T cell responses in aplastic anemia

August 29, 2001

Immunosuppressive drugs generally lead to substantially improved blood cell counts in individuals with aplastic anemia (AA), a severe decline of all blood cell lineages in which the marrow is deficient in hematopoietic cells. For this reason, although AA's pathogenesis is obscure, it seems likely that autoimmune responses block hematopoiesis at an early stage but do not entirely eliminate early pluripotent stem cells. Here, Zeng and coworkers provide a first glimpse at some quirks of the immune system in AA patients. These authors have prepared T cells from within the marrow of 5 people with serious but treatable aplastic anemia. Cloning and DNA analysis of the T cell receptors from one of these patients shows that one sequence form of the complementarity determining region CDR3 is highly represented in patients' marrow. This form, dubbed JZ1.1, carries a specific heptapeptide sequence that is also found in the other patients studied but is absent in controls. Isolated T cells of this TCR type can suppress hematopoietic stem cell proliferation in co-culture experiments, diminishing the growth of myeloid and erythroid cell precursors alike. Interestingly, these JZ1.1 T cells appear to be specific for autologous stem cells derived from the patient at a time of severe disease- marrow cells derived from a healthy, MHC-matched control donor, or even from the patient after successful treatment, are not killed by exposure to JZ1.1 cells. Hence, it appears that T cells of this type are activated to respond to some still-unknown determinant that is present on early hematopoietic stem cells during periods of acute disease.
-end-


JCI Journals

Related Immune System Articles from Brightsurf:

How the immune system remembers viruses
For a person to acquire immunity to a disease, T cells must develop into memory cells after contact with the pathogen.

How does the immune system develop in the first days of life?
Researchers highlight the anti-inflammatory response taking place after birth and designed to shield the newborn from infection.

Memory training for the immune system
The immune system will memorize the pathogen after an infection and can therefore react promptly after reinfection with the same pathogen.

Immune system may have another job -- combatting depression
An inflammatory autoimmune response within the central nervous system similar to one linked to neurodegenerative diseases such as multiple sclerosis (MS) has also been found in the spinal fluid of healthy people, according to a new Yale-led study comparing immune system cells in the spinal fluid of MS patients and healthy subjects.

COVID-19: Immune system derails
Contrary to what has been generally assumed so far, a severe course of COVID-19 does not solely result in a strong immune reaction - rather, the immune response is caught in a continuous loop of activation and inhibition.

Immune cell steroids help tumours suppress the immune system, offering new drug targets
Tumours found to evade the immune system by telling immune cells to produce immunosuppressive steroids.

Immune system -- Knocked off balance
Instead of protecting us, the immune system can sometimes go awry, as in the case of autoimmune diseases and allergies.

Too much salt weakens the immune system
A high-salt diet is not only bad for one's blood pressure, but also for the immune system.

Parkinson's and the immune system
Mutations in the Parkin gene are a common cause of hereditary forms of Parkinson's disease.

How an immune system regulator shifts the balance of immune cells
Researchers have provided new insight on the role of cyclic AMP (cAMP) in regulating the immune response.

Read More: Immune System News and Immune System Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.