Contagiousness in treated HIV-1 infection.

BACKGROUND: Effective antiretroviral treatment of HIV-1, defined as continuously undetectable virus in blood, has substantial effects on the infectiousness and spread of HIV. AIM: This paper outlines the assessment of the Swedish Reference Group for Antiviral Therapy (RAV) and Public Health Agency of Sweden regarding contagiousness of HIV-infected persons on antiretroviral therapy (ART). Results and Conclusion: The expert group concludes that there is no risk of transmission of HIV during vaginal or anal intercourse if the HIV-infected person fulfils the criteria for effective ART. Summary: The effective antiretroviral therapy (ART) for HIV-1 infection has dramatically reduced the morbidity and mortality among people who live with HIV. ART also has a noticeable effect on the infectiousness and on the spread of the disease in society. Knowledge about this has grown gradually. For ART to be regarded effective, the level of the HIV RNA in the plasma should be repeatedly and continuously undetectable and the patient should be assessed as continually having high adherence to treatment. Based on available knowledge the Swedish Reference Group for Antiviral Therapy (RAV) and the Public Health Agency of Sweden make the following assessment: There is no risk of HIV transmission during vaginal or anal intercourse if the HIV positive person fulfils the criteria for effective treatment. This includes intercourse where a condom is not used. However, there are a number of other reasons for recommending the use of condoms, primarily to protect against the transmission of other STIs (sexually transmitted infections) and hepatitis, as well as unwanted pregnancy. The occurrence of other STIs does not affect the risk of HIV transmission in persons on effective ART. It is plausible that the risk for transmission of HIV infection between people who inject drugs and share injection equipment is reduced if the individual with HIV is on effective ART, but there are no studies that directly show this. The risk of transmission from mother to child during pregnancy, labour and delivery is very low if the mother's treatment is initiated well before delivery and if the treatment aim of undetectable virus levels is attained. This is dependent on healthcare services being aware of the mother's HIV infection at an early stage. In most contacts with health and medical care, including dental care, the risk of transmission is not significant if the patient is on effective treatment, but the risk may remain, although considerably reduced, in more advanced interventions such as surgery. When an incident with risk of transmission occurs, the patient must always inform those potentially exposed about his or her HIV infection.

Six-week follow-up after HIV-1 exposure: a position statement from the Public Health Agency of Sweden and the Swedish Reference Group for Antiviral Therapy.

In 2014 the Public Health Agency of Sweden and the Swedish Reference Group for Antiviral Therapy (RAV) conducted a review and analysis of the state of knowledge on the duration of follow-up after exposure to human immunodeficiency virus (HIV). Up until then a follow-up of 12 weeks after exposure had been recommended, but improved tests and new information on early diagnosis motivated a re-evaluation of the national recommendations by experts representing infectious diseases and microbiology, county medical officers, the RAV, the Public Health Agency, and other national authorities. Based on the current state of knowledge the Public Health Agency of Sweden and the RAV recommend, starting in April 2015, a follow-up period of 6 weeks after possible HIV-1 exposure, if HIV testing is performed using laboratory-based combination tests detecting both HIV antibody and antigen. If point-of-care rapid HIV tests are used, a follow-up period of 8 weeks is recommended, because currently available rapid tests have insufficient sensitivity for detection of HIV-1 antigen. A follow-up period of 12 weeks is recommended after a possible exposure for HIV-2, since presently used assays do not include HIV-2 antigens and only limited information is available on the development of HIV antibodies during early HIV-2 infection. If pre- or post-exposure prophylaxis is administered, the follow-up period is recommended to begin after completion of prophylaxis. Even if infection cannot be reliably excluded before the end of the recommended follow-up period, HIV testing should be performed at first contact for persons who seek such testing.

The cost-effectiveness of introducing nucleic acid testing to test for hepatitis B, hepatitis C, and human immunodeficiency virus among blood donors in Sweden.

BACKGROUND: The purpose of this study was to estimate the cost-effectiveness of using individual-donor nucleic acid testing (ID-NAT) in addition to serologic tests compared with the sole use of serologic tests for the identification of hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) among blood donors in Sweden. STUDY DESIGN AND METHODS: The two strategies analyzed were serologic tests and ID-NAT plus serologic tests. A health-economic model was used to estimate the lifetime costs and effects. The effects were measured as infections avoided and quality-adjusted life-years (QALYs) gained. A societal perspective was used. RESULTS: The largest number of viral transmissions occurred with serologic testing only. However, the risks for viral transmissions were very low with both strategies. The total cost was mainly influenced by the cost of the test carried out. The cost of using ID-NAT plus serologic tests compared to serologic tests alone was estimated at Swedish Krona (SEK) 101 million (USD 12.7 million) per avoided viral transmission. The cost per QALY gained was SEK 22 million (USD 2.7 million). CONCLUSION: Using ID-NAT for testing against HBV, HCV, and HIV among blood donors leads to cost-effectiveness ratios that are far beyond what is usually considered cost-effective. The main reason for this is that with current methods, the risks for virus transmission are very low in Sweden.

Strong HIV-specific CD4+ and CD8+ T-lymphocyte proliferative responses in healthy individuals immunized with an HIV-1 DNA vaccine and boosted with recombinant modified vaccinia virus ankara expressing HIV-1 genes.

We investigated HIV-1 vaccine-induced lymphoproliferative responses in healthy volunteers immunized intradermally or intramuscularly (with or without adjuvant granulocyte-macrophage colony-stimulating factor [GM-CSF] protein) with DNA expressing HIV-1 gag, env, rev, and rt at months 0, 1, and 3 using a Biojector and boosted at 9 months with modified vaccinia virus Ankara (MVA) expressing heterologous HIV-1 gag, env, and pol (HIV-MVA). Lymphoproliferative responses to aldrithiol-2 (AT-2)-inactivated-HIV-1 antigen were tested by a [(3)H]thymidine uptake assay and a flow-cytometric assay of specific cell-mediated immune response in activated whole blood (FASCIA-WB) 2 weeks after the HIV-MVA boost (n = 38). A FASCIA using peripheral blood mononuclear cells (FASCIA-PBMC) was also employed (n = 14). Thirty-five of 38 (92%) vaccinees were reactive by the [(3)H]thymidine uptake assay. Thirty-two of 38 (84%) vaccinees were reactive by the CD4(+) T-cell FASCIA-WB, and 7 of 38 (18%) also exhibited CD8(+) T-cell responses. There was strong correlation between the proliferative responses measured by the [(3)H]thymidine uptake assay and CD4(+) T-cell FASCIA-WB (r = 0.68; P < 0.01). Fourteen vaccinees were analyzed using all three assays. Ten of 14 (71%) and 11/14 (79%) demonstrated CD4(+) T-cell responses in FASCIA-WB and FASCIA-PBMC, respectively. CD8(+) T-cell reactivity was observed in 3/14 (21%) and 7/14 (50%) using the FASCIA-WB and FASCIA-PBMC, respectively. All 14 were reactive by the [(3)H]thymidine uptake assay. The overall HIV-specific T-cell proliferative response in the vaccinees employing any of the assays was 100% (38/38). A standardized FASCIA-PBMC, which allows simultaneous phenotyping, may be an option to the [(3)H]thymidine uptake assay for assessment of vaccine-induced T-cell proliferation, especially in isotope-restricted settings.

High content cellular immune profiling reveals differences between rhesus monkeys and men.

A better understanding of similarities and differences in the composition of the cellular immune system in non-human primates (NHPs) compared with human subjects will improve the interpretation of preclinical studies. It will also aid in addressing the usefulness of NHPs as subjects for studying chronic diseases, vaccine development and immune reconstitution. We employed high content colour flow cytometry and analysed simultaneously the expression of CD3, CD4, CD8alpha, CD8beta, CD16/CD56, CD45RA, CCR7, CD27, CD28, CD107a and the interleukin-7 receptor alpha-chain (IL-7Ralpha) in peripheral blood mononuclear cells (PBMCs) of 27 rhesus macaques and 16 healthy human subjects. Regulatory T cells (Tregs) were identified using anti-CD3, -CD4, -CD25, -FoxP3, and -IL-7Ralpha monoclonal antibodies. Responsiveness to IL-7 was gauged in a signal transducer and activation of transcription 5 (STAT-5) phosphorylation assay. Human and NHP PBMCs showed a similar T-cell composition pattern with some remarkable differences. Similarities: human and NHP CD4(+) and CD8(+) cells showed a similar STAT-5 phosphorylation pattern in response to IL-7. Multicolour flow cytometric analysis identified a CD4(+) CD8alphaalpha(+) CD8alphabeta(+) T-cell population in NHPs as well as in human subjects that expressed the degranulation marker CD107a and may represent a unique CD4(+) T-cell subset endowed with cytotoxic capacity. Differences: we identified in PBMCs from NHPs a higher proportion (5.16% in CD3(+) T cells) of CD8alphaalpha(+) T cells when compared with human donors (1.22% in CD3(+) T cells). NHP CD8alphaalpha(+) T cells produced tumour necrosis factor-alpha / interferon-gamma (TNF-alpha/IFN-gamma) or TNF-alpha, whereas human CD8alphaalpha(+) T cells produced simultaneously TNF-alpha/IFN-gamma and IL-2. A minor percentage of human CD8(+) T cells expressed CD25(bright) and FoxP3 (0.01%). In contrast, 0.07% of NHP CD8(+) T cells exhibited the CD25(bright) FoxP3(+) phenotype. PBMCs from NHPs showed less IL-7Ralpha-positive events in all T-cell subsets including CD4(+) Tregs (median 5%) as compared with human (median 12%). The data visualize commonalities and differences in immune cell subsets in humans and NHPs, most of them in long-lived memory cells and cells with suppressive functions. This provides a matrix to assess future efforts to study diseases and vaccines in NHPs.

rBCG induces strong antigen-specific T cell responses in rhesus macaques in a prime-boost setting with an adenovirus 35 tuberculosis vaccine vector.

BACKGROUND: BCG vaccination, combined with adenoviral-delivered boosts, represents a reasonable strategy to augment, broaden and prolong immune protection against tuberculosis (TB). We tested BCG (SSI1331) (in 6 animals, delivered intradermally) and a recombinant (rBCG) AFRO-1 expressing perfringolysin (in 6 animals) followed by two boosts (delivered intramuscullary) with non-replicating adenovirus 35 (rAd35) expressing a fusion protein composed of Ag85A, Ag85B and TB10.4, for the capacity to induce antigen-specific cellular immune responses in rhesus macaques (Macaca mulatta). Control animals received diluent (3 animals). METHODS AND FINDINGS: Cellular immune responses were analyzed longitudinally (12 blood draws for each animal) using intracellular cytokine staining (TNF-alpha, IL-2 and IFN-gamma), T cell proliferation was measured in CD4(+), CD8alpha/beta(+), and CD8alpha/alpha(+) T cell subsets and IFN-gamma production was tested in 7 day PBMC cultures (whole blood cell assay, WBA) using Ag85A, Ag85B, TB10.4 recombinant proteins, PPD or BCG as stimuli. Animals primed with AFRO-1 showed i) increased Ag85B-specific IFN-gamma production in the WBA assay (median >400 pg/ml for 6 animals) one week after the first boost with adenoviral-delivered TB-antigens as compared to animals primed with BCG (<200 pg/ml), ii) stronger T cell proliferation in the CD8alpha/alpha(+) T cell subset (proliferative index 17%) as compared to BCG-primed animals (proliferative index 5% in CD8alpha/alpha(+) T cells). Polyfunctional T cells, defined by IFN-gamma, TNF-alpha and IL-2 production were detected in 2/6 animals primed with AFRO-1 directed against Ag85A/b and TB10.4; 4/6 animals primed with BCG showed a Ag85A/b responses, yet only a single animal exhibited Ag85A/b and TB10.4 reactivity. CONCLUSION: AFRO-1 induces qualitatively and quantitatively different cellular immune responses as compared with BCG in rhesus macaques. Increased IFN-gamma-responses and antigen-specific T cell proliferation in the CD8alpha/alpha+ T cell subset represents a valuable marker for vaccine-take in BCG-based TB vaccine trials.

Cytokine detection by multiplex technology useful for assessing antigen specific cytokine profiles and kinetics in whole blood cultured up to seven days.

Cytokine profile assessment is important to characterize immune responses to pathogens. To identify optimal time points for determination of cytokine profiles, we diluted whole blood 1:10, to enable daily cytokine measurements during one week. Cultures for 10 blood donors were set up in the presence of phytohemagglutinin (PHA), cytomegalovirus (CMV) or Candida. Supernatant levels of interleukin-2 (IL-2), IL-4, IL-5, IL-6, IL-10, IL-12, IL-13, IL-17, interferon-gamma (IFN-gamma), granulocyte/macrophage colony-stimulating factor, and tumor necrosis factor-alpha (TNF-alpha), were determined by multiplex technique, and intracellular cytokine staining (ICS) was employed to detect IFN-gamma, IL-2, IL-4 and IL-13 in CD3+ cells. The multiplex analysis detected representative cytokine profiles for the majority of the cytokines on day 7 by identifying peak levels or good correlation with peak levels, with the exception of IL-2 and TNF-alpha in PHA and CMV cultures and IL-10 in PHA cultures. For these cytokines an extracellular measurement on day 2-3 would be appropriate. The intracellular cytokines showed distinct kinetics for IFN-gamma and IL-2, while IL-4 and IL-13 were not detected at all with ICS. In conclusion, the combination of whole blood cultures with multiplex analysis is a simple and powerful tool that can be used to identify detailed cytokine profiles of specific cell-mediated immune responses.

A novel assay for assessment of HIV-specific cytotoxicity by multiparameter flow cytometry.

BACKGROUND: Assessment of CD8(+) T-cell activity is of significant importance for the evaluation of cellular immune responses to viral infections, especially in HIV. We present a new assay for the assessment of HIV-specific cytotoxicity by multiparameter flow cytometry. METHODS: Target cells, pulsed with peptide pools (Gag or Nef), were stained with 5- (and -6)-carboxyfluorescein diacetate succinimidyl ester (CFSE), cultured with specific or nonspecific effector cells, and finally stained with propidium iodide (PI). Determination of cytolysis is based on the enumeration of viable target cells (CFSE(hi)PI(-)) in the test sample (target and specific effector cells) as compared with that of the viable target cells in the control sample (target and nonspecific effector cells). The (51)Cr-release assay and IFN-gamma ELISpot were performed by standard procedures. RESULTS: A comparison with the Cr-release showed that the two assays were strongly correlated (r = 0.67; P < 0.001) but the sensitivity of the flow cytometric assay was significantly higher (P < 0.05), and the reproducibility good (CV, 7.7%). Good correlation was also found with the ELISpot assay (r = 0.66; P < 0.01). CONCLUSION: This new assay provides both specific and sensitive results when employed for the detection of HIV-specific CTL and can be a valuable tool for the evaluation of cytolytic activity in vaccine trials or in HIV-infected subjects, especially if such responses are present at low levels.