Association of HLA genes with diffuse panbronchiolitis in Chinese patients

Diffuse panbronchiolitis: A case report from a Chinese consanguineous marriage family and literature review

Diffuse panbronchiolitis (DPB) is a chronic diffuse airway inflammatory disease, which is strongly associated with the class I human leukocyte antigen (HLA) alleles. Here, we report a pair of sisters who have been suffering from chronic cough, expectoration and wheezing for many years. They were previously misdiagnosed as chronic bronchitis and bronchial asthma, and were recently diagnosed as diffuse panbronchiolitis. The 36-year-old elder sister suffered from diffuse panbronchiolitis complicated with pulmonary tuberculosis. The 30-year-old younger sister suffered from diffuse panbronchiolitis complicated with bronchial asthma and bronchiectasis. We have performed HLA genotyping research on the two sisters, their parents and younger brother. The results showed that all family members were positive for HLA-A24 and HLA-B13. The younger sister and mother were positive for HLA-A2. The younger brother and father were positive for HLA-A11. We suspect that the two sisters’ disease susceptibility may be caused by their parents’ consanguineous marriage. In this study, we reported the clinical characteristics of the two sisters with diffuse panbronchiolitis and shared the associated HLA genotyping results of this family cluster, hoping to provide reference for the etiology, diagnosis and treatment of this disease.

KGF-2 targets alveolar epithelia and capillary endothelia to reduce high altitude pulmonary oedema in rats

High altitude pulmonary oedema (HAPE) severely affects non-acclimatized individuals and is characterized by alveolar flooding with protein- rich oedema as a consequence of blood-gas barrier disruption. Limited choice for prophylactic treatment warrants effective therapy against HAPE. Keratinocyte growth factor-2 (KGF-2) has shown efficiency in preventing alveolar epithelial cell DNA damages in vitro. In the current study, the effects of KGF-2 intratracheal instillation on mortality, lung liquid balance and lung histology were evaluated in our previously developed rat model of HAPE. We found that pre-treatment with KGF-2 (5 mg/kg) significantly decreased mortality, improved oxygenation and reduced lung wet-to-dry weight ratio by preventing alveolar-capillary barrier disruption demonstrated by histological examination and increasing alveolar fluid clearance up to 150%. In addition, KGF-2 significantly inhibited decrease of transendothelial permeability after exposure to hypoxia, accompanied by a 10-fold increase of Akt activity and inhibited apoptosis in human pulmonary microvascular endothelial cells, demonstrating attenuated endothelial apoptosis might contribute to reduction of endothelial permeability. These results showed the efficacy of KGF-2 on inhibition of endothelial cell apoptosis, preservation of alveolar-capillary barrier integrity and promotion of pulmonary oedema absorption in HAPE. Thus, KGF-2 may represent a potential drug candidate for the prevention of HAPE.

Primary ciliary dyskinesia complicated with diffuse panbronchiolitis: a case report and literature review

Background

Fifty percent of patients with primary ciliary dyskinesia (PCD) have situs inversus. Diffuse panbronchiolitis (DPB) might be one of the characteristic features of the lung in PCD.

Methods

We reported a case of PCD without situs inversus, yet complicated with DPB, and did literature review.

Results

A 34-year-old nonsmoking Chinese woman with 6-year primary infertility suffered from recurrent episodes of respiratory tract infections since childhood. Lung auscultation revealed end-inspiratory coarse crackles. Pulmonary function tests demonstrated mild obstructive ventilation functional impairment. Lung biopsy showed respiratory bronchiolitis. Nasal mucosa cilia showed the absence of both outer and inner dynein arms of the microtubules. Saccharin test was positive. Chest images showed bronchiectasis and bronchiolitis but no situs inversus. Paranasal sinus computed tomography (CT) showed maxillary sinusitis and ethmoid sinusitis. A culture of bronchoalveolar lavage fluid was positive for Pseudomonas aeruginosa. Her conditions improved in clinical symptoms and CT images after 2 months of treatment with azithromycin. Literature review revealed that very rare patients were diagnosed as PCD complicated with diffuse DPB, and all of them had situs inversus.

Conclusions

The association of DPB might be one of the characteristic features of the lung in PCD. Further studies on the concurrence of these two diseases are suggested so as to elucidate the mechanism of both.

Please cite this paper as: Chen W, Shao C, Song Y and Bai C. Primary ciliary dyskinesia complicated with diffuse panbronchiolitis: a case report and literature review. Clin Respir J 2014; 8: 425–430.

New insights of aquaporin 5 in the pathogenesis of high altitude pulmonary edema

Background

High altitude pulmonary edema (HAPE) affects individuals and is characterized by alveolar flooding with protein-rich edema as a consequence of blood-gas barrier disruption. In this study, we hypothesized that aquaporin 5 (AQP5) which is one kind of water channels may play a role in preservation of alveolar epithelial barrier integrity in high altitude pulmonary edema (HAPE).

Methods

Therefore, we established a model in Wildtype mice and AQP5 −/− mice were assingned to normoxic rest (NR), hypoxic rest (HR) and hypoxic exercise (HE) group. Mice were produced by training to walk at treadmill for exercising and chamber pressure was reduced to simulate climbing an altitude of 5000 m for 48 hours. Studies using BAL in HAPE mice to demonstrated that edema is caused leakage of albumin proteins and red cells across the alveolarcapillary barrier in the absence of any evidence of inflammation.

Results

In this study, the Lung wet/dry weight ratio and broncholalveolar lavage protein concentrations were slightly increased in HE AQP5 −/− mice compared to wildtype mice. And histologic evidence of hemorrhagic pulmonary edema was distinctly shown in HE group. The lung Evan’s blue permeability of HE group was showed slightly increased compare to the wildtype groups, and HR group was showed a medium situation from normal to HAPE development compared with NR and HE group.

Conclusions

Deletion of AQP5 slightly increased lung edema and lung injury compared to wildtype mice during HAPE development, which suggested that the AQP5 plays an important role in HAPE formation induced by high altitude simulation.

Interstitial lung diseases-can pathologists arrive at an etiology-based diagnosis? A critical update

Interstitial lung diseases (ILD) encompass a group of diseases with a wide range of etiologies and a variety of tissue reactions within the lung. In many instances, a careful evaluation of the tissue reactions will result in a specific diagnosis or at least in a narrow range of differentials, which will assist the clinician to arrive at a definite diagnosis, when combining our interpretation with the clinical presentation of the patient and high-resolution computed tomography. In this review, we will exclude granulomatous pneumonias as well as vascular diseases (primary arterial pulmonary hypertension and vasculitis); however, pulmonary hypertension as a complication of interstitial processes will be mentioned. Few entities of pneumoconiosis presenting as an interstitial process will be included, whereas those with granulomatous reactions will be excluded. Drug reactions will be touched on within interstitial pneumonias, but will not be a major focus. In contrast to the present-day preferred descriptive pattern recognition, it is the author's strong belief that pathologists should always try to dig out the etiology from a tissue specimen and not being satisfied with just a pattern description. It is the difference of sorting tissue reactions into boxes by their main pattern, without recognizing minor or minute reactions, which sometimes will guide one to the correct etiology-oriented interpretation. In the author's personal perspective, tissue reactions can even be sorted by their timeliness, and therefore, ordered by the time of appearance, providing an insight into the pathogenesis and course of a disease. Also, underlying immune mechanisms will be discussed briefly as far as they are essential to understand the disease.

Differential association between HLA and diffuse panbronchiolitis in Northern and Southern Chinese

BACKGROUND

Diffuse panbronchiolitis (DPB) is a progressive inflammatory pulmonary disease that predominately affects East Asians. Genetic susceptibility to DPB is correlated with the human leukocyte antigens HLA-B54 in Japanese and HLA-A11 in Koreans. However, no systematic genetic study of DPB pathogenesis has been conducted in the Chinese population. The aim of this study was to investigate the possible association between HLA and disease susceptibility in Chinese patients with DPB.

METHODS

A literature review of both Chinese and English language studies on Chinese DPB patients, published between 1983 and 2010, was conducted. Seventy subjects met the inclusion criteria and were retrospectively analyzed for HLA gene frequency according to geographic region.

RESULTS

HLA-B54 frequency was significantly greater in DPB patients than in controls in the Northern Chinese group (35.7% vs. 4.6%, p=7.5×10(-7)). Although the HLA-B54 frequency was slightly increased in the Southern Chinese patients, the difference was not significant compared with control subjects (14.3% vs. 5.7%, p=0.28). The HLA-A11 frequency was significantly greater in DPB patients than controls in the Southern Chinese group (54.8% vs. 26.4%, p=0.009). Despite an increase of HLA-A11 frequency in the Northern Chinese group, no significant variation in HLA-A11 frequency was found compared with control subjects (42.9% vs. 30.8%, p=0.535). The HLA-A2 frequency was significantly decreased in DPB patients than in controls in the Southern Chinese group (22.9% vs. 66.0%, p=0.001). However, no significant difference in HLA-A2 frequency was found in the Northern Chinese group (50.0% vs. 46.9%, p=0.872).

CONCLUSION

HLA-B54 and HLA-A11 were positively associated with DPB in Northern and Southern Chinese, respectively. Population substructure may impact the genetic predisposition of DPB in China.

Genetic predisposition to diffuse panbronchiolitis

Diffuse panbronchiolitis is characterized by chronic inflammation in respiratory bronchioles and sinobronchial infection. The pathophysiology accompanying the persistent bacterial infection is noteworthy for the accumulation of lymphocytes and foamy macrophages around the small airways, for mucus hypersecretion, and for the number of neutrophils in the large airways. Until the establishment of long-term macrolide therapy, the prognosis was generally poor. Case studies of diffuse panbronchiolitis in East Asians, including Japanese, Koreans and Chinese, have frequently been reported, and genetic predisposition to the disease has been assumed in Asians. Immunogenetic studies revealed a strong association with human leukocyte antigen (HLA)-B54 in Japanese, whereas an association with HLA-A11 was reported in Koreans. These findings imply that a major susceptibility gene may be located between the HLA-A and HLA-B loci on the short arm of human chromosome 6. We have recently cloned novel mucin-like genes in this candidate region. In addition to accumulated knowledge of classical HLA genes and mucin genes, further analysis of newly identified genes may provide insights into the pathogenesis of the disease.

Molecular cloning of two novel mucin-like genes in the disease-susceptibility locus for diffuse panbronchiolitis

Diffuse panbronchiolitis (DPB) is a rare complex genetic disease affecting East Asians and is strongly associated with the class I human leukocyte antigens (HLA)-B54 in Japanese and HLA-A11 in Koreans. We recently showed that an HLA-associated major susceptibility gene for DPB is probably located within the 200 kb in the class I region 300 kb telomeric of the HLA-B locus on the chromosome 6p21.3. We cloned two novel mucin-like genes designated panbronchiolitis related mucin-like 1 and 2 (PBMUCL1 and PBMUCL2) in the candidate region, which form a mucin-like gene cluster together with two adjacent genes, MUC21 and DPCR1. PBMUCL1 gene expression was remarkably upregulated by polyinosine-polycytidylic acid [poly(I:C)] stimulation in normal human bronchial epithelial cells redifferentiated at the air-liquid interface. We found genetic polymorphisms in PBMUCL1 gene which were associated with DPB: the A-allele of the PBMUCL1 intron 2 single nucleotide polymorphism (SNP) was positively associated and variable numbers of tandem repeats (VNTR) polymorphism in exon 3 (1,890-base pair deletion) was negatively associated. Despite a strong association with HLA-B in the Japanese, the mucin-like gene PBMUCL1 is also one of the candidate genes of DPB susceptibility.

Pathology of small airways disease

CONTEXT

The term small airways disease encompasses a generally poorly understood group of lung diseases that may arise primarily within the small airways or secondarily from diseases primarily affecting the bronchi or lung parenchyma. Their histology may be confusing; however, because treatments and prognoses vary, correct pathologic diagnosis is important.

OBJECTIVE

To present a nonexhaustive review of the pathology of primary and secondary small airways diseases, including small airways disease related to tobacco; to various other exposures, including mineral dusts; to diseases involving other areas of the lung with secondary bronchiolar involvement; and to recently described bronchiolitic disorders.

DATA SOURCES

Current literature is reviewed.

CONCLUSIONS

Small airways diseases include a wide variety of diseases of which the pathologist must consider. Uncommon conditions such as diffuse idiopathic neuroendocrine cell hyperplasia and diffuse panbronchiolitis may show relatively specific diagnostic features histologically; however, most small airways diseases exhibit nonspecific histologic features. Conditions not considered primary pulmonary diseases, such as collagen vascular diseases, bone marrow transplantation, and inflammatory bowel disease, must also be considered in patients with small airways changes histologically. Clinical and radiologic correlation is important for obtaining the best possible diagnosis.

Small Airways Disease

Small airways diseases are best defined pathologically as a diverse group of conditions that primarily involve bronchioles and acartilagenous airways 2 mm or less in diameter, which include membranous bronchioles, respiratory bronchioles, and alveolar ducts. Small airways can be involved with disease primarily or secondarily. The concept of small airways disease varies among specialties, with clinicians generally considering them in terms of terminal airway changes causing airflow obstruction, radiologists considering them in the context of direct signs and indirect signs identified on high-resolution computed tomography scans, and pathologists evaluating them based entirely or almost entirely on the histologic changes present in the bronchioles, with or without associated changes involving bronchi and alveoli. The histologic features of small airways diseases may be confusing because they overlap. There may be incomplete assessment of the histologic process with limited biopsy. Other disease processes may occur along with a small airways disease, and may obscure or confound its histologic features. This article focuses on the histologic changes diagnostic of a variety of primary and secondary small airways diseases. Because the histologic features involve bronchioles, gross findings are often minimal and/or nonspecific. The article provides a nonexhaustive examination of conditions and diseases involving the small airways, focusing on the microscopic features, with emphasis on the limitations of histologic diagnosis and differential diagnosis.

Diffuse panbronchiolitis: not just an Asian disease: Australian case series and review of the literature

Diffuse panbronchiolitis is a disease of obscure aetiology that is traditionally associated with Asian ethnicity. We propose that this disease also occurs in Caucasians and the incidence in this population is greater than currently recognised. We further propose that high resolution computed tomography (HRCT) and response to macrolide therapy should be relied upon to make this diagnosis without verification by lung biopsy. In most circumstances, obtaining a biopsy for histopathology is not practical, and the disease may then be mistaken for other more common airway diseases. Accuracy of diagnosis is important as untreated disease is associated with a poor prognosis, and effective treatment is available. We report four out of a series of cases as evidence that DPB is in fact more common in the Western population than is currently understood.