Serologic responses to Pneumocystis carinii antigens in health and disease

Article Abstract:

People who have AIDS cannot easily fight infections caused by organisms which otherwise are ordinarily well-tolerated. Infection by Pneumocystis carinii (P. carinii) is an example of this, and it is responsible for the severe and lethal cases of pneumonia suffered by AIDS patients. Blood levels of antibodies that recognize these or other bacteria are frequently used to diagnose infections and study the epidemiology of infections. However, antibodies to P. carinii are found in healthy as well as P. carinii-infected people, and thus have not been helpful for these uses. A sophisticated analytical technique, Western blot (immunoblotting), has been used to determine which proteins from P. carinii evoke antibody reactions in healthy and ill people, and to study these antibody reactions in AIDS patients with one or more episodes of P. carinii pneumonia. For this study, infectious tissue was obtained almost exclusively from human lung, whereas previous studies had used crude extracts from rat lungs as well. Human blood samples were obtained from over 400 people of varied ages and health status who were from Iowa, Chicago, Cincinnati, or New York. One protein (characterized by its size of 40 kDa) was the most commonly recognized antigen among both healthy and ill patients, but little is known about its function. Other proteins (weighing 66, 92, and 116 kDa) were frequently recognized by antibodies as well. In immunocompromised patients (those with HIV infection, kidney transplants, or cancer of some immune system cells), the antibody levels were similar to or less than those in healthy people, and the pattern of protein-antibody reactions was not distinguishably different. A previously used technique (immunofluorescence) was compared with immunoblotting, and had slightly fewer positive responses. Strikingly, antibodies were produced in response to repeated P. carinii infections, even though AIDS patients cannot produce antibodies well. This is attributed to responses from the humoral, or B-cell, portion of the immune system, as compared with the loss of cellular, or T-cell, function which is the primary deficit in AIDS. Immunoblotting is time-consuming and expensive, and will probably not play a role in clinical diagnosis. It is possible that further studies using immunoblotting may determine which P. carinii proteins are useful in distinguishing new infections and developing a prognosis. In addition, the techniques may allow determination of which, if any, proteins trigger humoral immune responses and this may in turn allow development of new therapeutic approaches. (Consumer Summary produced by Reliance Medical Information, Inc.)

Physiological aspects, AIDS patients, Pneumocystis carinii, Western immunoblotting, Western blot

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Coccidioidomycosis in human immunodeficiency virus-infected patients

Article Abstract:

Coccidioidomycosis is endemic in the southwestern part of the United States, especially in Arizona and parts of the San Joaquin Valley of California. Coccidioides immitis is the fungus responsible for the infection, causing more than 50,000 new cases annually. In the average, otherwise healthy individual, the infection is usually subclinical and produces minimal and self-limiting lower respiratory disease. However, in immunologically vulnerable patients, coccidioidomycosis becomes life-threatening, and frequently leads to generalized, systemic disease. Cell-mediated immunity is essential for controlling this infection, and is a significant issue among patients who are also infected with human immunodeficiency virus (HIV, which causes AIDS). In HIV-infected patients, the clinical features of coccidioidomycosis resemble those of Pneumocystis carinii pneumonia (PCP); patients are usually febrile and dyspneic (have a fever and have difficulty breathing). Further, PCP may occur simultaneously in this population. Laboratory cultures of C. immitis are usually readily accomplished, and blood cultures are frequently positive. Other features of C. immitis infection in HIV-infected patients are similar to those observed in less vulnerable people, and include focal pulmonary lesions, meningitis, skin, knee and nodal involvement, and positive serology tests without any demonstrable lesions. Mixed antifungal therapy is usually required to treat coccidioidomycosis. The reactivation of old lesions has been reported, suggesting that recent travel to an endemic area is not essential for recurrence. The epidemiology of coccidioidomycosis in HIV-infected patients is described in detail. (Consumer Summary produced by Reliance Medical Information, Inc.)

Complications and side effects, Demographic aspects, HIV infection, HIV infections, Coccidioidomycosis, Coccidioides immitis, Ascomycota

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Prevaccination serologic screening for measles in health care workers

Article Abstract:

Measles continues to be a public health problem, despite the availability of an effective vaccine. Schools, colleges and other places of group assembly are important sites for the transmission of measles. Health care workers are also vulnerable; they accounted for 5.8 percent of measles cases reported to the Centers for Disease Control (CDC) in 1988. The guidelines for measles immunization have been modified from a single-dose to a two-dose schedule. Additionally, health care employees born after 1957, who do not have evidence of disease or vaccination, should receive two doses of measles vaccine. Prevaccination screening of this group may reduce the cost of a vaccination program and ensure that those at risk will be immunized. A total of 222 employees of a metropolitan medical center participated in a prevaccination screening program; 41 subjects were born after l957, and 181 were born during or before l957. They had no history of measles, no evidence of vaccination after 1980, and no documentation of immunity against measles. Blood tests revealed that, of the total group, 30 employees were not immune to measles; 27 of the 30 were born after 1957. Considering the number of at-risk persons and the cost of vaccinating the group, the prevaccination screening program was a cost effective means of immunizing those at risk for measles. (Consumer Summary produced by Reliance Medical Information, Inc.)

Economic aspects, Prevention, Medical personnel, Measles, Vaccination, Dosage and administration, Measles vaccine, Measles vaccines

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