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Infectious Disease
Published in John S. Axford, Chris A. O'Callaghan, Medicine for Finals and Beyond, 2023
Susanna J. Dunachie, Hanif Esmail, Ruth Corrigan, Maria Dudareva
The introduction of highly active antiretroviral therapy (HAART) has transformed the clinical landscape of HIV care. For patients, this therapy has brought about improvement in the CD4 count and a fall in the HIV viral load. ‘Treatment as prevention’ means that successful suppression of HIV viral load by HAART makes the risk of transmission of HIV from an infected person to their uninfected partner negligible.Some HAART regimens are now available as combined single-tablet, once a day treatment.Anti-HIV drugs are used as post-exposure prophylaxis (PEP), e.g. for a healthcare worker who receives a needlestick injury from someone with known uncontrolled HIV, or after high-risk sexual intercourse (PEPSI).It has recently been established that prescribing antiretrovirals to people at high risk of acquiring HIV through their sexual lifestyle is effective in lowering transmission (pre-exposure prophylaxis, PrEP).
HIV
Published in Vincenzo Berghella, Maternal-Fetal Evidence Based Guidelines, 2022
Jenani Jayakumaran, William R. Short
HIV primarily infects T lymphocytes that express the CD4 antigen, resulting in a progressive loss of these cells and impairment of cellular immunity as well as humoral immunity. When CD4 lymphocytes are sufficiently depleted there is the progression to AIDS, characterized by the development of opportunistic infections and malignancies.
Human immunodeficiency virus (HIV)
Published in Hung N. Winn, Frank A. Chervenak, Roberto Romero, Clinical Maternal-Fetal Medicine Online, 2021
Richard Basilan, William Salzer
HIV belongs to the family of human retroviruses (Retroviridae) and the subfamily of lentiviruses. HIV-1 is the predominant cause of HIV disease in the world. HIV-2, which can also cause AIDS, is closely related to simian immunodeficiency virus and is largely confined to West Africa, although occasional cases occur worldwide. The HIV virion is an icosahedral structure containing numerous external spikes formed by the two major envelope proteins, the external gp120, and the transmembrane gp41. The virion attaches via gp120 to cells expressing the CD4 molecule, which acts as the cell receptor for the virus. The CD4 molecule is expressed mainly in a subset of T lymphocytes responsible for helper function in the immune system, but can also be found on the surface of monocytes/macrophages and dendritic/Langerhans cells (13). A conformational change then occurs in the gp120 molecule, allowing it to bind to one of two cellular coreceptors (CCR5 or CXCR4). Binding is followed by insertion of viral gp41 into the CD4 cell, resulting in membrane fusion followed by release of the viral core into the cell cytoplasm.
Ocular Tuberculosis in Human Immunodeficiency Virus and Systemic Tuberculosis Co-infected Patients
Published in Ocular Immunology and Inflammation, 2021
Sahil Jain, Priya Bajgai, Savleen Kaur, Mohit Dogra, Aman Sharma, Kusum Sharma, Deeksha Katoch, Mangat R. Dogra, Vishali Gupta, Ramandeep Singh
The study included 85 Asian Indian subjects diagnosed with HIV and TB co-infection. There were 65 (76.5%) males and 20 (23.5%) females. The mean age of the patients was 35.4 ± 11.6 years (Range, 12 to 73 years). The mean CD4 count for all the patients was 178.7 ± 203 cells/µl (range 1–1200). The mean duration between diagnosis of HIV and diagnosis of systemic TB was 230 ± 420.16 days. Eighteen patients (21.2%) were on c-ART at the time of enrollment in the study. They were on Tenofovir 300 mg, lamivudine 300 mg and efavirenz 600 mg once daily in combination form. Sixty-nine patients (81.2%) were on ATT, of which 52 patients were on CAT-I ATT (HRZE-Isoniazid, rifampicin, ethambutol, pyrazinamide), 11 patients (relapse/defaulter cases) were on CAT-II ATT (HRZES, S-streptomycin) and 6 patients were on modified ATT (1 or more of drugs replaced by levofloxacin). Ocular manifestations
Changes of peripheral lymphocyte subset in patients with SARS-CoV-2 infection during the whole course of disease
Published in Expert Review of Respiratory Medicine, 2021
CD4+ T lymphocyte cells <200/ul is a recognized threshold for people living with HIV to be prone to various opportunistic infections. In this study, the relation of levels of pro-inflammatory biomarkers and CD4+ T lymphocyte counts is shown in Table 3. The levels of CRP, IL-6 and TNF-α in COVID-19 patients had CD4+ T lymphocyte cells <200/ul was higher than in those had CD4+ T lymphocyte cells ≥200/ul (67.1 ± 5.7 vs 18.8 ± 2.1 mg/l, P < 0.001; 121.46 ± 51.09 vs 45.13 ± 30.74 pg/ml, P = 0.035; 1.01 ± 0.37 vs 0.55 ± 0.18 pg/ml, P = 0.033). However, there were no statistically significant differences in IFN-γ, IL-2, IL-4 and IL-10 between COVID-19 patients who had CD4+ T lymphocyte cells <200/ul and those who had CD4+ T lymphocyte cells ≥200/ul.
Ocular Tuberculosis in HIV-infected Individuals
Published in Ocular Immunology and Inflammation, 2020
Salil Mehta, Remco PH Peters, Derrick P Smit, Vishali Gupta
HIV largely remains a sexually transmitted infection with an asymptomatic phase with the first-specific antibodies (anti-gp 41; anti-gp 120) or specific antigens (p24) being detected approximately one to 3 months later. The pathogenetic effects of HIV infection are exerted by the attachment to and destruction of CD4 + T cells, which causes an immunodeficiency at a later stage. Other cell types such as monocytes and dendritic cells are also affected.3 It may take 5–10 years, or even longer, to the development of the symptomatic stage (AIDS; acquired immune deficiency syndrome) which is related to the depletion of CD4+ cells (<200 cells/mm3) and associated immune suppression, where individuals are likely to develop secondary opportunistic infections including Mycobacterium tuberculosis, Mycobacterium avium, Pneumocystis jiroveci, disseminated CMV, toxoplasmosis, and oropharyngeal candidiasis. These are reflected in a WHO clinical staging system (Table 1).