The cost-effectiveness of human papillomavirus self-collection among cervical cancer screening non-attenders in El Salvador.

Cervical cancer screening with human papillomavirus (HPV) DNA testing has been incorporated into El Salvador's national guidelines. The feasibility of home-based HPV self-collection among women who do not attend screening at the clinic (i.e., non-attenders) has been demonstrated, but cost-effectiveness has not been evaluated. Using cost and compliance data from El Salvador, we informed a mathematical microsimulation model of HPV infection and cervical carcinogenesis to conduct a cost-effectiveness analysis from the societal perspective. We estimated the reduction in cervical cancer risk, lifetime cost per woman (2017 US$), life expectancy, and incremental cost-effectiveness ratio (ICER, 2017 US$ per year of life saved [YLS]) of a program with home-based self-collection of HPV (facilitated by health promoters) for the 18% of women reluctant to screen at the clinic. The model was calibrated to epidemiologic data from El Salvador. We evaluated health and economic outcomes of the self-collection intervention for women aged 30 to 59 years, alone and in concert with clinic-based HPV provider-collection. Home-based self-collection of HPV was projected to reduce population cervical cancer risk by 14% and cost $1210 per YLS compared to no screening. An integrated program reaching 99% coverage with both provider- and home-based self-collection of HPV reduced cancer risk by 74% (compared to no screening), and cost $1210 per YLS compared to provider-collection alone. Self-collection facilitated by health promoters is a cost-effective strategy for increasing screening uptake in El Salvador.

Evaluation of two alternative ablation treatments for cervical pre-cancer against standard gas-based cryotherapy: a randomized non-inferiority study.

INTRODUCTION: Gas-based cryotherapy is the conventional ablative treatment for cervical pre-cancer in low-income settings, but the use of gas poses significant challenges. We compared the depth of necrosis induced by gas-based cryotherapy with two gas-free alternatives: cryotherapy using CryoPen,and thermoablation. METHODS: We conducted a five-arm randomized non-inferiority trial: double-freeze carbon dioxide (CO2) cryotherapy (referent), single-freeze CO2 cryotherapy, double-freeze CryoPen, single-freeze CryoPen, and thermoablation. Subjects were 130 women scheduled for hysterectomy for indications other than cervical pathology, and thus with healthy cervical tissue available for histological evaluation of depth of necrosis post-surgery. The null hypothesis was rejected (ie, conclude non-inferiority) if the upper bound of the 90% confidence interval (90% CI) for the difference in mean depth of necrosis (referent minus each experimental method) was <1.14 mm. Patient pain during treatment was reported on a scale of 0 (no pain) to 10 (worst pain). RESULTS: A total of 133 patients were enrolled in the study. The slides from three women were deemed unreadable. One patient was excluded because her hysterectomy was postponed for reasons unrelated to the study, and two patients were excluded because treatment application did not follow the established protocol. For the remaining 127 women, mean depth of necrosis for double-freeze CO2 (referent) was 6.0±1.6 mm. Differences between this and other methods were: single-freeze CO2 = 0.4 mm (90% CI -0.4 to 1.2 mm), double-freeze CryoPen= 0.7 mm (90% CI 0.04 to 1.4 mm), single-freeze CryoPen= 0.5 mm (90% CI -0.2 to 1.2 mm), and thermoablation = 2.6 mm (90% CI 2.0 to 3.1 mm). Mean pain levels were 2.2±1.0 (double-freeze CO2 cryotherapy), 1.8±0.8 (single-freeze CO2 cryotherapy), 2.5±1.4 (double-freeze CryoPen), 2.6±1.4 (single-freeze CryoPen), and 4.1±2.3 (thermoablation). DISCUSSION: Compared with the referent, non-inferiority could not be concluded for other methods. Mean pain scores were low for all treatments. Depth of necrosis is a surrogate for treatment efficacy, but a randomized clinical trial is necessary to establish true cure rates.

Modulation of Decidual Macrophage Polarization by Macrophage Colony-Stimulating Factor Derived from First-Trimester Decidual Cells: Implication in Preeclampsia.

During human pregnancy, immune tolerance of the fetal semiallograft occurs in the presence of abundant maternal leukocytes. At the implantation site, macrophages comprise approximately 20% of the leukocyte population and act as primary mediators of tissue remodeling. Decidual macrophages display a balance between anti-inflammatory and proinflammatory phenotypes. However, a shift to an M1 subtype is reported in preeclampsia. Granulocyte-macrophage colony-stimulating-factor (GM-CSF) and macrophage colony-stimulating factor (M-CSF) are major differentiating factors that mediate M1 and M2 polarization, respectively. Previously, we observed the following: i) the preeclamptic decidua contains an excess of both macrophages and GM-CSF, ii) the preeclampsia-associated proinflammatory cytokines, IL-1ß and tumor necrosis factor-α, markedly enhance GM-CSF and M-CSF expression in cultured leukocyte-free first-trimester decidual cells (FTDCs), iii) FTDC-secreted GM-CSF polarizes macrophages toward an M1 subtype. The microenvironment is a key determinant of macrophage phenotype. Thus, we examined proinflammatory stimulation of FTDC-secreted M-CSF and its role in macrophage development. Immunofluorescence staining demonstrated elevated M-CSF-positive decidual cell numbers in preeclamptic decidua. In FTDCs, IL-1ß and tumor necrosis factor-α signal through the NF-κB pathway to induce M-CSF production, which does the following: i) enhances differentiation of and elevates CD163 expression in macrophages, ii) increases macrophage phagocytic capacity, and iii) inhibits signal-regulatory protein α expression by macrophages. These findings suggest that FTDC-secreted M-CSF modulates the decidual immune balance by inducing M2 macrophage polarization and phagocytic capacity in response to proinflammatory stimuli.

Placenta praevia and the risk of adverse outcomes during second trimester abortion: A retrospective cohort study.

BACKGROUND: There are few reports in the literature of the risks associated with second trimester abortion in women with placenta praevia (PP). We hypothesise that PP increases the risk of complications. AIMS: We sought to determine if PP is associated with a higher risk of blood loss and blood transfusion at the time of dilation and evacuation (D&E). MATERIALS AND METHODS: The records of 612 consecutive women undergoing abortion at 15-24 weeks of gestation were reviewed. Participant characteristics, need for blood transfusion, estimated blood loss (EBL) during the abortion and other complications were compared between women with and without ultrasound-documented PP. RESULTS: Eighty-seven of 612 (14.2%, 95% CI 11.5-17.2%) women had ultrasound-documented PP. The rate of blood transfusion was 3.4 and 1.3% in the group with PP and without PP, respectively (adjusted relative risk (RR = 2.8, 95% CI 0.7-11.3). An estimated blood loss of 500 cc or greater during the D&E procedure was observed in 12.6% of women in the PP group compared with 4.2% of women in the group without PP (adjusted RR 3.1, 95% CI 1.4-6.8, P = 0.004). CONCLUSIONS: Second-trimester abortion in women with PP is associated with a higher risk of blood loss of 500 cc or greater. Our study represents a larger sample size of patients with PP undergoing second-trimester abortion than previously reported in the literature. Women with PP may have a higher estimated blood loss and may require access to blood transfusion.

Interferon-γ protects first-trimester decidual cells against aberrant matrix metalloproteinases 1, 3, and 9 expression in preeclampsia.

Human extravillous trophoblast (EVT) invades the decidua via integrin receptors and subsequently degrades extracellular matrix proteins. In preeclampsia (PE), shallow EVT invasion elicits incomplete spiral artery remodeling, causing reduced uteroplacental blood flow. Previous studies show that preeclamptic decidual cells, but not interstitial EVTs, display higher levels of extracellular matrix-degrading matrix metalloproteinase (MMP)-9, but not MMP-2. Herein, we extend our previous PE-related assessment of MMP-2 and MMP-9 to include MMP-1, which preferentially degrades fibrillar collagens, and MMP-3, which can initiate a local proteolytic cascade. In human first-trimester decidual cells incubated with estradiol, tumor necrosis factor-α (TNF-α) significantly enhanced MMP-1, MMP-3, and MMP-9 mRNA and protein levels and activity measured by real-time quantitative RT-PCR, ELISA, immunoblotting, and zymography, respectively. In contrast, interferon γ (IFN-γ) reversed these effects and medroxyprogesterone acetate elicited further reversal. Immunoblotting revealed that p38 mitogen-activated protein kinase signaling mediated TNF-α enhancement of MMP-1, MMP-3, and MMP-9, whereas IFN-γ inhibited p38 mitogen-activated protein kinase phosphorylation. Unlike highly regulated MMP-1, MMP-3, and MMP-9, MMP-2 mRNA and protein expression was constitutive in decidual cells. Because inflammation underlies PE-associated shallow EVT invasion, these results suggest that excess macrophage-derived TNF-α augments expression of MMP-1, MMP-3, and MMP-9 in decidual cells to interfere with normal stepwise EVT invasion of the decidua. In contrast, decidual natural killer cell-derived IFN-γ reverses such TNF-α-induced MMPs to protect against PE.

Thermal Ablation Treatment for Cervical Precancer (Cervical Intraepithelial Neoplasia Grade 2 or Higher [CIN2+]).

Cervical cancer is a leading cause of mortality for women in low- and middle-income countries (LMICs). Invasive disease can be prevented through the treatment of high-grade cervical precancer lesions. Types of treatment for cervical precancer include excisional procedures that surgically remove the affected tissue and ablation treatments which utilize extreme temperatures to destroy precancerous cells. Excision is the first-line treatment in higher income countries, but requires specialized training and equipment that make it unsuitable for low-income settings. The most common treatment globally is cryotherapy, which utilizes cryogenic gas to freeze the area. However, the need for gas presents significant procurement and logistical challenges. The World Health Organization (WHO) has recently endorsed the use of thermal ablation, a method that utilizes heat to destroy precancerous tissue. This review describes three existing thermal ablation devices and protocols for their use, including step-by-step instruction guides to perform a successful treatment with each device and observations specific to each machine.

Cervical Cancer Prevention in El Salvador: Gains to Date and Challenges for the Future.

Cervical cancer is preventable through vaccination, early detection, and the treatment of pre-cancerous lesions. However, global inequalities mean that the disease remains a leading cause of cancer death around the world, with over 80% of new cases and 90% of deaths occurring in low- and middle-income countries (LMICs). In El Salvador, joint efforts between the Ministry of Health (MoH) and the non-profit organization Basic Health International (BHI) have been in place since 2008, with the goal of reducing the country's disease burden. While the World Health Organization's (WHO) call to action to eliminate cervical cancer provided worldwide momentum to implement new public health initiatives, the COVID-19 pandemic disrupted ongoing programs and jeopardized plans for the future. The purpose of this manuscript is to describe the progress that El Salvador has achieved in improving cervical cancer prevention, the impact of the pandemic on current strategies, and potential solutions that can help the country meet the WHO's strategic targets by 2030 to accelerate the elimination of cervical cancer.

Safety and Acceptability of Three Ablation Treatments for High-Grade Cervical Precancer: Early Data From a Randomized Noninferiority Clinical Trial.

PURPOSE: This ongoing trial is comparing the efficacy and safety of three ablation treatments for cervical intraepithelial neoplasia grade 2 or higher. Here, we present early data regarding pain, side effects, and acceptability of CO2 gas-based cryotherapy (CO2), nongas cryotherapy, and thermal ablation (TA). Efficacy results are expected to become available in late 2023. MATERIALS AND METHODS: This noninferiority randomized trial is taking place in El Salvador, China, and Colombia. Patients are 1,152 eligible women with biopsy-confirmed cervical intraepithelial neoplasia grade 2 or higher who will receive one of three ablation treatments. Pain is measured before, during, and after treatment with a visual analog scale (1-10). Side effects and acceptability are assessed at 6 weeks. RESULTS: To date, 1,024 of 1,152 (89%) women were randomly assigned to treatment. The median pain level was higher during TA (4, IQR = 4) than CO2 (2, IQR = 4) or nongas cryotherapy (2, IQR = 4) (P < .01, range: 0-10). The most common post-treatment symptom was watery discharge, reported by 97.9% of women, and it lasted longer in the CO2 group than the other two treatments (in days, median [IQR]: CO2 = 20[20], nongas cryotherapy = 15[10], TA = 18[15], P < .01). Bleeding was reported more frequently in women treated with TA (27.6%) than CO2 (17.5) or nongas cryotherapy (18.7%) (P < .01). The majority of patients reported being very satisfied with the treatment they received at 6 weeks (91%) and again at 12 months post-treatment (97%). CONCLUSION: Despite differences in pain and side effects across ablation treatments, all were safe and highly acceptable to patients. In addition to efficacy, considerations such as cost and portability may be more significant in choosing a treatment method.

Multi-site clinical validation of Isothermal Amplification based SARS-COV-2 detection assays using different sampling strategies.

BACKGROUND: Isothermal amplification-based tests were developed as rapid, low-cost, and simple alternatives to real-time reverse transcriptase-polymerase chain reaction (RT-PCR) tests for SARS-COV-2 detection. METHODS: Clinical performance of two isothermal amplification-based tests (Atila Biosystems iAMP COVID-19 detection test and OptiGene COVID-19 Direct Plus RT-LAMP test) was compared to clinical RT-PCR assays using different sampling strategies. A total of 1378 participants were tested across four study sites. RESULTS: Compared to standard of care RT-PCR testing, the overall sensitivity and specificity of the Atila iAMP test for detection of SARS-CoV-2 were 76.2% and 94.9%, respectively, and increased to 88.8% and 89.5%, respectively, after exclusion of an outlier study site. Sensitivity varied based on the anatomic collected site. Sensitivity for nasopharyngeal was 65.4% (range across study sites:52.8%-79.8%), mid-turbinate 88.2%, saliva 55.1% (range across study sites:42.9%-77.8%) and anterior nares 66.7% (range across study sites:63.6%-76.5%). The specificity for these anatomic collection sites ranged from 96.7% to 100%. Sensitivity improved in symptomatic patients (overall 82.7%) and those with a higher viral load (overall 92.4% for ct≤25). Sensitivity and specificity of the OptiGene Direct Plus RT-LAMP test, conducted at a single study-site, were 25.5% and 100%, respectively. CONCLUSIONS: The Atila iAMP COVID test with mid-turbinate sampling is a rapid, low-cost assay for detecting SARS-COV-2, especially in symptomatic patients and those with a high viral load, and could be used to reduce the risk of SARS-COV-2 transmission in clinical settings. Variation of performance between study sites highlights the need for site-specific clinical validation of these assays before clinical adoption.

Multisite Clinical Validation of Isothermal Amplification-Based SARS-CoV-2 Detection Assays Using Different Sampling Strategies.

Isothermal amplification-based tests have been introduced as rapid, low-cost, and simple alternatives to real-time reverse transcriptase PCR (RT-PCR) tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection. The clinical performance of two isothermal amplification-based tests (Atila Biosystems iAMP coronavirus disease of 2019 [COVID-19] detection test and OptiGene COVID-19 direct plus RT-loop-mediated isothermal amplification [LAMP] test) was compared with that of clinical RT-PCR assays using different sampling strategies. A total of 1,378 participants were tested across 4 study sites. Compared with standard of care RT-PCR testing, the overall sensitivity and specificity of the Atila iAMP test for detection of SARS-CoV-2 were 76.2% and 94.9%, respectively, and increased to 88.8% and 89.5%, respectively, after exclusion of an outlier study site. Sensitivity varied based on the anatomic site from which the sample was collected. Sensitivity for nasopharyngeal sampling was 65.4% (range across study sites, 52.8% to 79.8%), for midturbinate was 88.2%, for saliva was 55.1% (range across study sites, 42.9% to 77.8%), and for anterior nares was 66.7% (range across study sites, 63.6% to 76.5%). The specificity for these anatomic collection sites ranged from 96.7% to 100%. Sensitivity improved in symptomatic patients (overall, 82.7%) and those with a higher viral load (overall, 92.4% for cycle threshold [CT] of ≤25). Sensitivity and specificity of the OptiGene direct plus RT-LAMP test, which was conducted at a single study site, were 25.5% and 100%, respectively. The Atila iAMP COVID test with midturbinate sampling is a rapid, low-cost assay for detecting SARS-CoV-2, especially in symptomatic patients and those with a high viral load, and could be used to reduce the risk of SARS-CoV-2 transmission in clinical settings. Variation of performance between study sites highlights the need for site-specific clinical validation of these assays before clinical adoption. IMPORTANCE Numerous SARS-CoV-2 detection assays have been developed and introduced into the market under emergency use authorizations (EUAs). EUAs are granted primarily based on small studies of analytic sensitivity and specificity with limited clinical validations. A thorough clinical performance evaluation of SARS-CoV-2 assays is important to understand the strengths, limitations, and specific applications of these assays. In this first large-scale multicentric study, we evaluated the clinical performance and operational characteristics of two isothermal amplification-based SARS-CoV-2 tests, namely, (i) iAMP COVID-19 detection test (Atila BioSystems, USA) and (ii) COVID-19 direct plus RT-LAMP test (OptiGene Ltd., UK), compared with those of clinical RT-PCR tests using different sampling strategies (i.e., nasopharyngeal, self-sampled anterior nares, self-sampled midturbinate, and saliva). An important specific use for these isothermal amplification-based, rapid, low-cost, and easy-to-perform SARS-CoV-2 assays is to allow for a safer return to preventive clinical encounters, such as cancer screening, particularly in low- and middle-income countries that have low SARS-CoV-2 vaccination rates.

Human decidual natural killer cells are a unique NK cell subset with immunomodulatory potential.

Natural killer cells constitute 50-90% of lymphocytes in human uterine decidua in early pregnancy. Here, CD56(bright) uterine decidual NK (dNK) cells were compared with the CD56(bright) and CD56(dim) peripheral NK cell subsets by microarray analysis, with verification of results by flow cytometry and RT-PCR. Among the approximately 10,000 genes studied, 278 genes showed at least a threefold change with P < or = 0.001 when comparing the dNK and peripheral NK cell subsets, most displaying increased expression in dNK cells. The largest number of these encoded surface proteins, including the unusual lectinlike receptors NKG2E and Ly-49L, several killer cell Ig-like receptors, the integrin subunits alpha(D), alpha(X), beta1, and beta5, and multiple tetraspanins (CD9, CD151, CD53, CD63, and TSPAN-5). Additionally, two secreted proteins, galectin-1 and progestagen-associated protein 14, known to have immunomodulatory functions, were selectively expressed in dNK cells.

Outcomes for Step-Wise Implementation of a Human Papillomavirus Testing-Based Cervical Screen-and-Treat Program in El Salvador.

PURPOSE: The Cervical Cancer Prevention in El Salvador (CAPE) project is a public-sector intervention introducing lower-cost human papillomavirus (HPV) testing in all four departments of the Paracentral region that screened a total of 28,015 women. After demonstrating success of an HPV screen-and-treat (S&T) algorithm over colposcopy management in the first two phases, the third phase scaled up the S&T strategy. We present results from phase III and evaluate S&T components across the entire project. METHODS: During phase III, 17,965 women age 30-59 years underwent HPV testing. HPV-positive women were asked to return and, if eligible, received gas-based cryotherapy. We compare loss to follow-up and time intervals between S&T steps across the three phases. RESULTS: There were no differences in HPV positivity across phases (phase I, 11.9%; phase II, 11.4%; phase III, 12.3%; P = .173). Although most HPV-positive women completed indicated follow-up procedures within 6 months in phases I (93.3%, 111 of 119) and II (92.3%, 429 of 465), this proportion declined to 74.9% (1,659 of 2,214; P < .001) in phase III. Mean days between testing and delivery of results to patients increased over program phases (phase I, 23.2 days; phase II, 46.7 days; phase III, 99.8 days; P < .001). CONCLUSION: A public-sector implementation of an HPV-based S&T algorithm was successfully scaled up in El Salvador, albeit with losses in efficiency. After CAPE, the Ministry of Health changed its screening guidelines and procured additional tests to expand the program.

Cervical Cancer Screening with Human Papillomavirus Self-Sampling Among Transgender Men in El Salvador.

Purpose: Sexual and gender minority persons in low-income countries have very limited access to routine health services. This study evaluated the feasibility of using a self-sampled human papillomavirus (HPV) test to increase access to screening for cervical cancer among transgender men in El Salvador. Methods: We partnered with a local advocacy organization for recruitment. A total of 24 transgender men (men assigned female at birth) ages 19-55 were enrolled and provided consent. Questionnaires assessed sociodemographics, health and sexual histories, and knowledge about HPV and cervical cancer. Screening was performed with a self-sampled HPV test. Participants with a positive test were offered colposcopy and cryotherapy treatment, if appropriate. Those with a negative test were advised to return in 5 years for rescreening. Results: Out of 24 consenting participants, 23 (95.83%) agreed to conduct HPV self-sampling, and 22/23 (95.65%) expressed willingness to self-sample in the future. Among self-sampled individuals, 3/23 (13%) tested positive and accepted colposcopy and biopsy. Analyses of biopsied tissue revealed one case of cervical intraepithelial neoplasia grade 1. Conclusion: HPV self-sampling and subsequent procedures were accepted by the majority of participants. This screening method may be a viable alternative to cytology among transgender men in El Salvador.

The cost-effectiveness of implementing HPV testing for cervical cancer screening in El Salvador.

OBJECTIVE: To assess the cost-effectiveness of HPV-based screening and management algorithms for HPV-positive women in phase 2 of the Cervical Cancer Prevention in El Salvador (CAPE) demonstration, relative to the status quo of Pap-based screening. METHODS: Data from phase 2 of the CAPE demonstration (n=8000 women) were used to inform a mathematical model of HPV infection and cervical cancer. The model was used to project the lifetime health and economic outcomes of HPV testing every 5 years (age 30-65 years), with referral to colposcopy for HPV-positive women; HPV testing every 5 years (age 30-65 years), with immediate cryotherapy for eligible HPV-positive women; and Pap testing every 2 years (age 20-65 years), with referral to colposcopy for Pap-positive women. RESULTS: Despite slight decreases in the proportion of HPV-positive women who received treatment relative to phase 1, the health impact of screening in phase 2 remained stable, reducing cancer risk by 58.5%. As in phase 1, HPV testing followed by cryotherapy for eligible HPV-positive women remained the least costly and most effective strategy (US$490 per year of life saved). CONCLUSION: HPV-based screening followed by immediate cryotherapy in all eligible women would be very cost-effective in El Salvador.

The effect of consolidation of abortion services on patient outcomes.

BACKGROUND: In 2001, a service dedicated to family planning was created within a large public hospital to improve patient care services. This retrospective chart review demonstrates the benefit of focusing these services in a specialty clinic. STUDY DESIGN: A power analysis was performed and determined that a minimum of 136 charts were needed in each arm of the study to determine if, following an elective abortion, there was a significant increase in attendance at the scheduled postoperative visit. Secondary variables included analysis of contraceptive choice, incidence of continuation of injectable contraception and incidence of repeat pregnancy. RESULTS: After counseling services were initiated, there was a 27% increase in the number of patients returning for the postoperative clinic appointment within 8 weeks [32% (61/191) in 1998 vs. 59% (80/136) in 2001; p<.0001]. There was also a significant decrease in patients without a plan for contraception, 29% in 1998 vs. 11% in 2001, and a decrease in repeat pregnancies from 9% in 1998 to 1.5% in 2001. There was no difference in patient adherence with injectable contraception. CONCLUSION: Consolidation of abortion services improves subsequent use of contraception and reduces incidence of repeat pregnancy.

Cervical cancer prevention in El Salvador (CAPE)-An HPV testing-based demonstration project: Changing the secondary prevention paradigm in a lower middle-income country.

•CareHPV tests were used to compare screen-and-treat and colposcopy management.•Screen-and-treat strategy with HPV testing was found to be very cost-effective.•CAPE has screened > 25,000 women in the Paracentral region.•Over 70% of screen-positive women received recommended treatment within six months.•CAPE is an example of public-private partnership resulting in paradigm change.

Expression of Interferon γ by Decidual Cells and Natural Killer Cells at the Human Implantation Site: Implications for Preeclampsia, Spontaneous Abortion, and Intrauterine Growth Restriction.

Human first-trimester decidual cells (FTDCs) chemoattract CXCR3-expressing circulating CD56(bright)CD16(-) natural killer (NK) cells, which increase uteroplacental blood flow by remodeling spiral arteries and arterioles. This recruitment reflects elevated FTDC expression of NK cell-recruiting induced protein 10 and interferon (IFN)-inducible T-cell-α chemoattractant produced in response to the synergistic effects of tumor necrosis factor α (TNF-α) and IFN-γ stimulation. Decidual macrophages express TNF-α, whereas the cellular origin of IFN-γ is unclear. Therefore, this study aims to identify the cell source(s) of IFN-γ in human first trimester decidua. Immunostaining of decidual sections revealed that both FTDCs and decidual NK (dNK) cells express IFN-γ. Although individual dNK cells express higher IFN-γ levels, the more numerous FTDCs account for greater proportion of total IFN-γ immunostaining. Freshly isolated FTDCs express greater IFN-γ staining than dNK cells as measured by flow cytometry, whereas incubation of dNK cells with documented NK cell activators significantly increases IFN-γ above FTDC levels. Confluent FTDCs intrinsically produce, but paradoxically respond to, exogenous IFN-γ.