Tuesday, January 19, 2010


CLINICAL CASE 2: FOXP3 Positive T regulatory cells have shown to protect kidney allografts from rejecting. The more you have of Tregs, the safer is your graft. What is the disorder of Foxp3 deficiency called?
1.Polyenteropathy syndrome 0 (0%)
2.Immune dysregulation, polyendocrinopathy, enteropathy X linked (IPEX) 4 (80%)
3.FoxP3 deficiency syndrome 1 (20%)
4.Absent regulatory immunity syndrome(ARIS)

The correct answer is 2, or IPEX syndrome. great work everyone. What is IPEX syndrome and why do we care? The immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome, a rare disorder characterized by multiorgan autoimmunity, often results in death in infancy. The above image is from an allergy immunology blog of Cleveland Clinic. It summarizes the T cell deficiencies diseases.  The IPEX syndrome results from mutations in the forkhead box P3 (FOXP3) gene, which encodes a transcriptional repressor considered to be the master regulator of differentiation in CD4+ regulatory T (Treg) cells. A nice case was first described in NEJM issue in 2009.
A missense mutation abolishes the T regulatory function FOXP3 positive T cells. The systemic autoimmunity in these patients with the IPEX syndrome is probably the consequence of defective Treg-cell–mediated control of immune responses.
This is important in the transplant literature as recently FOXP3 positive T cells in biopsy samples and in the urine of kidney transplant recipients have some value. Consider them to me " policemen" cells and if they are in good quantity and around during the time of rejection, the outcome will be better as they can keep the "troublemaker" T cells, the cytotoxic ones in check. 
In a more broader senses, when we uses drugs that suppress T cells in general, are we also suppressing T regulatory cells that are good to have around? Perhaps!!
Another good reference for this in transplant patients is also in NEJM, link attached.

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