Francesca Prati

Performance of tests for latent tuberculosis in different groups of immunocompromised patients.

BACKGROUND Immunocompromised persons infected with Mycobacterium tuberculosis (MTB) have increased risk of tuberculosis (TB) reactivation, but their management is hampered by the occurrence of false-negative results of the tuberculin skin test (TST). The T-cell interferon (IFN)-gamma release blood assays T-SPOT.TB (TS.TB) [Oxford Immunotec; Abingdon, UK] and QuantiFERON-TB Gold In-Tube (QFT-IT) [Cellestis Ltd; Carnegie, VIC, Australia] might improve diagnostic accuracy for latent TB infection (LTBI) in high-risk persons, although their performance in different groups of immunocompromised patients is largely unknown. METHODS AND RESULTS Over a 1-year period, we prospectively enrolled patients in three different immunosuppressed groups, as follows: 120 liver transplantation candidates (LTCs); 116 chronically HIV-infected persons; and 95 patients with hematologic malignancies (HMs). TST, TS.TB, and QFT-IT were simultaneously performed, their results were compared, and intertest agreement was evaluated. Overall, TST provided fewer positive results (10.9%) than TS.TB (18.4%; p < 0.001) and QFT-IT (15.1%; p = 0.033). Significantly fewer HIV-infected individuals had at least one positive test (9.5%) compared with LTCs (35.8%; p < 0.001) and patients with HMs (29.5%; p < 0.001). Diagnostic agreement between tests was moderate (kappa = 0.40 to 0.65) and decreased in the HIV-infected group when the results of the TS.TB were compared with either TST (kappa = 0.16) or QFT-IT (kappa = 0.19). Indeterminate blood test results due to low positive control values were significantly more frequent with QFT-IT (7.2%) than with TS.TB (0.6%; p < 0.001). CONCLUSIONS Blood tests identified significantly more patients as being infected with MTB than TST, although diagnostic agreement varied across groups. Based on these results, we recommend tailoring application of the new blood IFN-gamma assays for LTBI in different high-risk groups and advise caution in their current use in immunosuppressed patients.

Cytotoxic granule release dominates gag-specific CD4+ T-cell response in different phases of HIV infection.

Background:The activity of virus-specific T lymphocytes, among which those capable of a polyfunctional response against the viral protein gag, is crucial to control HIV infection. Objective:The objective of this study is to investigate the polyfunctionality of gag-specific T cells in different phases of HIV infection, analyzing markers related to T-helper cell 1 (Th1) and degranulation/cytotoxicity, and the production of Th1 cytokines in peripheral blood lymphocytes from patients experiencing an acute primary infection, long-term nonprogressors, patients naive for antiretroviral drugs, and patients taking HAART. Materials and methods:Cells were stimulated with a pool of gag-derived peptides or with a superantigen (staphylococcal enterotoxin B). Using eight-color polychromatic flow cytometry, we analyzed the expression of interleukin-2, interferon-γ, CD154, and CD107a by CD4+ and CD8+ T cells. Results:The main finding was that in all HIV-positive patients, about half gag-specific CD4+ T cells were CD107a+, that is, able to degranulate. CD4+CD154+ cells unable to produce Th1 cytokines were the second most represented population. Truly polyfunctional CD4+ T cells were very rare and present only in a few long-term nonprogressors. Superantigen stimulation showed that CD4+ T lymphocytes from all patients displayed a typical Th response, including interleukin-2 and interferon-γ production, lacking CD107a expression. Conclusion:In all the aforementioned phases of HIV infection, the large majority of gag-specific CD4+ T lymphocytes cannot be identified by the sole expression of interleukin-2 and interferon-γ, which is early impaired. Degranulation and helper functions other than Th1 cytokine production are the predominant features of HIV-specific CD4+ lymphocytes.

Immunophenotype of HIV+ patients during CD4 cell-monitored treatment interruption: role of the IL-7/IL-7 receptor system.

Objective:To investigate immunological changes during CD4-guided therapy interruption in HIV+ patients who suspended HAART. Patients:Seventeen patients aged > 18 years, who had received HAART for at least 12 months, and had a pre-interruption CD4+ cell count > 500 cells/μl, interrupted treatment. Median nadir CD4+ cell count was 288 cells/μl. HIV plasma viral load at discontinuation was < 50 or > 50 copies/ml. Criteria for restarting treatment were: a CD4+ T-lymphocyte count < 350 cells/μl on two separate occasions, a clinical manifestation of AIDS, and the patients desire to resume HAART. Eleven patients were still off therapy after 12 months (group A); according to the first criterion, six patients restarted therapy within 12 months (group B). Methods:Haematological, viro-immunological, cytofluorimetic and molecular assays were performed at baseline and every 2 months following standard methods. Statistical analysis was performed under Stata 7.0. Results:In the first 2 months of treatment interruption, a significant increase in viral load and CD8+ lymphocyte activation occurred. Then such parameters decreased and remained stable. In all patients, a decrease in CD4+ lymphocytes took place as well, that affected in a similar manner naive, central memory, effector memory and terminally differentiated cells. Group B always presented lower amounts of CD4+ effector memory lymphocytes. The expression of CD127 was always higher in group A. Conclusions:The loss of CD4+ lymphocytes upon viral rebound is equal among naive and memory subsets. Patients with higher expression of CD127, who are likely to exert a better capacity to utilize endogenous interleukin-7 by T cells, could remain off therapy for longer periods.

CD4 + T-cell differentiation, regulatory T cells and gag-specific T lymphocytes are unaffected by CD4-guided treatment interruption and therapy resumption

Objectives:Despite limiting exposure to antiretroviral drugs, structured treatment interruptions can influence multiple aspects of T-cell immunity, particularly those regarding CD4+ T lymphocytes. We evaluated the impact of CD4-guided treatment interruption (CD4-GTI) and treatment resumption on regulatory T cells (Tregs), T-lymphocyte activation, differentiation and polyfunctional gag-specific response. Methods:Patients were analyzed just prior to treatment interruption, at 2 and 6 months after treatment interruption, just prior to treatment resumption and at 2 and 6 months after treatment resumption. Thawed peripheral blood mononuclear cells were stained immediately for phenotype analysis or stimulated with HIV-gag peptides and analyzed by polychromatic flow cytometry. Results:Treatment interruption resulted in a CD4+ cell count decrease and plasma viral load (pVL) increase, but did not preclude a good immune reconstitution and a complete suppression of pVL after treatment resumption. Treatment interruption did not influence CD4+ T-cell differentiation and Treg subsets. During treatment interruption, gag-specific CD4+ T cells were not lost, although the frequency of HIV-specific CD8+ cells increased. Most gag-specific CD4+ T cells were potentially cytotoxic (CD107a+) and were not influenced by pVL or by HAART. Most helper (CD154+) gag-specific CD4+ T lymphocytes did not produce interferon-&ggr; or interleukin-2. Conclusion:CD4-GTI did not cause depletion of memory cells, Tregs or HIV-specific CD4+ cells and, on the contrary, could induce HIV-specific responses. If guided by CD4+ T-cell count, treatment interruption does not provoke irreversible immune damages.

Transmitted HIV type 1 drug resistance and non-B subtypes prevalence among seroconverters and newly diagnosed patients from 1992 to 2005 in Italy.

The patterns of transmitted drug-resistant (TDR) HIV-1 variants, non-B subtype spread, and epidemiological trends were evaluated either in seroconverters or in newly diagnosed individuals in Italy over a 13-year period. We analyzed 119 seroconverters, enrolled from 1992 to 2003 for the CASCADE study, and 271 newly diagnosed individuals of the SPREAD study (2002-2005), of whom 42 had a known seroconversion date. Overall, TDR was 15.1% in the CASCADE and 12.2% in the SPREAD study. In the 1992-2003 period, men having sex with men (MSMs) and heterosexuals (HEs) were 48.7% and 36.8%, respectively; TDR was found to be higher in MSMs compared to HEs (78.9% vs. 21%, p = 0.006). The same groups were 39.1% and 53.3% in the SPREAD study; however, no association was detected between modality of infection and TDR. Overall, 9.2% and 22.1% of individuals harbored a non-B clade virus in the CASCADE and SPREAD study, respectively. As evidence of onward transmission, 40% (24/60) of non-B variants were carried by European individuals in the latter study; among these patients the F1 subtype was highly prevalent (p = 0.00001). One of every eight patients who received a diagnosis of HIV-1 in recent years harbored a resistant variant, reinforcing the arguments for baseline resistance testing to customize first-line therapy in newly infected individuals. The spread of non-B clades may act as a dilution factor of TDR concealing the proportion of TDR in seroconverters and MSMs.

NK-cell phenotype at interruption underlies widely divergent duration of CD4+-guided antiretroviral treatment interruption.

Long-term side effects may represent a relevant burden of antiretroviral treatment (ART) in HIV-infected patients with good CD4 immune reconstitution over extended time spans. CD4-guided treatment interruption (TI) has been evaluated to address this point and may result in a wide spectrum of time off ART in different patient cohorts. We studied whether differences in innate immune responses, in particular NK cells, are associated to patterns of longer (LoTI) or a shorter (ShTI) TI. Clinical cohort parameters were analyzed on a group of patients widely diverging for TI duration (<9 versus >18 months) on samples before TI, including NK-cell analysis and function by natural cytotoxicity receptor (NCR)-triggered γ-IFN production. Although persistently reduced NCR expression (NKp30) and function were observed in both LoTI and ShTI patients on ART compared with healthy donors, relevant differences were observed at baseline TI in those patients who subsequently developed LoTI course. Lower expression of NKG2D and NKp46 on NK cells. This also translates in reduced γ-IFN production in redirected functional assays. Thus, differences in innate immune balance exist during ART, may be associated to differential control of HIV infection and their understanding could explain clinical differences in individual patients that are not reflected by CD4(+) cell counts alone.

Congenital pyelectasis in children born from mothers on tenofovir containing therapy during pregnancy: report of two cases.

Given the success of highly active antiretroviral therapy in slowing HIV disease progression, an increasing proportion of HIV-infected women are choosing to become pregnant. Antiretroviral treatment decisions in these women must consider not only the immunological and virological efficacy of different drugs, but also their possible effects on the unborn baby. The FDA classifies antiretroviral drugs in five categories (A, B, C, D, and X) according to their possible teratogenic effect on humans or animal models [1]. The drugs with the most available safety data, due to their extensive use in Western and developed countries, are zidovudine, lamivudine, nevirapine, nelfinavir and saquinavir [2, 3]. At present, data concerning the teratogenicity of more recent drugs are lacking. Tenofovir disoproxil fumarate, a nucleotide reverse transcriptase inhibitor, is widely used in patients pre-exposed to other nucleoside analogues because of its efficacy and tolerability [4, 5]. The use of this drug during pregnancy is currently classified in FDA category B [6]. The routine use of prenatal ultrasonography has improved early identification of birth defects. Fetal urinary tract abnormalities are among the most commonly diagnosed prenatal malformations, with a reported prevalence as high as 1 per 100 pregnancies [7, 8]. Pyelectasis is defined as a renal pelvic dilatation, and is one of the most commonly founded urologic anomalies. The aim of this present communication is to describe a possible association between in utero tenofovir exposure and this renal congenital malformation. The Clinic of Infectious and Tropical Diseases of Modena, Italy, follows 1,200 patients with HIV infection. During pregnancy, all patients are followed by the same clinician and undergo a monthly blood test, which includes a baseline genotypic resistance test in patients with a detectable HIV plasma viral load using a polymerase chain reaction (Real Time HIV-1, Abbott Molecular). Patients undergo at least three ultrasonographic scans of the abdomen performed in order to confirm pregnancy and for dating in the first trimester, to look for congenital malformations at about 20 weeks of gestation, and at around 32 weeks or later to assess fetal growth. Ultrasonographic scans were performed by the same operator. In the period between January 2004 and June 2006, 33 HIVpositive pregnancies were followed in our clinic. None of the babies acquired HIV infection from their mothers; 7 of 33 women received tenofovir (21%) as a continuation of their previous antiretroviral regimen. Fetal pyelectasis was diagnosed by ultrasonography in two of seven patients receiving tenofovir as compared to 0 of 26 not receiving tenofovir.

Viro-immunological response of drug-naive HIV-1-infected patients starting a first-line regimen with viraemia >500,000 copies/ml in clinical practice

BACKGROUND Virological success (VS) and immunological reconstitution (IR) of antiretroviral-naive HIV-1-infected patients with pre-therapy viral load (VL) >500,000 copies/ml was assessed after 12 months of treatment according to initial drug-class regimens. METHODS An observational multicentre retrospective study was performed. VS was defined as the first VL <50 copies/ml from treatment start. IR was defined as an increase of at least 150 CD4+ T-lymphocytes from treatment start. Survival analysis was used to estimate the probability and predictors of VS and IR by 12 months of therapy. RESULTS 428 HIV-1-infected patients were analysed. Patients were grouped according to the different first-line drug-classes used: a non-nucleoside reverse transcriptase inhibitor (NNRTI) plus two nucleoside reverse transcriptase inhibitors (NRTIs; NNRTI-group; n=105 [24.5%]); a protease inhibitor (PI) plus two NRTIs (PI-group; n=260 [60.8%]); a four-drug regimen containing a PI-regimen plus an integrase inhibitor (PI+INI-group; n=63 [14.7%]). Patients in the PI-group showed the lowest probability of VS (PI-group: 72.4%; NNRTI-group: 75.5%; PI+INI-group: 81.0%; P<0.0001). By Cox regression, patients in PI+INI and NNRTI-groups showed a higher adjusted hazard ratio (95% CI) of VS compared to those in the PI-group (PI+INI-group: 1.48 [1.08, 2.03]; P=0.014; NNRTI-group: 1.37 [1.06-1.78]; P=0.015). The probability of IR was 76.2%, and was similar among groups. Patients with AIDS showed a lower adjusted hazard ratio (95% CI) of IR compared to non-AIDS presenters (0.70 [0.54, 0.90]; P=0.005). CONCLUSIONS In this multicentre retrospective study, patients with viraemia >500,000 copies/ml who start a first-line regimen containing PI+INI or NNRTI yield a better VS compared to those receiving a PI-based regimen.

Four-drugs regimen containing raltegravir is highly effective in HIV patients starting therapy with >500,000 copies/mL viral load.

Assessing virological response of four‐drugs antiretroviral regimen that include raltegravir (RAL) in naïve patients with high viral load (>500,000 copies/mL) selected from a multicentre Italian database.