Leptomeningeal involvement in chronic lymphocytic leukemia identified by polymerase chain reaction in stored slides: a case report.

The use of polymerase chain reaction (PCR) for routine detection of clonal immunoglobulin heavy-chain (IgH) gene rearrangements represents an attractive alternative to Southern hybridization analysis not only because PCR protocols are quicker and simpler, but also because of the ability to analyze very small population of cells in search of minimal residual disease. This can be especially important for the detection of clonal malignant cells in locations other than bone marrow or peripheral blood. We describe a case in which central nervous system involvement, a very rare complication of chronic lymphocytic leukemia, was confirmed by PCR analysis for IgH genes rearrangement of the lymphocytes found in cerebrospinal fluid. The cerebrospinal fluid and the peripheral blood lymphocytes (obtained from archival cytospins stored at the time of diagnosis, 5 years before) presented an identical IgH gene rearrangement, as shown by sequence analysis. Thus, the use of PCR for IgH genes rearrangement can be very useful in the detection of monoclonality in samples with a small number of cells and in the confirmation of the common origin of B cells in different specimens of the same patient.

Risk of exposure to Chagas' disease among seroreactive Brazilian blood donors.

BACKGROUND: Screening of blood donors for Chagas' disease by using currently available serologic tests is complicated by the lack of adequate sensitivity, discordant results between tests, and the absence of a gold standard. STUDY DESIGN AND METHODS: The study was designed to evaluate the serologic tests by using epidemiologic data relating to the risk of exposure to Trypanosoma cruzi in the urban centers of Brazil. The serologic results obtained from screening 411,617 voluntary blood donations in São Paulo during 1993 and 1994 were reviewed, as well as follow-up results on 1,267 donors who initially were repeatably reactive in at least one of three screening tests. Epidemiologic data were obtained from 321 individuals who on follow-up remained reactive in at least one test and who returned for medical counseling. Controls included 119 screen-negative blood donors and 45 blood donors who were repeatably reactive in at least one screening test but were negative on follow-up. RESULTS: Of the individuals who reacted in three screening tests, 94.6 percent remained reactive on follow-up. Of the individuals who were repeatably reactive in only one screening test, 70.8 percent were negative in all three tests on follow-up. Most individuals who reacted in two or three tests on follow-up had epidemiologic evidence of a risk of exposure to Chagas' disease. A significant proportion (29.1%) of those who were reactive in only one test on follow-up had epidemiologic evidence of exposure to the Chagas' disease vector as compared to 14.6 percent of controls (p = 0.007). This suggests that some of these individuals truly were infected. CONCLUSION: No single test for Chagas' disease is sufficiently sensitive to prevent transfusion transmission of the disease in the urban centers of Brazil.

Prevalência de anticorpos anti-HTLVI/II em doadores de sangue da Fundaçäo Pró-Sangue Hemocentro de Säo Paulo / Prevalence of anti-HTLVI/II antibodies in blood donors of Fundaçäo Pró-Sangue Hemocentro de Säo Paulo

O teste ELISA ant-HTLVI/II foi introduzido na triagem sorlógica de doadores de sangue na Fundaçäo Pró-sangue Hemocentro de Säo Paulo (FPS/HSP) em julho de 1991. NO período compreendido entre julho de 1991 e julho de 1994 foram submetidos à triagem serológica 597.727 doadores. Destes, 7682 foram recusados por terem apresentado reatividade no teste ELISA anti-HTLVI/II. A positividade observada, para o referido teste, foi diminuindo com o correr do tempo: 2,12 por cento em 1991; 1,6 por cento em 1992; 0,8 por cento em 1993 e 1,0 por cento em 1994, sendo esse fato atribuido a melhora da especialidade e reprodutividade dos kits comerciais. Foi utilizado o teste suplementar de Western Blot para confirmar os resultados dos testes ELISA. Em 249 amostras de soros de doadores, com resultado repetidamente positivo (RRP) no teste ELISA (hemobio), o poder confirmatório do Western Blot (Cambridge Biotech) foi de 24.9 por cento (IC/90 por cento: 20,4 por cento-29,39 por cento). Baseados nesses dados, considera-se uma expectativa de prevalência de indivíduos infectados pelo HTLVI/II, na populaçäo de doadores de sangue da FPS/HSP de 0,142 por cento (IC/90 por cento; 0,116 por cento-0,167 por cento). Em 437 amostras de soro de doadores que retornaram ao Banco de Sangue, para confirmar o resultado inicial e apresentaram RRP no teste ELISA, o poder confirmatório do Western Blot foi de 34,55 por cento (IC/90 por cento: 30,82 por cento-38,28 por cento)...