A Higher Manometric Esophageal Length to Height Ratio in Achalasia Explains the Lower Prevalence of Hiatal Hernia

Background/Aims

The evidence suggests that a shorter esophageal length (EL) in gastroesophageal reflux disease (GERD) patients is associated with the presence of hiatal hernia (HH). However, there are no reports of this association in patients with achalasia. The aim is to (1) determine the prevalence of hiatal hernia in achalasia patients, (2) compare achalasia EL with GERD patients and healthy volunteers (HV), (3) measure achalasia manometric esophageal length to height (MELH) ratio, and (4) determine if there are differences in symptoms between patients with and without hiatal hernia.

Methods

This retrospective and cross-sectional study consist of 87 pre-surgical achalasia patients, 22 GERD patients, and 30 HV. High-resolution manometry (HRM), barium swallow, and upper endoscopy were performed to diagnose HH. The EL and MELH ratio were measured by HRM. Symptoms were assessed with Eckardt, Eating Assessment Tool, and GERD-health-related quality of life questionnaires.

Results

The HH in GERD's prevalence was 73% vs 3% in achalasia patients (P < 0.001). Achalasia patients had a longer esophagus and a higher MELH ratio than HV and GERD patients (P < 0.001). GERD patients had a lower MELH ratio than HV (P < 0.05). EAT-10 (P < 0.0001) and Eckardt (P < 0.05) scores were higher in achalasia without HH vs HH.

Conclusions

The prevalence of HH in achalasia is significantly lower than in GERD. The longer EL and the higher MELH ratio in achalasia could explain the lower prevalence of HH. Despite the low prevalence of HH in achalasia patients, the surgeon should be encouraged not to rule out HH since the risk of postoperative reflux may increase if this condition is not identified and corrected.

Autoantigen characterization in the lower esophageal sphincter muscle of patients with achalasia

BACKGROUND

Serum anti-myenteric autoantibodies define autoimmune achalasia and tissue MMP-9 activity may locally process autoantigenic proteins in the muscle of the lower esophageal sphincter (LES) of achalasia patients.

METHODS

Biopsies of the LES muscle from 36 achalasia patients, 6 esophagogastric junction outflow obstruction (EGJOO) patients, and 16 transplant donors (TD) were compared in a blind cross-sectional study. Histological characteristics such as inflammation, fibrosis, presence of ganglion cells, cells of Cajal, GAD65, PNMA2, S-100, P substance, and MMP-9 proteoforms in tissue were assessed by H&E and Picrosirius Red staining and immunohistochemistry analysis. Anti-neuronal antibodies, onconeural antigens, recoverin, SOX-1, titin, zic4, GAD65, and Tr were evaluated by immunoblot/line assay.

KEY RESULTS

Tissue of achalasia patients had heterogeneous inflammatory infiltrates with fibrosis and contrasting higher levels of activated MMP-9, as compared with EGJOO and TD. Moreover, lower ganglion cell percentages and cell of Cajal percentages were determined in esophageal tissues of achalasia patients versus TD. The tissues of achalasia versus EGJOO patients had higher GAD65 and PNMA2 protein expression. Unexpectedly, these proteins were absent in TD tissue. S-100 and P substance had similar expression levels in tissues of achalasia patients versus TD and EGJOO. Most of the achalasia sera had anti-GAD65 (83%) and anti-PNMA2 (90%) autoantibodies versus EGJOO (17% and 33%, respectively) and healthy volunteers (10% and 0%, respectively).

CONCLUSIONS AND INFERENCES

Tissue-specific ectopic expression of GAD65 and PNMA/Ta2 and active MMP-9, associated with the presence of specific autoantibodies directed against these proteins, might participate in the pathophysiology of achalasia triggering and/or perpetuating autoimmune disease.

Exposing the Great Imitator: Proposal for a Holistic Diagnosis of Oral Secondary Syphilis in People Living with HIV

Oral secondary syphilis may mimic various infectious, neoplastic, or immune-mediated processes; hence, its diagnosis may represent a challenge. Early diagnosis of syphilis, a disease that has increased in recent decades, is essential for adequate management, particularly in people living with HIV (PLWH). This study aimed to comprehensively characterize oral secondary syphilis in a group of 47 PLWH. A group of PLWH with oral secondary syphilis attending four HIV-referral centers in Mexico City was included (2004-2021). Clinical and laboratory data were retrieved, and an exhaustive oral examination was performed following the established criteria. Demographic, clinicopathological, immunohistochemical, and serological features of the patients were analyzed. Approximately 11% of PLWH with oral secondary syphilis demonstrated negative Venereal Disease Research Laboratory tests. A noticeable feature was the absence of symptoms in 95.7% of cases, despite the clinically evident appearance of the lesions. In contrast to previous results, 18% of ulcerations were detected to be deep, crateriform, and infiltrative, and 22% of the mucous patches were highly keratotic lesions. Most samples (77.3%) showed superficial lymphoplasmacytic infiltrates in the superficial lamina propria, with perivascular and perineural patterns, and immunohistochemistry was positive in 66.7% of the cases. The "great imitator" appears not only clinically but also histopathologically and immunohistochemically, where features may be comparable with those of chronic inflammatory processes, deep infections, or malignant processes. Although not recommended as a routine assay, IHC could be a critical tool, particularly in PLWH with atypical clinical features or with negative and/or dubious serology.

An enriched environment reestablishes metabolic homeostasis by reducing obesity-induced inflammation

Obesity can lead to chronic inflammation in different tissues, generating insulin and leptin resistance and alterations in glucose and lipid metabolism, favoring the development of degenerative diseases, including type II diabetes. Congruently, the inflammatory signaling inhibition prevents the development of obesity and restores insulin sensitivity. Via the enhancement of central nervous system activity, an enriched environment (EE) has beneficial effects on learning and memory as well as on immune cell functions and inflammation in different disease models. Here, we explored whether an EE can restore energy balance in obese mice that previously presented metabolic alterations. We discovered that an EE improved glucose metabolism, increased insulin signaling in liver, and reduced hepatic steatosis and inflammation, and increased lipolysis and browning in the white adipose tissue of high-fat diet (HFD)-fed mice. Finally, we found reduced inflammatory signaling and increased anorexigenic signaling in the hypothalamus of HFD-fed mice exposed to an EE. These data indicate that an EE is able to restore the metabolic imbalance caused by HFD feeding. Thus, we propose EE as a novel therapeutic approach for treating obesity-related metabolic alterations.

This article has an associated First Person interview with the first author of the paper.

Summary: A series of physiological, histochemical and molecular analyses reveal that enriched environment decreases inflammation in adipose tissue and in hypothalamus, re-establishing glucose metabolism in metabolically compromised mice.

Esophagogastric junction outflow obstruction: Characterization of a new entity? Clinical, manometric, and neuroimmunological description

OBJECTIVE

To determine the differences between clinical, manometric, and neuroimmunological profile of esophagogastric junction outflow obstruction (EGJOO) and achalasia patients.

METHODS

Seven EGJOO and 27 achalasia patients were enrolled in a blind cross-sectional study. Peripheral blood (PB) of 10 healthy donors and 10 lower esophageal sphincter (LES) muscle biopsies from organ transplant donors were included as controls. The presence of ganglion cells, cells of Cajal, Th22/Th7/Th2/Th1/Tregs/Bregs/pDCregs in tissue, and PB was assessed by immunohistochemistry and flow cytometry. Serum concentration of IL-22/IL-17A/IL-17F/IL-4/IFN-γ/IL-1β/IL-6/IL-23/IL-33/TNF-α/IL-10 was determined using bioplex plates. ANAs and antineuronal antibodies were evaluated by immunofluorescence and Western blot.

KEY RESULTS

EGJOO and achalasia patients had lower ganglion cells and cells of Cajal percentage vs. controls, while fibrosis was present only in achalasia patients. EGJOO and controls had lower cell percentage of Th22/Th17/Th2 vs. achalasia. EGJOO tissue had lower Th1/Treg cell number vs. achalasia, but higher levels vs. control group. Bregs and pDCregs percentage was higher in EGJOO vs. control group. Percentage of PB subpopulations in EGJOO was not significantly different from control group. Serum cytokine levels were higher for IL-1β/IL-6/TNF-α, while IL-17A levels were lower in EGJOO vs. achalasia and control group. EGJOO group was negative for ANAs, while in achalasia group, 54% were positive. GAD65 and PNMa/Ta2 antibodies were present in achalasia, whereas Yo and recoverin were positive in EGJOO group.

CONCLUSIONS AND INFERENCES

Although EGJOO shares some clinical characteristics with achalasia, the neuroimmunological profile is completely different, suggesting that EGJOO might be a different entity.

Tumor Necrosis Factor-Induced miR-146a Upregulation Promotes Human Lung Adenocarcinoma Metastasis by Targeting Merlin

Inflammation plays a key role in carcinogenesis and metastasis. This process involves the inactivation of tumor suppressor molecules, yet the molecular mechanisms by which inflammation impairs tumor suppressors are not completely understood. In this study, we show that proinflammatory signals such as tumor necrosis factor (TNF) support lung cancer metastasis by reducing the levels of the tumor suppressor Merlin through regulation of miR-146a. Immunodeficient mice inoculated with A549 cells expressing high miR-146a levels and low Merlin protein levels exhibited reduced survival, which correlated with the number of metastatic nodes formed. Accordingly, restoring Merlin protein levels inhibited metastasis and increased survival of the mice. Consistent with these results, we found that elevated miR-146a expression levels correlated with low Merlin protein levels in human lung adenocarcinoma. Furthermore, human invasive and metastatic tumors showed higher TNF and miR-146a levels, but lower Merlin protein levels than noninvasive tumors. These findings indicate that upregulation of miR-146a by TNF in lung adenocarcinoma promotes Merlin protein inhibition and metastasis. Thus, we suggest that the ratio between miR-146a and Merlin protein levels could be a relevant molecular biomarker that can predict lung cancer progression and that the TNF/miR-146a/Merlin pathway is a promising new therapeutic target to inhibit lung adenocarcinoma progression.

Effects of Sildenafil and Tadalafil on Edema and Reactive Oxygen Species Production in an Experimental Model of Lung Ischemia-Reperfusion Injury

BACKGROUND

Lung ischemia-reperfusion injury is characterized by formation of reactive oxygen species and cellular swelling leading to pulmonary edema and primary graft dysfunction. Phosphodiesterase 5 inhibitors could ameliorate lung ischemia-reperfusion injury by interfering in many molecular pathways. The aim of this work was to evaluate and compare the effects of sildenafil and tadalafil on edema and reactive oxygen species formation in an ex vivo nonhuman animal model of lung ischemia-reperfusion injury.

METHODS

Thirty-two Wistar rats were distributed, treated, perfused and the cardiopulmonary blocks were managed as follows: control group: immediate excision and reperfusion without pretreatment; ischemia reperfusion group: treatment with dimethylsulfoxide 0.9% and excision 1 hour later; sildenafil group: treatment with sildenafil (0.7 mg/kg) and excision 1 hour later; and tadalafil group: treatment with tadalafil (0.15 mg/kg) and excision 2 hours later. All cardiopulmonary blocks except control group were preserved for 8 hours and then reperfused. Pulmonary arterial pressure, pulmonary venous pressure, and capillary filtration coefficient were measured. Reactive oxygen species were measured.

RESULTS

Edema was similar between control and sildenafil groups, but significantly greater in the ischemia-reperfusion (P ≤ .04) and tadalafil (P ≤ .003) groups compared with the sildenafil group. The malondialdehyde levels were significantly lower in the sildenafil (P ≤ .001) and tadalafil (P ≤ .001) groups than the ischemia-reperfusion group.

CONCLUSIONS

Administration of sildenafil, but not tadalafil, decreased edema in lung ischemia-reperfusion injury. Both drugs decreased reactive oxygen species formation in a lung ischemia-reperfusion injury model.

[Immunohistochemical Expression of CD117 (c-kit) in 75 Renal Cell Tumors]

OBJECTIVE

c-kit encodes the membrane-bound tyrosine kinase c-kit, whose expression has been identified in several human neoplasms. We analyzed the immunohistochemical expression of c-kit in renal cell tumors.

METHODS

75 cases of renal cell tumors were obtained from the surgical pathology archives at the ABC Medical Center in Mexico, for the period 2001 to 2011. We selected one representative paraffin block of the tumor and immunohistochemical staining for CD117 (c-kit) was performed. Immunopositivity was analyzed according cell location, intensity and percentage.

RESULTS

c-kit was positive in 20 cases (26.66%), all the oncocytomas and chromophobe renal cell carcinoma were positive. A total of 8.27% of conventional clear cell renal cell carcinomas showed cytoplasmic positivity and one case of papillary renal cell carcinoma was positive. In chromophobe renal cell carcinoma c-kit was positive in the membrane and 44.44% showed combined staining. In oncocytoma four cases showed cytoplasmic positivity, with heterogeneous and less intense staining than chromophobe renal cell carcinoma.

CONCLUSION

c-kit is a useful marker for the diagnosis of chromophobe renal cell carcinoma and oncocytoma vs. other renal cell tumors. Also it is important to define the cell location, intensity, and percentage of neoplastic cells for the differential between chromophobe renal cell carcinoma and oncocytoma.

Kinetics and cellular sources of cathelicidin during the course of experimental latent tuberculous infection and progressive pulmonary tuberculosis

In spite of advances in immunology on mycobacterial infection, there are few studies on the role of anti-microbial peptides in tuberculosis. The cathelin-related anti-microbial peptide (CRAMP) is the only cathelicidin isolated from mice. In this work we investigated the cellular sources and the production kinetics of this molecule during experimental tuberculosis, using two well-characterized models of latent or chronic infection and progressive disease. The lung of non-infected control mice expressed CRAMP at very low levels. In both models of experimental tuberculosis the main cells immunolabelled for CRAMP were bronchial epithelial cells, macrophages and pneumocytes types II and I. After intratracheal infection with a high bacilli dose (H37Rv strain) in Balb/c mice to produce progressive disease, a high CRAMP gene expression was induced showing three peaks: very early after 1 day of infection, at day 21 when the peak of protective immunity in this model is raised, and at day 28 when the progressive phase starts and the immunoelectronmicroscopy study showed intense immunolabelling in the cell wall and cytoplasm of intracellular bacilli, as well as in cytoplasmic vacuoles. Interestingly, at day 60 post-infection, when advanced progressive disease is well established, characterized by high bacillary loads and extensive tissue damage, CRAMP gene expression decreased but strong CRAMP immunostaining was detected in vacuolated macrophages filled with bacilli. Thus, cathelicidin is highly produced during experimental pulmonary tuberculosis from diverse cellular sources and could have significant participation in its pathogenesis.

[Plasmablastic lymphoma of the gastrointestinal tract in AIDS patients]

The risk of developing non-Hodgkin lymphoma (NHL) is 200 times higher in HIV-positive patients than otherwise healthy persons. Plasmablastic lymphoma (PL) represents < 3% of all NHL associated with HIV infection. The aim of this study was to review the clinical-pathologic features of PL of the gastrointestinal tract in 5 patients with HIV/aids disease. We performed a retrospective study of PL of the gastrointestinal tract diagnosed at the National Institute of Cancer at Mexico City, from 2000 to 2009. Clinical and pathological information was obtained and immunohistochemical studies were performed in paraffin-embedded tissue sections. The presence of Epstein-Barr Virus (EBV) was examined by in situ polymerase chain reaction (PCR). Four male and 1 female were included with a median of age of 29 years. Three tumors involved the ano-rectal area, one tumor the ascendant colon and one tumor the stomach. All tumors were histologically characterized by a monotonous proliferation of large lymphoid cell with plasmablastic features. Tumor cells were CD 138 / MUM-1 positive and CD 20 / PAX-5 negative in all cases. EVB genome was detected by in situ PCR in 4 cases. The median of follow-up was 18 months, and revealed that three patients are alive with neoplasm disease and two patients are still alive with no evidence of the neoplasm. Recognition of this entity by pathologists and clinicians is important in order to establish the correct diagnosis and the early treatment of these patients.

In vivo activity of plant-based interleukin-12 in the lung of Balb/c mouse

Background

In the last years, plants are being used for the production of a wide variety of biopharmaceuticals, including cytokines, and have the potential to serve as vehicles for mucosal administration of these molecules. We had previously reported the expression of a cytokine, interleukin-12 (IL-12), in transgenic tomato plants and had demonstrated that it retained its biologic activity in vitro.

Findings

In this work, we administered crude extracts of IL-12-containing tomato fruits to mice through the intratracheal route, measuring endogenous IL-12 and determining biologic activity by quantification of interferon-gamma (IFN-γ) in lungs and by histological analysis. IFN-γ expression in lungs, as well as histological analysis, indicate that tomato-expressed IL-12 retains its biologic activity and, most importantly, its effects are restricted to the site of administration.

Conclusion

Our results indicate that the functional activity of tomato-expressed IL-12 is comparable to that of commercial recombinant IL-12 when given via the mucosal route. This opens the possibility of using crude extracts prepared from tomatoes expressing IL-12 for certain immunotherapies.

Therapeutic effect of recombinant adenovirus encoding interferon-gamma in a murine model of progressive pulmonary tuberculosis

We constructed recombinant adenoviruses encoding murine interferon-gamma (AdIFNgamma) and tested its therapeutic efficiency in a well characterized model of progressive pulmonary tuberculosis (TB) in Balb/c mice, infected through the trachea with the laboratory drug-susceptible H37Rv strain or multidrug-resistant (MDR) clinical isolate. When the disease was in a late phase, 2 months after infection, we administered by intratracheal cannulation a single dose [1.7 x 10(9) plaque forming units (pfu)] of AdIFNgamma or the control adenovirus. Groups of mice were killed at different time-points and the lungs were examined to determine bacilli colony forming units (CFU), cytokine/chemokine gene expression, and CD4/CD8 subpopulations, and also subjected to automated histomorphometry. In comparison with the control group, after 2 weeks of treatment and during the next 6 months, AdIFNgamma-treated animals infected with either the H37Rv strain or the MDR strain showed significantly lower bacilli loads and tissue damage (pneumonia), higher expressions of IFN-gamma, tumor necrosis factor (TNF), and inducible nitric oxide synthase (iNOS), and bigger granulomas. When compared with the results from conventional chemotherapy or AdIFNgamma treatment alone, the combined treatment with AdIFNgamma plus conventional chemotherapy shortened the time taken for reduction of bacillary load. This shows that gene therapy with AdIFNgamma efficiently reconstituted the protective immune response and controlled the progress of pulmonary TB produced by MDR or non-MDR strains.

[Neutrophil participation in early control and immune activation during experimental pulmonary tuberculosis]

BACKGROUND

Macrophages and neutrophils are professional phagocytes that participate in the control of mycobacterial infection.

OBJECTIVE

We compared the pro-inflammatory cytokine production of both cell types during early pulmonary tuberculosis.

MATERIAL AND METHODS

Balb/c mice were infected by intratracheal route with the H37Rv virulent strain, and bronchial washing cells were studied by cytofluorometry.

RESULTS

A higher number of neutrophils with immunoreactivity against interleukin 1, interleukin 8 and tumor necrosis factor alpha were observed during the first week of infection. After, macrophages were the predominant cell type. In a second part of the study, infected mice were treated with the RB6-8C5 anti-neutrophil monoclonal antibody, and the course of the infection was observed. In comparison with controls, neutropenic mice showed higher bacillary loads in lungs and spleen, lower inflammatory infiltrate, smaller granulomas and lesser cutaneous delayed type hypersensitivity.

CONCLUSIONS

These results show that neutrophils are the most abundant inflammatory cell type during early murine pulmonary tuberculosis, and they participate in the lung bacilli clearance and prevention of blood dissemination. Neutrophils are also an important source of proinflammatory cytokines, contributing to the early recruitment and activation of macrophages and lymphocytes, favoring cell mediated immunity against mycobacterial infection.

A combination of a transforming growth factor-beta antagonist and an inhibitor of cyclooxygenase is an effective treatment for murine pulmonary tuberculosis

Transforming growth factor-beta (TGF-beta) and prostaglandins (PG) regulate the cell-mediated immune response, so it has been proposed that they affect the progression of pulmonary tuberculosis. Here we report that the administration of soluble betaglycan, a potent TGF-beta antagonist, and niflumic acid, a PG synthesis inhibitor, during the chronic phase of experimental murine tuberculosis enhanced Th1 and decreased Th2 cytokines, increased the expression of iNOS and reduced pulmonary inflammation, fibrosis and bacillary load. This immunotherapeutic approach resulted in significant control of the disease comparable to that achieved by anti-microbial treatment alone. Importantly, the combination of immunotherapy and anti-microbials resulted in an accelerated clearance of bacilli from the lung. These results confirm that TGF-beta and PG have a central pathophysiological role in the progression of pulmonary tuberculosis in the mouse and suggest that the addition of immunotherapy to conventional anti-microbial drugs might result in improved treatment of the disease.

Macrophage and T lymphocyte apoptosis during experimental pulmonary tuberculosis: their relationship to mycobacterial virulence

The kinetics of macrophage and T lymphocyte apoptosis were determined in a well-characterized mouse model of pulmonary tuberculosis, comparing strains of intermediate (H37Rv) and high virulence (Beijing strain, code 9501000). Both strains induced a high percentage of apoptotic activated macrophages at days 1 and 3 post infection, although this was twofold lower in Beijing-infected mice. Progressive pneumonia started at day 14 (Beijing) or 21 (H37Rv) post infection. Pneumonic areas contained numerous macrophages with vacuolated cytoplasm (VM). In H37Rv infection few VM were apoptotic (8.7% at day 60), and the percentage was even lower in Beijing infection (1.4% at day 28). A high percentage of VM expressed the anti-apoptotic molecule Bcl-2 (H37Rv, 83%; Beijing, 95%). Both strains induced a progressive increase of apoptotic Th1 lymphocytes, peaking at day 60 in H37Rv infection, or 28 in Beijing infection. The peak was twofold higher in the latter. VM had strong FasL immunostaining, and confocal microscopy showed numerous apoptotic Th1 cells closely associated with them, suggesting that VM might induce apoptosis of Th1 cells. These results support the hypothesis that apoptosis of macrophages is associated with protection, while apoptosis of Th1 cells favors disease progression, and is related to the virulence of the mycobacterial strain.

Airways infection with virulent Mycobacterium tuberculosis delays the influx of dendritic cells and the expression of costimulatory molecules in mediastinal lymph nodes

Despite tuberculosis resurgence and extensive dendritic cell (DC) research, there are no in vivo studies evaluating DC within regional lymphoid tissue during airways infection with virulent Mycobacterium tuberculosis (Mtb) H37Rv. Using DC-specific antibodies, immunocytochemistry, flow cytometry and Ziehl-Neelsen (ZN) for bacilli staining, we searched for Mtb and DC changes within mediastinal lymph nodes, after intratracheal (ITT) inoculation of virulent Mtb. ZN and immunocytochemistry in frozen and paraffin sections of mediastinal lymph nodes identified Mtb until day 14 after ITT inoculation, associated with CD11c(+) and Dec205(+) DC. Analysing CD11c, MHC-CII, and Dec205 combinations by flow cytometry in MLN suspensions revealed that CD11c(+)/MHC-CII(+) and CD11c(+)/Dec205(+) DC did not increase until day 14, peaked on day 21, and sharply declined by day 28. No changes were seen in control, saline-inoculated animals. The costimulatory molecules evaluated in CD11c(+) DCs followed a similar trend; the CD80 increase was negligible, slightly surpassed by CD40. CD86 increased earlier and the three markers peaked at day 21, declining by day 28. While antigen-specific proliferation was not evident for MLN CD4(+) T cells at 2 weeks postinfection, delayed-type hypersensitivity responses upon ITT inoculation revealed that, as early as day 3 and 7, both the priming and peripheral systemic immune responses were clearly established, persisting until days 14-21. While airways infection with virulent Mtb triggers an early, systemic peripheral response maintained for three weeks, this seems dissociated from regional events within mediastinal lymph nodes, such as antigen-specific T-cell reactivity and a delay in the influx and local activation of DC.

In situ analysis of lung antigen-presenting cells during murine pulmonary infection with virulent Mycobacterium tuberculosis

Scarce information exists about the role of lung antigen-presenting cells (APCs) in vivo during pulmonary tuberculosis. As APCs activate cellular immunity, following intratracheal inoculation with virulent Mycobacterium tuberculosis, we assessed in situ lung APC recruitment, distribution, granuloma involvement, morphology and mycobacterial burden by using MHC-CII, CD14, scavenger receptor class A (SRA), the murine dendritic cell (DC)-restricted marker CD11c and Ziehl-Neelsen staining. CD11c(+) DC and CD14(+) cell recruitment into lungs appeared by day 14, continuing until day 60. MHC-CII(+) cells increased since day 7, persisting until day 60. Thus, virulent mycobacteria delays (14-21 days) lung APC recruitment compared to model antigens and nonvirulent bacilli (24-48 h). Regarding granuloma constitution, highly bacillary CD14(+) and SRA(+) cells were centrally located. MHC-CII(+) cells were more peripheral, with less mycobacteria. CD11c(+) cells were heterogeneously distributed within granulomas, with scarce bacilli. When labelling lung suspensions for MHC-CII and classifying cells as macrophages or DC, then staining for Ziehl-Neelsen, a remarkable segregation was found regarding bacillary burden. Most macrophage-like cells contained numerous bacilli, while DC had no or scarce mycobacteria. This implies differential APC contributions in situ during pulmonary tuberculosis regarding mycobacterial uptake, granuloma involvement and perhaps bacillary growth.