# Null cell

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Lymphocytes without surface receptors

Null cell NK cell

**Null cells**, a subset of large circulating [white blood cells](/source/White_blood_cell), mimic the appearance of [T](/source/T_cell) or [B](/source/B_cell) [lymphocytes](/source/Lymphocyte) but do not possess their defining surface receptors. Predominantly, these include [natural killer cells](/source/Natural_killer_cell) (NK cells), with a lesser portion being [hematopoietic stem cells](/source/Hematopoietic_stem_cell) traversing freely within the [bloodstream](/source/Circulatory_system).[1]

## Oncology

In the realm of [oncology](/source/Oncology), certain [pathological](/source/Pathology) null cells contribute to the development of [cancers](/source/Cancer), such as null cell [adenomas](/source/Adenoma) within the [pituitary gland](/source/Pituitary_gland). These adenomas often grow slowly and secrete [hormones](/source/Hormone) in patterns that are not well understood, potentially leading to [necrosis](/source/Necrosis) of surrounding [brain tissue](/source/Human_brain), thereby affecting neurological functions.[2] The discovery of null cells in the benign [adenohypophysis](/source/Anterior_pituitary) suggests that such adenomas might evolve from pre-existing benign null cells, shedding light on the tumors' origins and potential interventions.[3]

Histology of a null cell adenoma

## Viruses

In relation to [viral infections](/source/Viral_disease), the interaction between [viruses](/source/Virus) and the [immune system](/source/Immune_system) can lead to the emergence of null cells with impaired functionality. For example, [Cytomegalovirus](/source/Cytomegalovirus) (CMV) has been shown to induce [T-lymphocytes](/source/T-lymphocytes) to stop expressing [CD28](/source/CD28) and other critical surface molecules. This alteration essentially converts these T-cells into a form of null cell, lacking the additional properties of [NK cells](/source/Natural_killer_cell) and therefore failing to contribute to the immune response, which can result in conditions of [immunodeficiency](/source/Immunodeficiency).[4]

## Conclusion

Understanding the roles and mechanisms of null cells within the immune system and in pathological conditions such as cancer and viral infections not only provides insights into fundamental [biological processes](/source/Biological_process) but also opens avenues for therapeutic interventions targeting these unique cell types.

## See also

- [Natural killer cell](/source/Natural_killer_cell)

## References

1. **[^](#cite_ref-1)** Paulsen, D.F. (2022). "Chapter 12: Peripheral Blood". *Histology and Cell Biology: Examination & Board Review* (6th ed.). McGraw Hill.

1. **[^](#cite_ref-2)** Ogawa, Yoshikazu; Watanabe, Mika; Tominaga, Teiji (June 2010). ["Somatostatin-Producing Atypical Null Cell Adenoma Manifesting as Severe Hypopituitarism and Rapid Deterioration—Case Report"](http://link.springer.com/10.1007/s12022-010-9110-2). *Endocrine Pathology*. **21** (2): 130–134. [doi](/source/Doi_(identifier)):[10.1007/s12022-010-9110-2](https://doi.org/10.1007%2Fs12022-010-9110-2). [ISSN](/source/ISSN_(identifier)) [1046-3976](https://search.worldcat.org/issn/1046-3976).

1. **[^](#cite_ref-3)** Kovacs, Kalman; Horvath, Eva; Ryan, Nancy; Ezrin, Calvin (1980-06-01). ["Null cell adenoma of the human pituitary"](https://doi.org/10.1007/BF00430697). *Virchows Archiv A*. **387** (2): 165–174. [doi](/source/Doi_(identifier)):[10.1007/BF00430697](https://doi.org/10.1007%2FBF00430697). [ISSN](/source/ISSN_(identifier)) [1432-2307](https://search.worldcat.org/issn/1432-2307). [PMID](/source/PMID_(identifier)) [7456308](https://pubmed.ncbi.nlm.nih.gov/7456308). [S2CID](/source/S2CID_(identifier)) [9959115](https://api.semanticscholar.org/CorpusID:9959115).

1. **[^](#cite_ref-4)** Shabir, S.; Smith, H.; Kaul, B.; Pachnio, A.; Jham, S.; Kuravi, S.; Ball, S.; Chand, S.; Moss, P.; Harper, L.; Borrows, R. (April 2016). ["Cytomegalovirus-Associated CD4+CD28null Cells in NKG2D-Dependent Glomerular Endothelial Injury and Kidney Allograft Dysfunction"](https://linkinghub.elsevier.com/retrieve/pii/S1600613522008772). *American Journal of Transplantation*. **16** (4): 1113–1128. [doi](/source/Doi_(identifier)):[10.1111/ajt.13614](https://doi.org/10.1111%2Fajt.13614).

## External links

- [Null+cells](https://meshb.nlm.nih.gov/record/ui?name=Null+cells) at the U.S. National Library of Medicine [Medical Subject Headings](/source/Medical_Subject_Headings) (MeSH)

v t e Lymphocytes B cells B1 cell Plasmablast Plasma Memory Follicular Marginal zone Naïve Pre-B Breg cell B10 cell Transitional B cell Lymphoplasmacytoid cell T cells Thymocyte αβ (Cytotoxic CD8+ Helper CD4+ / TFH / Th3 / Th17 / Regulatory) Naïve Memory T cell TCM TEM TRM TVM Innate-like T cells Natural killer T cell γδ Mucosal associated invariant T cell Innate lymphoid cells NK cells Cytokine-induced killer cell Lymphokine-activated killer cell Null cell Adaptive NK cell Uterine natural killer cells Type 1 innate lymphoid cells Type 2 innate lymphoid cells Nuocytes Type 3 innate lymphoid cells LTi cells Lymphopoiesis Hematopoietic stem cell Lymphoblast Prolymphocyte Category Commons

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