

Exclusions from above levels

  • 4A01.00 – autosomal recessive agammaglobulinaemia (Swiss type)
  • 02 – Neoplasms
  • 18 – Complications of pregnancy, childbirth and the puerperium
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  • 20 – Developmental anomalies

Sibling codes

  • 4A01.10 – Severe combined immunodeficiencies
  • 4A01.11 – Major histocompatibility complex class I deficiency
  • 4A01.1Y – Other specified combined immunodeficiencies
  • 4A01.1Z – Combined immunodeficiencies, unspecified

Foundation entity

Major histocompatibility complex class II deficiency – http://id.who.int/icd/entity/2021339495

Part of: 4A01.1: Combined immunodeficiencies › 4A01: Primary immunodeficiencies due to disorders of adaptive immunity › 04: Diseases of the immune system