The high-risk sexual practices of crack-smoking sex workers recruited from the streets of three American cities. The Multicenter Crack Cocaine and HIV Infection Study Team.

BACKGROUND AND OBJECTIVES: Small ethnographic and clinic-based studies indicate that crack-smoking sex workers are at high risk for human immunodeficiency virus (HIV) and sexually transmitted diseases (STD). STUDY GOALS: To examine the prevalence of risky sexual behaviors and HIV and STD in a large sample of street-recruited crack-smoking sex workers. STUDY DESIGN: From 1991 to 1992, 419 crack-smoking sex workers were recruited from urban neighborhoods, interviewed, and serologically tested. RESULTS: Many female and male sex workers reported sex with injectors (30% to 41%) or HIV-infected persons (8% to 19%), past STD (73% to 93%), and inconsistent condom use (> 50% for all types of sex). Sex workers who worked in crack houses or vacant lots, were paid with crack, or injected drugs had the riskiest sex practices. Most sex workers initiated sex work before they first smoked crack. More than 25% were infected with HIV (27.9%), syphilis (37.5%), or herpes simplex virus type 2 (66.8%). CONCLUSIONS: Interventions to prevent HIV/STD transmission among crack-smoking sex workers are urgently needed.

Background to crack cocaine addiction and HIV high-risk behavior: the next epidemic.

BACKGROUND: Increasing rates of sexually transmitted diseases among users of noninjection drugs prompt speculation that crack cocaine users who do not inject are at particularly high risk of HIV (human immunodeficiency virus) infection. METHODS: A street recruitment technique was employed to enroll 331 primarily African-American men aged 18-29 in an area of San Francisco where crack cocaine is sold openly. One-half were regular crack users and the other half had never used the drug. Few reported injection drug use or male-to-male sex. In a face-to-face interview, participants reported on their drug use, knowledge of HIV, sexual practice, condom use, and demographic characteristics. Following counseling, each was tested for HIV and syphilis. RESULTS: Comparisons showed that demographically similar, crack users reported more sexual partners in the last 12 months, more sexually transmitted diseases (STDs) in their lifetime, and greater frequencies of paying for sex, exchanging sex for drugs, and having sex with injection drug users. Users reported greater current depression, anxiety, and social isolation. They reported earlier initiation into alcohol use and less positive parenting experiences during their adolescence. CONCLUSION: These results are consistent with findings that report the comorbidity of drug abuse and mental illness. Implications are drawn for reducing HIV infection among this high-risk population for early adolescent, community mental health, and substance abuse treatment programs.

Summary of validation studies from twenty-six forensic laboratories in the United States and Canada on the use of the AmpliType PM PCR amplification and typing kit.

A cooperative study was undertaken to collect and summarize the results of validation studies from forensic laboratories in the United States and Canada on the use of the AmpliType PM PCR amplification and typing kit for genetic typing of forensic biological evidence. This report compiles data from 26 laboratories on: 1) reproducibility studies on DNA extracted from various samples, 2) genetic typing of DNA extracted from a variety of biological samples on various substrates, 3) the effects of exogenous chemicals, materials, and environmental factors on test results, 4) sensitivity studies to determine the least detectable amount of extracted genomic DNA that can be reliably typed, 5) analysis of mixtures containing two sources of genomic DNA, 6) cross-hybridization with DNA extracted from various nonhuman species, and 7) evaluation of assay performance on parallel studies with other genetic typing systems on proficiency test panels, mock cases, and adjudicated/nonprobative casework. Equivalent results were obtained by each laboratory that supplied data, demonstrating the reliability and consistency of the test. Overall, it can be concluded from this study that the AmpliType PM PCR amplification and typing kit meets the guidelines of the Technical Working Group on DNA Analysis Methods (TWGDAM) and there is general scientific acceptability of this kit for forensic DNA testing.

Crack cocaine smokers who turn to drug injection: characteristics, factors associated with injection, and implications for HIV transmission. The Multicenter Crack Cocaine and HIV Infection Study Team.

A survey of 1220 street-recruited crack cocaine smokers revealed that crack smokers may turn to drug injection to ease crack withdrawal. Crack smokers who later injected tended to smoke crack more heavily and for longer periods than those who did not inject. The initiation of injection was significantly associated with ever snorting heroin (prevalence ratio [PR] = 3.4, 95% confidence interval [CI] = 2.0-5.9) or snorting heroin specifically while smoking crack (PR = 2.3, 95% CI = 1.3-4.0), suggesting that snorted heroin use may mediate the transition to injection among crack smokers. Programs to prevent and treat crack dependence may prevent later injection and injection-related infections including HIV.

Crack cocaine smoking and oral sores in three inner-city neighborhoods.

Crack cocaine causes blisters, sores, and cuts on the lips and in the mouths of persons who smoke it, and such sores may facilitate the oral transmission of HIV. We recruited young adults aged 18-29 years, who either were current regular crack smokers, or who had never smoked crack, from inner city neighborhoods in New York, Miami, and San Francisco. Participants were interviewed for HIV risk behaviors and history of recent oral sores and were tested for HIV, syphilis, and herpes simplex virus (HSV) antibodies. Among the 2,323 participants recruited, 1,404 (60%) were crack smokers. Crack smokers (10.0%) were more likely than nonsmokers (4.5%) to report having had oral sores in the past 30 days [prevalence odds ratio (POR) 2.4, 95% confidence interval (CI) 1.7-3.4]. Sores were also more prevalent among those who had ever injected drugs (14.3%) than among those who had not (6.7%; POR 2.3, 95% CI 1.7-3.4), and among those with HIV infection (14.3%) than among those without it (8.0%; POR 1.9, 95% CI 1.3-2.8). Among the 429 participants who reported receptive oral sex, those who reported oral sores were more likely than those who did not to have HIV infection, after other HIV risk factors were controlled for (adjusted POR 1.9, 95% CI 1.0-3.6). Our results confirm that crack smokers have a high prevalence of oral sores and provides evidence that these sores, although infrequently, may facilitate oral transmission of HIV.

The developmental implications of prenatal and/or postnatal crack cocaine exposure in preschool children: a preliminary report.

Previous studies examining the development of prenatally cocaine-exposed children through 3 years of age have found no significant differences between exposed and control groups. This study explored the developmental correlates of prenatal and/or postnatal crack cocaine exposure in children between 4 and 6 years of age. Three groups were studied: Group 1, 18 prenatally-exposed children whose mothers continue to use crack; Group II, 28 children without prenatal exposure whose mothers presently use crack; and Group III, 28 children whose mothers never used crack. Mothers were street-recruited and were comparable in race and socioeconomic status. The three groups of children did not differ on neurological gross motor and expressive language measures. However, prenatally exposed children performed significantly worse than others on receptive language and visual motor drawing tests. Prenatal crack exposure predicted poor visual motor performance even after control for intrauterine alcohol and marijuana exposure, age, birth weight, and duration of maternal crack use.

Urban rape survivors: characteristics and prevalence of human immunodeficiency virus and other sexually transmitted infections. Multicenter Crack Cocaine and HIV Infection Study Team.

OBJECTIVE: To determine the prevalence of recent rape, the characteristics or recent rape survivors, and the seroprevalence of human immunodeficiency virus (HIV), syphilis, and genital herpes (HSV-2) among recent rape survivors. METHODS: We surveyed women 18-29 years old who were recruited from places unassociated with medical or drug treatment or the criminal justice system in three urban communities where illicit drug use is common. We compared characteristics and HIV, syphilis, and HSV-2 seroprevalence of women who reported recent rape with those of women who denied recent rape. RESULTS: One hundred fifty-one of 1104 (13.7%) women reported having been raped in the year before our interview. Rape survivors were more likely than women who denied recent rape to smoke crack cocaine (86.8 versus 56.7%; odds ratio [OR] 5.0, 95% confidence interval [CI] 3.2-7.8), to be homeless (17.2 versus 6.1%; OR 3.2, CI 2.0-5.2), to report a recent sexually transmitted disease (38.7 versus 18.7%; OR 2.7, CI 1.9-3.9), and to be infected with syphilis (42.4 versus 28.4%; OR 1.9, CI 1.3-2.6) and HSV-2 (71.9 versus 57.5%; OR 1.9, CI 1.3-2.8). Survivors were more likely to acknowledge any HIV risk behavior (including sex work) (85.4 versus 49.5%; OR 5.9, CI 3.9-9.0) and to be HIV-infected (23.3 versus 13.4%; OR 1.9, CI 1.3-2.9). Rape was not independently associated with HIV (OR 0.8, 95% CI 0.4-1.3), syphilis (OR 0.9, 95% CI 0.6-1.3), or HSV-2 (OR 1.3, 95% CI 0.9-2.0) infections after adjustment for confounding factors. CONCLUSION: One in seven women reported being raped recently. Rape was most common among sex workers, crack smokers, and the homeless. Most survivors reported HIV risk behaviors, and many were HIV-infected. Programs to prevent repeated rape, voluntary HIV counseling and testing, and other medical and social services may benefit survivors in these and similar communities.

Intersecting epidemics--crack cocaine use and HIV infection among inner-city young adults. Multicenter Crack Cocaine and HIV Infection Study Team.

BACKGROUND AND METHODS: The smoking of "crack" cocaine is thought to be associated with high-risk sexual practices that accelerate the spread of infection with the human immunodeficiency virus (HIV). We studied 2323 young adults, 18 to 29 years of age, who smoked crack regularly or who had never smoked crack. The study participants, recruited from the streets of inner-city neighborhoods in New York, Miami, and San Francisco, were interviewed and tested for HIV. This report presents the findings for the 1967 participants (85 percent) who had never injected drugs. RESULTS: Of the 1137 crack smokers, 15.7 percent were positive for HIV antibody, as compared with 5.2 percent of the 830 nonsmokers (prevalence ratio adjusted for the city, 2.4; 99 percent confidence interval, 1.7 to 3.6). The prevalence of HIV was highest among the crack-smoking women in New York (29.6 percent) and Miami (23.0 percent). Of the 283 women who had sex in exchange for money or drugs, 30.4 percent were infected with HIV as compared with 9.1 percent of the 286 other women (prevalence ratio, 3.1; 99 percent confidence interval, 1.9 to 5.1); of the 91 men who had anal sex with other men, 42.9 percent were infected with HIV as compared with 9.3 percent of the 582 men who did not have anal sex with other men (prevalence ratio, 4.7; 99 percent confidence interval, 3.0 to 7.4). In multivariable analyses, these high-risk sexual practices accounted for the higher prevalence of HIV infection among the crack smokers, as compared with those who did not smoke crack. Women who had recently had unprotected sex in exchange for money or drugs were as likely to be infected as men who had had sex with men (40.9 percent vs. 42.9 percent). CONCLUSIONS: In poor, inner-city communities young smokers of crack cocaine, particularly women who have sex in exchange for money or drugs, are at high risk for HIV infection. Crack use promotes the heterosexual transmission of HIV.

High-risk sex behavior among young street-recruited crack cocaine smokers in three American cities: an interim report. The Multicenter Crack Cocaine and HIV Infection Study Team.

Since crack cocaine appeared in urban areas in the United States in the mid-1980s, reports have suggested that crack smokers may be at increased risk of sexually transmitted diseases (STDs), including infection with HIV, because they have multiple sex partners, trade sex for money or drugs, and rarely use condoms. A cross-sectional survey is being conducted in urban neighborhoods in Miami, New York and San Francisco--where crack use is common--to explore these issues. Indigenous street outreach workers are recruiting men and women who are either current regular crack smokers or who have never smoked crack; each group is further stratified according to whether participants had ever injected drugs. Participants were interviewed about their sexual and drug-use practices. Overall, crack smokers, whether injectors or not, engaged in higher-risk sexual behaviors than nonsmokers, reported greater numbers of sex partners than nonsmokers, and were more likely than nonsmokers to have exchanged sex for money or drugs or to have had an STD. Differences between crack smokers and nonsmokers were generally greater among non-injectors than among injectors, and generally greater among women than among men. Condom use, although somewhat more common with paying than nonpaying partners, was infrequent overall. Most of the subjects had not been in substance abuse treatment in the preceding 12 months, and a majority had never been in substance abuse treatment. Education and prevention programs specifically targeted at crack smokers not currently in substance abuse treatment are needed to reach these high-risk persons.

Isolation of deoxyribonucleic acid (DNA) from saliva and forensic science samples containing saliva.

Saliva and saliva-stained materials were examined as potential sources of deoxyribonucleic acid (DNA) for DNA analysis and identity testing. In this paper, the authors demonstrate that DNA was isolated and DNA banding patterns suitable for DNA typing were obtained from fresh saliva and various saliva-stained materials, such as envelopes, buccal swabs, gags, and cigarettes. Furthermore, DNA and DNA banding patterns were obtained from actual forensic evidentiary samples containing mixed saliva/semen stains. The DNA banding patterns obtained from saliva or saliva-stained material were indistinguishable from the patterns obtained from blood or hair from the same individual. Intact DNA was readily isolated and DNA banding patterns were obtained from saliva stored at -20 degrees C and dried saliva stains stored under varying conditions. We conclude that saliva and saliva-stained material can be good sources of DNA for analysis and for DNA typing in certain forensic settings.

Immunoglobulin D switching can occur through homologous recombination in human B cells.

Prototypical class switching in mouse and human immunoglobulin heavy chains occurs through recombination of tandem blocks of short repeats located 5' to each heavy chain constant region (CH) except C delta. Deletion of C mu in immunoglobulin D (IgD)-secreting murine plasmacytomas occurs illegitimately. We demonstrate here that in human IgD-secreting myeloma cells freshly isolated from patient bone marrow and in normal peripheral blood B lymphocytes, an IgD switch can occur through homologous recombination of a direct repeat consisting of a 442-bp sequence 1.5 kbp 3' of the JH complex and a 443-bp sequence that is duplicated almost perfectly (96% similarity) 1.7 kbp 5' of the C delta gene (442/443-base-pair [bp] repeat). This homologous recombination mechanism is not exclusive for IgD switching, since C mu deletion endpoints in two established IgD-secreting myeloma cell lines fall outside the 442/443-bp repeat. The 442/443-bp mediated recombination shows cell type specificity, and we propose that it represents a unique mode for increased levels of IgD secretion in humans.

Antisera to the secretory component recognize the murine Fc receptor for IgA.

Studies were undertaken to determine a possible structural relationship between the secretory component (SC) and the receptor for IgA (Fc alpha R). An IgA-mediated rosetting technique was used to assess the presence of Fc alpha R+ cells in various lymphoid tissues from normal BALB/c mice and mice bearing an IgA plasmacytoma (MOPC 315). Tissues from the MOPC 315-bearing BALB/c mice were found to have a significantly higher percentage of Fc alpha R+ cells; thus, nonadherent spleen cells from MOPC 315-bearing mice were used as a source of Fc alpha R+ cells in these studies. The cells were preincubated with anti-SC and then assayed for the ability of IgA to bind to the Fc alpha R. Antisera to SC from various species inhibited the formation of IgA-mediated rosettes, although preincubation of the Fc alpha R+ cells with antisera directed against other cell surface molecules (e.g., Thy1.2, Lyt1, Lyt2, Fc gamma R, MHC class I and II) or preimmune sera had no significant effect on IgA-mediated rosette formation. Preabsorption of the anti-SC with secretory IgA or with free SC removed the inhibitory effect; preabsorption with myeloma IgA had no effect. These data suggest that SC and Fc alpha R are related serologically and may be structurally related, possible in the IgA-binding region.

The human immunoglobulin C mu-C delta locus: complete nucleotide sequence and structural analysis.

The entire nucleotide sequence (approximately 20 kbp) spanning the human immunoglobulin IgM (mu) and IgD (delta) heavy chain constant region genes has been determined from DNA of mu-delta producing chronic lymphocytic leukemic B cells. As in the murine IgM + IgD double-producing B cells, no rearrangement has occurred in the C mu-C delta region in the leukemic cells. The C mu locus is highly conserved between mouse and human with the exception of the nucleotide sequence between the C mu 4 and mu M1 exons, which has diverged dramatically. The intergenic sequence between human C mu and C delta is three times larger than the analogous region in the mouse and contains notable features absent from the mouse, including a 443 bp segment that is 96% identical to a 442 bp sequence that occurs just 3' to the heavy chain enhancer, a 366 bp sequence that is directly repeated with 76% homology, and 12 tandem copies of a 35 bp sequence. The human C delta gene contains two additional exons relative to mouse C delta, but shares with the mouse the unique distal location of both secreted and membrane coding segments. Several polymorphisms in the human population have been identified in the intergenic region and in C delta but not in C mu.

The human immunoglobulin C mu-C delta locus: regulation of mu and delta RNA expression during B cell development.

Whether the immunoglobulin (Ig) heavy chain genes C mu and C delta are expressed singly or in combination, their transcripts undergo differentiation-specific alterations in membrane (M) versus secreted (S) forms as well as in abundance. To better understand this regulation, we have cloned cDNAs for human delta m and delta s to establish the 3' end of the C mu-C delta transcription unit. Steady state mRNA levels and transcription rates were then analyzed in normal and transformed human B cells representing different maturation and activation states. The ratio of micron/microsecond RNA and of delta m/delta s RNA correlated with developmental stage, with a higher ratio at earlier stages. Steady state ratios of total mu/delta RNA paralleled ratios of C mu/C delta nascent transcription, suggesting no major posttranscriptional control for differential expression. However, at all developmental stages, transcription termination occurred downstream of the micron exons, suggesting a strong posttranscriptional regulatory component for production of secreted versus membrane forms of mu RNA. The relative abundance of mature delta S RNA was considerably higher in the human than in the mouse, correlating with the increased levels of circulating IgD in the former species. Stimulation of human splenocytes with mitogens did not increase delta RNA; in fact, splenocytes activated with pokeweed mitogen were nearly devoid of delta RNA, and Staphylococcus aureus Cowan I caused only a minor change.

Double isotype production by a neoplastic B cell line. II. Allelically excluded production of mu and gamma 1 heavy chains without CH gene rearrangement.

In our accompanying paper, we described a switch variant (BCL1.2.58) that expresses membrane and secreted forms of IgM and IgG1. Both IgM and IgG1 share the same idiotype and use the same VDJ rearrangement. Here, a detailed Southern blot analysis of the entire constant region of the Ig heavy chain (Ig CH) locus of parental (BCL1.B1) and variants (BCL1.B2) DNA showed no detectable rearrangement. Similar analysis of the JH-C mu region led to the conclusion that two heavy chain alleles present in the IgM/IgG1-producing variants carried the same VDJ rearrangement but differed in their 3' flanking regions. One chromosome 12 did not carry any Ig CH genes, whereas, the other chromosome 12 carried one copy of CH genes. In BCL1.B1, however, each of the chromosome 12 alleles carried a full copy of CH genes. Karyotypic analysis confirmed the presence of two translocated t(12;16) chromosomes in both BCL1.2.58 and BCL1.B1 cells, with a break 5' to the VH locus at the distal region (12F2) of chromosome 12, and at the proximal region below the centromere (16B3) of chromosome 16. We conclude that double production of IgM and IgG1 in BCL1.B2 is accomplished by transcription of the corresponding CH genes in germline configuration using a single VDJ on the same chromosome 12.

Double isotype production by a neoplastic B cell line. I. Cellular and biochemical characterization of a variant of BCL1 that expresses and secretes both IgM and IgG1.

We have subcloned the in vitro-adapted murine B cell leukemia, BCL1.B1, to obtain a variant that expresses both IgM and IgG1. By fluorescence analysis, radioiodination, and immunoprecipitation of cell surface Ig, and by RIA of medium from limiting dilution cultures, we have shown that: (a) all the cells express and secrete both isotypes. The heavy chains of both IgG1 and IgM have the apparent molecular weights of membrane mu and gamma 1 chains; (b) both isotypes bear the same idiotype as determined by immunoprecipitation with antiidiotypic antibody, and both use the same VDJ rearrangement as shown by Southern blotting; and (c) the cells express the membrane and secreted forms of mRNA for both mu and gamma 1 but not gamma 2b or gamma 3. Taken together, the data suggest that all the cells are synthesizing, expressing on their surface, and secreting two isotypes that use the same VDJ rearrangement in the DNA and express the same serologically-defined idiotype. The molecular basis responsible for the production of the two isotypes in a single cell is the subject of the accompanying paper.

Regulation of IgA expression by isotype-specific T cells and soluble binding factors.

The data presented here suggest a model for isotype-specific regulation of IgA synthesis by Fc alpha R+ T cells (Figure 1). Immature mIgM+ +/- mIgD+ B cells are induced by T switch cells to express cell surface IgA (a phenotypic switch). If the T switch cell induces mIgA expression via a long primary RNA transcript from an unrearranged C alpha allele, the hypothetical intermediate switch B cell results (step 1); this may be the mechanism of heavy chain expression in memory B cells that express low levels of Ig. Alternatively, T switch cells may induce a DNA rearrangement in the CH locus of the B cell (a genotypic switch), which results in a deletion of all CH loci except C alpha (step 2). TH inducer cells promote maturation of mIgA+ B cells to IgA-secreting plasma cells. This may involve a DNA switch rearrangement (step 3) or the maturation of previously switched cells (step 4), and appears to be mediated via an IgABF with enhancing activity. Not shown in this figure, but inherent in this model, is a suppressive regulatory arm that may be mediated via IgABF with suppressive activity released from Fc alpha R+ suppressor T cells. Due to the presence of Fc alpha R on a variety of cell types, IgABF may suppress synthesis of IgA by acting not only on mIgA+ B cells but also on regulatory cells (T cells, B cells, and macrophages) bearing IgA bound to Fc alpha R. If the IgA system is analogous with the IgE system, mIgA-bearing B cells may be the direct target of IgABF. Binding of Ig to FcR has been shown to (a) increase the number of Fc receptors per cell, (b) enhance the number of cells expressing Fc receptors, (c) induce the release of IgBF that either suppress or enhance Ig secretion, and (d) effectively convert surface Ig- cells into surface Ig+ cells that are therefore receptive to IgBF. Thus, FcR+ cells may interact with IgBF and Ig via a regulatory network to stimulate or inhibit the immune response in an isotype-specific manner. Cell surface molecules (mIg, FcR) may serve as sensors that allow the cell to detect and respond to fluctuations in the levels of immune mediators that serve to modulate Ig synthesis and secretion. The relationship between IgBF and FcR is not known, nor is it known whether Fc receptors expressed by different cell types are encoded by the same gene and are controlled similarly.(ABSTRACT TRUNCATED AT 400 WORDS)

Human immunoglobulin D: genomic sequence of the delta heavy chain.

The DNA coding for the human immunoglobulin D(IgD) heavy chain (delta, delta) has been sequenced including the membrane and secreted termini. Human delta, like that of the mouse, has a separate exon for the carboxyl terminus of the secreted form. This feature of human and mouse IgD distinguishes it from all other immunoglobulins regardless of species or class. The human gene is different from that of the mouse; it has three, rather than two, constant region domains; and its lengthy hinge is encoded by two exons rather than one. Except for the third constant region, the human and mouse genes are only distantly related.