Development of lymphoma in Autoimmune Lymphoproliferative Syndrome (ALPS) and its relationship to Fas gene mutations
ABSTRACT Autoimmune Lymphoproliferative Syndrome (ALPS) is generally the result of a mutation in genes associated with apoptosis, like Fas, Fas ligand, Casp 8 and Casp 10. As a result, the normal homeostasis of T- and B-lymphocytes is disturbed and a proliferation of polyclonal T lymphocytes occurs. This leads to hepatosplenomegaly and lymphadenopathy and in most patients also to autoimmune phenomena like anemia and thrombocytopenia. The proliferating T cells are TCRalphabeta and/or TCRgammadelta positive but lack both CD4 and CD8. Hence they are termed double negative (DN) T cells. In addition, there is an increase of CD5 positive B cells. Individuals with germline mutations in the Fas gene have a high risk to develop non Hodgkin lymphomas (x 14) as well as Hodgkin lymphomas (x 51), in particular NLP Hodgkin lymphoma. Somatic mutations of Fas are frequently acquired during the normal germinal center reaction. Non Hodgkin lymphomas carry somatic mutations of the Fas gene in 11% and of the Casp 10 gene in 14.5% of the patients. In Hodgkin lymphomas, Fas mutations can be demonstrated in Reed-Sternberg cells in 10-20% of the patients. These data implicate a role for Fas-mediated apoptosis in preventing lymphomas. Inherited defects in receptor-mediated lymphocyte apoptosis represent a risk factor for lymphomas and somatic mutations of these genes may also play a role in the development and/or progression of lymphomas.
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ABSTRACT: Thyroid cancer is usually surrounded by a significant number of immune reactive cells. Tumor associated lymphocytes as well as background lymphocytic thyroiditis is frequently mentioned in pathology reports of patients operated for thyroid cancer. The nature of this lymphocytic reaction in not well understood. Evidently, the fact that cancer can survive in this adverse microenvironment speaks for immune regulation. We characterized the lymphocytic infiltration that accompanies thyroid cancer and compared it to that present in thyroid autoimmunity. We found that double-negative (DN) T cells were significantly more abundant in thyroid cancer than in thyroid autoimmunity. Although FOXP3+ Tregs were also present, DN T cells were the dominant cell type associated with thyroid cancer. Furthermore, upon stimulation, the DN T cells associated with cancer remained unchanged while the few (<5%) DN T cells associated with thyroid autoimmunity increased in numbers (>20%). CD25 expression on DN T cells remained unchanged after stimulation which suggests that the increase in the absolute number of DN T cells in thyroid autoimmunity was at the expense of inactivation of single positive T cells. We concluded that in the setting of thyroid cancer, DN T cells appear to suppress tumor immunity. In contrast, in thyroid autoimmunity, DN T cells were barely present and only increased at the expense of inactivated, single positive T cells upon induction. Together, these findings suggest that thyroid cancer associated DN T cells might regulate proliferation and effector function of T cells and thereby contribute to tumor tolerance and active avoidance of tumor immunity.Endocrine Related Cancer 03/2014; DOI:10.1530/ERC-13-0436 · 4.91 Impact Factor
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ABSTRACT: Hermansky Pudlak type 2 syndrome (HPS2) is a rare autosomal recessive primary immune deficiency caused by mutations on β3A gene (AP3B1 gene). The defect results in the impairment of the adaptor protein 3 (AP-3) complex, responsible for protein sorting to secretory lysosomes leading to oculo-cutaneous albinism, bleeding disorders and immunodeficiency. We have studied peripheral blood and lymph node biopsies from two siblings affected by HPS2. Lymph node histology showed a nodular lymphocyte predominance type Hodgkin lymphoma (NLPHL) in both HPS2 siblings. By immunohistochemistry, CD8 T-cells from HPS2 NLPHL contained an increased amount of perforin (Prf) + suggesting a defect in the release of this granules-associated protein. By analyzing peripheral blood immune cells we found a significant reduction of circulating NKT cells and of CD56(bright)CD16(-) Natural Killer (NK) cells subset. Functionally, NK cells were defective in their cytotoxic activity against tumor cell lines including Hodgkin Lymphoma as well as in IFN-γ production. This defect was associated with increased baseline level of CD107a and CD63 at the surface level of unstimulated and IL-2-activated NK cells. In summary, these results suggest that a combined and profound defect of innate and adaptive effector cells might explain the susceptibility to infections and lymphoma in these HPS2 patients.PLoS ONE 11/2013; 8(11):e80131. DOI:10.1371/journal.pone.0080131 · 3.53 Impact Factor
Blood 03/2014; 123(13):1978. DOI:10.1182/blood-2014-01-549477 · 9.78 Impact Factor