Chronic Mycobacterial Infection Research Articles

Transcriptomic Profiling of Peripheral B Cells in Antibody Positive Sjogren's Patients Reveals Interferon Signature.

Sjögren's disease (SjD) is a common systemic autoimmune disease that affects mainly women. Key pathologic features include the infiltration of exocrine glands by lymphocytes and the activation of B lymphocytes with the production of autoantibodies. We aimed to analyze the transcriptome of circulating B cells from patients with SJD and healthy controls to decipher the B-cell-specific contribution to SJD. RNA from peripheral blood B cells of five untreated female patients with SjD and positive ANA, positive anti-SSA (both Ro-52 and Ro-60), positive anti-SSB and positive rheumatoid-factor, and five healthy controls was subjected to whole-transcriptome sequencing. A false discovery rate of < 0.1 was applied to define differentially expressed genes (DEG). RNA-sequencing identified 56 up and 23 down DEG. Hierarchal clustering showed a clear separation between the two groups. Ingenuity pathway analysis revealed that these genes may play a role in interferon signaling, chronic mycobacterial infection, and transformation to myeloproliferative disorders. We found upregulated expression of type-I and type-II interferon (IFN)-induced genes, as well as genes that may contribute to other concomitant conditions, including infections and a higher risk of myeloproliferative disorders. This adds insight into the autoimmune process and suggests potential targets for future functional and prognostic studies.

Induction of IL-32 in the immune response of keratinocytes to Mycobacterium marinum infection.

Keratinocytes are the predominant cell type in the skin epidermis, and they not only protect the skin from the influence of external physical factors but also function as an immune barrier against microbial invasion. However, little is known regarding the immune defence mechanisms of keratinocytes against mycobacteria. Here, we performed single-cell RNA sequencing (scRNA-seq) on skin biopsy samples from patients with Mycobacterium marinum infection and bulk RNA sequencing (bRNA-seq) on M. marinum-infected keratinocytes in vitro. The combined analysis of scRNA-seq and bRNA-seq data revealed that several genes were upregulated in M. marinum-infected keratinocytes. Further in vitro validation of these genes by quantitative polymerase chain reaction and western blotting assay confirmed the induction of IL-32 in the immune response of keratinocytes to M. marinum infection. Immunohistochemistry also showed the high expression of IL-32 in patients' lesions. These findings suggest that IL-32 induction is a possible mechanism through which keratinocytes defend against M. marinum infection; this could provide new targets for the immunotherapy of chronic cutaneous mycobacterial infections.

Multidisciplinary Treatment of Persistent Nontuberculous Mycobacterial Spinal Hardware Infection with a Pedicled Superior Gluteal Artery Perforator Flap.

Nontuberculous mycobacterial hardware infections are extremely challenging to treat. Multidisciplinary care involving removal of infected hardware, thorough debridement, and durable soft tissue coverage in conjunction with antibiotic therapy is essential for successful management. This case report presents a patient with chronic mycobacterial spinal hardware infection that underwent successful treatment with aggressive serial debridements and reconstruction with a large pedicled superior gluteal artery perforator flap coverage.

IMB-BZ as an Inhibitor Targeting ESX-1 Secretion System to Control Mycobacterial Infection.

Resistance to anti-tuberculosis (TB) drugs is a major issue in TB control, and demands the discovery of new drugs targeting the virulence factor ESX-1. We first established a high-throughput screen (HTS) assay for the discovery of ESX-1 secretion inhibitors. The positive hits were then evaluated for the potency of diminishing the survival of virulent mycobacteria and reducing bacterial virulence. We further investigated the probability of inducing drug resistance and the underlying mechanism using mycobacterial protein fragment complementation. A robust HTS assay was developed to identify small molecules that inhibit ESX-1 secretion without impairing bacterial growth in vitro. A hit named IMB-BZ specifically inhibits the secretion of CFP-10 and reduces virulence in an ESX-1-dependent manner, therefore resulting in significant reduction in intracellular and in vivo survival of mycobacteria. Blocking the CFP-10-EccCb1 interaction directly or indirectly underlies the inhibitory effect of IMB-BZ on the secretion of CFP-10. Importantly, our finding shows that the ESX-1 inhibitors pose low risk of drug resistance development by mycobacteria in vitro as compared with traditional anti-TB drugs, and exhibit high potency against chronic mycobacterial infection. Targeting ESX-1 may lead to the development of novel therapeutics for tuberculosis. IMB-BZ holds the potential for future development into a new anti-TB drug.

Dual Nature of Relationship between Mycobacteria and Cancer.

Although the therapeutic effect of mycobacteria as antitumor agents has been known for decades, recent epidemiological and experimental studies have revealed that mycobacterium-related chronic inflammation may be a possible mechanism of cancer pathogenesis. Mycobacterium tuberculosis and non-tuberculous Mycobacterium avium complex infections have been implicated as potentially contributing to the etiology of lung cancer, whereas Mycobacterium ulcerans has been correlated with skin carcinogenesis. The risk of tumor development with chronic mycobacterial infections is thought to be a result of many host effector mechanisms acting at different stages of oncogenesis. In this paper, we focus on the nature of the relationship between mycobacteria and cancer, describing the clinical significance of mycobacteria-based cancer therapy as well as epidemiological evidence on the contribution of chronic mycobacterial infections to the increased lung cancer risk.

Infection makes micro-CHIPs into macro-CHIPs.

In this issue of Cell Stem Cell, Hormaechea-Agulla etal. (2021) demonstrate that IFNγ signaling following an infection in mice provides a selective pressure that drives growth of Dnmt3a-/- hematopoietic stem cells. This clonal expansion is mediated by global methylation changes that lead to an increased self-renewing capacity.

Single-port thoracoscopic anatomic resection for chronic inflammatory lung disease

BackgroundIt is challenging to proceed thoracoscopic anatomic resection when encountering severe pleural adhesion or calcified peribronchial lymphadenopathy. Compared with multiple-port video-assisted thoracoscopic surgery (MP-VATS), how to overcome these challenges in single-port (SP-) VATS is still an intractable problem. In the present study, we reported the surgical results of chronic inflammatory lung disease and shared some useful SP-VATS techniques.MethodsWe retrospectively assessed the surgical results of chronic inflammatory lung disease, primarily bronchiectasis, and mycobacterial infection, at our institution between 2010 and 2018. The patients who underwent SP-VATS anatomic resection were compared with those who underwent MP-VATS procedures. We analyzed the baseline characteristics, perioperative data, and postoperative outcomes, and illustrated four special techniques depending on the situation: flexible hook electrocautery, hilum-first technique, application of Satinsky vascular clamp, and staged closure of bronchial stump method.ResultsWe classified 170 consecutive patients undergoing thoracoscopic anatomic resection into SP and MP groups, which had significant between-group differences in operation time and overall complication rate (P = 0.037 and 0.018, respectively). Compared to the MP-VATS group, the operation time of SP-VATS was shorter, and the conversion rate of SP-VATS was relatively lower (3.1% vs. 10.5%, P = 0.135). The most common complication was prolonged air leakage (SP-VATS, 10.8%; MP-VATS, 2.9%, P = 0.045).ConclusionsFor chronic inflammatory lung disease, certain surgical techniques render SP-VATS anatomic resection feasible and safe with a lower conversion rate.

Donor-defined mesenchymal stem cell antimicrobial potency against nontuberculous mycobacterium.

Chronic nontuberculous mycobacterial infections with Mycobacterium avium and Mycobacterium intracellulare complicate bronchiectasis, chronic obstructive airway disease, and the health of aging individuals. These insidious intracellular pathogens cause considerable morbidity and eventual mortality in individuals colonized with these bacteria. Current treatment regimens with antibiotic macrolides are both toxic and often inefficient at providing infection resolution. In this article, we demonstrate that human marrow‐derived mesenchymal stem cells are antimicrobial and anti‐inflammatory in vitro and in the context of an in vivo sustained infection of either M. avium and/or M. intracellulare.

Chronic infection drives Dnmt3a-loss-of-function clonal hematopoiesis via IFNγ signaling.

Age-related clonal hematopoiesis (CH) is a risk factor for malignancy, cardiovascular disease, and all-cause mortality. Somatic mutations in DNMT3A are drivers of CH, but decades may elapse between the acquisition of a mutation and CH, suggesting that environmental factors contribute to clonal expansion. We tested whether infection provides selective pressure favoring the expansion of Dnmt3a mutant hematopoietic stem cells (HSCs) in mouse chimeras. We created Dnmt3a-mosaic mice by transplanting Dnmt3a-/- and WT HSCs into WT mice and observed the substantial expansion of Dnmt3a-/- HSCs during chronic mycobacterial infection. Injection of recombinant IFNγ alone was sufficient to phenocopy CH by Dnmt3a-/- HSCs upon infection. Transcriptional and epigenetic profiling and functional studies indicate reduced differentiation associated with widespread methylation alterations, and reduced secondary stress-induced apoptosis accounts for Dnmt3a-/- clonal expansion during infection. DNMT3A mutant human HSCs similarly exhibit defective IFNγ-induced differentiation. We thus demonstrate that IFNγ signaling induced during chronic infection can drive DNMT3A-loss-of-function CH.

Answer to September 2020 Photo Quiz

Answer: Chronic pulmonary coccidioidomycosis. An IgG antibody to Aspergillus fumigatus was not present in the patient’s serum, and Aspergillus fumigatus was not detected in either BAL sample by PCR. However, a serum Coccidioides IgG complement fixation titer was positive at 1:32. Coccidioides immitis/Coccidioides posadasii was isolated from culture of the BAL fluid and was also detected by a specific PCR assay. Treatment with fluconazole was initiated (1). The patient’s lengthy history of pulmonary illness suggests that she had acquired her infection in Mexico or Arizona, but autochthonous coccidioidomycosis has also been reported in Washington State (2). Most coccidioidal pneumonia is self-limited, and fewer than 1% of patients develop chronic progressive pulmonary infections, which may be indistinguishable from other chronic fungal or mycobacterial infections (3). Diabetes mellitus is a risk factor for chronic infection. Radiologic manifestations of chronic disease include residual nodules, chronic cavities, persistent pneumonia with or without lymphadenopathy, pleural effusion, and regressive changes such as localized fibrosis, bronchiectasis, and calcification (4). The pulmonary imaging in this patient was not specific for Coccidioides infection; however, the presence of the air crescent sign in the dependent area of the cavitating lesion was not felt to be typical for an aspergilloma, and sparing of the lung apex reduced the likelihood of tuberculosis.

1008 – INTERFERON GAMMA-MEDIATED REGULATION OF HSCS: MECHANISMS AND ROLE IN CLONAL HEMATOPOIESIS.

Inflammatory conditions such as chronic infection or autoimmune disease are frequently associated with impaired hematopoiesis. Chronic interferon gamma (IFNγ)-mediated inflammatory signaling damages hematopoietic stem cells (HSC) by disrupting quiescence, promoting excessive terminal differentiation, and increasing the propensity for secondary stress-induced apoptosis. In recent studies, we examined the mechanisms underlying IFNγ-mediated HSC activation. Using intravital three-dimensional microscopy, we found that IFNγ disrupts the normally close interaction between HSCs and CXCL12-abundant reticular (CAR) cells in the HSC niche. IFNγ-dependent relocalization and HSC activation are dependent on the cell surface protein BST2, which is induced by IFNγ. HSCs from mice lacking BST2 were more quiescent and resistant to depletion upon chronic infection. Thus, BST2 is a key regulator of HSC quiescence that promotes inflammation-induced niche relocalization and activation. Given that prolonged IFNγ signaling can lead to the depletion of HSCs, we examined the impact of IFNγ-mediated HSC responses on clonal hematopoiesis (CH), with particular attention to loss of function (LOF) mutations in <i>Dnmt3a</i>, the most commonly mutated gene in CH. We used a murine model to investigate the prediction that infection provides selective pressure favoring expansion of <i>Dnmt3a</i>-knock out HSCs. We created <i>Dnmt3a</i> mosaic mice by transplanting a mixed population of Dnmt3a-KO and WT HSCs into WT mice and observed substantial expansion of Dnmt3a-KO HSCs during chronic mycobacterial infection. Transcriptional profiling and functional studies indicate reduced differentiation and reduced secondary stress-induced apoptosis account for <i>Dnmt3a</i> KO clonal expansion during infection. Whole genome bisulfite sequencing reveals possible mechanisms for these effects. Thus, we demonstrate that IFNg signaling during chronic infection can drive DNMT3A-mutant CH. Our future work will continue to elucidate the avenues by which infections and inflammation alter primitive hematopoiesis.

Comparative evaluation of Mycobacterium avium subspecies paratuberculosis (MAP) recombinant secretory proteins as DTH marker for paratuberculosis

Delayed type hypersensitivity (DTH) based skin test is an important onsite animal herd screening procedure for detecting the early stages of the chronic mycobacterial infections. DTH testing plays a vital role in the diagnosis of paratuberculosis infection. However, there are questions over the specificity of this test due to cross-reactive epitopes present on the purified protein derivative (PPD) prepared from the whole cell secretory proteins. PPD may contain proteins shared with other mycobacteria especially environmental species. Therefore, it is needed to test alternate paratuberculosis specific secretory antigens. Present study explored the potential of recombinant secretory proteins (MAP2168c, MAP1693c, MAP3547c, MAP4308c and MAP2677c) as DTH markers. The published literature shows that these proteins as strong cell mediated markers with specificity to paratuberculosis bacilli. To determine the positive skin thickness cutoff, herds of farm animals with history of endemic paratuberculosis were selected and thickness of >2.0 mm was reported as the positive cutoff. Preliminary findings on pilot scale animals report the usefulness of recombinant secretory proteins as DTH markers over traditional Johnin assay. Traditional Johnin reported more false positives and negatives compared to gold standard fecal PCR and field reference plate ELISA test. Present findings encourage and demand further research.

IFNg Signaling is a Driver of Dnmt3a-Mutant Clonal Hematopoiesis

Age-related clonal hematopoiesis (CH) is a risk factor for malignancy, cardiovascular disease and all-cause mortality. Somatic mutations in DNMT3A are drivers of CH, but decades may elapse between acquisition of a mutation and CH, suggesting that environmental factors contribute to clonal expansion. We used a murine model to investigate the prediction that infection provides selective pressure favoring expansion of Dnmt3a-mutant hematopoietic stem cells (HSCs). We created Dnmt3a mosaic mice by transplanting a mixed population of Dnmt3a-mutant and WT HSCs into WT mice and observed substantial expansion of Dnmt3a-mutant HSCs during chronic mycobacterial infection. Transcriptional profiling and functional studies indicate reduced differentiation and reduced secondary stress-induced apoptosis account for Dnmt3a-mutant clonal expansion during infection. Both injection of recombinant IFNγ alone and infecting mice transplanted with HSCs lacking the differentiation factor Batf2 partially phenocopied CH by Dnmt3a-mutant HSCs upon infection. This is the first study demonstrating that IFNγ signaling induced during chronic infection can drive DNMT3A-mutant CH.

Characterization of immune response against Mycobacterium marinum infection in the main hematopoietic organ of adult zebrafish (Danio rerio)

Tuberculosis remains a major global health challenge. To gain information about genes important for defense against tuberculosis, we used a well-established tuberculosis model; Mycobacterium marinum infection in adult zebrafish. To characterize the immunological response to mycobacterial infection at 14 days post infection, we performed a whole-genome level transcriptome analysis using cells from kidney, the main hematopoietic organ of adult zebrafish. Among the upregulated genes, those associated with immune signaling and regulation formed the largest category, whereas the largest group of downregulated genes had a metabolic role. We also performed a forward genetic screen in adult zebrafish and identified a fish line with severely impaired survival during chronic mycobacterial infection. Based on transcriptome analysis, these fish have decreased expression of several immunological genes. Taken together, these results give new information about the genes involved in the defense against mycobacterial infection in zebrafish.

A clinical profile of leprosy patients in a tertiary hospital, Karnataka: a retrospective study

&lt;p class="abstract"&gt;&lt;strong&gt;Background:&lt;/strong&gt; Leprosy is a chronic mycobacterial infection and is still a major health hazard in India.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; This was a retrospective study over 12 years of all cases diagnosed clinically as leprosy in a tertiary hospital at Hassan district, Karnataka. Confirmation of diagnosis was based on slit skin smear and biopsy was done in doubtful cases.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results:&lt;/strong&gt; Out of 214 patients, 152 were males and 62 were females. The prevalence was maximum in the age group 21-30 years. Borderline group formed the major part of the spectrum, consisting of 154 (71.96%) patients. Maximum patients 97 (45.3%) were of borderline tuberculoid (BT) leprosy, followed by 59 (27.57%) cases of borderline lepromatous leprosy (BL). 25 (11.68%) cases had tuberculoid leprosy (TT) and 20 (9.34%)cases were of lepromatous leprosy among which 3 were diagnosed as histoid leprosy. 6 patients had pure neuritic leprosy and 4 patients were in relapse.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; Even though leprosy is eliminated, it continues to be a public health problem in our country. Stricter surveillance for early diagnosis and treatment is needed to eradicate leprosy from India.&lt;/p&gt;

Borderline tuberculoid leprosy, lupus vulgaris and pulmonary tuberculosis: A rare association

Tuberculosis and leprosy are chronic mycobacterial infections that elicit granulomatous inflammation. The incidence of co-existence of pulmonary tuberculosis and leprosy has ranged from 2.5%-13.4%.1 Cutaneous tuberculosis is a variant of extrapulmonary tuberculosis and its simultaneous occurrence with leprosy is uncommon. The concomitant presence of leprosy, pulmonary as well as cutaneous tuberculosis is rare.&#x0D; We report a case of borderline tuberculoid leprosy, lupus vulgaris and pulmonary tuberculosis in a 45 years male who presented to the dermatology outpatient department with three morphologically distinct skin lesions over the posterior aspect of right leg. Ours is presumably the first case reported from Nepal, a country where both of these mycobacterial infections are endemic.

Unusual presentation of an uncommon disease

Leprosy as a disease has been associated with mankind for ages. Leprosy a chronic mycobacterial infection has a long natural history with end results being debilitating and mutilating for the patient. Most of the cases of leprosy present with skin manifestations, involvement of peripheral nerves and peripheral neuropathy. Systemic involvement is extremely rare and is seen as reactions in patients suffering from lepromatous leprosy. We hereby present a case of Borderline leprosy presenting as pancytopenia.

Higher Interleukin-7 serum concentrations in patients with cystic fibrosis correlate with impaired lung function

BackgroundPatients with cystic fibrosis (CF) are highly susceptible to infection and colonization of pulmonary epithelia. Repeated and chronic infections may affect disease course and efficacy of host immune protection. Higher Interleukin (IL)-7 serum levels, indicating impaired T-cell response to IL-7, have been described for chronic viral and mycobacterial infections. MethodsTime course measures of IL-7 serum concentrations in patients with CF (n = 164; n = 78 for the second time point) and healthy controls (n = 60) were done. CF patients were characterized for disease severity parameters as well as infection status and association with IL-7 serum levels was determined. ResultsCF patients had significantly higher IL-7 serum concentrations as compared to healthy controls (9.79 pg/ml, IQR 6.76–13.6 versus 4.55 pg/ml, IQR 2.76–9.51, p < .001). IL-7 serum levels were negatively correlated with individual CF patient's BMI (r = −0.19, p = .021) and a tendency of increased IL-7 levels in Staphylococcus aureus infected CF patients was found. Linear regression of multiple parameters revealed significant negative correlation of FEV1%pred with IL-7 serum concentrations in patients with CF (ß-coefficient: −0.04, 95% confidence interval [−0.08; −0.003], p = .034). Time course analyses after 1 year +/− 6 months showed increased IL-7 serum levels (time point 1:9.26 pg/ml, IQR 6.94–13.12 time point 2:10.86 pg/ml, IQR 9.14–14.76, p = .016) that correlated negatively with decreased FEV1%pred during CF disease course. ConclusionsHigh IL-7 serum levels were found in CF patients and correlated with impaired lung function during CF disease course. As a candidate biomarker of T-cell dysfunction, higher IL-7 serum level may also indicate worsened immune competence of patients with CF.

Interleukin 10 mutant zebrafish have an enhanced interferon gamma response and improved survival against a Mycobacterium marinum infection

Tuberculosis ranks as one of the world’s deadliest infectious diseases causing more than a million casualties annually. IL10 inhibits the function of Th1 type cells, and IL10 deficiency has been associated with an improved resistance against Mycobacterium tuberculosis infection in a mouse model. Here, we utilized M. marinum infection in the zebrafish (Danio rerio) as a model for studying Il10 in the host response against mycobacteria. Unchallenged, nonsense il10e46/e46 mutant zebrafish were fertile and phenotypically normal. Following a chronic mycobacterial infection, il10e46/e46 mutants showed enhanced survival compared to the controls. This was associated with an increased expression of the Th cell marker cd4-1 and a shift towards a Th1 type immune response, which was demonstrated by the upregulated expression of tbx21 and ifng1, as well as the down-regulation of gata3. In addition, at 8 weeks post infection il10e46/e46 mutant zebrafish had reduced expression levels of proinflammatory cytokines tnfb and il1b, presumably indicating slower progress of the infection. Altogether, our data show that Il10 can weaken the immune defense against M. marinum infection in zebrafish by restricting ifng1 response. Importantly, our findings support the relevance of M. marinum infection in zebrafish as a model for tuberculosis.

Rice body formation without rheumatic disease or tuberculosis infection in a sausage ring finger – a case report

Subcutaneous masses in the finger gather numerous lesions, among which tumors, inflammation-induced lesions, and post-traumatic lesions. Rice bodies are very unfrequent lesions, encountered in rheumatoid or tuberculous chronic synovitis. We present the case of a young patient with no history of tuberculosis infection or rheumatoid pathology who required surgical treatment for a rice body formation localized on the palmar side of the fourth left finger. A 31-year old, right dominant hand man presented with a 15 years history of progressively growing “sausage-like swelling” of the finger. There was an inamovible, painless mass with restriction of the DIP and PIP joints range of motion, without skin lesion, redness or stiffness. Imaging showed a large non-agressive mass within the tendon sheath. We realized a complete excision of the mass. Histopathological examination showed synovial villus with body rice shape and central necrosis evoking tuberculous synovitis or reumatoid arthritis. However, there was no argument for mycobacterial infection nor rheumatoid pathology. Rice bodies mostly evoke chronic synovitis or arthritis in northern countries, but may also be found in infectious diseases such as mycobacterial infections, related to chronic bursitis. No physiopathological mechanism has been formally identified (microinfarctions after intra-articular synovial inflammation and ischemia + de novo formation and progressive enlargement by fibrin + alteration in fluid viscosity and fibrinogen content of the synovial fluid). Different locations of rice bodies have been documented such as shoulder, knee, extensor tendon in the hand, wrist and carpal tunnel and flexor tendon sheath, but at the knowledge of the authors, this is the first reported case of digit flexor sheath rice body formation not related to inflammatory disease such as mycobacteria infection or rheumatoid arthritis. Differential diagnosis include synovial chondromatosis, pigmented villonodular synovitis, gout, sarcoidosis, systemic lupus erythematosus, chronic fungal infection and atypical mycobacterial infection, but the absence of suggestive complications, negative bacterial and fungal cultures, and laboratory test results, allowed us to assume the absence of classic etiology. In a case like ours, even less described than tuberculosis or arthritis, there is no established treatment standard. Despite the absence of associated systemic therapy, radical excision of the mass should provide definitive treatment. Therefore, prolonged observation will be necessary to confirm absence of recurrence with radical excision. Rice body formation should be better known as a muskulosqueletal form of mycobacterial infection or rheumatoid affection either by radiologists, surgeons and pathologists to provide optimal care for patients.