Publications

BACKGROUND

Indoleamine 2,3-dioxygenase, catalyzing tryptophan (Trp) metabolism through the kynurenine (Kyn) metabolic pathway, plays important roles in immune suppression and the CNS. In this article, we report a simple, rapid and specific LC-MS/MS method for accurate determination of Kyn and Trp concentrations in human plasma from HIV-infected patients.

RESULTS

The human plasma sample (100 µl) was mixed with Kyn-d4 and Trp-d5 internal standards and then precipitated with trifluoroacetic acid. The supernatant was directly analyzed by LC-MS/MS. The assay using surrogate matrix calibrators was validated for precision, accuracy, matrix effect, extraction efficiency and stability. Some assay validation issues for endogenous substance bioanalysis using an LC-MS/MS method are discussed.

CONCLUSION

A simple, specific and reproducible LC-MS/MS method has been developed and validated for measuring Kyn and Trp in human plasma samples.

We assessed laboratory monitoring after combination antiretroviral therapy initiation among 3678 patients in a large US multisite clinical cohort, censoring participants at last clinic visit, combination antiretroviral therapy change, or 3 years. Median days (interquartile range) to first hematologic, hepatic, renal, and lipid tests were 30 (18-53), 31 (19-56), 33 (20-59), and 350 (96-1106), respectively. At 1 year, approximately 80% received more than 2 hematologic, hepatic, and renal tests consistent with guidelines. However, only 40% received 1 or more lipid tests. Monitoring was more frequent in specific subgroups, likely reflecting better clinic attendance or clinician perception of higher susceptibility to toxicities.

OBJECTIVE

Many people living with HIV in sub-Saharan Africa desire biological children. Implementation of HIV prevention strategies that support the reproductive goals of people living with HIV while minimizing HIV transmission risk to sexual partners and future children requires a comprehensive understanding of pregnancy in this population. We analyzed prospective cohort data to determine pregnancy incidence and predictors among HIV-positive women initiating antiretroviral therapy (ART) in a setting with high HIV prevalence and fertility.

METHODS

Participants were enrolled in the Uganda AIDS Rural Treatment Outcomes (UARTO) cohort of HIV-positive individuals initiating ART in Mbarara. Bloodwork (including CD4 cells/mm(3), HIV viral load) and questionnaires (including socio-demographics, health status, sexual behavior, partner dynamics, HIV history, and self-reported pregnancy) were completed at baseline and quarterly. Our analysis includes 351 HIV-positive women (18-49 years) who enrolled between 2005-2011. We measured pregnancy incidence by proximal and distal time relative to ART initiation and used multivariable Cox proportional hazards regression analysis (with repeated events) to identify baseline and time-dependent predictors of pregnancy post-ART initiation.

RESULTS

At baseline (pre-ART initiation), median age was 33 years [IQR: 27-37] and median prior livebirths was four [IQR: 2-6]. 38% were married with 61% reporting HIV-positive spouses. 73% of women had disclosed HIV status to a primary sexual partner. Median baseline CD4 was 137 cells/mm(3) [IQR: 81-207]. At enrolment, 9.1% (31/342) reported current pregnancy. After ART initiation, 84 women experienced 105 pregnancies over 3.8 median years of follow-up, yielding a pregnancy incidence of 9.40 per 100 WYs. Three years post-ART initiation, cumulative probability of at least one pregnancy was 28% and independently associated with younger age (Adjusted Hazard Ratio (AHR): 0.89/year increase; 95%CI: 0.86-0.92) and HIV serostatus disclosure to primary sexual partner (AHR: 2.45; 95%CI: 1.29-4.63).

CONCLUSIONS

Nearly one-third of women became pregnant within three years of initiating ART, highlighting the need for integrated services to prevent unintended pregnancies and reduce periconception-related risks for HIV-infected women choosing to conceive. Association with younger age and disclosure suggests a role for early and couples-based safer conception counselling.

Transient low-level viremia (TLLV) of 50-400 HIV RNA copies per milliliter is common during antiretroviral therapy, but its pathogenesis, consequences, and optimal management are unclear. Heightened immune activation is associated with detrimental outcomes, including impaired CD4 T-cell reconstitution. Using CD38/HLA-DR expression on CD8 T cells measured in 2 large studies, we determined associations between TLLV and immune activation levels before, during, and after TLLV. We found that TLLV does not significantly change CD8 T-cell activation and that higher CD8 T-cell activation during viral suppression <50 copies per milliliter is associated with a modest increase in the risk of a subsequent TLLV.

The CCR5 inhibitor maraviroc has been hypothesized to decrease T-cell activation in HIV-infected individuals, but its independent immunologic effects have not been established in a placebo-controlled trial. We randomized 45 HIV-infected subjects with CD4 counts <350 cells per mm(3) and plasma HIV RNA levels <48 copies per mL on antiretroviral therapy (ART) to add maraviroc vs placebo to their regimen for 24 weeks followed by 12 weeks on ART alone. Compared with placebo-treated subjects, maraviroc-treated subjects unexpectedly experienced a greater median increase in % CD38+HLA-DR+ peripheral blood CD8+ T cells at week 24 (+2.2% vs -0.7%, P = .014), and less of a decline in activated CD4+ T cells (P < .001). The % CD38+HLA-DR+ CD4+ and CD8+ T cells increased nearly twofold in rectal tissue (both P < .001), and plasma CC chemokine receptor type 5 (CCR5) ligand (macrophage-inflammatory protein 1β) levels increased 2.4-fold during maraviroc intensification (P < .001). During maraviroc intensification, plasma lipopolysaccharide declined, whereas sCD14 levels and neutrophils tended to increase in blood and rectal tissue. Although the mechanisms explaining these findings remain unclear, CCR5 ligand-mediated activation of T cells, macrophages, and neutrophils via alternative chemokine receptors should be explored. These results may have relevance for trials of maraviroc for HIV preexposure prophylaxis and graft-versus-host disease. This trial was registered at www.clinicaltrials.gov as #NCT00735072.