Superior Sensitivity of Ex Vivo IFN-γ Release Assays as Compared to Skin Testing in Immunocompromised Patients

Prevalence of latent tuberculosis infection and its risk factors in Japanese hemodialysis patients

BACKGROUND

The majority of active tuberculosis (TB) cases develop from latent tuberculosis infection (LTBI). Since the risk of TB in hemodialysis (HD) patients is particularly high, interferon-gamma release assay (IGRA) for LTBI screening in HD patients is considered important. However, the prevalence and characteristics of LTBI in Japanese HD patients remain obscure.

METHODS

We performed an observational cross-sectional study of LTBI using IGRA QFT-3G tests in 118 HD outpatients enrolled at 3 hospitals of varying location and function.

RESULTS

Of the 118 patients, 96 were QFT negative, 7 were QFT indeterminate, 14 were QFT positive, and 1 was QFT judgment impossible. No patient had active TB. Confirmed (QFT positive) and possible (QFT positive + indeterminate) LTBI patients totaled 14 (11.9%) and 21 (17.8%), respectively. The LTBI possible group was significantly older and had a significantly higher rate of nephrosclerosis versus the QFT-negative group. The indeterminate group had a significantly longer HD period. The QFT results were not remarkably affected by other clinical data, including hospital characteristics. The possible LTBI rate increased age-dependently, with higher values from 60 years of age.

CONCLUSIONS

The prevalence of LTBI is high in Japanese HD patients, especially from the age of 60 years. Older age was a significant risk factor for LTBI, with prediction difficult using other clinical data. Extended HD may mask IGRA results. Therefore, aggressive screening for LTBI is advised in all HD patients regardless of hospital region or type, especially in patients over 60 years of age or newly commencing HD.

Pulmonary Tuberculosis and Management of Contact Patients in a Department of Nephrology and Kidney Transplantation

OBJECTIVES

To describe the investigation, follow-up, management and outcomes in a cohort of chronic kidney disease and kidney transplant recipients exposed to a case of pulmonary tuberculosis.

METHODS

Contacts were investigated following a concentric circles approach and followed-up according to their level of priority. In those with an evidence of latent tuberculous infection, treatment decision was based on the level of exposure, individual vulnerability, as well as the results of an interferon-gamma release assay.

RESULTS

130 patients with chronic kidney disease and 180 kidney transplant recipients were identified as contacts and followed-up over a two-year period.Only few vulnerable high-priority contacts received an anti-tuberculosis treatment, including the 2 (100%)highly exposed patients in circle 1, 11/78(14.1%)chronic kidney disease patients and 4/142 (2.8%) kidney transplant recipients in circle 2, and10/52 (19.2%) chronic kidney disease patients and 2/36 (5.6%) kidney transplant recipients in circle 3;all having a positive interferon-gamma release assay result. No incident case of tuberculosis disease occurred.

CONCLUSIONS

These findings suggest that latent tuberculosis treatment, as recommended in European guidelines, might be reasonably avoided in vulnerable high-priority contacts of circle 2 with a negative interferon-gamma release assay in countries with low prevalence of tuberculosis.

Interferon gamma release assay tests are associated with persistence and completion of latent tuberculosis infection treatment in the United States: Evidence from commercial insurance data

Background

Risk-targeted testing and treatment of latent tuberculosis infection (LTBI) is a critical component of the United States’ (US) tuberculosis (TB) elimination strategy, but relatively low treatment completion rates remain a challenge. Both treatment persistence and completion may be facilitated by diagnosing LTBI using interferon gamma release assays (IGRA) rather than tuberculin skin tests (TST).

Methods

We used a national sample of administrative claims data to explore associations diagnostic test choice (TST, IGRA, TST with subsequent IGRA) and treatment persistence and completion in persons initiating a daily dose isoniazid LTBI treatment regimen in the US private healthcare sector between July 2011 and March 2014. Associations were analyzed with a generalized ordered logit model (completion) and a negative binomial regression model (persistence).

Results

Of 662 persons initiating treatment, 327 (49.4%) completed at least the 6-month regimen and 173 (26.1%) completed the 9-month regimen; 129 (19.5%) persisted in treatment one month or less. Six-month completion was least likely in persons receiving a TST (42.2%) relative to persons receiving an IGRA (55.0%) or TST then IGRA (67.2%; p = 0.001). Those receiving an IGRA or a TST followed by an IGRA had higher odds of completion compared to those receiving a TST (aOR = 1.59 and 2.50; p = 0.017 and 0.001, respectively). Receiving an IGRA or a TST and subsequent IGRA was associated with increased treatment persistence relative to TST (aIRR = 1.14 and 1.25; p = 0.027 and 0.009, respectively).

Conclusions

IGRA use is significantly associated with both higher levels of LTBI treatment completion and treatment persistence. These differences are apparent both when IGRAs alone were administered and when IGRAs were administered subsequent to a TST. Our results suggest that IGRAs contribute to more effective LTBI treatment and consequently individual and population protections against TB.

Tests for latent tuberculosis in candidates for solid organ transplantation: A systematic review and meta-analysis

Reactivation of latent tuberculosis following solid organ transplantation has serious consequences for the recipient. The most useful diagnostic test for latent TB is not clear. We conducted a systematic review and meta-analysis to assess the relative test performance of interferon gamma release assays (IGRAs) and the tuberculin skin test (TST) in people undergoing solid organ transplantation. The clinical or radiological risk factors were used as the proxy reference standard. Test performance was expressed as an odd ratio (OR). We identified 24 studies (N = 7811), 12 studies compared IGRAs with TST directly, nine studies evaluated only TST and three studies only IGRAs. Direct comparison between tests and clinical risk factors indicated both tests were strongly associated with the presence of clinical risk factors for TB (TST: OR 3.17; 95%CI 1.55-6.48, IGRA: OR 2.78; 95%CI 1.55-5.01), and radiological evidence of past TB (TST: OR 3.26; 95%CI 1.85-5.73, IGRA: OR 3.85; 95%CI 2.16-6.86). Relative comparison indicated IGRAs positivity was more strongly associated with presence of radiological evidence of TB than TST (relative OR: 3.24; 95%CI 1.10-9.56). While there is no strong evidence in supporting use of IGRAs over TST for diagnosing latent TB, IGRAs positivity is more associated with the presence of radiological evidence of previous TB.

Pathophysiological basis of systemic treatments in psoriasis

Over the past 15 years, the spectrum of systemic antipsoriatic treatments has dramatically expanded. Until the end of the last millennium, systemic therapy had been restricted to four oral agents: methotrexate, cyclosporine, acitretin, and fumaric acid esters. Today, there are additionally seven biologics and one new oral antipsoriatic drug, as well as the first available biosimilars. Six more biologics with novel target structures and at least four biosimilars are currently being developed (phase III). This progress has been based on new insights into the pathogenesis of psoriasis, in which tumor necrosis factor and especially Th17 immune responses with their associated cytokines interleukin 23 and 17 play a key role. The development of new-generation biologics as well as immunomodulatory small molecules can be attributed to these pathophysiological findings. Phosphodiesterase 4 inhibitors, dimethyl fumarate, and Janus kinase inhibitors all interact with Th17 immune responses. Some of these drugs are in advanced clinical development and are also beneficial in psoriatic arthritis. Today, psoriasis and psoriatic arthritis therefore rank among the most readily treatable inflammatory autoimmune disorders. Dermatology is increasingly becoming a specialty of modern targeted immunotherapies.

The best of both worlds: reaping the benefits from mammalian and bacterial therapeutic circuits

Synthetic biology has revolutionized the field of biology in the last two decades. By taking apart natural systems and recombining engineered parts in novel constellations, it has not only unlocked a staggering variety of biological control mechanisms but it has also created a panoply of biomedical achievements, such as innovative diagnostics and therapies. The most common mode of action in the field of synthetic biology is mediated by synthetic gene circuits assembled in a systematic and rational manner. This review covers the most recent therapeutic gene circuits implemented in mammalian and bacterial cells designed for the diagnosis and therapy of an extensive array of diseases. Highlighting new tools for therapeutic gene circuits, we describe a future that holds a plethora of potentialities for the medicine of tomorrow.