Ian Maclean

Male circumcision for HIV prevention in young men in Kisumu, Kenya: a randomised controlled trial

BACKGROUND Male circumcision could provide substantial protection against acquisition of HIV-1 infection. Our aim was to determine whether male circumcision had a protective effect against HIV infection, and to assess safety and changes in sexual behaviour related to this intervention. METHODS We did a randomised controlled trial of 2784 men aged 18-24 years in Kisumu, Kenya. Men were randomly assigned to an intervention group (circumcision; n=1391) or a control group (delayed circumcision, 1393), and assessed by HIV testing, medical examinations, and behavioural interviews during follow-ups at 1, 3, 6, 12, 18, and 24 months. HIV seroincidence was estimated in an intention-to-treat analysis. This trial is registered with ClinicalTrials.gov, with the number NCT00059371. FINDINGS The trial was stopped early on December 12, 2006, after a third interim analysis reviewed by the data and safety monitoring board. The median length of follow-up was 24 months. Follow-up for HIV status was incomplete for 240 (8.6%) participants. 22 men in the intervention group and 47 in the control group had tested positive for HIV when the study was stopped. The 2-year HIV incidence was 2.1% (95% CI 1.2-3.0) in the circumcision group and 4.2% (3.0-5.4) in the control group (p=0.0065); the relative risk of HIV infection in circumcised men was 0.47 (0.28-0.78), which corresponds to a reduction in the risk of acquiring an HIV infection of 53% (22-72). Adjusting for non-adherence to treatment and excluding four men found to be seropositive at enrollment, the protective effect of circumcision was 60% (32-77). Adverse events related to the intervention (21 events in 1.5% of those circumcised) resolved quickly. No behavioural risk compensation after circumcision was observed. INTERPRETATION Male circumcision significantly reduces the risk of HIV acquisition in young men in Africa. Where appropriate, voluntary, safe, and affordable circumcision services should be integrated with other HIV preventive interventions and provided as expeditiously as possible.

Polymorphisms in Chlamydia trachomatis tryptophan synthase genes differentiate between genital and ocular isolates

We previously reported that laboratory reference strains of Chlamydia trachomatis differing in infection organotropism correlated with inactivating mutations in the pathogens tryptophan synthase (trpBA) genes. Here, we have applied functional genomics to extend this work and find that the paradigm established for reference serovars also applies to clinical isolates - specifically, all ocular trachoma isolates tested have inactivating mutations in the synthase, whereas all genital isolates encode a functional enzyme. Moreover, functional enzyme activity was directly correlated to IFN-gamma resistance through an indole rescue mechanism. Hence, a strong selective pressure exists for genital strains to maintain a functional synthase capable of using indole for tryptophan biosynthesis. The fact that ocular serovars (serovar B) isolated from the genital tract were found to possess a functional synthase provided further persuasive evidence of this association. These results argue that there is an important host-parasite relationship between chlamydial genital strains and the human host that determines organotropism of infection and the pathophysiology of disease. We speculate that this relationship involves the production of indole by components of the vaginal microbial flora, allowing chlamydiae to escape IFN-gamma-mediated eradication and thus establish persistent infection.

Antibody to Chlamydial hsp60 Predicts an Increased Risk for Chlamydial Pelvic Inflammatory Disease

To determine whether serum antibody to Chlamydia trachomatis antigens alters the risk of C. trachomatis pelvic inflammatory disease (PID), 280 female sex workers were prospectively evaluated over a 33-month period for incident C. trachomatis and Neisseria gonorrhoeae cervical infection and for clinical PID. At enrollment, women were tested for antibody to C. trachomatis elementary bodies by an indirect microimmunofluorescence assay and to recombinant chlamydial hsp60 (Chsp60) by an ELISA format. At each follow-up visit, women were tested for cervical chlamydial and gonococcal infection and were identified as having clinical PID if they complained of lower abdominal pain and were found to have uterine and adnexal tenderness on pelvic examination. The data demonstrate that antibody to Chsp60 predicts a 2- to 3-fold increased risk for C. trachomatis PID.

Increased Interleukin-10 in the Endocervical Secretions of Women With Non-Ulcerative Sexually Transmitted Diseases: A Mechanism for Enhanced HIV-1 Transmission?

OBJECTIVE Although non-ulcerative sexually transmitted diseases (STD) and bacterial vaginosis are implicated as cofactors in heterosexual HIV-1 transmission, the mechanisms have not been defined. Recent in vitro data suggest that interleukin (IL)-10 may increase susceptibility of macrophages to HIV-1 infection. Therefore, we performed this study to assess whether non-ulcerative STD are associated with detection of IL-10 in the female genital tract. METHODS Women with clinical pelvic inflammatory disease with or without cervicovaginal discharge were recruited from an STD clinic in Nairobi, Kenya. Endocervical and endometrial specimens were obtained for Neisseria gonorrhoeae and Chlamydia trachomatis DNA detection, Trichonomas vaginalis culture, and CD4 and CD8 T-cell enumeration. Bacterial vaginosis was diagnosed by Gram stain. IL-10 was detected in endocervical specimens using enzyme-linked immunosorbent assay. Blood was obtained for HIV-1 serology. RESULTS One hundred and seventy-two women were studied. N. gonorrhoeae, C. trachomatis, bacterial vaginosis, and T. vaginalis were detected in 38 (21%), 17 (9%), 71 (43%), and 22 (12%) women, respectively. Cervical IL-10 was detected more often in women with N. gonorrhoeae [adjusted odds ratio (AOR), 3.4; 95% confidence interval (CI), 1.4-8.4], C. trachomatis (AOR, 4.4; 95% CI, 1.2-15.6), and bacterial vaginosis (AOR, 3.1; 95% CI, 1.4-6.9) than in women without these infections. CONCLUSIONS The association of non-ulcerative STD and bacterial vaginosis with increased frequency of IL-10 detection in endocervical secretions suggests a potential mechanism through which these infections may alter susceptibility to HIV-1 infection in women.

HIV-1 target cells in foreskins of African men with varying histories of sexually transmitted infections

Numerous epidemiologic studies have found significant associations between lack of circumcision and HIV-1 acquisition in men. To our knowledge, this is the first study of human foreskin tissue that examines biologic mechanisms that increase susceptibility of uncircumcised African men to HIV-1. Foreskin specimens from 20 men with and 19 men with no history of sexually transmitted infections were examined for HIV-1 target cells. Most Langerhans cells were found in the epithelium; most CD4+ T cells and macrophages were in the submucosa. There were no differences in HIV-1 target cells between men with and those without history of sexually transmitted infections. However Langerhans cells and macrophages were more abundant in the group with a history of infection. The densities and positions of HIV-1 target cells in the foreskin tissue of these Kenyan men indicate that the inner mucosal surface of the human foreskin contains cells that make it highly susceptible to HIV infection.

Chlamydia trachomatis from individuals in a sexually transmitted disease core group exhibit frequent sequence variation in the major outer membrane protein (omp1) gene.

60 cervical Chlamydia trachomatis infections identified by antigen detection from 51 prostitute women in Nairobi, Kenya were evaluated for sequence polymorphism in the major outer membrane protein (omp1) gene. DNA from clinical specimens was amplified by the polymerase chain reaction and cycle sequenced through variable domains (VD) 1, 2, and 4.37 (63%) samples had variant VD sequences, 19 (32%) samples had prototype VD sequences, and 4 (6%) samples had prototype VD sequences, and 4 (6%) samples contained omp1 sequences from two or more C. trachomatis strains. Among the 37 variant strains, 18 had two or fewer nucleotide substitutions in one or two VDs and represented point mutational drift variants. 19 strains had a larger number of nucleotide changes and displayed mosaic omp1 sequences that may have been generated by omp1 VD recombination. We conclude that the prevalence of C. trachomatis omp1 DNA polymorphism is substantial among prostitute women in Nairobi, Kenya and that this is the likely result of immune selection pressure.

Adult Male Circumcision Does Not Reduce the Risk of Incident Neisseria gonorrhoeae, Chlamydia trachomatis, or Trichomonas vaginalis Infection: Results from a Randomized, Controlled Trial in Kenya

BACKGROUND We examined the effect of male circumcision on the acquisition of 3 nonulcerative sexually transmitted infections (STIs). METHODS We evaluated the incidence of STI among men aged 18-24 years enrolled in a randomized trial of circumcision to prevent human immunodeficiency virus (HIV) infection in Kisumu, Kenya. The outcome was first incident nonulcerative STI during 2 years of follow-up. STIs examined were laboratory-detected Neisseria gonorrhoeae, Chlamydia trachomatis, and Trichomonas vaginalis infection. RESULTS There were 342 incident infections among 2655 men followed up. The incidences of infection due to N. gonorrhoeae, C. trachomatis, and T. vaginalis were 3.48, 4.55, and 1.32 cases per 100 person-years, respectively. The combined incidence of N. gonorrhoeae and C. trachomatis infection was 7.26 cases per 100 person-years (95% confidence interval, 6.49-8.13 cases per 100 person-years). The incidences of these STIs, individually or combined, did not differ by circumcision status as a time-dependent variable or a fixed variable based on assignment. Risks for incident STIs in multivariate analysis included an STI at enrollment, multiple sex partners within <30 days, and sexual intercourse during menses in the previous 6 months; condom use was protective. CONCLUSIONS Circumcision of men in this population did not reduce their risk of acquiring these nonulcerative STIs. Improved STI control will require more-effective STI management, including partner treatment and behavioral risk reduction counseling.

Increased Risk of HIV Acquisition among Kenyan Men with Human Papillomavirus Infection

BACKGROUND Few data on the effect of human papillomavirus (HPV) infection on human immunodeficiency virus (HIV) acquisition are available. METHODS HIV-seronegative, sexually active, 18-24-year-old Kenyan men participating in a randomized trial of male circumcision provided exfoliated penile cells from 2 anatomical sites (glans/coronal sulcus and shaft) at baseline. The GP5+/6+ polymerase chain reaction assay ascertained a wide range of HPV DNA types at the baseline visit. The risk of HIV infection was estimated using Kaplan-Meier methods and hazard ratios from proportional hazards models. RESULTS Of 2168 uncircumcised men with baseline HPV data, 1089 (50%) were positive for HPV DNA. The cumulative incidence of HIV infection by 42 months was 5.8% (95% confidence interval [CI], 3.6%-7.9%) among men with HPV-positive glans/coronal sulcus specimens, versus 3.7% [95% CI, 1.8%-5.6%] among men with HPV-negative glans/coronal sulcus specimens (P = .01). Controlling for subsequent circumcision status, baseline herpes simplex virus type 2 serostatus, and sexual and sociodemographic risk factors, the hazard ratio for HIV infection among men with HPV-positive glans/coronal sulcus specimens was 1.8 (95% CI, 1.1-2.9), compared with men with HPV-negative glans/coronal sulcus specimens. CONCLUSION The results suggest an independent increased risk of HIV seroconversion among HPV-positive men. If this finding is confirmed in other studies, HPV prevention could be another tool for HIV prevention.

The association of herpes simplex virus type 2 (HSV-2), Haemophilus ducreyi, and syphilis with HIV infection in young men in northern Thailand

To evaluate the association between sexually transmitted diseases that commonly may cause genital ulceration and prevalent and incident HIV infections, we conducted three case control studies in a cohort of 21-year-old male military conscripts in northern Thailand. The men were evaluated at baseline in 1991 and semiannually until their discharge 2 years later. Serologic evidence of infection with herpes simplex virus type 2 (HSV-2), Haemophilus ducreyi, and HIV were more frequent at baseline in 83 men with a history of genital ulcer than in 97 men without such a history. Seropositivity to H. ducreyi (odds ratio [OR] = 3.46), HSV-2 (OR = 3.83), and syphilis (OR = 1.53) were more common in HIV-positive than HIV-negative men. Men (N = 45) who seroconverted to HIV while in the military were more often seropositive for H. ducreyi and HSV-2 before HIV seroconversion and also were more likely to seroconvert to HSV-2 and H. ducreyi during the same interval as their HIV seroconversion compared with men who remained HIV-negative. These data suggest that HSV-2 and H. ducreyi may be both markers for high-risk sexual behavior and risk factors for HIV infection among young men in Thailand.

Antibody to Rmp (outer membrane protein 3) increases susceptibility to gonococcal infection.

The severe adverse effects of gonococcal infection on human fertility suggests that Neisseria gonorrhoeae would exert powerful selection for the development of a protective immune response in humans. N. gonorrhoeae is an obligate human pathogen and must persist in humans to survive. Since it is an ecologically successful organism, it must have evolved strategies to evade any human immune response it elicits. In a longitudinal study among 243 women working as prostitutes and experiencing frequent gonococcal infection, younger women, women with HIV infection, and women with antibody to the gonococcal outer membrane protein 3 (Rmp) were at increased risk of infection (adjusted odds ratio 3.4, CI95% 1.1-10.4, P < 0.05). Rmp is highly conserved in N. gonorrhoeae and the blocking of mucosal defences may be one of its functions. As similar proteins occur in many gram negative mucosal pathogens, the enhancing effect of such proteins may be a general strategy whereby bacteria evade human immune responses.