All Posts Tagged With: "lymphopenia"

Full article: http://www.cidrap.umn.edu/cidrap/content/influenza/swineflu/news/jul2110newsscan.html 

Excerpt:

Among new tick-related infectious disease findings presented at the International Conference on Emerging Infectious Disease (ICEID), which ended Jul 14 in Atlanta, were a report on the first zoonotic babesiosis case documented in Tennessee and a report on ehrlichiosis infections in Minnesota and Wisconsin involving a species that had not previously been identified in North America. In the first report, a group from the Tennessee Department of Health, Vanderbilt University, and the CDC diagnosed babesiosis in an immunosuppressed patient who began to have fever, fatigue, and headache. He had not traveled outside Tennessee in several years and had been exposed to ticks during hunting trips. Babesia parasites were noted on the man’s blood smear, and molecular analysis revealed that it was a novel species, but attempts to isolate it were unsuccessful. The man’s symptoms resolved after 10 days of treatment. The researchers said efforts to identify the animal host and tick vectors are ongoing and that the case serves as a reminder that patients can have babesiosis without exposure to known endemic areas and without testing positive to previously known species. In the second report, local health officials and CDC and Mayo Clinic experts described the identification of Ehrlichia DNA from Mayo Clinic blood samples of patients from the two states involving a species similar to E muris that had not been previously identified in North America. The organism was found in 2009 in the blood of 4 patients, 3 from Wisconsin and 1 from Minnesota. All had reported fever and headache, and all had lymphopenia. All recovered with doxycycline treatment. Serological studies also suggested 40 more probable cases among Wisconsin residents. A survey of the patients found dog contact in 91% and possible tick exposure in 85%. The group concluded that more studies are needed to identify the epidemiologic and clinical features of infections with the E muris–like organism and that better testing in the region could help identify the infections.

Excerpt:

The ability of the thymus to generate a population of T cells that is, for the most part, self-restricted and self-tolerant depends to a great extent on the Ags encountered during differentiation. We recently showed that mycobacteria disseminate to the thymus, which raised the questions of how mycobacteria within the thymus influence T cell differentiation and whether such an effect impacts host-pathogen interactions. Athymic nude mice were reconstituted with thymic grafts from Mycobacterium avium-infected or control noninfected donors. T cells generated from thymi of infected donors seemed generally normal, because they retained the ability to reconstitute the periphery and to respond to unspecific stimuli in vitro as well as to antigenic stimulation with third-party Ags, such as OVA, upon in vivo immunization. However, these cells were unable to mount a protective immune response against a challenge with M. avium. The observation that thymic infection interferes with T cell differentiation, generating T cells that are tolerant to pathogen-specific Ags, is of relevance to understand the immune response during chronic persistent infections. In addition, it has potential implications for the repertoire of T cells generated in patients with a mycobacterial infection recovering from severe lymphopenia, such as patients coinfected with HIV and receiving antiretroviral therapy.