Rare diseases · Sign or symptom
Decreased T cell activation
HP:0005419
What it means
Decreased or impaired activation of T cells in response to a mitogen, cytokine, chemokine, cellular ligand, or an antigen for which it is specific.
Rare diseases that can present with this2
The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions, and Orphanet separately records 1 disease where this sign is specifically absent. A sign on this page is a conversation to have with a clinician, not a conclusion.
Part of the broader category
Also called: Decreased T lymphocyte activation · Decreased T-cell activation · Decreased T-lymphocyte activation · Defective T cell activation · Profound depletion of T4+ lymphocytes
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Start free with EleplanThis page uses the Human Phenotype Ontology (2026-06-23) — Human Phenotype Ontology Consortium, hpo.jax.org. Disease associations from Orphanet (INSERM), CC BY 4.0. Content is educational and is not medical advice.