Association between diabetes mellitus and tuberculosis in United States-born and foreign-born populations in San Francisco.

SETTING: The impact of diabetes on tuberculosis in United States and foreign-born populations in San Francisco has not been studied. OBJECTIVE: To determine the characteristics, prevalence and temporal trends of diabetes in US and foreign-born persons attending the San Francisco Tuberculosis Clinic. DESIGN: We analyzed data from individuals seeking medical attention at the San Francisco Tuberculosis Clinic. We included patients with diagnosis of tuberculosis, latent infection, or not infected with Mycobacterium tuberculosis. We assessed the temporal trend and the characteristics of individuals with and without diabetes. RESULT: Between 2005 and 2012, there were 4371 (19.0%) individuals without evidence of tuberculosis infection, 17,856 (77.6%) with latent tuberculosis, and 791 (3.4%) with tuberculosis. 66% were born in the United States, China, Mexico, and the Philippines. The prevalence of diabetes was the highest among individuals with tuberculosis and increased during the study period. Patients with tuberculosis and diabetes were more likely to be male, older than 45 years and born in the Philippines. There was a disproportionate association of TB and DM relative to LTBI and DM among Filipinos in individuals older than 45 years old. CONCLUSIONS: Our data suggest that Filipinos older than 45 years old are more likely to have tuberculosis probably due to a higher prevalence of diabetes. In San Francisco, tuberculosis-screening programs in individuals with diabetes and latent tuberculosis may be beneficial in patients older than 45 years old especially from the Philippines.

Molecular epidemiology of tuberculosis in foreign-born persons living in San Francisco.

RATIONALE: In San Francisco, 70% of the tuberculosis cases occur among foreign-born persons, mainly from China, the Philippines, and Mexico. We postulate that there are differences in the characteristics and risk factors for tuberculosis among these populations. OBJECTIVES: To determine the clinical, epidemiological and microbiological characteristics of tuberculosis caused by recent infection and rapid evolution in the major groups of foreign-born and the U.S.-born populations. METHODS: We analyzed data from a 20-year prospective community-based study of the molecular epidemiology of tuberculosis in San Francisco. We included all culture-positive tuberculosis cases in the City during the study period. MEASUREMENTS AND MAIN RESULTS: We calculated and compared incidence rates, clinical and microbiological characteristics, and risk factors for being a secondary case between the various foreign-born and U.S.-born tuberculosis populations. Between 1991 and 2010, there were 4,058 new cases of tuberculosis, of which 1,226 (30%) were U.S.-born and 2,832 (70%) were foreign-born. A total of 3,278 (81%) were culture positive, of which 2,419 (74%) had complete data for analysis. The incidence rate, including the incidence rate of tuberculosis due to recent infection and rapid evolution, decreased significantly in the U.S.-born and the major foreign-born populations. The clinical and microbiological characteristics and the risk factors for tuberculosis due to recent infection differed among the groups. CONCLUSIONS: There are differences in the characteristics and the risk factors for tuberculosis due to recent transmission among the major foreign-born and U.S.-born populations in San Francisco. These differences should be considered for the design of targeted tuberculosis control interventions.

Accuracy of do not resuscitate (DNR) in administrative data.

This article evaluates the accuracy of reporting do not resuscitate (DNR) orders in administrative data for use in risk-adjusted hospital assessments. We compared DNR reporting by 48 California hospitals in 2005 patient discharge data (PDD) with gold-standard assessments made by registered nurses (RNs) who reabstracted 1,673 records of patients with myocardial infarction, pneumonia, or heart failure. The PDD agreed with the RN reabstraction in 1,411 (84.3%) cases. The administrative data did not reflect a DNR order in 71 of 512 records where the RN indicated there was (14% false negative rates), and reflected a DNR order in 191 of 1,161 records where the RN indicated there was not (16% false positive rate). The accuracy of DNR was more problematic for patients who died, suggesting that hospital-reported DNR is problematic for capturing patient preferences for resuscitation that can be used for risk-adjusted outcomes assessments.

The accuracy of present-on-admission reporting in administrative data.

OBJECTIVE: To test the accuracy of reporting present-on-admission (POA) and to assess whether POA reporting accuracy differs by hospital characteristics. DATA SOURCES: We performed an audit of POA reporting of secondary diagnoses in 1,059 medical records from 48 California hospitals. STUDY DESIGN: We used patient discharge data (PDD) to select records with secondary diagnoses that are powerful predictors of mortality and could potentially represent comorbidities or complications among patients who either had a primary procedure of a percutaneous transluminal coronary angioplasty or a primary diagnosis of acute myocardial infarction, community-acquired pneumonia, or congestive heart failure. We modeled the relationship between secondary diagnoses POA reporting accuracy (over-reporting and under-reporting) and hospital characteristics. DATA COLLECTION: We created a gold standard from blind reabstraction of the medical records and compared the accuracy of the PDD against the gold standard. PRINCIPAL FINDINGS: The PDD and gold standard agreed on POA reporting in 74.3 percent of records, with 13.7 percent over-reporting and 11.9 percent under-reporting. For-profit hospitals tended to overcode secondary diagnoses as present on admission (odds ratios [OR] 1.96; 95 percent confidence interval [CI] 1.11, 3.44), whereas teaching hospitals tended to undercode secondary diagnoses as present on admission (OR 2.61; 95 percent CI 1.36, 5.03). CONCLUSIONS: POA reporting of secondary diagnoses is moderately accurate but varies by hospitals. Steps should be taken to improve POA reporting accuracy before using POA in hospital assessments tied to payments.

Interferon gamma release assay compared with the tuberculin skin test for latent tuberculosis detection in pregnancy.

OBJECTIVE: To estimate agreement and correlation between the tuberculin skin test and an interferon gamma release assay for detecting latent tuberculosis (TB) infection in pregnant women. METHODS: We conducted a cross-sectional study of pregnant women initiating prenatal care at a university-affiliated public hospital between January 5, 2009, and March 15, 2010. Eligible women received a questionnaire about TB history and risk factors as well as the tuberculin skin test and phlebotomy for the interferon gamma release assay. Agreement and correlation between tests were estimated, and different cutoffs for interferon gamma release assay positivity were used to assess effect on agreement. Furthermore, predictors of test positivity and test discordance were evaluated using multivariable analysis. RESULTS: Of the 220 enrolled women, 199 (90.5%) returned for tuberculin skin test evaluation. Over 70% were Hispanic and 65% were born in a country with high TB prevalence. Agreement between the tuberculin skin test and interferon gamma release assay was 77.39 (κ=0.26). This agreement was not significantly changed using different cutoffs for the assay. Birth bacille Calmette-Guérin vaccination was associated with tuberculin skin test positivity (odds ratio [OR] 4.33, 95% confidence interval [CI] 1.4-13.48, P=.01), but not interferon gamma release assay positivity. There were no statistically significant predictors of the tuberculin skin test and interferon gamma release assay result discordance; however, birth in a high-prevalence country was marginally associated with tuberculin skin test-positive and interferon gamma release assay-negative results (OR 2.94, 95% CI 0.86-9.97 P=.08). CONCLUSION: Comparing the tuberculin skin test and interferon gamma release assay results in pregnancy, concordance and agreement were poor. Given that much is still unknown about the performance of interferon gamma release assays in pregnancy, further research is necessary before the tuberculin skin test is abandoned for screening of latent TB infection in pregnancy. LEVEL OF EVIDENCE: III.

Racial differences in tuberculosis infection in United States communities: the coronary artery risk development in young adults study.

Previously reported associations between race/ethnicity and tuberculosis infection have lacked sufficient adjustment for socioeconomic factors. We analyzed race/ethnicity and self-reported tuberculosis infection data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, a well-characterized cohort of 5115 black and white participants, and found that after adjusting for sociodemographic and clinical factors, black participants were more likely to report tuberculosis infection and/or disease (odds ratio, 2.0; 95% confidence interval, 1.5-2.9).

Recent decline in the incidence of human immunodeficiency virus infection among California men who have sex with men.

Monitoring the incidence of human immunodeficiency virus (HIV) infection among men who have sex with men (MSM) is imperative for developing targeted prevention programs and evaluating their effectiveness. The authors used California counseling and testing data to estimate the temporal trend in HIV incidence among MSM in California. HIV incidence rates were retrospectively calculated among MSM who had received at least 1 HIV test at a public California counseling and testing site between 1997 and 2007 and had a prior HIV-negative test from any HIV testing source. All study subjects were weighted on the basis of the interval between the last HIV-negative test and the current HIV test to account for the right-truncation bias introduced by more frequent testers. The authors observed that the HIV incidence rate among MSM in California increased from 2.0/100 person-years (95% confidence interval (CI): 1.8, 2.2) in 1997 to 2.4/100 person-years (95% CI: 2.2, 2.6) in 2003 and then decreased to 1.9/100 person-years (95% CI: 1.7, 2.0) in 2006. Trend analyses showed that both the increase (P < 0.001) and the decrease (P < 0.01) were statistically significant. The study showed that HIV incidence among MSM in California had decreased since 2003.

Factors associated with mortality in patients with drug-susceptible pulmonary tuberculosis.

BACKGROUND: Tuberculosis is a leading cause of death worldwide, yet the determinants of death are not well understood. We sought to determine risk factors for mortality during treatment of drug-susceptible pulmonary tuberculosis under program settings. METHODS: Retrospective chart review of patients with drug-susceptible tuberculosis reported to the San Francisco Tuberculosis Control Program from 1990-2001. RESULTS: Of 565 patients meeting eligibility criteria, 37 (6.6%) died during the study period. Of 37 deaths, 12 (32.4%) had tuberculosis listed as a contributing factor. In multivariate analysis controlling for follow-up time, four characteristics were independently associated with mortality: HIV co-infection (HR = 2.57, p = 0.02), older age at tuberculosis diagnosis (HR = 1.52 per 10 years, p = 0.001); initial sputum smear positive for acid fast bacilli (HR = 3.07, p = 0.004); and experiencing an interruption in tuberculosis therapy (HR = 3.15, p = 0.002). The association between treatment interruption and risk of death was due to non-adherence during the intensive phase of treatment (HR = 3.20, p = 0.001). The median duration of treatment interruption did not differ significantly in either intensive or continuation phases between those who died and survived (23 versus 18 days, and 37 versus 29 days, respectively). No deaths were directly attributed to adverse drug reactions. CONCLUSIONS: In addition to advanced age, HIV and characteristics of advanced tuberculosis, experiencing an interruption in anti-tuberculosis therapy, primarily due to non-adherence, was also independently associated with increased risk of death. Improving adherence early during treatment for tuberculosis may both improve tuberculosis outcomes as well as decrease mortality.

Comparison of restriction fragment length polymorphism with the polymorphic guanine-cytosine-rich sequence and spoligotyping for differentiation of Mycobacterium tuberculosis isolates with five or fewer copies of IS6110.

The use of IS6110 as a marker for molecular epidemiological studies is limited when a Mycobacterium tuberculosis isolate has five or fewer copies of IS6110. Restriction fragment length polymorphism analysis with a highly polymorphic GC-rich repetitive sequence located in the plasmid pTBN12 (PGRS RFLP) and spoligotyping (based on the polymorphism of the DR region) are two frequently used secondary typing methods. The aim of this study was to compare the performance of these two methods in a population-based study in San Francisco. We included all patients with culture-positive tuberculosis from 1999 to 2007 with IS6110 RFLP results presenting five or fewer bands. PGRS RFLP and spoligotyping were performed using standardized methods. We determined the concordance between the two methods regarding cluster status and the risk factors for an isolate to be in a cluster with each of the methods. Our data indicate that both methods had similar discriminatory power and that the risk factors associated with clustering by either method were the same. Although the cluster/unique status was concordant in 84% of the isolates, patients were clustered differently depending on the method. Therefore, the methods are not interchangeable, and the same method should be used for longitudinal studies.

Use of saliva as a lubricant in anal sexual practices among homosexual men.

OBJECTIVES: Compared with other sexually active adults, men who have sex with men (MSM) are more frequently infected with several pathogens including cytomegalovirus, hepatitis B virus, and Kaposi sarcoma-associated herpesvirus. Because one common element between these organisms is their presence in saliva, we evaluated saliva exposure among MSM in a heretofore relatively unrecognized route-via use of saliva as a lubricant in anal sex. METHODS: MSM in a San Francisco population-based cohort were interviewed regarding use of saliva by the insertive partner as a lubricant in various anal sexual practices. RESULTS: Among 283 MSM, 87% used saliva as a lubricant in insertive or receptive penile-anal intercourse or fingering/fisting at some point during their lifetime; 31%-47% did so, depending upon the act, in the prior 6 months. Saliva use as a lubricant was more common among younger men and among HIV-infected men when with HIV-infected partners. Even among MSM following safe sex guidelines by avoiding unprotected penile-anal intercourse, 26% had anal exposure to saliva via use as a lubricant. CONCLUSIONS: Among MSM, use of saliva as a lubricant is a common, but not ubiquitous, practice in anal sex. The findings provide the rationale for formal investigation of whether saliva use in this way contributes to transmission of saliva-borne pathogens in MSM.

Clinical characteristics and treatment outcomes of patients with isoniazid-monoresistant tuberculosis.

BACKGROUND: Risk factors and treatment outcomes under program conditions for isoniazid (INH)-monoresistant tuberculosis have not been well described. METHODS: Medical charts were retrospectively reviewed for all cases of culture-confirmed, INH-monoresistant tuberculosis ( n = 137) reported to the San Francisco Department of Public Health Tuberculosis Control Section from October 1992 through October 2005, and those cases were compared with a time-matched sample of drug-susceptible tuberculosis cases (n = 274) RESULTS: In multivariate analysis, only a history of treatment for latent tuberculosis (odds ratio [OR], 3.1; 95% confidence interval [CI], 1.5-6.4; P = .003) or for active tuberculosis (OR, 2.7; 95% CI, 1.4-5.0; P = .002) were significantly associated with INH-monoresistant tuberculosis. Of the 119 patients who completed treatment, 49 (41%) completed a 6-month treatment regimen. Treatment was extended to 7-12 months for 53 (45%) of the patients and to >12 months for 17 (14%). Treatment was most commonly extended because pyrazinamide was not given for the recommended 6-month duration (35 patients [29%]). Despite variation in treatment regimens, the combined end point of treatment failure or relapse was uncommon among patients with INH-monoresistant tuberculosis and was not significantly different for patients with drug-susceptible tuberculosis (1.7% vs. 2.2%; P = .73). CONCLUSIONS: A history of treatment for latent or active tuberculosis was associated with subsequent INH monoresistance. Treatment outcomes for patients with INH-monoresistant tuberculosis were excellent and were no different from those for patients with drug-susceptible tuberculosis. However, new, short-course regimens are needed because a small proportion of patients completed the 6-month treatment regimen recommended by the American Thoracic Society, Centers for Disease Control and Prevention, and Infectious Diseases Society of America, primarily because of pyrazinamide intolerance.

Mediators of childhood sexual abuse and high-risk sex among men-who-have-sex-with-men.

OBJECTIVE: Mediators of childhood sexual abuse (CSA) and HIV risk behavior were examined for men-who-have-sex-with-men (MSM). METHOD: Data from a dual frame survey of urban MSM (N=1078) provided prevalence estimates of CSA, and a test of two latent variable models (defined by partner type) of CSA-risk behavior mediators. RESULTS: A 20% prevalence of CSA was reported. For MSM in secondary sexual relationships, our modeling work identified two over-arching but inter-related pathways (e.g., both pathways include effects on interpersonal skills) linking CSA and high-risk behavior: (1) CSA-Motivation-Scripts-Skills-Risk Behavior; and (2) CSA-Motivation-Coping-Risk Appraisal-Skills-Risk Behavior. For men in primary relationships, there was one over-arching pathway including CSA-Motivation-Coping-Risk Appraisal-Risk Behavior processes. Exploratory analyses indicated that men with a history of CSA in only primary relationships versus only secondary relationships had, for example, fewer motivational problems, and better coping and interpersonal skills. CONCLUSIONS: CSA contributes to the ongoing HIV epidemic among MSM by distorting or undermining critical motivational, coping, and interpersonal factors that, in turn, influence adult sexual risk behavior. Further, the type of adult relationships men engage in serve as markers for adult CSA-related problems. The findings are discussed in the context of current theory and HIV prevention strategies. PRACTICE IMPLICATIONS: Direct extrapolation from our findings to practice is limited. However, there are general implications that may be drawn. First, the complex challenges faced by men with severe CSA experiences may limit the effectiveness of typical short-term HIV risk reduction programs; more intensive treatment maybe needed. Secondly, Clinical Psychologists and Psychiatrists with MSM patients with CSA histories should, if not already, routinely consider issues of sexual health; patterns and types of sexual partners may be useful markers for identifying more problematic cases. Lastly, public service messages directed at destigmatizing CSA for MSM may increase use of health and mental health services.

Poor performance of universal sample processing method for diagnosis of pulmonary tuberculosis by smear microscopy and culture in Uganda.

Laboratory methods to improve smear microscopy are an urgent priority for global tuberculosis control. The novel universal sample processing (USP) method has been reported to improve conventional diagnostic testing for tuberculosis while also providing inhibitor-free specimens for molecular assays. However, no studies evaluating the method in the field have been conducted. In this study, we compared the performance of the USP method to that of the standard N-acetyl-L-cysteine-NaOH (NALC) method for conventional diagnosis of tuberculosis in 252 adults admitted to Mulago Hospital in Kampala, Uganda, with a clinical suspicion of pneumonia. A single early-morning sputum specimen collected from each patient was divided into two aliquots, each of which was assigned a random identification number. One randomly numbered specimen was processed by the USP method and the other by the NALC method. Mycobacterial cultures were more frequently negative in USP compared to NALC specimen aliquots (58% versus 43%; P < 0.001). There was no difference in the proportion of contaminated mycobacterial cultures (12% versus 11%; P = 0.87). The sensitivity and specificity of smear microscopy for the USP method were 52% and 86%, respectively, and were not significantly different from those for the NALC method (56% and 86%, respectively) using mycobacterial culture results as a reference standard. These results suggest that the USP method did not provide any significant advantage over the standard NALC method for conventional diagnosis of tuberculosis in our setting and illustrate the importance of well-designed, field-level evaluations of novel diagnostic techniques.

Awareness of Kaposi's sarcoma-associated herpesvirus among men who have sex with men.

BACKGROUND: Despite burgeoning scientific knowledge about Kaposi's sarcoma-associated herpesvirus (KSHV), the etiologic agent of Kaposi's sarcoma (KS), little is known about awareness of this virus in the general community. This is particularly the case for men who have sex with men (MSM), the group at greatest risk for infection. METHODS: The California Health Interview Survey was a random digit- dial survey of over 50,000 households. Men aged 18 to 64 years who self-identified as gay or bisexual were subsequently recontacted for a follow-up study of HIV-related knowledge and behavior in which they were asked if they had heard of KS and to describe the cause of KS. RESULTS: Of 398 MSM interviewed, 73.0% (95% CI 65.0-79.7) had heard of KS. However, only 6.4% (95% CI 4.4-9.2) of participants correctly identified that KS is caused by KSHV or a virus other than HIV. Postgraduate education, urban residence, and concurrent HIV infection were all independently associated with greater awareness of the viral origin of KS. CONCLUSION: Awareness of KSHV is very low, overall, among MSM and only somewhat higher, but still unacceptably low, among HIV-infected MSM. Significant efforts are needed to increase awareness of KSHV as a sexually transmitted infection in this population.

Detailed analysis of the radiographic presentation of Mycobacterium kansasii lung disease in patients with HIV infection.

BACKGROUND: Published criteria for the diagnosis of Mycobacterium kansasii lung disease require the presence of clinical symptoms, positive microbiologic results, and radiographic abnormalities. In patients with HIV infection, the radiographic findings of M kansasii lung disease are not well described. METHODS: Medical records and chest radiographs of all patients with HIV infection and at least one respiratory specimen culture positive for M kansasii at San Francisco General Hospital between December 1989 and July 2002 were reviewed. RESULTS: Chest radiographic results were abnormal in 75 of 83 patients (90%) included in the study. Radiographic abnormalities were diverse, with consolidation (66%) and nodules (42%) as the most frequent findings. The mid or lower lung zones were involved in 89% of patients. The pattern of radiographic abnormalities did not differ based on acid-fast bacilli smear status, the presence or absence of coexisting pulmonary infections, or CD4+ T-lymphocyte count. In multivariate Cox regression analysis, cavitation was the only radiographic abnormality independently associated with mortality (hazard ratio, 4.8; 95% confidence interval, 1.2 to 19.6). CONCLUSION: Patients with HIV infection and M kansasii lung disease present with diverse radiographic patterns, most commonly consolidation and nodules predominantly located in the mid and lower lung zones. This finding is in contrast to the upper-lobe cavitary presentation described in patients without HIV infection. Although rare, the presence of cavitary disease in patients with HIV infection and M kansasii independently predicts worse outcome. The diversity in the radiographic presentation of M kansasii lung disease implies that clinicians should obtain sputum mycobacterial culture samples from any patient with HIV infection and an abnormal chest radiograph finding.

Changes in prevalence of HIV infection and sexual risk behavior in men who have sex with men in San Francisco: 1997 2002.

OBJECTIVES: We assessed differences in HIV prevalence and sexual risk behavior among men who have sex with men (MSM) between 1997 and 2002 in San Francisco. METHODS: We used 2 population-based random-digit-dial telephone surveys of MSM households in San Francisco in 1997 (n=915) and 2002 (n=879). RESULTS: Estimated HIV prevalence increased from 19.6% in 1997 to 26.8% in 2002. Measures of sexual risk also increased. Unprotected anal intercourse with a partner of different or unknown HIV serostatus increased from 9.3% to 14.6%. Mean number of male partners increased from 10.7 to 13.8. The largest reported increase was 18.9% to 26.8% for "serosorting," or choosing unprotected anal intercourse partners believed to have the same HIV serostatus as oneself. Men aged 30 to 50 reported the largest increase in unprotected anal intercourse, whereas men aged 18 to 29 reported the largest increase in serosorting. Changes in the age distribution did not explain the increase in risky behavior. CONCLUSIONS: Both HIV prevalence and sexual risk increased substantially among MSM in San Francisco between 1997 and 2002. Serosorting is being adopted more frequently than condom use by young MSM, but its effectiveness as a harm reduction strategy is not known.

Treatment outcomes of patients with HIV and tuberculosis.

RATIONALE: The optimal length of tuberculosis treatment in patients coinfected with HIV is unknown. OBJECTIVES: To evaluate treatment outcomes for HIV-infected patients stratified by duration of rifamycin-based tuberculosis therapy. METHODS: We retrospectively reviewed data on all patients with tuberculosis reported to the San Francisco Tuberculosis Control Program from 1990 through 2001. Patients were followed for up to 12 months after treatment completion. MEASUREMENTS AND MAIN RESULTS: Of 700 patients, 264 (38%) were HIV infected, 315 (45%) were not infected, and 121 (17%) were not tested. Mean duration of treatment was extended to 10.2 months for HIV-infected patients versus 8.4 months for uninfected/unknown patients (p < 0.001). Seventeen percent of the HIV-infected and 37% of the HIV uninfected/unknown patients received 6 months of rifamycin-based therapy. The relapse rate among HIV-infected was 9.3 per 100 person-years versus 1.0 in HIV-uninfected/unknown patients (p < 0.001). HIV-infected individuals who received a standard 6-month rifamycin-based regimen were more likely to relapse than those treated longer (adjusted hazard ratio, 4.33; p = 0.02). HIV-infected individuals who received intermittent therapy were also more likely to relapse than those treated on daily basis (adjusted hazard ratio, 4.12; p = 0.04). The use of highly active antiretroviral therapy was associated with more rapid conversion of smears and cultures and with improved survival. CONCLUSIONS: HIV-infected patients who received a 6-month rifamycin-based course of tuberculosis treatment or who received intermittent therapy had a higher relapse rate than HIV-infected subjects who received longer therapy or daily therapy, respectively. Standard 6-month therapy may be insufficient to prevent relapse in patients with HIV.

Impaired V(D)J recombination and increased apoptosis among B cell precursors in the bone marrow of c-Abl-deficient mice.

Previous studies on c-Abl-deficient mice have shown high post-natal mortality and lymphopenia. However, the mechanisms by which c-Abl may influence B lymphopoiesis remain obscure. In this study, we analyzed B cell sub-populations at various differentiation stages in the bone marrow (BM) of c-Abl-deficient mice. Phenotypic analyses revealed that c-Abl(-/-) pro-B cells were reduced to half of normal incidence and absolute number, while pre-B cells showed an even greater reduction. Both c-Abl(-/-) pro-B and pre-B cell populations showed considerably elevated apoptosis ex vivo and in short-term culture but their cell cycle progression was not impaired. In contrast, apoptosis of immature IgM(+)IgD(-) B lymphocytes remained at normal control levels. Inhibition of c-Abl activity by STI571 in normal BM cultures significantly increased apoptosis in B cell precursors while the survival of immature B cells was not affected. To determine whether c-Abl deficiency affects Ig heavy-chain rearrangement, we found that the frequency of V(D)J recombination was markedly reduced by 15-fold in c-Abl(-/-) pro-B cells compared with the control values. However, no perturbation in the levels of signal-end recombination intermediates was found. Taken together, we propose that c-Abl mediates a stage-specific anti-apoptotic response in precursor B cells and is required for efficient V(D)J recombination during B cell development.

Knowledge of sexual partner's HIV serostatus and serosorting practices in a California population-based sample of men who have sex with men.

OBJECTIVES: To describe knowledge of primary and secondary sexual partner's HIV serostatus and sexual practices, including serosorting, among men who have sex with men (MSM) living in California. METHODS: Men who self-identified as gay/bisexual in the 2001 California Health Interview Survey, a statewide biennial random-digit-dial survey interviewing more than 50,000 adults on a variety of health topics, were recontacted in 2002 and interviewed by telephone about injection drug use, their own and partner's HIV serostatus, and sexual risk behaviors. RESULTS: Among 220 men who reported a primary partner, 86% [95% confidence interval (CI): 77-92] knew their primary partner's serostatus; 62% (95% CI, 52-70) of the 250 men who reported a secondary partner knew their most recent secondary partner's HIV serostatus. Knowledge of one's most recent secondary partner's HIV serostatus was inversely related to history of injecting recreational drugs (odds ratio, 0.22; P < 0.01), and reporting a primary partner in the past year (odds ratio, 0.37; P < 0.05). Two-fifths (41%) of HIV-positive men and three-fifths (62%) of HIV-negative men engaged in serosorting (serocordant unprotected anal intercourse) with their primary partners, whereas 33% HIV-positive men and 20% HIV-negative men did so with their most recent secondary partners. CONCLUSIONS: This population-based survey documented the extent to which MSM know their partners' serostatus and practice serosorting behaviors. The findings emphasize the need for studies to report serocordant and serodiscordant unprotected anal intercourse separately, as the former presents significant lower risk of HIV transmission.