Increased number and function of natural killer cells in human immunodeficiency virus 1-positive subjects co-infected with herpes simplex virus 2.

Natural killer (NK) cells bridge the interface between innate and adaptive immunity and are implicated in the control of herpes simplex virus 2 (HSV-2) infection. In subjects infected with human immunodeficiency virus 1 (HIV-1), the critical impact of the innate immune response on disease progression has recently come into focus. Higher numbers of NK cells are associated with lower HIV-1 plasma viraemia.

Central nervous system involvement in patients with mycosis fungoides and cutaneous large-cell transformation.

Central nervous system (CNS) involvement in mycosis fungoides (MF) is a rare occurrence with devastating consequences. Large-cell transformation (LCT) of MF is associated with a poor prognosis and increased extracutaneous manifestations. In this report, we present 5 patients with MF, LCT, and CNS disease to better define their presentation, treatment, and prognosis and present critical differences they have compared with their nontransformed counterparts.

Elevated frequency of gamma interferon-producing NK cells in healthy adults vaccinated against influenza virus.

Recent studies indicate that innate immunity in influenza virus infection is an area of substantial importance for our understanding of influenza virus pathogenesis, yet our knowledge of the mechanisms controlling innate immunity remains limited. Further delineation of the roles of NK cells and innate immunity in viral infection may have important implications for the development of improved influenza virus vaccines. In this study, we evaluated the phenotype and function of NK and T lymphocytes, as well as influenza virus-specific immunoglobulin G production, prior to and following vaccination with the routinely administered trivalent influenza virus vaccine.

Natural killer cells in perinatally HIV-1-infected children exhibit less degranulation compared to HIV-1-exposed uninfected children and their expression of KIR2DL3, NKG2C, and NKp46 correlates with disease severity.

NK cells play an integral role in the innate immune response by targeting virally infected and transformed cells with direct killing and providing help to adaptive responses through cytokine secretion. Whereas recent studies have focused on NK cells in HIV-1-infected adults, the role of NK cells in perinatally HIV-1-infected children is less studied. Using multiparametric flow cytometric analysis, we assessed the number, phenotype, and function of NK cell subsets in the peripheral blood of perinatally HIV-1-infected children on highly active antiretroviral therapy and compared them to perinatally exposed but uninfected children.

CD4 on CD8(+) T cells directly enhances effector function and is a target for HIV infection.

Costimulation of purified CD8(+) T lymphocytes induces de novo expression of CD4, suggesting a previously unrecognized function for this molecule in the immune response. Here, we report that the CD4 molecule plays a direct role in CD8(+) T cell function by modulating expression of IFN-gamma and Fas ligand, two important CD8(+) T cell effector molecules. CD4 expression also allows infection of CD8 cells by HIV, which results in down-regulation of the CD4 molecule and impairs the induction of IFN-gamma, Fas ligand, and the cytotoxic responses of activated CD8(+) T cells.