HIV-Infected Patients Developing Tuberculosis Disease Show Early Changes in the Immune Response to Novel Mycobacterium tuberculosis Antigens.

Background: In individuals living with HIV infection the development of tuberculosis (TB) is associated with rapid progression from asymptomatic TB infection to active TB disease. Sputum-based diagnostic tests for TB have low sensitivity in minimal and subclinical TB precluding early diagnosis. The immune response to novel Mycobacterium tuberculosis in-vivo expressed and latency associated antigens may help to measure the early stages of infection and disease progression and thereby improve early diagnosis of active TB disease. Methods: Serial prospectively sampled cryopreserved lymphocytes from patients of the Swiss HIV Cohort Study developing TB disease ("cases") and matched patients with no TB disease ("controls") were stimulated with 10 novel Mycobacterium tuberculosis antigens. Cytokine concentrations were measured in cases and controls at four time points prior to diagnosis of TB: T1-T4 with T4 being the closest time point to diagnosis. Results: 50 samples from nine cases and nine controls were included. Median CD4 cell count at T4 was 289/ul for the TB-group and 456/ul for the control group. Viral loads were suppressed in both groups. At T4 Rv2431c-induced and Rv3614/15c-induced interferon gamma-induced protein (IP)-10 responses and Rv2031c-induced and Rv2346/Rv2347c-induced tumor necrosis factor (TNF)-α responses were significantly higher in cases compared to controls (p < 0.004). At T3 - being up to 2 years prior to TB diagnosis - Rv2031c-induced TNF-α was significantly higher in cases compared to controls (p < 0.004). Area under the receiver operating characteristics (AUROC) curves resulted in an AUC > 0.92 for all four antigen-cytokine pairs. Conclusion: The in vitro Mycobacterium tuberculosis-specific immune response in HIV-infected individuals that progress toward developing TB disease is different from those in HIV-infected individuals that do not progress to developing TB. These differences precede the clinical diagnosis of active TB up to 2 years, paving the way for the development of immune based diagnostics to predict TB disease at an early stage.

Diagnosis of latent tuberculosis infection is associated with reduced HIV viral load and lower risk for opportunistic infections in people living with HIV.

Approximately 28% of the human population have been exposed to Mycobacterium tuberculosis (MTB), with the overwhelming majority of infected individuals not developing disease (latent TB infection (LTBI)). While it is known that uncontrolled HIV infection is a major risk factor for the development of TB, the effect of underlying LTBI on HIV disease progression is less well characterized, in part because longitudinal data are lacking. We sorted all participants of the Swiss HIV Cohort Study (SHCS) with at least 1 documented MTB test into one of the 3 groups: MTB uninfected, LTBI, or active TB. To detect differences in the HIV set point viral load (SPVL), linear regression was used; the frequency of the most common opportunistic infections (OIs) in the SHCS between MTB uninfected patients, patients with LTBI, and patients with active TB were compared using logistic regression and time-to-event analyses. In adjusted models, we corrected for baseline demographic characteristics, i.e., HIV transmission risk group and gender, geographic region, year of HIV diagnosis, and CD4 nadir. A total of 13,943 SHCS patients had at least 1 MTB test documented, of whom 840 (6.0%) had LTBI and 770 (5.5%) developed active TB. Compared to MTB uninfected patients, LTBI was associated with a 0.24 decreased log HIV SPVL in the adjusted model (p < 0.0001). Patients with LTBI had lower odds of having candida stomatitis (adjusted odds ratio (OR) = 0.68, p = 0.0035) and oral hairy leukoplakia (adjusted OR = 0.67, p = 0.033) when compared to MTB uninfected patients. The association of LTBI with a reduced HIV set point virus load and fewer unrelated infections in HIV/TB coinfected patients suggests a more complex interaction between LTBI and HIV than previously assumed.

Unmasked: when a clinically malignant disease turns out infectious. A rare case of tularemia.

This article reports on a 62-year-old man, who presented with cervical mass and rather nonspecific symptoms. The medical history and clinical workup initially favored a malignant disease such as a carcinoma of unknown primary as the underlying cause. Eventually, the patient was diagnosed with a granulomatous lymphadenitis caused by Francisella tularensis subsp holarctica. Tularemia is a rare disease in Western Europe and can present in multiple ways encompassing almost asymptomatic infections and fatal disease. A rapid diagnosis is often hampered by nonspecific symptoms and the generally low prevalence and incidence of this disease in endemic countries. This case report also provides a comprehensive review of the literature on cervical tularemia and discusses the differential diagnoses.

Active tuberculosis is characterized by an antigen specific and strictly localized expansion of effector T cells at the site of infection.

Mycobacterium tuberculosis (MTB)-specific cytokine responses in the peripheral blood and at the site of infection may differ significantly within the same individual, but the under-lying T-cell subset changes are largely unknown. Here, we measured effector and memory T-cell markers on CD4⁺ T cells (CD45RO, cysteine chemokine receptor (CCR)7, and CD27) in peripheral blood and at the site of active tuberculosis (TB). Additionally, T cells were stimulated overnight with purified protein derivative (PPD) and early secretory antigenic target (ESAT)-6 to determine which T-cell subset produces MTB-specific interferon (IFN)-γ. A striking decrease in CCR7 and CD27 expression on T cells was noted at the site of active TB. Likewise, IFN-γ expressing, ESAT-6 specific CD4⁺CD45RO⁺CD27⁻ T cells were dramatically increased at the site of infection but were not detectable in peripheral blood. An antigen-specific expansion of differentiated T cells at the site of active TB infection was poorly reflected in peripheral blood. Insight in these changes in MTB-specific effector T cells in different compartments of the body could lead to new approaches for immune-based diagnosis and interventions.

Specific cytokine patterns of pulmonary tuberculosis in Central Africa.

Different cytokines have been suggested to be involved in the pathogenesis of pulmonary tuberculosis (TB). The frequencies of Mycobacterium tuberculosis (MTB) specific CD4(+) and CD8(+) T cells, CD4(+)CD25(+) Forkhead Box Protein (FoxP)3(+) T cells, interleukin (IL)-6, interferon (IFN)-γ, Tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-ß and IL-10 were assessed in HIV-negative, pulmonary tuberculosis (TB) patients (n=30) and in healthy controls (n=23) in Gabon. Peripheral blood mononuclear cells (PBMC) were stimulated with purified protein derivative (PPD) and early secretory antigenic target-6 (ESAT-6). In patients, a pronounced pro-inflammatory cytokine response with highly significant increased levels of IL-6 and TNF-α accompanied by increased TGF-ß was detectable. Differences in IFN-γ responses between patients and healthy individuals were less pronounced than expected. FoxP3 expression did not differ between groups. A distinct cytokine pattern is associated with active pulmonary TB in patients from Central Africa.

T cells co-producing Mycobacterium tuberculosis-specific type 1 cytokines for the diagnosis of latent tuberculosis.

Patients treated with tumor necrosis factor (TNF)-alpha-antagonizing medication are at increased risk of developing active tuberculosis (TB), brought about mainly by reactivation of latent infection. Thus, screening for latent TB infection (LTBI) prior to administration of anti-TNF-alpha-therapy is required. For a long time, the tuberculin skin test (TST) was the only means of diagnosing LTBI, however, interferon-gamma-release assays (IGRAs), are promising new tools. Fifty two patients with dermatological disorders were included prior to implementation of anti-TNF-alpha therapy. Mycobacterium tuberculosis (MTB)-specific cytokine production, including interferon (IFN)-gamma, TNF-alpha, interleukin (IL)-2 and IL-10, was measured in CD4+ and CD8+ T cells by cytokine flow cytometry following stimulation of peripheral blood mononuclear cells (PBMC) with purified protein derivative (PPD) and early secretion antigenic target (ESAT)-6. Simultaneously, a TST was administered and 11 were TST-positive. Generally, MTB-specific IFN-gamma produced by CD4+ T cells correlated well with TST results. CD4+ T cells co-producing specific IFN-gamma and TNF-alpha after ESAT-6 stimulation showed the highest overall agreement with the TST (Kappa [kappa] = 0.87). Each single cytokine displayed individual patterns, the expression of IFN-gamma, however, showed the highest concordance with the TST (kappa = 0.82). This suggests that the enumeration of MTB-specific CD4+ T cells might introduce greater specificity for the diagnosis of latent TB, compared to the TST.

Bone marrow infection with bacillus Calmette-Guérin (BCG) after intravesical immunotherapy.

Instillation of bacillus Calmette-Guérin (BCG) into the urine bladder is an effective treatment of superficial bladder cancer. BCG-mediated anti-tumor activity appears to be a local phenomenon in which cell-mediated immunity, involving cytotoxic T cells, lymphokine-activated killer cells and natural killer cells, is important for the elimination of malignant cells. Serious side-effects of BCG therapy are rare; nevertheless, BCG is a live, attenuated strain of Mycobacterium (M.) bovis and may exhibit invasive properties. Both local and distant or generalized infections have been reported after treatment with BCG. We describe the case of a 68-year-old man who developed bone marrow infection with BCG two years after intravesical instillation of BCG for treatment of superficial bladder cancer. He presented with intermittent fever, weight loss and pronounced pancytopenia. A bone marrow biopsy specimen showed granulomatous inflammation and BCG was cultured from the urine. Anti-mycobacterial treatment with isoniazid, rifampicin and ethambutol (pyrazinamide is inactive against M. bovis) led to full clinical recovery of the patient.