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The Acquired Immunodeficiency Syndrome (AIDS)
Published in Constantin A. Bona, Francisco A. Bonilla, Textbook of Immunology, 2019
Constantin A. Bona, Francisco A. Bonilla
Currently, idiopathic CD4+ T lymphocytopenia is defined as a CD4+ cell count of < 300/mm3 on at least two occasions. Part of the difficulty with this definition is that simply by the laws of statistics, some individuals will lie outside of the “established normal ranges.” This is not, by itself, an indication of pathology. There are differences in CD4 counts between genders and ethnic groups. Furthermore, there may be quite large variations of CD4 counts in one individual with time of day, season, age, physical or emotional stress, and substance use (e.g., nicotine). The daily fluctuation alone may be 60% of the total count.
Encephalitozoon
Published in Dongyou Liu, Handbook of Foodborne Diseases, 2018
Alexandra Valencakova, Lenka Luptakova, Monika Halanova, Olga Danisova
The human infections caused by E. cuniculi are continuously reported particularly from Europe and the United States. Most often, they are infected patients with HIV/AIDS, patients after organ transplantation, and patients with idiopathic CD4+ lymphocytopenia. The prevalence rates of the disease in humans ranged from 0% to 42%,21 depending on the geographical locations, population studied, sample selection technique, and diagnostic methods used. Current knowledge suggests that the prevalence of anti–E. cuniculi antibodies in the human population is relatively common, but clinical symptoms appear only occasionally. Because the zoonotic origin of E. cuniculi is evident, the sources of infection for humans can be a wide range of mammals, including humans. The presence of pathogens in the respiratory and gastrointestinal tracts of infected individuals and their excretion by body fluids (urine, stool, and respiratory secretions), shows that horizontal transmission of infection comprising fecal-oral and urino-oral transmission is likely. The inhalation of contaminated aerosols and ingestion of contaminated food or water remain among the most common modes of transmission, in both human as well as in animal populations, and thus play probably the most important role in its dissemination. Vertical, transplacental transmission in humans has not been previously described. However, it plays an important role in the epizootiology and pathogenesis of infections in animals, especially in carnivores and rodents, in which placental transfer occurs after the development of an acute, often lethal form of the disease in newborn pups.35
Mycobacterium genavense infections in non-HIV immunocompromised hosts: a systematic review
Published in Infectious Diseases, 2018
Maryam Mahmood, Saira Ajmal, Omar M. Abu Saleh, Alexandra Bryson, Jasmine R. Marcelin, John W. Wilson
In patients with HIV, the risk of infection is closely related to the CD4 T cell count [31]. The risk of infection in other immunocompromised hosts also appears to be related to impaired cellular immunity but may not directly correlate with quantitative CD4 T cell count. Of the published cases, 11 reported CD4 T cell counts with a median of 105 cells/µl (IQR 75-160). One of our patients with disseminated infection was found to have idiopathic CD4 lymphocytopenia. Interestingly sarcoidosis, which accounted for 14% of underlying conditions in this systematic review, is associated with both T cell and B cell lymphopenia [35]. Qualitative T-cell dysfunction, in addition to quantitative defects, may also affect the risk of infection [36].