MDR1 rs1045642 and MTHFR rs1801133 should be considered as diagnostic candidates for the identification of pediatric patients with a high risk of suffering adverse events during ALL treatment.

No abstract

T he quantification of CD4ϩ and CD8 ϩ T lymphocytes is the most important laboratory test used to evaluate and monitor the success of antiretroviral treatment for HIV infection (1, 2). In Mexico, this test has been performed for more than 12 years. However, the reference values for healthy people are adopted from textbooks or the flow cytometry supplier and are usually based on Caucasian populations. Studies in different countries have reported variations in T lymphocyte subset reference values, emphasizing the importance of considering gender, age, environment, and ethnicity when evaluating cell counts (3, 4). The objective of this study was to determine reference values for absolute CD4 ϩ and CD8 ϩ T cell counts for the adult Mexican population according to sex and age.Subjects. A total of 400 healthy Mexicans (200 women and 200 men) participated in this study. A demographic and epidemiological questionnaire was administered to all participants to gather information on age, address, education level, and family history. All individuals who were born in Mexico City and had ancestors born in Mexico City for at least three generations were included. Individuals from well-delimited ethnicities were not included in this analysis. The epidemiology of HIV in Mexico has been reported to be 4 HIV-infected adults for every 1,000 Mexicans. With regard to age group, people between 25 and 34 years of age represent the highest percentage of AIDS cases. Thus, the participants in the present study were grouped into the following 4 age ranges: 20 to 25, 26 to 30, 31 to 35, and 36 to 40 years old. We analyzed 50 individuals in each age and gender group. All study participants were examined by a medical doctor. The health statuses of the participants were assessed by reviewing their medical records and conducting a physical examination and clinical laboratory tests, including a negative HIV probe. The participants were recruited from private medical care facilities and medical societies. The samples were analyzed at the National Reference Institute Instituto de Diagnostico y Referencias Epidemiologicos in Mexico City. Patient information and informed consent letters were signed by all participants.Specimen characteristics. Whole blood was collected with a Vacutainer system in 5-ml tubes containing EDTA. The samples were processed within 10 h of collection.Flow cytometric analysis. Lymphocyte subsets were analyzed with a FACSCount (Becton, Dickinson) with monoclonal antibodies (MAbs) against the following proteins: immunoglobulin G1 and immunoglobulin G2 as controls, CD3, CD3-CD4, and CD3-CD8. In addition to the monoclonal antibodies, the reagent tubes also contained fluorochrome-labeled reference beads, which act as a fluorescence standard to identify lymphocytes and a quantification standard (CD3 PE-Cy5 and CD4 phycoerythrin [PE], CD3 PE-Cy5 and CD8 PE). To evaluate accuracy and linearity, the instrument was calibrated with control beads at four different concentrations (0, 50, 250, and 1,000 particles/50 l). In brief, 50 l of w...

Recently we read contributions from La Scola et al. (4), Luna et al. (5), and Bell et al. (1) published in this journal about their experiences with screening and laboratory analysis carried out to identify anthrax in human samples (nasal swabs) and environmental samples (mail pieces and packages), essentially by using B. anthracis DNA detection by LightCycler PCR. This paper reports our experience with extensive screening of suspected mail and packages with anthrax spores using biochemical testing of isolates and conventional PCR techniques.Proximity to the United States, which is a main target for a bioterrorist attack, and intense trading of merchandise demanded a response of the Mexican public health system. It established several strategies, one of which was to reinforce laboratory surveillance for anthrax.Suspicious pieces were obtained from the Mexican Postal Service or the population and sent to the nearest public health laboratory for presumptive identification; those positive samples were sent to the national laboratory for confirmation. If the packages did not contain any dust, a scraping of the internal surface with a sterilized swab was taken. If a package contained dust, a sample was taken, and in both cases the sample was put into 5 ml of distilled sterile water with 5 ml of tripticase medium and incubated at 62.5°C for 15 min to induce spore germination. Subsequently, several dilutions were placed in sheep blood and polymyxin-lysosyme-EDTA-thallous acetate selective agars. After incubation for 24 h at 37°C, colonies developed were Gram stained, and those with suggestive morphology were tested with the API CHB 50 biochemical assay (Biomerieux, Anglum Road, Mo.). Simultaneously, testing of motility, penicillin susceptibility, and phage gamma lysis (donated by the Centers for Disease Control) was done. To confirm bacterial identity, nested PCR was carried out to detect the virulence determinants edema factor (EF) in pXO1 and Cap C genes in the plasmid pXO2 (2, 3). Colonies of B. anthracis, Sterne and Pasteur strains, were used as positive controls, and Bacillus cereus (ATTC 14579), Bacillus subtilis, Escherichia coli and Streptococcus faecalis were used as negative controls.We analyzed 6,230 suspicious pieces. All nonhemolytic colonies detected were processed as mentioned above. Only 37 isolates were strongly suggestive and were analyzed by nested PCR, and four were positive for the B. anthracis Sterne vaccine strain. The virulence associated with strains of B. anthracis is due to exotoxin compounded by protective antigen, EF, and lethal factor, which are placed in pXO1, and by poly-D-glutamic acid capsular polypeptide (located in pXO2). In our four positive samples we detected only pXO1. This demonstrated that all mail pieces analyzed did not contain the pathogen B. anthracis and these four isolates correspond to vaccine strains, since live vaccines are developed using strains that contain only pXO1 and which do not produce the capsule proteins. Regarding efficiency and efficacy, we concluded that...

This study suggests that the CYP1A1 (3801 T>C) m2/m2 genotype may contribute to breast cancer susceptibility in Mexican women.