X-Linked Lymphoproliferative Disease: A Progressive Immunodeficiency

Abstract

Our understanding of the X-linked lymphoproliferative syndrome (XLP) has advanced significantly in the last two years. The gene that is altered in the condition (SAP/SH2D1A) has been cloned and its protein crystal structure solved. At least two sets of target molecules for this small SH2 domain-containing protein have been identified: A family of hematopoietic cell surface receptors, i.e. the SLAM family, and a second molecule, which is a phosphorylated adapter. A SAP-like protein, EAT-2, has also been found to interact with this family of surface receptors. Several lines of evidence, including structural studies and analyses of missense mutations in XLP patients, support the notion that SAP/SH2D1A is a natural inhibitor of SH2-domain-dependent interactions with members of the SLAM family. However, details of its role in signaling mechanisms are yet to be unravelled. Further analyses of the SAP/SH2D1A gene in XLP patients have made it clear that the development of dys-gammaglobulinemia and B cell lymphoma can occur without evidence of prior EBV infection. Moreover, preliminary results of virus infections of a mouse in which the SAP/SH2D1A gene has been disrupted suggest that EBV infection is not per se critical for the development of XLP phenotypes. It appears therefore that the SAP/SH2D1A gene controls signaling via the SLAM family of surface receptors and thus may play a fundamental role in T cell and APC interactions during viral infections.

Analysis of the activating receptors and cytolytic function of human natural killer cells undergoing in vivo differentiation after allogeneic bone marrow transplantation

“…Lymphocytes recovered in patients undergoing allogeneic BMT were analyzed at different time intervals, starting from engraftment (occurring at day [12][13][14][15][16][17][18][19][20].…”

“…As a consequence SHP-1 phosphatase can be recruited by 2B4 itself. Remarkably, the inhibitory 2B4 may provide an efficient fail-safe mechanism in cells that don't yet express inhibitory receptors specific for HLA class I molecules [11,12].…”

X'e Bağli Geçi̇ş Gösteren Lenfoproli̇ferati̇f Sendrom: Kli̇ni̇k, Patogenez Ve Geneti̇kle İlgi̇li̇ Geli̇şmeler

“…Hastalıklı erkekler EBV'ye bu kadar duyarlı olmasına karşın, diğer herpes ve herpes dışı virüslere ve bakteriyel patojenlere normal immün yanıt verirler (9)(10)(11).…”

“…CD8+ ve CD4+ T lenfositlerdeki ekspresyonu aktivasyonla artar (2,9,21). 2B4, MHC Klas 1'den bağımsız olarak, NK hücre aktivasyonunu düzenler.…”

“…2B4, MHC Klas 1'den bağımsız olarak, NK hücre aktivasyonunu düzenler. Mab ile uyarımı hücre aracılı sitotoksisiteyi, IFNγ ve IL-2 sekresyonunu, granül ekzositozunu ve γδ T hücre proliferasyonunu arttırır (9,21). Benzer etkiler fizyolojik ligandı olan CD48 ile angajmanı sonrası da görülür.…”