Rare diseases · Sign or symptom
Decreased total lymphocyte count
Decreased blood lymphocyte number
HP:0001888
What it means
A reduced number of lymphocytes in the blood.
Rare diseases that can present with this44
Very common80–99%
9- Ataxia-telangiectasia
- Autoimmune hemolytic anemia-autoimmune thrombocytopenia-primary immunodeficiency syndrome due to TPP2 deficiency
- Cernunnos-XLF deficiency
- Hennekam syndrome
- Marburg hemorrhagic fever
- Short-limb skeletal dysplasia with severe combined immunodeficiency
- T-B+NK- severe combined immunodeficiency due to gamma chain deficiency
- WHIM syndrome
- Wiskott-Aldrich syndrome
Common30–79%
25- Acute radiation syndrome
- Adult idiopathic neutropenia
- Aplasia cutis congenita-intestinal lymphangiectasia syndrome
- Autosomal dominant severe congenital neutropenia
- Avian influenza
- Congenital progressive bone marrow failure-B-cell immunodeficiency-skeletal dysplasia syndrome
- Cushing disease
- Cushing syndrome due to ectopic ACTH secretion
- Ebola hemorrhagic fever
- ICF syndrome
- Lujo hemorrhagic fever
- Myalgia-eosinophilia syndrome associated with tryptophan
- Pediatric systemic lupus erythematosus
- PGM3-CDG
- Primary intestinal lymphangiectasia
- Schimke immuno-osseous dysplasia
- Secondary intestinal lymphangiectasia
- Skeletal dysplasia-T-cell immunodeficiency-developmental delay syndrome
- STAT1-related autoimmune enteropathy and endocrinopathy-susceptibility to chronic infections syndrome
- T-B-NK- severe combined immunodeficiency due to adenosine deaminase deficiency
- T-B+NK+ severe combined immunodeficiency due to CD3delta/CD3epsilon/CD3zeta deficiency
- T-B-NK+ severe combined immunodeficiency due to complete RAG1/2 deficiency
- T-B+NK+ severe combined immunodeficiency due to IL-7Ralpha deficiency
- T-B+NK- severe combined immunodeficiency due to JAK3 deficiency
- Transcobalamin II deficiency
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: Absolute lymphocyte count decrease · Low lymphocyte number · Lymphocytopenia · Lymphopenia
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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.