Immunodeficiency

Abstract: Volume 1: anatomical basis of the immune system architecture of immunity induction and regulation of immune responses. Volume 2: advances in technology immunological intervention allergy connective tissue disease immunodeficiency. Volume 3: immunology of infection transplantation tumour immunology organ-based immunology.

Abstract: This article describes 5 cases of Pneumocystis carinii pneumonia occurring in homosexual men in Los Angeles California. All 5 patients had previous or current cytomegalovirus and candidal mucosal infection. The men 2 of whom have died ranged from 29-36 years of age. The patients did not know each other and had no known common contacts or knowledge of sexual partners with similar illnesses. The 5 did not have comparable histories of sexually transmitted disease. 4 had serologic evidence of past hepatitis B infection but no evidence of current hepatitis B surface antigen. 2 of the men reported frequent homosexual contact with various partners. All 5 reported use of inhalant drugs. The 3 patients in whom lymphocyte studies were performed had profoundly depressed in vitro proliferative responses to mitogens and antigens. The occurrence of pneumocystosis in these 5 previously healthy men without a clinically apparent underlying immunodeficiency is unusual but seems to reflect some association with a homosexual lifestyle or disease acquired through sexual contact. Cytomegalovirus infection has been shown to induce transient abnormalities of in vitro cellular immune function in healthy homosexual men with and without antibody and a high prevalence of cytomegalovirus infections has been reported among male homosexuals. In additon there is some evidence that seminal fluid may be an important vehicle of cytomegalovirus transmission. Although the role of cytomegalovirus infection in the pathogenesis of pneumocystosis reamins unknown the possibility of P. carinii infection should be carefully considered in previously healthy homosexuals with dyspnea and pneumonia.

Abstract: It has recently been established that both acute human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) infections are accompanied by a dramatic and selective loss of memory CD4+ T cells predominantly from the mucosal surfaces. The mechanism underlying this depletion of memory CD4+ T cells (that is, T-helper cells specific to previously encountered pathogens) has not been defined. Using highly sensitive, quantitative polymerase chain reaction together with precise sorting of different subsets of CD4+ T cells in various tissues, we show that this loss is explained by a massive infection of memory CD4+ T cells by the virus. Specifically, 30-60% of CD4+ memory T cells throughout the body are infected by SIV at the peak of infection, and most of these infected cells disappear within four days. Furthermore, our data demonstrate that the depletion of memory CD4+ T cells occurs to a similar extent in all tissues. As a consequence, over one-half of all memory CD4+ T cells in SIV-infected macaques are destroyed directly by viral infection during the acute phase-an insult that certainly heralds subsequent immunodeficiency. Our findings point to the importance of reducing the cell-associated viral load during acute infection through therapeutic or vaccination strategies.

Abstract: We report the updated classification of primary immunodeficiencies compiled by the Primary Immunodeficiency Expert Committee (PID EC) of the International Union of Immunological Societies (IUIS). In the two years since the previous version, 34 new gene defects are reported in this updated version. For each disorder, the key clinical and laboratory features are provided. In this new version we continue to see the increasing overlap between immunodeficiency, as manifested by infection and/or malignancy, and immune dysregulation, as manifested by auto-inflammation, auto-immunity, and/or allergy. There is also an increased number of genetic defects that lead to susceptibility to specific organisms which reflects the finely tuned nature of immune defense systems. This classification is the most up to date catalogue of all known and published primary immunodeficiencies and acts as a current reference of the knowledge of these conditions and is an important aid for the genetic and molecular diagnosis of patients with these rare diseases.