The Tuberculous Granuloma and Preexisting Immunity.

Pulmonary granulomas are widely considered the epicenters of the immune response to Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB). Recent animal studies have revealed factors that either promote or restrict TB immunity within granulomas. These models, however, typically ignore the impact of preexisting immunity on cellular organization and function, an important consideration because most TB probably occurs through reinfection of previously exposed individuals. Human postmortem research from the pre-antibiotic era showed that infections in Mtb-naïve individuals (primary TB) versus those with prior Mtb exposure (postprimary TB) have distinct pathologic features. We review recent animal findings in TB granuloma biology, which largely reflect primary TB. We also discuss our current understanding of postprimary TB lesions, about which much less is known. Many knowledge gaps remain, particularly regarding how preexisting immunity shapes granuloma structure and local immune responses at Mtb infection sites.

The Formation and Function of Granulomas.

Granulomas are organized aggregates of macrophages, often with characteristic morphological changes, and other immune cells. These evolutionarily ancient structures form in response to persistent particulate stimuli-infectious or noninfectious-that individual macrophages cannot eradicate. Granulomas evolved as protective responses to destroy or sequester particles but are frequently pathological in the context of foreign bodies, infections, and inflammatory diseases. We summarize recent findings that suggest that the granulomatous response unfolds in a stepwise program characterized by a series of macrophage activations and transformations that in turn recruit additional cells and produce structural changes. We explore why different granulomas vary and the reasons that granulomas are protective and pathogenic. Understanding the mechanisms and role of granuloma formation may uncover new therapies for the multitude of granulomatous diseases that constitute serious medical problems while enhancing the protective function of granulomas in infections.

Interleukin 1α and the inflammatory process.

Inflammation occurs after disruption of tissue homeostasis by cell stress, injury or infection and ultimately involves the recruitment and retention of cells of hematopoietic origin, which arrive at the affected sites to resolve damage and initiate repair. Interleukin 1α (IL-1α) and IL-1ß are equally potent inflammatory cytokines that activate the inflammatory process, and their deregulated signaling causes devastating diseases manifested by severe acute or chronic inflammation. Although much attention has been given to understanding the biogenesis of IL-1ß, the biogenesis of IL-1α and its distinctive role in the inflammatory process remain poorly defined. In this review we examine key aspects of IL-1α biology and regulation and discuss its emerging importance in the initiation and maintenance of inflammation that underlie the pathology of many human diseases.

Granulomatous myopathy: Sarcoidosis and beyond.

Non-necrotizing granulomatous inflammation is a rare but easily recognized histopathological finding in skeletal muscle biopsy. A limited number of diseases are known to be associated with non-necrotizing granulomatous myopathy. Once identified, a careful evaluation for evidence of extramuscular granulomatosis and other signs suggestive of sarcoidosis is warranted as about half of the patients have sarcoid myopathy. In addition, the presence of granulomatous myopathy should trigger a search for clinical and pathological clues of inclusion body myositis (IBM), which accounts for most of the remaining patients and can coexist with sarcoidosis. Recognizing the features of IBM in patients with granulomatous myopathy can potentially spare the patients from unnecessary exposure to immunosuppressive therapies. In patients whose granulomatous myopathy remain unexplained, further investigations should aim at identifying myasthenia gravis and other autoimmune disorders, especially those known to cause granulomatous inflammation in other organs. Laboratory investigations should include acetylcholine receptor, antimitochondrial, antineutrophil cytoplasmic, thyroglobulin, and thyroid peroxidase autoantibodies. In the appropriate clinical context, exposure to immune checkpoint inhibitors and chronic graft-vs-host disease can be causes of granulomatous myopathy. In cases of unexplained granulomatous myopathy, natural killer/T-cell lymphoma should be considered and careful histopathological examination for atypical cells and appropriate immunostaining is crucial. Identifying the etiology of granulomatous myopathy in each patient can guide appropriate treatment.

Underlying Systemic Diseases in Interstitial Granulomatous Dermatitis and Palisaded Neutrophilic Granulomatous Dermatitis: A Systematic Review.

BACKGROUND: Interstitial granulomatous dermatitis (IGD) and palisaded neutrophilic granulomatous dermatitis (PNGD) are uncommon presentations of reactive granulomatous dermatitis. Histologic lesions characterized by IGD/PNGD patterns have been associated with systemic diseases, causing an unmet need for revealing clinical correlates. OBJECTIVE: The aim of this study was to unravel the systemic diseases beyond dermatitis of IGD/PNGD. METHODS: This study analyzed data from case studies, case series, and retrospective cohorts by searching PubMed, Embase, Web of Science, and the Cochrane Library, with no start date or language restrictions on Sep 4, 2021. RESULTS: One hundred ninety-six publications were included (458 cases in total, 216 with details). Systemic diseases associated with IGD/PNGD were classified into 5 groups. Autoimmune disorders (n = 103, 47.6%) including rheumatoid arthritis (n = 51, 23.6%), systemic lupus erythematosus (n = 20, 9.3%), and others were the most common across all underlying diseases, followed by drug eruption (n = 52, 24.1%) such as tumor necrotic factor inhibitor reaction (n = 18, 8.3%) and malignancies (n = 27, 12.5%) such as hematologic malignancy (n = 20, 9.3%). The rest were infectious diseases (n = 12, 5.6%) and accidental conditions (n = 3, 1.4%). CONCLUSION: IGD/PNGD might be associated with autoimmune disorders, drug eruption, malignancies, infectious diseases, and accidental conditions. Patients with IGD/PNGD need further follow-up.

Granuloma formation after repeated episodes of peritoneal dialysis catheter-related infection, a case report.

BACKGROUND: Peritoneal catheter related infection is one of the main complications and the major cause of technical failure of peritoneal dialysis (PD) treatment. However, PD catheter tunnel infection can be difficult to diagnosis and resolve. We presented a rare case in which a granuloma formation after repeated episodes of peritoneal dialysis catheter-related infection. CASE PRESENTATION: A 53-year-old female patient with kidney failure due to chronic glomerulonephritis treated with peritoneal dialysis for 7 years. The patient had repeated exit-site and tunnel inflammation, and repeated suboptimal courses of antibiotics. She switched to hemodialysis after 6 years in a local hospital without the peritoneal dialysis catheter being removed. The patient complained of an abdominal wall mass that lasted for several months. She was admitted to the Department of surgery to undergo mass resection. The resected tissue of the abdominal wall mass was sent for pathological examination. The result showed foreign body granuloma with necrosis and abscess formation. After the surgery, the infection did not recur. CONCLUSIONS: The following key points can be learned from this case: 1. It is important to strengthen patient follow-up. 2.The PD catheter should be removed as early as possible in patients who do not need long-term PD, especially in patients with a history of exit-site and tunnel infections. 3. For patients presenting abnormal subcutaneous mass, attention should be paid to the possibility of the granuloma formation of infected Dacron cuffs of the PD catheter. If catheter infection occurs repeatedly, catheter removal and debridement should be considered.

Tympanomastoid cholesterol Granulomas presenting as a Blue Eardrum in children.

OBJECTIVE(S): This clinical study was performed to analyze the characteristics of cholesterol granuloma (CG) and evaluate our results in children. METHODS: The clinical records of children diagnosed with CG were retrospectively reviewed. RESULTS: The total of 17 children (20 ears) with CGs were included in this study. Endoscopy revealed pars flaccida retractions and lipoid tissue deposition behind the intact blue tympanic membrane (TM). CT scan revealed bony erosion and extensive soft tissue in the middle ear and mastoid. No ossicular chain destruction was found. All 20 ears underwent canal wall-up mastoidectomy and ventilation tube (VT) insertion, 3 sets of VT were performed in 5 ear and 2 sets in one. The residual perforation was seen in 2 ears following VT. The CT revealed well-pneumatized antra and tympanic cavities at postoperative 12-24 months. CONCLUSION(S): The CG should be suspected for the patients with yellow lipoid deposition behind the blue TM. CT of CG usually revealed bony erosion and extensive soft tissue in the middle ear and mastoid. Mastoidectomy combined with VT insertion and etiological treatment have a favorable prognosis for CG in children.

Cryptococcal granuloma of the the basal ganglia with fatal haemorrhage after stereotactic biopsy: case report.

This paper presents a male, immunocompetent case aged 62-year-old with cryptococcal granuloma in the basal ganglia. No cryptococcal infection occurred in other areas. The diagnosis was made by biopsy. Cryptococcal granuloma was tough and unsuitable for sterotactic biopsy. The patient died of postoperative bleeding and we suggest avoiding stereotactic biopsy of lesions suspected of being cryptococcal granulomas.

Rubella vaccine-induced granulomas are a novel phenotype with incomplete penetrance of genetic defects in cytotoxicity.

BACKGROUND: Rubella virus-induced granulomas have been described in patients with various inborn errors of immunity. Most defects impair T-cell immunity, suggesting a critical role of T cells in rubella elimination. However, the molecular mechanism of virus control remains elusive. OBJECTIVE: This study sought to understand the defective effector mechanism allowing rubella vaccine virus persistence in granulomas. METHODS: Starting from an index case with Griscelli syndrome type 2 and rubella skin granulomas, this study combined an international survey with a literature search to identify patients with cytotoxicity defects and granuloma. The investigators performed rubella virus immunohistochemistry and PCR and T-cell migration assays. RESULTS: This study identified 21 patients with various genetically confirmed cytotoxicity defects, who presented with skin and visceral granulomas. Rubella virus was demonstrated in all 12 accessible biopsies. Granuloma onset was typically before 2 years of age and lesions persisted from months to years. Granulomas were particularly frequent in MUNC13-4 and RAB27A deficiency, where 50% of patients at risk were affected. Although these proteins have also been implicated in lymphocyte migration, 3-dimensional migration assays revealed no evidence of impaired migration of patient T cells. Notably, patients showed no evidence of reduced control of concomitantly given measles, mumps, or varicella live-attenuated vaccine or severe infections with other viruses. CONCLUSIONS: This study identified lymphocyte cytotoxicity as a key effector mechanism for control of rubella vaccine virus, without evidence for its need in control of live measles, mumps, or varicella vaccines. Rubella vaccine-induced granulomas are a novel phenotype with incomplete penetrance of genetic disorders of cytotoxicity.

Granulomatous gastritis induced by chronic peanut ingestion.

Granulomatous gastritis (GG) is a rare condition, with incidence between 0.08 and 0.35% in gastric biopsies. Various infectious and non-infectious aetiologies can be considered to cause granulomatous gastritis. Foreign bodies are a rare aetiology of GG and may result from foods, suture materials, or medications. We report a 59-year-old woman who had eaten large amounts of peanuts for more than 10 years and presented with epigastric discomfort. Esophagogastroduodenoscopy revealed multiple nodular lesions with ulcer scars at the stomach, which was diagnosed as GG probably caused by chronic peanut ingestion on endoscopic mucosal resection.

Spectrum of cutaneous granulomatous lesions: A 5-year experience in a tertiary care centre in Sarawak.

INTRODUCTION: Granulomatous skin lesions can have various histopathological features leading to diagnostic confusion. The study aimed to determine the frequency and pattern of different granulomatous skin lesions. MATERIALS AND METHODS: This was a 5-year retrospective study done between April 2017 and March 2022 at Dermatology Department, Sarawak General Hospital. Subjects with a clinicopathological diagnosis of granulomatous diseases were included in the analysis. RESULTS: A total of 1718 skin biopsies were done during the study periods, with 49 (2.8%) confirmed granulomatous skin lesions. Most patients were aged 40-60 with a male predominance of 51%. Most of the skin biopsy samples were taken from the upper limb (36%). In this study, epitheloid granuloma was the commonest subtype (21, 43%) followed by suppurative granuloma (12, 24%), tuberculoid granuloma (8, 16%) and foreign body granuloma (5, 10%). The commonest aetiology of granulomatous skin lesions in our study was infections (30, 61%) followed by foreign body inoculation (8, 16%). Fungal infection was the most common infective cause, followed by cutaneous tuberculosis. CONCLUSION: The major cause of granulomatous dermatoses in developing countries is still infections, fungal and tuberculosis being the leading causes.

[Granulomatous disease with liver injury as the main manifestation].

Hepatic granuloma is a kind of disease caused by both infection or non-infection etiologies, and it is found in approximately 2% to 15% of liver biopsies. Some of which could be identified by the pathological morphology. This article reviews the common etiology, pathological manifestations, diagnosis, and differential diagnosis of hepatic granuloma, which is hopeful to improve clinicians' and pathologists' awareness.

[Undistinguishable Cryptococcus-related granulomatous lesion from carcinoma in the tail of the pancreas: a case report].

Abdominal computed tomography revealed a 19×13mm delayed enhancing mass and dilation of the distal pancreatic duct in the head of the pancreas. Magnetic resonance cholangiopancreatography showed pancreatic duct stenosis in the tail of the pancreas. Endoscopic retrograde pancreatography revealed an abrupt interruption of the main pancreatic duct at the tail of the pancreas. We could not assess the distal side of the pancreatic stenosis due to the large extent of obstruction. The pancreatic head mass was diagnosed as adenocarcinoma using endoscopic ultrasound-fine needle aspiration biopsy. However, we could not determine whether the pancreatic duct stenosis in the tail of the pancreas was malignant. Nevertheless, we performed a total pancreatectomy with splenectomy. Histological examination showed poorly differentiated adenocarcinoma in the pancreatic head mass but the pancreatic duct stenosis in the tail of the pancreas was diagnosed as pancreatic granuloma caused by Cryptococcus. Fungal infections may reportedly promote the development of pancreatic cancer, as further suggested by this case of cryptococcal infection.

Microgranulomas at Diagnosis Are Associated With Need for Antitumor Necrosis Factor Escalation in Pediatric Crohn Disease.

INTRODUCTION: Granulomas are a pathologic hallmark of Crohn disease (CD) although they are found in only a subset of patients. Well-formed granulomas are associated with an aggressive phenotype although it is unknown if microgranulomas confer a similar phenotype. This study sought to define the incidence of microgranulomas in pediatric CD and compare the clinical course with cases with granulomas and those without granulomatous inflammation. METHODS: We performed a single-center, retrospective study of pediatric CD patients who had at least 3 years of follow-up. initial diagnostic biopsies were systematically re-examined by a gastrointestinal pathologist. A priori definitions of granuloma (10+ histiocytes) and microgranuloma (4-9 histiocytes) were used. Disease outcomes of hospitalization, development of complicated disease behavior, perianal disease, and the use of anti-tumor necrosis factor (anti-TNF) therapy were assessed by Kaplan-Meier survival plots. RESULTS: This study included 138 subjects with an average follow-up of 4.6 years. Granulomas were seen in 38 of 138 subjects (27.5%) and an additional 38 subjects (27.5%) had at least 1 microgranuloma (in the absence of granulomas). Escalation to anti-TNF therapy was higher in CD with granulomas (P  = 0.001) and microgranulomas (P  = 0.0001) compared with those without granulomatous inflammation. CONCLUSIONS: A significant subset of pediatric CD patients have microgranulomas (in the absence of well-defined granulomas). Children with CD who have microgranulomas are escalated to anti-TNF therapy more frequently than those without granulomatous inflammation (and at a similar rate to those with granulomas). Pathologists should have a low threshold to report microgranulomas as they may help to predict disease behavior.

Mouse innate-like B-1 lymphocytes promote inhaled particle-induced in vitro granuloma formation and inflammation in conjunction with macrophages.

The current paradigm for explaining lung granulomatous diseases induced by inhaled particles is mainly based on macrophages. This mechanism is now challenging because B lymphocytes also infiltrate injured tissue, and the deficiency in B lymphocytes is associated with limited lung granulomas in silica-treated mice. Here, we investigated how B lymphocytes respond to micro- and nanoparticles by combining in vivo and in vitro mouse models. We first demonstrated that innate-like B-1 lymphocytes (not conventional B-2 lymphocytes or plasma cells) specifically accumulated during granuloma formation in mice instilled with crystalline silica (DQ12, 2.5 mg/mouse) and carbon nanotubes (CNT Mitsui, 0.2 mg/mouse). In comparison to macrophages, peritoneal B-1 lymphocytes purified from naïve mice were resistant to the pyroptotic activity of reactive particles (up to 1 mg/mL) but clustered to establish in vitro cell/particle aggregates. Mouse B-1 lymphocytes (not B-2 lymphocytes) in coculture with macrophages and CNT (0.1 µg/mL) organized three-dimensional spheroid structures in Matrigel and stimulated the release of TIMP-1. Furthermore, purified B-1 lymphocytes are sensitive to nanosilica toxicity through radical generation in culture. Nanosilica-exposed B-1 lymphocytes released proinflammatory cytokines and alarmins. In conclusion, our data indicate that in addition to macrophages, B-1 lymphocytes participate in micrometric particle-induced granuloma formation and display inflammatory functions in response to nanoparticles.

Connective tissue disease and sarcoidosis: a true association or a secondary granulomatous reaction?

Sarcoidosis occurs much more commonly in cohorts of connective tissue disease (1%) compared to the general population (0.01-0.04%). We present a case of concomitant connective tissue disease and cutaneous sarcoidal granulomas and discuss whether the observed granulomas represent a reactive phenomenon or true sarcoidosis. Click here for the corresponding questions to this CME article.

Dermatomal Granulomatous Dermatitis and Vasculitis Following Herpes Zoster Ophthalmicus.

Cutaneous granulomatous dermatoses are uncommon sequelae of herpes zoster (HZ) infection that have been documented in the literature, with granulomatous vasculitis described in rare cases. Here, we report a patient with HZ ophthalmicus who developed edematous plaques with central scarring in a V1 dermatomal distribution with histopathological changes of a granulomatous dermatitis including features of granulomatous vasculitis. J Drugs Dermatol. 2022;21(10):1127-1128. oi:10.36849/JDD.6749.

A case of wild-type rubella-associated cutaneous granuloma in ataxia telangiectasia.

Granulomatous skin disease is known to be associated with various primary immunodeficiencies, including ataxia telangiectasia (AT). Recent reports of persistence of live vaccine strain rubella within such cutaneous granulomas have raised concern regarding the safety of vaccination. Here we report a case of cutaneous granuloma in association with AT, demonstrating wild type, rather than vaccine strain rubella. This supports the persistence of rubella as a causative mechanism, but suggests it is not vaccine strain-specific, and thus may impact the decision of those considering not vaccinating this subset of children.

Sperm granulomas: Predictive factors and impacts on patency post vasectomy reversal.

The objective of this study was to identify factors that predict for sperm granuloma formation and the impact of sperm granuloma presence and quantity on vasectomy reversal (VR) outcomes. A cross sectional retrospective review of prospectively collected data, on the impact of granuloma on VR outcomes from a single academic center was performed. The impact of age, obstructive interval, intraoperative vasal fluid findings, anastomosis type, body mass index, tobacco use and total motile count (TMC) was determined. A total of 1550 men underwent VR between January 2000 and August 2019. Granulomas were present unilaterally in 23.3% (n = 361) and bilaterally in 14.2% (n = 220). On univariate analysis, increasing patient age negatively correlated with a larger number of granulomas (p = .011). Granuloma presence was associated with finding intact and motile sperm from the vasal stump intraoperatively (p = .001), and vasoepididymostomy anastomosis (p < .001). However, granuloma presence (and quantity) did not correlate with obstructive interval or maximum TMC. Tobacco use and body mass index (BMI) were not associated with granuloma presence. On multivariate analysis, granuloma quantity was not associated with TMC. Obstructive interval and vasovasostomy anastomosis were associated with higher TMC, while BMI was negatively associated with TMC. In conclusion, increasing age was negatively correlated with granuloma formation. Granuloma presence was associated with more favourable intraoperative fluid findings and anastomosis type, but not post-VR TMC, suggesting men with and without granulomas undergoing skilled microsurgery will have similar patency rates. Heavier men should be encouraged for weight loss prior to vasectomy reversal as increasing BMI was associated with lower TMC.