Lower blood levels of isavuconazole in critically ill patients compared with other populations: possible need for therapeutic drug monitoring.

BACKGROUND: Isavuconazole is first-line treatment of invasive aspergillosis. Therapeutic drug monitoring (TDM) is deemed not necessary, since most patients reached therapeutic levels (>1 mg/L) in large studies. Low levels were reported in some critically ill patients admitted to the ICU. The aim was to compare isavuconazole levels between critically ill and non-critically ill patients. MATERIALS AND METHODS: Retrospective analysis of data from all patients treated with standard-dose isavuconazole between 1 January 2019 and 26 October 2022 was performed. The following data were collected: TDM results from the first 30 days of therapy; ward of admission; demographic and clinical characteristics; continuous renal replacement therapy; extracorporeal membrane oxygenation; and co-administered drugs. RESULTS: Seventy-two patients (median age 65 years) and 188 TDM measurements (mean number of samples per patient 2.6 ±â€Š1.7) were included; 33 (45.8%) were ICU patients (3 also had haematological disorders); 39 (54.2%) were non-ICU patients, of whom 31 had haematological disorders. In all patients, the mean isavuconazole blood level was 3.33 ±â€Š2.26 mg/L. Significantly lower levels were observed in the ICU versus the non-ICU population: mean 2.02 ±â€Š1.22 versus 4.15 ±â€Š2.31 mg/L (P < 0.001). Significantly higher rates of subtherapeutic levels were observed in ICU patients compared with the non-ICU population: all determinations <2 mg/L in 33.3% versus 7.7%, and all determinations <1 mg/L in 12.1% versus 0%, respectively. Predictors of lower isavuconazole levels were admission to the ICU, BMI > 25 kg/m2, bilirubin > 1.2 mg/dL and the absence of haematological disorder. CONCLUSIONS: ICU patients had significantly lower isavuconazole blood levels compared to non-ICU population. The TDM of isavuconazole for efficacy should be performed in ICU.

Triple Combination Therapy With 2 Antivirals and Monoclonal Antibodies for Persistent or Relapsed Severe Acute Respiratory Syndrome Coronavirus 2 Infection in Immunocompromised Patients.

BACKGROUND: Severely immunocompromised patients are at risk for prolonged or relapsed Coronavirus Disease 2019 (COVID-19), leading to increased morbidity and mortality. We aimed to evaluate efficacy and safety of combination treatment in immunocompromised COVID-19 patients. METHODS: We included all immunocompromised patients with prolonged/relapsed COVID-19 treated with combination therapy with 2 antivirals (remdesivir plus nirmatrelvir/ritonavir, or molnupiravir in case of renal failure) plus, if available, anti-spike monoclonal antibodies (mAbs), between February and October 2022. The main outcomes were virological response at day 14 (negative Severe Acute Respiratory Syndrome Coronavirus 2 [SARS-CoV-2] swab) and virological and clinical response (alive, asymptomatic, with negative SARS-CoV-2 swab) at day 30 and the last follow-up. RESULTS: Overall, 22 patients (Omicron variant in 17/18) were included: 18 received full combination of 2 antivirals and mAbs and 4 received 2 antivirals only; in 20 of 22 (91%) patients, 2 antivirals were nirmatrelvir/ritonavir plus remdesivir. Nineteen (86%) patients had hematological malignancy, and 15 (68%) had received anti-CD20 therapy. All were symptomatic; 8 (36%) required oxygen. Four patients received a second course of combination treatment. The response rate at day 14, day 30, and last follow-up was 75% (15/20 evaluable), 73% (16/22), and 82% (18/22), respectively. Day 14 and 30 response rates were significantly higher when combination therapy included mAbs. Higher number of vaccine doses was associated with better final outcome. Two patients (9%) developed severe side effects (bradycardia leading to remdesivir discontinuation and myocardial infarction). CONCLUSIONS: Combination therapy including 2 antivirals (mainly remdesivir and nirmatrelvir/ritonavir) and mAbs was associated with high rate of virological and clinical response in immunocompromised patients with prolonged/relapsed COVID-19.

Outcome of early treatment of SARS-CoV-2 infection in patients with haematological disorders.

Outcome of early treatment of COVID-19 with antivirals or anti-spike monoclonal antibodies (MABs) in patients with haematological malignancies (HM) is unknown. A retrospective study of HM patients treated for mild/moderate COVID-19 between March 2021 and July 2022 was performed. The main composite end-point was treatment failure (severe COVID-19 or COVID-19-related death). We included 328 consecutive patients who received MABs (n = 120, 37%; sotrovimab, n = 73) or antivirals (n = 208, 63%; nirmatrelvir/ritonavir, n = 116) over a median of two days after symptoms started; 111 (33.8%) had non-Hodgkin lymphoma (NHL); 89 (27%) were transplant/CAR-T (chimaeric antigen receptor T-cell therapy) recipients. Most infections (n = 309, 94%) occurred during the Omicron period. Failure developed in 31 patients (9.5%). Its independent predictors were older age, fewer vaccine doses, and treatment with MABs. Rate of failure was lower in the Omicron versus the pre-Omicron period (7.8% versus 36.8%, p < 0.001). During the Omicron period, predictors of failure were age, fewer vaccine doses and diagnosis of acute myeloid leukaemia/myelodysplastic syndrome (AML/MDS). Independent predictors of longer viral shedding were age, comorbidities, hospital admission at diagnosis, NHL/CLL, treatment with MABs. COVID-19-associated mortality was 3.4% (n = 11). The mortality in those who developed severe COVID-19 after early treatment was 26% in the Omicron period. Patients with HM had a significant risk of failure of early treatment, even during the Omicron period, with high mortality rate.

Extensive activation, tissue trafficking, turnover and functional impairment of NK cells in COVID-19 patients at disease onset associates with subsequent disease severity.

The SARS-CoV-2 infection causes severe respiratory involvement (COVID-19) in 5-20% of patients through initial immune derangement, followed by intense cytokine production and vascular leakage. Evidence of immune involvement point to the participation of T, B, and NK cells in the lack of control of virus replication leading to COVID-19. NK cells contribute to early phases of virus control and to the regulation of adaptive responses. The precise mechanism of NK cell dysregulation is poorly understood, with little information on tissue margination or turnover. We investigated these aspects by multiparameter flow cytometry in a cohort of 28 patients hospitalized with early COVID-19. Relevant decreases in CD56brightCD16+/- NK subsets were detected, with a shift of circulating NK cells toward more mature CD56dimCD16+KIR+NKG2A+ and "memory" KIR+CD57+CD85j+ cells with increased inhibitory NKG2A and KIR molecules. Impaired cytotoxicity and IFN-γ production were associated with conserved expression of natural cytotoxicity receptors and perforin. Moreover, intense NK cell activation with increased HLA-DR and CD69 expression was associated with the circulation of CD69+CD103+ CXCR6+ tissue-resident NK cells and of CD34+DNAM-1brightCXCR4+ inflammatory precursors to mature functional NK cells. Severe disease trajectories were directly associated with the proportion of CD34+DNAM-1brightCXCR4+ precursors and inversely associated with the proportion of NKG2D+ and of CD103+ NK cells. Intense NK cell activation and trafficking to and from tissues occurs early in COVID-19, and is associated with subsequent disease progression, providing an insight into the mechanism of clinical deterioration. Strategies to positively manipulate tissue-resident NK cell responses may provide advantages to future therapeutic and vaccine approaches.

Aspergillus-PCR in bronchoalveolar lavage - diagnostic accuracy for invasive pulmonary aspergillosis in critically ill patients.

BACKGROUND: The diagnosis of invasive pulmonary aspergillosis (IPA) in intensive care unit (ICU) patients is challenging, and the role of Aspergillus-PCR in bronchoalveolar lavage (BAL) is unknown. OBJECTIVES: This study evaluated diagnostic accuracy of Aspergillus-PCR in BAL in IPA in three different cohorts: ICU-admitted patients with COVID-19, ICU-admitted patients without COVID-19 and immunocompromised patients. METHODS: All stored available BAL samples collected from three patient groups were tested with Aspergillus-PCR (AsperGenius® ). IPA was diagnosed according to appropriate criteria for each patient group. RESULTS: We included 111 BAL samples from 101 patients: 52 (51%) patients admitted to ICU for COVID-19, 24 (24%) admitted to ICU for other reasons and 25 (25%) immunocompromised. There were 31 cases of IPA (28%). Aspergillus-PCR sensitivity was 64% (95% CI 47-79) and specificity 99% (95% CI 93-100). Aspergillus-PCR sensitivity was 40% (95%CI 19-64) in ICU COVID-19, 67% (95% CI 21-93) in non-COVID-19 ICU patients and 92% (95%CI 67-98) in the immunocompromised. The concordance between positive BAL-GM and BAL-PCR in patients with and without IPA was significantly lower in ICU patients (32%; 43% in COVID-19, 18% in non-COVID-19) than in the immunocompromised (92%), p < .001. CONCLUSIONS: Aspergillus-PCR in BAL improves the diagnostic accuracy of BAL-GM in ICU patients.

Prevalence of Viral Hepatitis in Unselected, Consecutively Enrolled Patients Hospitalised for SARS-CoV-2.

Diagnosing people living with chronic viral hepatitis is challenging due to the absence of symptoms as long as liver decompensated cirrhosis come out. The aim of this retrospective study was to evaluate the prevalence of HBV and/or HCV infections in a non-selected population, hospitalised for SARS-CoV-2 infection in a tertiary care hospital in Northern Italy. During the study period 1,429 patients were admitted to hospital for SARS-CoV-2 infection, serologic tests for HBV and/or HCV were available for 382 (27%) patients and 3 were excluded due to their previous known serologic status. Among 379 patients, 235 (62%) were male, median age was 70 years (range 21-103), 360 (95%) were Caucasian. Among them, 372/379 (98%) were screened for HBsAg, 320/379 (84%) for HBcAb. HBsAg was positive in 2/372 (0.5%, 95% CI 0.0006-0.02) patients (only in one HBV-DNA was performed that was negative), while HBcAb was found positive in 55/320 (17%, 95% CI 0.13-0.22). Among 370/379 (98%) patients screened for HCV, 11/370 (3%, 95% CI 0.02-0.05) had positive HCV-Ab. Five out of 11 (45%) were tested for HCV-RNA that resulted positive in two patients (0.5%, 95% CI 0.0006-0.02). Considering this data, even though the screening was performed in only 27% of study population, a tailored screening in people with known risk factors for hepatitis might be preferable to universal screening in low prevalence areas. Also a prompt diagnostic workout should begin in case of clinical or laboratory suspicion of hepatitis and in those starting immunosuppressive treatments.

HCMV-controlling NKG2C+ NK cells originate from novel circulating inflammatory precursors.

BACKGROUND: There is limited knowledge on the origin and development from CD34+ precursors of the ample spectrum of human natural killer (NK) cells, particularly of specialized NK subsets. OBJECTIVE: This study sought to characterize the NK-cell progeny of CD34+DNAM-1brightCXCR4+ and of other precursors circulating in the peripheral blood of patients with chronic viral infections (eg, HIV, hepatitis C virus, cytomegalovirus reactivation). METHODS: Highly purified precursors were obtained by flow cytometric sorting and cultured in standard NK-cell differentiation media (ie, SCF, FLT3, IL-7, IL-15). Phenotypic and functional analyses on progenies were performed by multiparametric cytofluorimetric assays. Transcriptional signatures of NK-cell progenies were studied by microarray analysis. Inhibition of cytomegalovirus replication was studied by PCR. RESULTS: Unlike conventional CD34+ precursors, Lin-CD34+DNAM-1brightCXCR4+ precursors from patients with chronic infection, rapidly differentiate into cytotoxic, IFN-γ-secreting CD94/NKG2C+KIR+CD57+ NK-cell progenies. An additional novel subset of common lymphocyte precursors was identified among Lin-CD34-CD56-CD16+ cells and characterized by expression of CXCR4 and lack of perforin and CD94. Lin-CD34-CD56-CD16+Perf-CD94-CXCR4+ precursors are also endowed with generation potential toward memory-like NKG2C+NK cells. Maturing NK-cell progenies mediated strong human cytomegalovirus-inhibiting activity. Microarray analysis confirmed a transcriptional signature compatible with NK-cell progenies and with maturing adaptive NK cells. CONCLUSIONS: During viral infections, precursors of adaptive NK cells are released and circulate in the peripheral blood.

Early and Polyantigenic CD4 T Cell Responses Correlate with Mild Disease in Acute COVID-19 Donors.

We assessed SARS-CoV-2-specific CD4+ and CD8+ T cell responses in samples from 89 acute COVID-19 patients, utilizing blood samples collected during the first wave of COVID-19 in Italy. The goal of the study was to examine correlations between SARS-CoV-2-specific T cell responses in the early phase comparing mild, moderate, or severe COVID-19 disease outcomes. T cell responses to the spike (S) and non-S proteins were measured in a combined activation-induced marker (AIM) and intracellular cytokine staining (ICS) assay. Early CD4+ T cell responses to SARS-CoV-2 S correlated with milder disease by both AIM and IFNγ ICS readouts. The correlation of S-specific CD4+ T cell responses with milder disease severity was most striking within the first two weeks of symptom onset compared to later time points. Furthermore, donors with milder disease were associated with polyantigenic CD4+ T cell responses that recognized more prominently non-S proteins in addition to S, while severe acute COVID-19 was characterized by lower magnitudes of CD4+ T cell responses and a narrower repertoire. In conclusion, this study highlights that both the magnitude and breadth of early SARS-CoV-2-specific CD4+ T cell responses correlated with milder disease outcomes in acute COVID-19 patients.

Characterization of T lymphocytes in severe COVID-19 patients.

In this observational study, 13 patients with severe COVID-19 and 10 healthy controls were enrolled. The data concerning the analysis of circulating T cells show that, in severe COVID-19 patients, the expansion of these cell compartments is prone to induce antibody response, inflammation (CCR4+ and CCR6+ TFH) and regulation (CD8+ Treg). This pathogenic mechanism could lead us to envision a possible new form of biological target therapy.

Bronchoalveolar lavage fluid characteristics and outcomes of invasively mechanically ventilated patients with COVID-19 pneumonia in Genoa, Italy.

BACKGROUND: The primary objective of the study is to describe the cellular characteristics of bronchoalveolar lavage fluid (BALF) of COVID-19 patients requiring invasive mechanical ventilation; the secondary outcome is to describe BALF findings between survivors vs non-survivors. MATERIALS AND METHODS: Patients positive for SARS-CoV-2 RT PCR, admitted to ICU between March and April 2020 were enrolled. At ICU admission, BALF were analyzed by flow cytometry. Univariate, multivariate and Spearman correlation analyses were performed. RESULTS: Sixty-four patients were enrolled, median age of 64 years (IQR 58-69). The majority cells in the BALF were neutrophils (70%, IQR 37.5-90.5) and macrophages (27%, IQR 7-49) while a minority were lymphocytes, 1%, TCD3+ 92% (IQR 82-95). The ICU mortality was 32.8%. Non-survivors had a significantly older age (p = 0.033) and peripheral lymphocytes (p = 0.012) were lower compared to the survivors. At multivariate analysis the percentage of macrophages in the BALF correlated with poor outcome (OR 1.336, CI95% 1.014-1.759, p = 0.039). CONCLUSIONS: In critically ill patients, BALF cellularity is mainly composed of neutrophils and macrophages. The macrophages percentage in the BALF at ICU admittance correlated with higher ICU mortality. The lack of lymphocytes in BALF could partly explain a reduced anti-viral response.

A comparative analysis of the first and second COVID-19 wave in Italy: evaluation of mortality in the Infectious Disease Unit of Genoa University Hospital.

This retrospective study describes demographics and outcomes of adult patients with SARS-CoV-2 infection admitted to our ward during the first wave (from February 25 to May 30, 2020) and during the second wave (from August 5 to November 30, 2020). The primary study objective was to evaluate overall in-hospital mortality, which was 21.1% (60/285) vs 10.3% (27/261) (p=.0006). This study seems to corroborate and expand the concept that the second wave of COVID-19 was less deadly than the first. Despite some limitations, the clinical and managerial experience gained during the first wave trained us to handle and control the second one.

Bloodstream infections in critically ill patients with COVID-19.

BACKGROUND: Little is known about the incidence and risk of intensive care unit (ICU)-acquired bloodstream infections (BSI) in critically ill patients with coronavirus disease 2019 (COVID-19). MATERIALS AND METHODS: This retrospective, single-centre study was conducted in Northern Italy. The primary study objectives were as follows: (a) to assess the incidence rate of ICU-acquired BSI and (b) to assess the cumulative risk of developing ICU-acquired BSI. RESULTS: Overall, 78 critically ill patients with COVID-19 were included in the study. Forty-five episodes of ICU-acquired BSI were registered in 31 patients, with an incidence rate of 47 episodes (95% confidence interval [CI] 35-63) per 1000 patient-days at risk. The estimated cumulative risk of developing at least one BSI episode was of almost 25% after 15 days at risk and possibly surpassing 50% after 30 days at risk. In multivariable analysis, anti-inflammatory treatment was independently associated with the development of BSI (cause-specific hazard ratio [csHR] 1.07 with 95% CI 0.38-3.04 for tocilizumab, csHR 3.95 with 95% CI 1.20-13.03 for methylprednisolone and csHR 10.69 with 95% CI 2.71-42.17 for methylprednisolone plus tocilizumab, with no anti-inflammatory treatment as the reference group; overall P for the dummy variable = 0.003). CONCLUSIONS: The incidence rate of BSI was high, and the cumulative risk of developing BSI increased with ICU stay. Further study will clarify if the increased risk of BSI we detected in COVID-19 patients treated with anti-inflammatory drugs is outweighed by the benefits of reducing any possible pro-inflammatory dysregulation induced by SARS-CoV-2.

A very rare case of mycobacterium gordonae infection of the breast.

Mastitis is a common disease in women with both infectious and noninfectious causes. Most cases occur during lactation and are caused by Staphylococcus aureus and Streptococcus species; parasites and Mycobacteria have rarely been reported to cause breast infections (Mandell, Douglas, and Bennett's principles and practice of infectious diseases (9th edn);2019, Am J Respir Crit Care Med. 2007;175:367). Nontuberculous mycobacteria (NTM) which are also referred to as atypical mycobacteria, mycobacteria other than tuberculosis (MOTT), or environmental mycobacteria are a large group of Mycobacteria which are becoming increasingly common cause of infection all over the world (Arch Dermatol. 2006;142:1287). NTM can cause infection diseases especially in immunocompromised patients, such as HIV-positive hosts, most commonly in the lungs, skin and soft tissue, lymph nodes or rarely spread with multiorgan dissemination (Arch Plast Surg. 2014;41:759). Mycobacterium gordonae (M. gordonae) is a slow-growing atypical mycobacterium that is considered the least pathogenic NTM. The organism is ubiquitous, and mostly isolated from soil and water. Despite its nonvirulent nature, clinically significant infections have been reported also in some immunocompetent patients (J Formosan Med Assoc. 2020, Clin Infect Dis. 1992;1229). We report the first documented case of breast infection in a young immunocompetent woman sustained by Mycobacterium Gordonae.

Positioning of darunavir/cobicistat-containing antiretroviral regimens in real life: results from a large multicentre observational prospective cohort (SCOLTA).

BACKGROUND: Study aim was to evaluate the safety and durability of darunavir/cobicistat (DRV/c) in a real life setting. METHODS: Multicentre prospective cohort study performed in the context of SCOLTA (Surveillance Cohort Long-Term Toxicity Antiretrovirals). Patients were evaluated at baseline, week 24 and 48. Changes were evaluated using the paired t test or signed rank test. The multivariable analysis was performed using a general linear model, after ranking of not normally distributed variables. RESULTS: A total of 249 patients were included, 72 (29%) were in DRV/c-based dual therapies (DT). Hypercholesterolemia, HC, (total cholesterol (TC) ≥ 200 mg/dL or low density-C (LDL-C) ≥ 130 or statin use) was present in 121 (48.6%) and hypertriglyceridemia, (triglycerides (TG) ≥ 200 mg/dl or fibrate use) in 41 (16.5%) patients. Blood lipid profile did not change significantly in either the global population or patients with HC. After a median observation of 17 months (IQR 13-20), 59 (25.3%) patients discontinued DRV/c, of which 13 were in DT. The durability DT resulted higher than that of triple therapy (log-rank test p = 0.01). Main reasons for stopping DRV/c were simplification (15 patients), adverse events (13 patients), planned discontinuation for treatment initiation with DAA (4 patients), treatment failure (2 patients); death (2 patients), other causes (10 patients). Twenty-six were lost to follow-up. CONCLUSIONS: DRV/c was safe and well tolerated. Dual therapies showed a better profile of tolerability and a longer durability compared to triple therapies.

CD8+CD28-CD127loCD39+ regulatory T-cell expansion: A new possible pathogenic mechanism for HIV infection?

BACKGROUND: HIV-associated immunodeficiency is related to loss of CD4+ T cells. This mechanism does not explain certain manifestations of HIV disease, such as immunodeficiency events in patients with greater than 500 CD4+ T cells/µL. CD8+CD28-CD127loCD39+ T cells are regulatory T (Treg) lymphocytes that are highly concentrated within the tumor microenvironment and never analyzed in the circulation of HIV-infected patients. OBJECTIVES: We sought to analyze the frequency of CD8+CD28-CD127loCD39+ Treg cells in the circulation of HIV-infected patients. METHODS: The frequency of circulating CD8+CD28-CD127loCD39+ Treg cells was analyzed and correlated with viral load and CD4+ T-cell counts/percentages in 93 HIV-1-infected patients subdivided as follows: naive (n = 63), elite controllers (n = 19), long-term nonprogressors (n = 7), and HIV-infected patients affected by tumor (n = 4). The same analyses were performed in HIV-negative patients with cancer (n = 53), hepatitis C virus-infected patients (n = 17), and healthy donors (n = 173). RESULTS: HIV-infected patients had increased circulating levels of functional CD8+CD28-CD127loCD39+ Treg cells. These cells showed antigen specificity against HIV proteins. Their frequency after antiretroviral therapy (ART) correlated with HIV viremia, CD4+ T-cell counts, and immune activation markers, suggesting their pathogenic involvement in AIDS- or non-AIDS-related complications. Their increase after initiation of ART heralded a lack of virologic or clinical response, and hence their monitoring is clinically relevant. CONCLUSION: HIV infection induces remarkable expansion of CD8+CD28-CD127loCD39+ Treg cells, the frequency of which correlates with both clinical disease and signs of chronic immune cell activation. Monitoring their frequency in the circulation is a new marker of response to ART when effects on viremia and clinical response are not met.

Control of the HIV-1 DNA Reservoir Is Associated In Vivo and In Vitro with NKp46/NKp30 (CD335 CD337) Inducibility and Interferon Gamma Production by Transcriptionally Unique NK Cells.

The size of lentiviral DNA reservoirs reflects the effectiveness of immune responses against lentiviruses. So far, abundant information has been gathered on the control of HIV-1 replication. Understanding the innate mechanisms contributing to containment of the HIV DNA reservoir, however, are only partly clarified and are relevant to guiding interventions for reservoir containment or eradication. We studied the contribution of natural killer (NK) cell functional features in HIV patients controlling replication either spontaneously (HIV controllers [HIC]) or after progression and antiretroviral treatment (progressor patients [PP]). An inverse correlation between HIV DNA copy numbers (either total or integrated) in circulating CD4+ cells and NK cell function was observed. Induced interferon gamma (IFN-γ) production and NKp46/NKp30 activating receptor-induced expression correlated inversely with reservoir size. The correlation was present not only for a homogeneous cohort of HIC patients but also when PP were included in the analysis. Adaptive (NKG2C+ CD57+) NK cell features were not associated with reservoir size. However, a distinct set of 370 differentially expressed transcripts was found to underlie functional differences in NK cells controlling HIV DNA reservoir size. In proof-of-principle in vitro experiments of CD4+ cell infection with HIV-1, purified NK cells with the above-mentioned functional/transcriptional features displayed 10- and 30-fold higher abilities to control HIV replication and DNA burdens in vitro, respectively, than those of other NK cells. Thus, NK cells with a specific functional and transcriptional signature contribute to control of the HIV reservoir in CD4+ cells. Their selection, expansion, and/or adoptive transfer may support strategies to eradicate HIV-1 infection or to safely deescalate antiretroviral treatment.IMPORTANCE The most relevant feature of HIV-1 infection is represented by its DNA reservoir size in the body, which guarantees lifelong infection and resumption of virus replication after antiretroviral treatment interruption. So far, there has been little success in the identification of factors contributing to HIV-1 reservoir containment. In this study, by studying quantitative total and integrated HIV-1 DNA levels and NK cells in HIV-1 patients with either progressive or nonprogressive disease, we observed that inducible IFN-γ and natural cytotoxicity receptor (NCR) expression in a specific subset of NK cells with a characteristic transcriptional signature represents a correlate for HIV-1 reservoir control. This represents an advance in our understanding of the mechanism(s) that controls the lentivirus reservoir. Monitoring, selection, expansion, and adoptive transfer of these NK cells may allow monitoring of treatment efficacy and the likelihood of reservoir control and may support protocols for HIV-1 eradication.

Natural killer cells in HIV controller patients express an activated effector phenotype and do not up-regulate NKp44 on IL-2 stimulation.

Control of HIV replication in elite controller (EC) and long-term nonprogressor (LTNP) patients has been associated with efficient CD8(+)cytotoxic T-lymphocyte function. However, innate immunity may play a role in HIV control. We studied the expression of natural cytotoxicity receptors (NKp46, NKp30, and NKp44) and their induction over a short time frame (2-4 d) on activation of natural killer (NK) cells in 31 HIV controller patients (15 ECs, 16 LTNPs). In EC/LTNP, induction of NKp46 expression was normal but short (2 d), and NKp30 was induced to lower levels vs. healthy donors. Notably, in antiretroviral-treated aviremic progressor patients (TAPPs), no induction of NKp46 or NKp30 expression occurred. More importantly, EC/LTNP failed to induce expression of NKp44, a receptor efficiently induced in activated NK cells in TAPPs. The specific lack of NKp44 expression resulted in sharply decreased capability of killing target cells by NKp44, whereas TAPPs had conserved NKp44-mediated lysis. Importantly, conserved NK cell responses, accompanied by a selective defect in the NKp44-activating pathway, may result in lack of killing of uninfected CD4(+)NKp44Ligand(+) cells when induced by HIVgp41 peptide-S3, representing a relevant mechanism of CD4(+) depletion. In addition, peripheral NK cells from EC/LTNP had increased NKG2D expression, significant HLA-DR up-regulation, and a mature (NKG2A-CD57(+)killer cell Ig-like receptor(+)CD85j(+)) phenotype, with cytolytic function also against immature dendritic cells. Thus, NK cells in EC/LTNP can maintain substantially unchanged functional capabilities, whereas the lack of NKp44 induction may be related to CD4 maintenance, representing a hallmark of these patients.