Cancer risk in Korean patients with Behçet's disease: A nationwide population-based study

Incidence of cancer in chronic inflammatory demyelinating polyneuropathy: a nationwide cohort study in South Korea

Background

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare disease, and the potential risk of cancer in patients with CIDP remains an important concern during treatment. However, a comprehensive epidemiological study examining this association is yet to be conducted. This study aimed to investigate the incidence of cancer in patients with CIDP in South Korea using data from the Korean Health Insurance Review and Assessment Service (HIRA) database.

Methods

Data from the HIRA database between January 2016 and June 2021 were analyzed. The actual incidence of cancer in patients with CIDP was compared with the expected incidence based on the general population statistics in South Korea, with adjustments for age.

Results

In total, 888 patients with CIDP were included in the analysis, of whom 50 (5.63% of malignancy incidence) were newly diagnosed with cancer during the study period. Among the patients with CIDP diagnosed with cancer, 32 (64.00%) were aged 60 years or older, and 36 (72.00%) were male. The observed number of cancer diagnoses corresponded to an incidence rate of 5.63%, with a standardized incidence ratio (SIR) of 2.83 (95% confidence interval [CI]: 1.89-4.39) compared to the expected cancer incidence rate of 2.00%. Notably, the SIR for malignancies of lymphoid, hematopoietic, and related tissues, excluding malignant immunoproliferative diseases, multiple myeloma, and plasma cell neoplasms (C81-96, except C88 and C90), was the highest at 8.51 (95% CI: 4.18-19.83).

Conclusion

Our study shows a potential association between CIDP and an increased risk of hematological malignancies, which is consistent with previous investigations. Further studies are required to better understand the relationship between CIDP and cancer.

Intestinal Behcet’s syndrome with an unusual complication bladder-intestines fistula and urinary tract infections—A case report

A 33-year-old male patient with a 17-year Behcet’s syndrome history showed abdominal pain and fever symptoms. The abdominal CT was suggestive of an acute ileocecal intestinal perforation. In addition, the symptoms disappeared after the conservative treatment. Some related examinations, including capsule endoscopy, were performed to explain the phenomenon of the food residue urine. These results indicated the intestine-urinary tract fistula formation, supposed to be the outcome of intestinal Behcet’s syndrome perforation. This is a rare case of intestinal Behcet’s syndrome with abdominal symptoms as the main manifestation. It was complicated by entero-urinary fistula formation and urinary tract infections. Now, we report this story to emphasize that capsule endoscopy is conducive to the diagnosis and assessment of the intestinal Behcet’s syndrome; moreover, anti-inflammatory treatment including biological agents is effective to relieve the disease at the acute stage in addition to surgical methods.

Epidemiology of Ankle Fractures in Korea: A Nationwide Population-Based Study

BACKGROUND

Although ankle fractures are among the most common fractures, nationwide population-based data on the epidemiology of patients with ankle fractures are scarce. This study aimed to perform an epidemiological analysis of all ankle fractures in Korea from 2010 through 2018.

METHODS

We used national registries from the Korean Health Insurance Review and Assessment Service from 2009 to 2018. The annual incidence of the ankle fracture was calculated. The incidence was also calculated according to gender and age. Trends of fracture subtypes were also analyzed. Then, the incidence of ankle fractures by seasonal variation was investigated.

RESULTS

A total of 735,073 ankle fractures were identified in 461,497,758 people for 10 years. The annual incidence of ankle fracture was 171.37/100,000 persons in 2018, with a male to female ratio of 0.78. Interesting differences in the ankle fracture trends were observed between gender. Male shows the highest incidence in adolescence, and the even distribution has lasted for the rest of their lives. In females, the incidence of ankle fracture showed an increasing tendency as their age increased. There was a clear difference in the incidence rate of each season according to age. Ankle fractures occurred more in spring and autumn in children and adolescents and most in winter in the elderly.

CONCLUSION

Ankle fracture risk was different between sex and exhibited seasonal variations. Our findings can be used for epidemiological awareness and prevention campaigns for ankle fractures.

Foot contact forces can be used to personalize a wearable robot during human walking

Individuals with below-knee amputation (BKA) experience increased physical effort when walking, and the use of a robotic ankle-foot prosthesis (AFP) can reduce such effort. The walking effort could be further reduced if the robot is personalized to the wearer using human-in-the-loop (HIL) optimization of wearable robot parameters. The conventional physiological measurement, however, requires a long estimation time, hampering real-time optimization due to the limited experimental time budget. This study hypothesized that a function of foot contact force, the symmetric foot force-time integral (FFTI), could be used as a cost function for HIL optimization to rapidly estimate the physical effort of walking. We found that the new cost function presents a reasonable correlation with measured metabolic cost. When we employed the new cost function in HIL ankle-foot prosthesis stiffness parameter optimization, 8 individuals with simulated amputation reduced their metabolic cost of walking, greater than 15% (p < 0.02), compared to the weight-based and control-off conditions. The symmetry cost using the FFTI percentage was lower for the optimal condition, compared to all other conditions (p < 0.05). This study suggests that foot force-time integral symmetry using foot pressure sensors can be used as a cost function when optimizing a wearable robot parameter.

Emerging Trends in Mesenchymal Stem Cells Applications for Cardiac Regenerative Therapy: Current Status and Advances

Irreversible myocardium infarction is one of the leading causes of cardiovascular disease (CVD) related death and its quantum is expected to grow in coming years. Pharmacological intervention has been at the forefront to ameliorate injury-related morbidity and mortality. However, its outcomes are highly skewed. As an alternative, stem cell-based tissue engineering/regenerative medicine has been explored quite extensively to regenerate the damaged myocardium. The therapeutic modality that has been most widely studied both preclinically and clinically is based on adult multipotent mesenchymal stem cells (MSC) delivered to the injured heart. However, there is debate over the mechanistic therapeutic role of MSC in generating functional beating cardiomyocytes. This review intends to emphasize the role and use of MSC in cardiac regenerative therapy (CRT). We have elucidated in detail, the various aspects related to the history and progress of MSC use in cardiac tissue engineering and its multiple strategies to drive cardiomyogenesis. We have further discussed with a focus on the various therapeutic mechanism uncovered in recent times that has a significant role in ameliorating heart-related problems. We reviewed recent and advanced technologies using MSC to develop/create tissue construct for use in cardiac regenerative therapy. Finally, we have provided the latest update on the usage of MSC in clinical trials and discussed the outcome of such studies in realizing the full potential of MSC use in clinical management of cardiac injury as a cellular therapy module.

Epidemiological changes in cytomegalovirus end-organ diseases in a developed country: A nationwide, general-population-based study

BACKGROUND

Cytomegalovirus (CMV) can cause tissue-invasive diseases in various organs after primary infection or through reactivation of latent-to-lytic switch over a lifetime. The number of individuals who are at risk of CMV diseases, such as elderly or immunocompromised patients, is constantly increasing; however, recent epidemiological changes associated with CMV disease have not been fully evaluated.

METHODS

We used claims data of about 50 million individuals between 2010 and 2015 from the Korean Health Insurance Review and Assessment Service nationwide database. The code for CMV end-organ diseases in the 'Relieved Co-payment Policy' program matches the ICD-10 code of B25, except for congenital CMV infection and mononucleosis. A 628 cases of CMV and 3140 controls (without CMV disease), matched for age and sex, were selected from this dataset in order to evaluate the effect of adult CMV diseases on all-cause death.

RESULTS

The overall unadjusted incidence rate (IR) of CMV end-organ diseases was 0.52/100,000 individuals. The standardized IR, adjusted for age and sex, have continuously increased from 0.32/100,000 in 2010 to 0.75/100,000 in 2015. The overall unadjusted IR in adult population was highest in 70-79 years for six years (0.96/100,000). In the model adjusted for age, sex, immunocompromised status including solid-organ or hematopoietic stem cell transplant recipients, hematologic malignancies, and human immunodeficiency virus diseases, the hazard ratio of case group was 5.2 (95% confidence interval, 3.6-7.4) for all-cause mortality.

CONCLUSION

Nationwide data indicates that CMV end-organ disease has steadily increased in the past six years and is associated with higher mortality.

Pharmacotherapy for Behçet's Disease and the Risk of Malignancy

Background: Behçet’s disease (BD) is associated with an increased risk of cancer. Few reports have been published on the relationship between drug exposure and the risk of cancer in patients with BD. Herein, we explored the relationship between pharmacologic interventions for BD and the risk of cancer.

Methods: we carried out a retrospective nested case-control study in a cohort of BD patients from attending our institution. Among 1,148 patients, 22 cancer patients were individually 1:2 matched to 44 cancer-free controls. The following biochemical indicators were evaluated: routine blood analysis, liver and kidney function tests, inflammatory indexes, blood gas analysis, blood electrolyte and previous pharmacologic interventions to manage BD including systemic glucocorticoids, methotrexate, cyclosporine-A, azathioprine, cyclophosphamide (CYC), and thalidomide, which are considered the primary medicines used for the management of BD.

Results: Among the 22 BD patients with cancers, myelodysplastic syndrome (MDS) (22.72%) was the most common type. Furthermore, CYC administration was significantly higher in BD patients with cancer compared with the cancer-free matched control group. Further, we observed that complement 4 (C4) (odds ratio [OR] = 0.0001, 95% confidence interval [CI]: 0.001–0.065) and hemoglobin (Hb) (OR = 0.891, 95% CI: 0.795–0.998) levels were independent protective factors for predicting cancer risk in BD patients on multivariate analyses.

Conclusion: Our study revealed that CYC was associated with a high risk of cancer in BD patients. Furthermore, C4 and Hb are independent protective factors for oncogenesis in BD patients. These findings may provide references and suggestions for clinicians to select appropriate treatments and for the early recognition of high-risk patients to reduce cancer incidence in BD patients.

Autoimmune disease and oral squamous cell carcinoma: A systematic review

BACKGROUND

Oral cancer is typically related to environmental carcinogen exposure including tobacco and alcohol. Other less investigated risk factors may be related to a suppressed or dysregulated immune state, and in oral cancer, various levels of immune dysregulation have been found to affect survival and recurrence rates. The rationale for this systematic review was to investigate the possible role that a growing chronic host condition like an autoimmune disease may play in this disease.

METHODS

A systematic search of the literature was carried out using four electronic databases in order to identify original research of any analytic study design type that investigated the relationship between autoimmune disease and oral cancer. Out of 1,947 identified records, 24 observational studies were included for qualitative synthesis.

RESULTS

The studies varied in end points ranging from overall survival (OS), standardized incidence ratio (SIR), and hazard ratio (HR). Due to the heterogenous sampling of studies even within the same study design group, a meta-analysis was not employed. The current state of the literature is varied and heterogenous in both study design and endpoints.

CONCLUSION

Major limitations existed introducing significant bias especially in determining cancer risk such as lack of information surrounding known etiologic risk factors such as alcohol and tobacco consumption. Despite these limitations, a signal was seen between autoimmune disease and oral cancer outcomes and risk. Future studies investigating the relationship between autoimmune disease and oral cancer in a more focused and quantitative manner are therefore needed.

Advances in the Treatment of Behcet's Disease

Purpose of Review

To assess current management of Behcet’s disease (BD). Controversies on therapeutic approaches to different manifestations, whether conventional immunosuppressives (IS) or biologic agents, should be chosen, and options for refractory disease are discussed.

Recent Findings

Glucocorticoids are still the main agents for remission-induction and azathioprine the first-line conventional IS in maintenance phase to prevent relapses of major organ involvement. Apremilast is shown to be a safe and effective option approved by the FDA for oral ulcers. Large case series confirmed the efficacy and safety of TNFα inhibitors and Interferon-α. Promising results are observed with IL-1 inhibitors, ustekinumab, secukinumab, and tocilizumab for refractory BD.

Summary

Although both conventional IS and biologic agents are effectively used to suppress inflammation in BD, there is still an unmet need for clear therapeutic strategies in the management for different manifestations. Further controlled studies with new biologic agents, anticoagulants and the benefit of concomitant IS usage with biologics are needed to optimize the management of BD.

Long term follow-up of Behçet's syndrome patients treated with cyclophosphamide

OBJECTIVES

CYC remains an important treatment option for Behçet's syndrome (BS) patients with life-threatening manifestations. However, adverse events may occur with CYC and this has led to increased use of biologic agents in other vasculitides. We investigated short and long term adverse events associated with CYC use in BS patients.

METHODS

We conducted a retrospective chart review of all BS patients treated with CYC between 1972 and 2006. Patients were called in and a standard form was used for collecting demographic characteristics, indication for CYC, its cumulative dose and short term adverse events, defined as those causing discontinuation of CYC, hospitalization and/or death, long term adverse events, including infertility and malignancy, and outcome.

RESULTS

Of 5790 BS patients, 198 (3.4%) had used at least one dose of CYC. Main indications were vascular or neurological involvement. After a median follow-up of 17 years, 52 (26%) patients had died, 113 (57%) could be contacted, and 33 (17%) were lost to follow-up. Vascular involvement was the leading cause of death (n = 27). Seventeen (9%) patients experienced short term adverse events with haemorrhagic cystitis being the most common. After a median follow-up of 25 years (interquartile range: 15-26 years), 17 malignancies occurred in 15 (8%) patients. Infertility was experienced by 26 (30%) patients.

CONCLUSION

Long term adverse events such as malignancy and infertility were major problems in our BS patients treated with CYC. These results underline the need for safer treatment modalities that are at least as effective as CYC.

The impact of overactive bladder on health-related quality of life in Korea: based on the results of a Korean Community Health Survey

PURPOSE

This study aimed to assess the impact of overactive bladder on health-related quality of life (HRQoL) in a community-based sample of Korean population.

METHODS

The data of adults aged 19 and over that who participated in the 2012 Korean Community Health Survey were analyzed. Overactive bladder severity was classified as normal, mild, moderate, or severe using the Overactive Bladder Symptom scores, and HRQoL was evaluated using EQ-5D-3L. Relations between HRQoL and the severities and symptoms of OAB were investigated. Sampling weighted adjusted multiple regression analysis was performed to determine the effect of OAB symptom severity on HRQoL.

RESULTS

Of the 226,867 study subjects, 12,303 (5.4%) had OAB, and 552 (0.2%) had an OABSS of ≥ 12, indicating severe OAB. The problem -reporting rate significantly increased in all EQ-5D-3L dimensions as OAB severity increased. After adjusting for other variables, OAB severity had a significant effect on EQ-5D-3L index. Urge incontinence had greatest impact on quality of life.

CONCLUSIONS

As the severity of OAB increased from mild to severe, quality of life decreased significantly. OAB was found to negatively affect HRQoL.

Obesity and metabolic health status are determinants for the clinical expression of hypertrophic cardiomyopathy

Aims

We sought to investigate the association of obesity and metabolic health status with the incidence of clinical hypertrophic cardiomyopathy (HCM) diagnosis in the general population. Our goal was to identify modifiable risk factors to attenuate clinical expression of HCM, enabling management evolution from a mostly passive strategy of risk stratification to a proactive strategy of modifying disease expression.

Methods

Using nationwide population-based data from the Korean National Health Insurance Service, 28,679,891 people who were free of prevalent HCM and who underwent health examinations between 2009 and 2015 were followed until 31 December 2016. The primary outcome was clinical HCM that was defined as incident diagnosis of HCM during the follow-up, after a blanking period of 12 months.

Results

Over a median follow-up of 5.2 years, 0.027% (n = 7851) of the study participants were diagnosed as incident HCM. The incidence rate per 1000 person-years was 0.059. A significant association was found between body mass index (BMI) and the incidence of clinical HCM after multivariate adjustment, with a hazard ratio per 1 kg/m2 increase in BMI of 1.063 (95% confidence interval 1.051–1.075). Metabolically unhealthy participants had a greater incidence of HCM than metabolically healthy participants, regardless of obesity status. The effect of BMI was more pronounced in several subgroups, including participants with no hypertension, those aged less than 65 years and men.

Conclusion

We found that individuals with obesity and/or metabolic abnormalities had a significantly higher incidence of clinical HCM diagnosis than their counterparts. Efforts to manage obesity and metabolic abnormalities may be important in modifying clinical expression of HCM.

Cancer incidence in Behçet's disease

BACKGROUND

Previous studies demonstrated an increased cancer risk in autoimmune diseases. Behçet's disease (BD) was also reported to be associated with an increased risk of cancer, although the data is limited.

AIMS

In this study, we aimed to assess cancer incidence in a large cohort of BD patients and to compare with the data of the same age and gender groups.

METHODS

The study cohort consisted of BD patients of > 18 years of age who were prospectively recorded in the Hacettepe University Vasculitis Center. Data on any cancer was collected from the patient files. Cancer incidence was compared with age- and gender-specific cancer incidence rates of the normal population retrieved from the 2014 Turkish National Cancer Registry (TNCR) data using standardized incidence rates (SIR).

RESULTS

Totally, 451 adult cases with BD were included. The median age of the cohort was 43 (20-75), and 52.5% of the patients were males. Eleven cancer cases were observed during a median of 124 months follow-up. Behçet's disease was associated with an increase in cancer risk compared with expected counts in the corresponding age and sex group (SIR 2.84, 95% CI 1.50-4.94, p < 0.001). Patients with papulopustular lesions had a trend toward a decreased risk of cancer (p = 0.060), and patients using azathioprine had a significantly decreased cancer risk (p = 0.031).

CONCLUSION

This study revealed BD patients had approximately three times increased cancer risk compared with corresponding age and sex groups. Besides the routine care, increased attention for cancer surveillance is required in the follow-up of BD patients.

Genetic Polymorphisms in IL-10 Promoter Are Associated With Smoking and Prostate Cancer Risk in African Americans

BACKGROUND/AIM

Even though prostate cancer (PCa) has good prognosis, there is a discrepancy in the risk among ethnic groups, with high morbidity in African American men. Single nucleotide polymorphisms (SNPs) in interleukin 10 (IL-10) have been associated with inflammation and cancer risk. We investigated the association of five SNPs in the IL-10 promoter with clinical features such as Gleason score and smoking.

MATERIALS AND METHODS

A total of 413 DNA samples were obtained from a nested case-control study of African American males who were genotyped for 5 SNPs utilizing pyrosequencing. Multiple and binary logistic regression models were applied to analyze the clinical and genotypic data.

RESULTS

rs12122923 and rs1800871 were associated with PCa risk. Smoking was also found to increase the risk of PCa by 1.6-fold. rs1800893 was found to be associated with lower grades for prostate cancer.

CONCLUSION

IL-10 promoter polymorphisms might be a risk factor for PCa development in smoking subjects and PCa progression.

Parasitic infections and medical expenses according to Health Insurance Review Assessment claims data in South Korea, 2011-2018

Introduction

In South Korea, Health Insurance Review and Assessment claims data contain comprehensive information on healthcare services for almost the entire population. The present study used claims data on parasitic diseases from 2011 to 2018, and associated medical expenses to investigate infection trends associated with endemic parasitic diseases in South Korea, including those not monitored by Korea Centers for Disease Control and Prevention.

Methods

Basic data regarding each parasitic disease were curated from the Healthcare Bigdata Hub (http://opendata.hira.or.kr). Ten endemic parasitic diseases, three pandemic protozoan diseases, and three ectoparasitic diseases were evaluated between 2011 and 2018. Data on each parasitic disease included the number of patients of each sex, age range within 5 years, province, and total medical expenses. Heatmap and principal component analysis were performed to visualize the incidence pattern of parasitic diseases by provinces.

Results

Clonorchiasis and pinworm infections decreased remarkably from 6,097 and 4,018 infections in 2011 to 3,008 and 1,988 infections in 2018, respectively. Other endemic parasitic diseases mostly declined or remained steady over the 8-year period, except for anisakiasis, which doubled from 409 in 2011 to 818 in 2018. Provinces close to North Korea had a higher frequency of claims for Plasmodium vivax infection. The highest rate of clonorchiasis was in Gyeongsangnam-do, while that of anisakiasis was in southern Korea. Jeju province had the highest number of claims for cysticercosis, anisakiasis, pinworm infection, and soil-transmitted helminth infections. The total medical expense for anisakiasis was 65 million Korean won (57,000 US$) in 2011, rising to 237 million Korean won (206,000 US$) in 2018. The medical expense for trichomoniasis was 6,063 million won and for scabies was 1,669 million won in 2018. Since the claims data include only data reported by healthcare providers, some discrepancies might have occurred.

Conclusion

Our findings provide the basis for a health policy to reduce further infections and medical expense.

Risk of malignancy in Behcet disease: A meta-analysis with systematic review

BACKGROUND

Several studies have reported the association of Behcet disease (BD) with the risk of diverse kinds of cancers. However, its association is controversial. Therefore, we conducted a bioinformatics-analysis to explore any possible association.

METHODS

We obtained relevant findings published before October 2018 through literature survey of the PubMed, EMBASE, and Web of Science databases. STATA 12.0 software was used for statistical analysis.

RESULTS

After screening, the meta-analysis comprised 5 studies. We observed a significant positive association between BD and enhanced malignancy risk (pooled relative risk [RR], 1.19; 95% confidence interval [CI]: 1.09-1.30), especially for hematological cancer (pooled RR, 2.58; 95% CI: 1.61-3.55) and thyroid cancer (pooled RR, 1.25; 95% CI: 1.04-1.47). However, high heterogeneity was also observed in the results (I = 81.3%). Subgroup analysis indicated that female BD patients from Korean population are at highest predisposition to overall malignancy. Besides, publication bias was not observed with our choice of surveys.

CONCLUSION

We conclude that patients suffering from BD have an overall increased risk for malignancy. Greater numbers of exhaustive temporal studies are essential for definitive inferences.

Assessment of Cytokine Release against Oral Mucosal Cell Line Culture (TR146) Stimulated by Neutrophil Elastase Associated with Behcet's Disease

Aim

Cytokines and chemokines may be involved in the onset of oral ulcer in Behcet's disease. The aim of our study is to assess the cytotoxic effects of proinflammatory cytokines and chemokines on reconstructed oral mucosal cell line (TR146) when treated with different concentrations of neutrophil elastase (NE).

Objective

For this purpose, a culture of the oral mucosal model (OMM) prepared from a cell line derived from an oral squamous cell carcinoma of buccal mucosa (TR146) is treated with different concentrations of neutrophil elastase. The cultures were incubated for 4- and 24-hour intervals and designed as follows: culture + artificial saliva served as the negative control; culture + 0.01% SLS (sodium lauryl sulphate) served as the positive control; and culture + NE (10, 50, 100, and 200 nM) served as the treated group.

Materials and Methods

We used sandwich ELISA technique to isolate IL-1β (interleukin 1β), IL-8, and TNF-α (tumor necrosis factor).

Results

We found no significant level of IL-8 and TNF-α when treated with different concentrations of neutrophil elastase after 4- and 24-hour incubation. The IL-1β level was slightly higher when treated with 100 and 200 nM NE after 24 hours of incubation although a significantly high level was observed at 100 nM NE after 4 hours of incubation. Hence, we found an increase in the level of IL-1β when stimulating the reconstructed oral mucosal model (OMM) with different concentrations of NE. This is a preliminary in vitro study; however, further research is required to evaluate the cytotoxic effects of cytokines and chemokines released when treated with NE. Moreover, high concentrations of NE are recommended to stimulate the release of cytokines and chemokines against the OMM.

Myeloid disorders after autoimmune disease

Autoimmune diseases (ADs) are associated with an increased risk not only of lymphoproliferative disorders but also of myeloid malignancies. The excess risk of myelodysplastic syndromes and/or acute myeloid leukemia is observed across several AD types, including systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disorders, multiple sclerosis, among others. The risk of developing myeloid neoplasms (MNs) is dependent on several variables, including the specific AD type, chronicity and severity of the AD, type and duration of exposure of disease modifying anti-rheumatic drugs or cytotoxics/immunosuppressives, and genetic predisposition risk. Putative triggering factors linking AD to elevated MN risk include AD-directed medications, shared genetic susceptibilities between the two disease entities, and chronic immune stimulation or bone marrow infiltration by the AD. Molecular mechanisms underpinning leukemogenesis remain largely speculative and warrant further investigation. Leukemias arising in patients with AD are not always 'therapy-related' in that MNs may develop in certain AD subtypes even among patients with no prior therapy exposure. Only a few studies have attempted to determine factors associated with MN development in AD but failed to demonstrate consistent characteristic clinical or paraclinical features. These reports have failed to demonstrate a clear correlation between individual agent exposure and subsequent leukemia development due to the low rates of therapy exposure compounded by the rarity of MN occurrence. Notwithstanding, the leukemogenic potential is best documented with agents such as azathioprine, cyclophosphamide, and mitoxantrone; this risk of MN development does not appear to be shared by biologic approaches such as anti-tumor necrosis factors-alpha inhibitors. In this article, we discuss plausible biologic mechanisms underlying MN pathogenesis in AD and review the data available on the development of MNs in patients with AD.