Sema4D, also known as CD100, is a constitutively expressed immune semaphorin on T cells and NK cells. CD100 has important immune regulatory functions that improve antigen-specific priming by antigen-presenting cells, and can also act as a costimulatory molecule on T cells. We investigated the consequence of HIV-1 infection on CD100 expression by T cells, and whether CD100 expression signifies functionally competent effector cells.
CD100 expression on T cells from healthy
Background
Psoriasis is a hyper-proliferative disease of the skin in which immunological mechanisms play a direct pathogenetic role. There have been limited studies of natural killer (NK) cells in psoriasis.
Objectives
To examine the phenotype of NK cells in skin biopsies and peripheral blood mononuclear cells from patients with psoriasis and healthy controls.
Methods
CD56+CD16− and CD56+CD16+ NK cells were isolated from lesional skin, unaffected skin and PBMC of psoriasis patients, and normal skin and PBMC from healthy controls. The expression of CD57, NKG2A, and NKG2C was assessed by flow cytometry.
Results
NK cells in psoriasis skin lesions were skewed in their expression of CD57, a marker of NK cell maturity, with CD57 expression significantly reduced and NKG2A expression increased on NK cells in lesional and unaffected skin compared to controls.
Conclusions
These data suggest that in this patient cohort NK cells could be isolated from psoriasis lesions and exhibit an immature phenotype.
BackgroundHuman herpesvirus 8 (HHV-8) is the etiological agent for Kaposi Sarcoma, which occurs especially in HIV-infected subjects. HHV-8 infection and its clinical correlates have not been well characterized in recently HIV-1-infected subjects, especially men who have sex with men (MSM).Methodology/ Principal FindingsWe assessed the HHV-8 seroprevalence, clinical correlates, and incidence after one year of follow-up in a cohort of 228 recently HIV-1-infected individuals, of whom 83.6% were MSM, using indirect immunofluorescence assay. The prevalence of HHV-8 infection at the time of cohort enrollment was 25.9% (59/228). In the univariate model, there were significant associations with male gender, black ethnicity, MSM practice, and previous hepatitis B virus and syphilis infections. In the multivariate model we could still demonstrate association with MSM, hepatitis B, and black ethnicity. No differences in mean CD4+ cell counts or HIV viral load according to HHV-8 status were found. In terms of incidence, there were 23/127 (18.1%) seroconversions in the cohort after 1 year.ConclusionsHHV-8 is highly prevalent among recently HIV-1-infected subjects. Correlations with other sexually transmitted infections suggest common transmission routes.
We report 2 instances in which reactional borderline leprosy manifested itself as an immune reconstitution phenomenon in patients with acquired immunodeficiency syndrome. We discuss the clinical, laboratory-based, histopathologic, and immunohistochemical characteristics of both patients. Furthermore, we review similar reports from the literature.
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