HIF-1α targeted deletion in myeloid cells decreases MDSC accumulation and alters microbiome in neonatal mice.

The newborn's immune system is faced with the challenge of having to learn quickly to fight off infectious agents, but tolerating the colonization of the body surfaces with commensals without reacting with an excessive inflammatory response. Myeloid-derived suppressor cells (MDSC) are innate immune cells with suppressive activity on other immune cells that regulate fetal-maternal tolerance during pregnancy and control intestinal inflammation in neonates. Until now, nothing is known about the role of MDSC in microbiome establishment. One of the transcription factors regulating MDSC homeostasis is the hypoxia-inducible factor 1α (HIF-1α). We investigated the impact of HIF-1α on MDSC accumulation and microbiome establishment during the neonatal period in a mouse model with targeted deletion of HIF-1α in myeloid cells (Hif1a loxP/loxP LysMCre+). We show that in contrast to wildtype mice, where an extensive expansion of MDSC was observed, MDSC expansion in neonatal Hif1a loxP/loxP LysMCre+ mice was dramatically reduced both systemically and locally in the intestine. This was accompanied by an altered microbiome composition and intestinal T-cell homeostasis. Our results point toward a role of MDSC in inflammation regulation in the context of microbiome establishment and thus reveal a new aspect of the biological role of MDSC during the neonatal period.

Salivary gland function in HIV-infected patients treated with highly active antiretroviral therapy (HAART).

OBJECTIVE: This study was undertaken to determine if HAART alters salivary oral host defense in HIV(+) men. STUDY DESIGN: Whole, parotid, and submandibular/sublingual saliva was collected from 39 healthy men and 147 HIV(+) patients with mild to moderate immune dysfunction (69 treated with HAART [HAART(+)]; 78 not treated [HAART(-)]). Salivary flow rates, anticandidal activities, electrolytes, and antimicrobial/antifungal proteins were determined. RESULTS: While CD4(+) cell counts were not different between the HIV(+) groups, the median viral load for HAART(-) was 15 times greater than HAART(+). For both HAART groups, salivary yeast carriage rates and concentration were comparable and both showed similar reductions in salivary flow rates. Salivary anticandidal activities were not altered. Saliva composition of both HIV(+) groups was different from control, but only uric acid in parotid saliva of HAART(+) differed from HAART(-). CONCLUSIONS: HAART does not adversely affect inherent salivary oral host defense in HIV(+) patients with mild to moderate immune dysfunction.

Salivary secretory leukocyte protease inhibitor increases in HIV infection.

BACKGROUND: Secretory leukocyte protease inhibitor (SLPI) is an antimicrobial protein found in saliva and having anti-HIV activity. The concentrations of SLPI in parotid and submandibular/sublingual (SMSL) saliva were determined in an HIV(+) population and compared with uninfected controls. The effect of highly active antiretroviral therapy (HAART) on the concentrations in saliva was determined. METHODS: Stimulated parotid and SMSL saliva was collected from 65 HIV(+) patients and 19 healthy controls. Flow rates, total protein and SLPI concentrations were determined as well as the effect of HAART on these measurements. RESULTS: Mean flow rates were reduced for parotid (64%) and SMSL (44%) saliva of HIV(+) patients. Flow rate reductions were unaffected by HAART. Total protein concentration in HIV(+) parotid saliva was increased 56%; patients on HAART had higher concentrations than control. For both groups, SLPI concentrations of SMSL saliva were twice that of parotid saliva. For HIV(+) patients SLPI concentrations of both saliva types were 70% greater than control; the increase in parotid saliva was greater for those taking HAART. For each saliva type, the secretory rate and specific SLPI protein concentration were not different between the groups. Patients with low CD4(+) counts had greater SLPI concentrations in parotid saliva than control. There was a negative correlation between CD4(+) counts and the SLPI concentration of parotid saliva. CONCLUSIONS: Salivary flow rate is decreased and the concentration of SLPI is increased in the presence of HIV infection. SLPI concentration in parotid and SMSL saliva is greater with HAART.

Long-term efficacy of routine access to antiretroviral-resistance testing in HIV type 1-infected patients: results of the clinical efficacy of resistance testing trial.

The long-term efficacy of making resistance testing routinely available to clinicians has not been established. We conducted a clinical trial at 6 US military hospitals in which volunteers infected with human immunodeficiency virus type-1 were randomized to have routine access to phenotype resistance testing (PT arm), access to genotype resistance testing (GT arm), or no access to either test (VB arm). The primary outcome measure was time to persistent treatment failure despite change(s) in antiretroviral therapy (ART) regimen. Overall, routine access to resistance testing did not significantly increase the time to end point. Time to end point was significantly prolonged in the PT arm for subjects with a history of treatment with > or =4 different ART regimens or a history of treatment with nonnucleoside reverse-transcriptase inhibitors before the study, compared with that in the VB arm. These results suggest that routine access to resistance testing can improve long-term virologic outcomes in HIV-infected patients who are treatment experienced but may not impact outcome in patients who are naive to or have had limited experience with ART.

Diverse HIV-1 subtypes and clinical, laboratory and behavioral factors in a recently infected US military cohort.

OBJECTIVE: To describe the demographics, risk behaviors, and HIV-1 subtypes in a large cohort of recently HIV-infected military personnel. DESIGN: Descriptive, cross-sectional study. METHODS: US military personnel with recent HIV seroconversion from six medical referral centers were enrolled with a self-administered questionnaire, CD4 cell counts, syphilis and hepatitis B serologies, plasma viral RNA levels, and HIV-1 subtype nucleic acid sequencing. RESULTS: Between February 1997 and May 2000, 520 patients were enrolled. Most [488 (94.3%)] were infected with HIV-1 subtype B. The most prevalent non-B subtype was a circulating recombinant form (CRF01_AE) [17 (61%)]; however, two pure subtypes (C and D), as well as CRF02_AG, CRF09_cpx and a BE recombinant were identified. The likely area of HIV-1 acquisition was the United States for 70% of the volunteers. At least three non-B subtype infections (two subtype C, one subtype CRF01_AE) were apparently acquired domestically. Risk behaviors and comorbid sexually transmitted diseases were reported during the seroconversion period. Volunteers with non-B subtype HIV infection were more likely to report heterosexual contacts [92% vs. 39%; odds ratio (OR), 10.0], including contacts with commercial sex workers (41% vs. 13%; OR, 4.9). The Roche Amplicor version 1.0 assay was less sensitive for non-B subtype infections than the Roche Amplicor version 1.5 assay. CONCLUSION: There is a high prevalence and diversity of non-B HIV subtypes in this large cohort. Efficient diagnosis of acute primary HIV-1 infection was identified as a goal for prevention programs. Modifiable risk behaviors and target populations for intervention were identified.

What is the shelf life of physician-mixed antibiotic-impregnated calcium sulfate pellets?

This pilot study was undertaken to evaluate the short-term in vitro antimicrobial stability of both vancomycin- and tobramycin-impregnated calcium sulfate pellets mixed and stored in a clinical setting. Powdered tobramycin sulfate (500 mg) and vancomycin hydrochloride (500 mg) were blended into separate basins containing 25 g of surgical-grade calcium sulfate powder, then mixed with 8 mL of sterile saline. From this admixture, 6.0-mm pellets were produced. These were removed from the sterile container (stored at room temperature) at 1, 7, 30, 60, 90, and 120 days and tested against a variety of pathogenic bacterial isolates by using a modification of the standardized Kirby-Bauer test. Control pellets containing no antibiotic were also evaluated. There was no inhibition of bacterial growth by the non-antibiotic-impregnated (control) pellets. There was no appreciable difference in the zones of inhibition for any of the organisms with pellets stored for 1, 7, 30, 60, 90, or 120 days. Zones of inhibition for the various antibiotics to the strain of organism tested ranged from 17 mm to 30 mm, depending on the pathogenic isolate and the antibiotic evaluated. The zones of inhibition observed were similar to those designating antibiotic susceptibility in the Kirby-Bauer test. The results of this preliminary study suggest that clinician-mixed calcium sulfate pellets containing either vancomycin or tobramycin, when stored under normal room temperature and ambient humidity, appear to maintain their antimicrobial characteristics for at least 120 days.

Correlates of human herpesvirus-8 seropositivity among U.S. military members recently infected with human immunodeficiency virus.

BACKGROUND: Human herpesvirus 8 (HHV-8), the cause of Kaposi's sarcoma, is common among HIV-infected persons. The exact route of transmission of HHV-8 in various populations is still debated. GOAL: The goal was to define the correlates of HHV-8 infection among men recently infected with human immunodeficiency virus. STUDY DESIGN: Three hundred forty-two HIV-infected U.S. military men were evaluated using a questionnaire regarding potential risk factors and laboratory data, including HHV-8, herpes simplex virus 2 (HSV-2), syphilis, hepatitis B, and hepatitis C serologies. RESULTS: The seroprevalence of HHV-8 was 32%. HHV-8 was significantly associated with hepatitis B seropositivity (odds ratio [OR], 2.44; 95% confidence interval [CI], 1.5-4.1), and black ethnicity was negatively associated with HHV-8 (OR, 0.6; 95% CI, 0.3-0.9) in the multivariate analysis. HHV-8 was not associated with drug use or hepatitis C seropositivity. Among men who have sex with men (MSM), HHV-8 infection correlated with hepatitis B seropositivity (OR, 2.2; 95% CI, 1.1-4.3) and HSV-2 (OR, 2.6; 95% CI, 1.4-4.9). Among heterosexuals, the correlates of HHV-8 were different; blacks as compared with whites (OR, 0.3; 95% CI, 0.1-0.8) and married versus single status (OR, 0.4; 95% CI, 0.2-0.9) were associated with a lower rate of HHV-8 infection. Among heterosexuals, hepatitis B, HSV-2, and sexual behaviors were not associated with HHV-8. CONCLUSION: This study suggests that the seroprevalence of HHV-8 is increased in both MSM and heterosexual men with HIV infection, and that the route(s) of HHV-8 acquisition might be different between MSM and heterosexuals.

HIV-1 infection and AIDS dementia are influenced by a mutant MCP-1 allele linked to increased monocyte infiltration of tissues and MCP-1 levels.

Studies in humans and in experimental models of HIV-1 infection indicate an important role for monocyte chemoattractant protein-1 (MCP-1; also known as CC chemokine ligand 2), a potent chemoattractant and activator of mononuclear phagocytes (MP) in the pathogenesis of HIV-associated dementia (HAD). We determined the influence of genetic variation in MCP-1 on HIV-1 pathogenesis in large cohorts of HIV-1-infected adults and children. In adults, homozygosity for the MCP-1 -2578G allele was associated with a 50% reduction in the risk of acquiring HIV-1. However, once HIV-1 infection was established, this same MCP-1 genotype was associated with accelerated disease progression and a 4.5-fold increased risk of HAD. We examined the molecular and cellular basis for these genotype-phenotype associations and found that the mutant MCP-1 -2578G allele conferred greater transcriptional activity via differential DNA-protein interactions, enhanced protein production in vitro, increased serum MCP-1 levels, as well as MP infiltration into tissues. Thus, MCP-1 expression had a two-edged role in HIV-1 infection: it afforded partial protection from viral infection, but during infection, its proinflammatory properties and ability to up-regulate HIV-1 replication collectively may contribute to accelerated disease progression and increased risk of dementia. Our findings suggest that MCP-1 antagonists may be useful in HIV-1 infection, especially for HAD, and that HIV+ individuals possessing the MCP-1 -2578G allele may benefit from early initiation of antiretroviral drugs that effectively cross the blood-brain barrier. In a broader context, the MCP-1 -2578G allele may serve as a genetic determinant of outcome of other disease states in which MP-mediated tissue injury is central to disease pathogenesis.