CD4+T cells

Group of transmembrane proteins engaged in the presentation of small peptide fragments to T-cells. Two classes of Major histocompatibility complex (MHC) molecules exist both of which are encoded by a highly polymorphic gene cluster. MHC class I and class II proteins present peptide fragments to CD8+ and CD4+ T-cells, respectively. The human MHC is also known as HLA, the murine MHC as H-2 complex. 

Second, the INSTl, but not an RTl, may conceivably inhibit the virus production from the pool of resting CD4 T cells that are in a state of pre-integration latency (Murray et al. 2007). Upon activation, the preformed pro-viral DNA that is already located in the nucleus integrates into the genome of these cells, allowing them to contribute to the viral load. 

Heredia A, Gilliam B, DeVico A, Le N, Bamba D, Flinko R, Lewis G, Gallo RC, Redfield RR (2007) CCR5 density levels on primary CD4 T cells impact the replication and Enfuvirtide susceptibility of R5 HlV-1. Aids 21 1317-1322... 

Caekelbergh et al. calculated the direct costs of HIV/AIDS in Belgium from the health care pay perspective. On the basis of 150 patients, they determined the costs of antiretrovirals, outpatient and inpatient resource use for the year 2005. They realize that the costs strongly depend on the CD4- - T-cell count, that is, the annual costs per patient are on average about US 2,900 for a patient with a CD4+ T-cell count >500, US 3,200 (CD4 351-500), US 8,650 (CD4 210-350), US 16,600 (CD4 101-200), US 31,300 (CD4 51-100), and US 49,400 (CD4 0-50), respectively. Consequently, the early detection of an HIV-infection as well as proper management that prohibits disease transition is of high cost-importance. 

M, Murphy KM Thl7 an effector CD4 T cell lineage with regulatory T cell ties. Immunity 2006 24 677-688. 

Cause WC. Urban JF. Linsley P. Lu P Role of B7 signaling in the differentiation of naive CD4+ T cells 122 to effector interIeukin-4-producing T-helper cells. Immunol Res 1995 14 176-188. 

Brinch-Nielsen A. Arnved J. Ipsen H Blocking antibodies induced by specific allergy vaccination prevent the activation of CD4+ T cells by inhibiting serum-IgE-facilitated allergen presentation. J Immunol 1999 163 2944-2952. 

Imai Y, Fujimori Y, Nakanishi K Basophils contribute to TH2-IgE responses in vivo via IL-4 production and presentation of peptide-MHC class II complexes to CD4+ T cells. Nat Immunol 2009 42 10 706-712. 

Perrigoue JG, Saenz SA, Siracusa MC, Allenspach EJ, Taylor BC, Giacomin PR, Nair MG, Du Y, Zaph C, van Rooijen N, Comeau MR, Pearce EJ, Laufer TM, Artis D MHC class Il-dependent basophil-CD4+ T-cell interactions promote Th2 cytokine-dependent immunity. Nat Immunol 2009 10 697-705. 

Decreased macrophage infiltration and demyelination Decreased CD4+ T cell trafficking into the CNS, impaired viral clearance No effect on CD8+ T cell trafficking into the CNS Enhanced fatality with delayed CD 8+ T cell infiltration No effect CCR5A32 not protective... 

Oligoclonal CD4+ T-cell response Spleen, thymus Balb/c mouse No Increased in splenic, not in thymic Heo et al. (1997)... 

HIV RNA plasma concentrations and CD4+ T-cell counts are used to assess risk of progression to AIDS (or risk for opportunistic infection) and to monitor efficacy and durability of treatment. 

Degree of immune function preservation also correlates with decreased viral replication, and is measured by CD4+ T-cell counts. CD4 measures are the best predictor of progression to AIDS, and help decide when to initiate treatment. At CD4+ T-cell counts of 200 cells/mm3 and lower, patients require drug prophylaxis for opportunistic infections. Table 84—2 details the monitoring endpoints of HIV treatment for HIV RNA and CD4+ T-cell counts. 

Clinical event Assess need for ART Assess need for Ol chemoprophylaxis Start therapy in appropriate patients Start therapy when less than 200 cells/mm3 Clinical event or decrease in CD4+ T-cell count Receiving ART assess if event is due to virologic failure Not receiving ART assess need to begin therapy Change regimen if needed (drugs or doses) Start therapy in appropriate patients... 

Nevirapine in place of efavirenz in selected populations (due to a more frequent incidence of hepatotoxicity, nevirapine should only be used in patients with low to moderate CD4+ T-cell counts less than or equal to 250 cells/mm3 for females, less than or equal to 400 cells/mm3 for males)... 

Therapies not recommended for initial treatment due to poor potency or significant toxicity include delavirdine, nevirapine in patients with moderate to high CD4+ T-cell counts, indinavir or saquinavir used without ritonavir ( unboosted ), ritonavir used without another protease inhibitor, and tenofovir plus didanosine with an NNRTI. 

Reinhardt RL, Khoruts A, Merica R, Zell T, Jenkins MK. Visualizing the generation of memory CD4 T cells in the whole body. Nature 2001 410 101-105. 

Debes GF, Hopken UE, Hamann A. In vivo differentiated cytokine-producing CD4(+) T cells express functional CCR7. J Immunol 2002 168 5441-5447. 

Debes GF, Bonhagen K, Wolff T, et al. CC chemokine receptor 7 expression by effector/memory CD4+ T cells depends on antigen specificity and tissue localization during influenza A virus infection. J Virol 2004 78 7528-7535. 

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