Review series: Aspects of interstitial lung disease. Sarcoidosis

The critical role of histology in distinguishing sarcoidosis from common variable immunodeficiency disorder (CVID) in a patient with hypogammaglobulinemia

Background

Common variable immunodeficiency disorders (CVID) are a rare group of primary immune defects, where the underlying cause is unknown. Approximately 10–20% of patients with typical CVID have a granulomatous variant, which has closely overlapping features with sarcoidosis.

Case presentation

Here we describe a young man who sequentially developed refractory Evans syndrome, cauda equina syndrome and most recently renal impairment. Following immunosuppression, he has made a recovery from all three life-threatening autoimmune disorders. As the patient was hypogammaglobulinemic for most of the time while on immunosuppression, vaccine challenges and other tests were not possible. Histological features were in keeping with sarcoidosis rather than the granulomatous variant of CVID. In the brief period when immunosuppression was lifted between the cauda equina syndrome and renal impairment, he normalised his immunoglobulins, confirming sarcoidosis rather than CVID was the underlying cause.

Conclusion

We discuss diagnostic difficulties distinguishing the two conditions, and the value of histological features in our diagnostic criteria for CVID in identifying sarcoidosis, while the patient was hypogammaglobulinemic. The key message from this case report is that the characteristic histological features of CVID can be very helpful in making (or excluding) the diagnosis, particularly when other tests are not possible.

Pulmonary manifestations of rheumatologic diseases

PURPOSE OF REVIEW

The present review intends to provide an overview of the diversity and complexity of pulmonary manifestations of rheumatologic diseases and gaps in knowledge to effectively manage them.

RECENT FINDINGS

Diffuse lung disease in children with rheumatologic diseases represents a heterogeneous group of autoimmune disorders. Despite their significant morbidity and mortality, we have limited understanding about their pathogenesis. Here, we provide an overview of the pathophysiology and current management approach of these disorders, highlighting tools which assist with diagnosis, risk stratification and therapy. In this context, we address the need to develop a standardized approach to diagnose at-risk patients with rheumatologic disease and to predict their progression and the need to develop robust studies which evaluate the factors and interventions that influence pulmonary disease outcome.

SUMMARY

Diffuse lung disease in children with rheumatologic diseases represents a heterogeneous group of severe autoimmune disorders. By adopting a collaborative research approach among multicenters to help diagnose, risk stratify, and understand disease progression, effective management decisions can be optimized to improve clinical outcome.

Sarcoidosis in iron-steel industry: mini case series

Sarcoidosis is a disease of unknown etiology. Despite the proposed connection between the development of sarcoidosis and exposure to environmental and toxic substances, no definitive associations could be established. Also, the role of silica and silicates in the etiology of this condition is currently unknown. Heat-treatment of silica results in the generation of tridymite and cristobalite forms and iron-steel industry represents one branch of industry in which silicone element is exposed to temperatures around 2000°C. Studies reporting on the incidence of sarcoidosis in the workers of iron-steel industry are scarce in number, and workers of this industrial branch are known to be exposed to silica in the form of cristobalite, nano-particulate silicone, metal oxides, and silicates. These substances, which have respiratory toxic properties and have been reported to be associated with autoimmune conditions, may also play a role in the pathogenesis of sarcoidosis. In our clinic, sarcoidosis was diagnosed in a total of 4 individuals, who works in the iron-steel industry. Through this report involving a series of patients with sarcoidosis, we also wanted to discuss the role of crystalline silica forms and silicates in the etiology of sarcoidosis, which is also considered to be an auto-immune condition. (Sarcoidosis Vasc Diffuse Lung Dis 2017; 34: 365-372).

Interstitial lung disease: raising the index of suspicion in primary care

Interstitial lung disease (ILD) describes a group of diseases that cause progressive scarring of the lung tissue through inflammation and fibrosis. The most common form of ILD is idiopathic pulmonary fibrosis, which has a poor prognosis. ILD is rare and mainly a disease of the middle-aged and elderly. The symptoms of ILD—chronic dyspnoea and cough—are easily confused with the symptoms of more common diseases, particularly chronic obstructive pulmonary disease and heart failure. ILD is infrequently seen in primary care and a precise diagnosis of these disorders can be challenging for physicians who rarely encounter them. Confirming a diagnosis of ILD requires specialist expertise and review of a high-resolution computed tomography scan (HRCT). Primary care physicians (PCPs) play a key role in facilitating the diagnosis of ILD by referring patients with concerning symptoms to a pulmonologist and, in some cases, by ordering HRCTs. In our article, we highlight the importance of prompt diagnosis of ILD and describe the circumstances in which a PCP’s suspicion for ILD should be raised in a patient presenting with chronic dyspnoea on exertion, once more common causes of dyspnoea have been investigated and excluded.

Regulatory T cells with reduced repressor capacities are extensively amplified in pulmonary sarcoid lesions and sustain granuloma formation

Sarcoidosis can evolve into a chronic disease with persistent granulomas accompanied by progressive fibrosis. While an unlimited inflammatory response suggests an impaired immune control in sarcoid lesions, it stands in contrast to the massive infiltration with CD4(+)CD25(high)FoxP3(+) regulatory T cells. We here revealed that those Treg cells in affected lung lesions were mainly derived from activated natural Treg cells with GARP (LRRC32)-positive phenotype but exhibited reduced repressor capacities despite high IL-10 and TGF-beta 1 levels. The repressive capacity of blood Treg cells, in contrast, was not impaired compared to age-matched healthy donors. Treg derived cells in granuloma lesions have undergone extensive rounds of amplifications indicated by shortened telomeres compared to blood Treg cells of the same patient. Lesional Treg derived cells moreover secreted pro-inflammatory cytokines including IL-4 which sustains granuloma formation through fibroblast amplification and the activation of mast cells, the latter indicated by the expression of membrane-bound oncostatin M.