Sarcoidosis-Like Granulomatous Lymphadenopathy Mistaken for Neoplastic Disease on Positron Emission Tomography

This is a rare case of sarcoidosis-like granulomatous lymphadenopathy that was initially mistaken for a neoplastic process due to the degree of hypermetabolic changes observed on positron emission tomography (PET) scan. Sarcoid-like granulomatous pulmonary disease is a disorder that has been described in WTC (World Trade Center) Rescue Workers, and also known as post 9/11 sarcoidosis. We present an interesting case of a man who presented with several months of progressive dyspnea and was later discovered to have significant bilateral hilar adenopathy, which was PET avid. Even more interesting, this patient’s symptoms completely resolved without the use of systemic steroids or immune suppressants. This is a condition that requires awareness in order to avoid repeating unnecessary tests of performing interventions on a benign condition that may resolve on its own.

Granulomatous lung disease in two workers making light bulbs

BACKGROUND

Associations between sarcoidosis or sarcoid-like granulomatous lung disease and exposure to silica and other inorganic agents have been suggested in several studies.

CASES

We describe granulomatous lung disease in two workers of a small production unit making metal-halide lamps. Initially, both were diagnosed with sarcoidosis. However, in both men, birefringent particles were observed in the lung or mediastinal lymph node biopsies. Clipping of glass tubes led to moderate exposure to dust, consisting mainly of amorphous fused silica, with some cristobalite. After removal from exposure, both subjects improved clinically, radiologically, and functionally.

CONCLUSION

The present cases support the hypothesis that silica might be a trigger for sarcoid-like granulomatous lung disease. Sarcoidosis should be considered a diagnosis of exclusion and clinicians should carefully collect occupational and environmental exposure histories to identify workplace triggers.

Metal-specific CD4+ T-cell responses induced by beryllium exposure in HLA-DP2 transgenic mice

Chronic beryllium disease (CBD) is a granulomatous lung disorder that is associated with the accumulation of beryllium (Be)-specific CD4(+) T cells into the lung. Genetic susceptibility is linked to HLA-DPB1 alleles that possess a glutamic acid at position 69 (βGlu69), and HLA-DPB1*02:01 is the most prevalent βGlu69-containing allele. Using HLA-DP2 transgenic (Tg) mice, we developed a model of CBD that replicates the major features of the human disease. Here we characterized the T-cell receptor (TCR) repertoire of Be-responsive CD4(+) T cells derived from the lungs of Be oxide-exposed HLA-DP2 Tg mice. The majority of Be-specific T-cell hybridomas expressed TCR Vβ6, and a subset of these hybridomas expressed identical or nearly identical β-chains that were paired with different α-chains. We delineated mimotopes that bind to HLA-DP2 and form a complex recognized by Be-specific CD4(+) T cells in the absence of Be. These Be-independent peptides possess an arginine at p5 and a tryptophan at p7 that surround the Be-binding site within the HLA-DP2 acidic pocket and likely induce charge and conformational changes that mimic those induced by the Be(2+) cation. Collectively, these data highlight the interplay between peptides and Be in the generation of an adaptive immune response in metal-induced hypersensitivity.

MyD88 dependence of beryllium-induced dendritic cell trafficking and CD4⁺ T-cell priming

Beryllium exposure results in beryllium hypersensitivity in a subset of exposed individuals, leading to granulomatous inflammation and fibrosis in the lung. In addition to its antigenic properties, beryllium has potent adjuvant activity that contributes to sensitization via unknown pathways. Here we show that beryllium induces cellular death and release of interleukin (IL)-1α and DNA into the lung. Release of IL-1α was inflammasome independent and required for beryllium-induced neutrophil recruitment into the lung. Beryllium enhanced classical dendritic cell (cDC) migration from the lung to draining lymph nodes (LNs) in an IL-1R-independent manner, and the accumulation of activated cDCs in the LN was associated with increased priming of CD4(+) T cells. DC migration was reduced in Toll-like receptor 9 knockout (TLR9KO) mice; however, cDCs in the LNs of TLR9-deficient mice were highly activated, suggesting a role for more than one innate receptor in the effects on DCs. The adjuvant effects of beryllium on CD4(+) T-cell priming were similar in wild-type, IL-1R-, caspase-1-, TLR2-, TLR4-, TLR7-, and TLR9-deficient mice. In contrast, DC migration, activation, and the adjuvant effects of beryllium were significantly reduced in myeloid differentiation primary response gene 88 knockout (MyD88KO) mice. Collectively, these data suggest that beryllium exposure results in the release of damage-associated molecular patterns that engage MyD88-dependent receptors to enhance pulmonary DC function.

Hypersensitivity pneumonitis-like granulomatous lung disease with nontuberculous mycobacteria from exposure to hot water aerosols

OBJECTIVE

Human activities associated with aerosol-generating hot water sources are increasingly popular. Recently, a hypersensitivity pneumonitis (HP)-like granulomatous lung disease, with non-tuberculous mycobacteria from exposure to hot water aerosols from hot tubs/spas, showers, and indoor swimming pools, has been described in immunocompetent individuals (also called "hot tub lung"). Our objective in this study was to examine four additional cases of hot tub lung and compare these cases with others reported in the English print literature on this disease.

DATA SOURCES AND EXTRACTION

We retrospectively reviewed all cases (n = 4) of presumptively diagnosed hot tub lung in immunocompetent individuals at the various physician practices in Springfield, Illinois, during 2001-2005. In addition, we searched MEDLINE for cases of hot tub lung described in the literature.

DATA SYNTHESIS

We summarized the clinical presentation and investigations of four presumptive cases and reviewed previously reported cases of hot tub lung.

CONCLUSIONS

There is a debate in the literature whether hot tub lung is an HP or a direct infection of the lung by nontuberculous mycobacteria. Primary prevention of this disease relies on ventilation and good use practices. Secondary prevention of this disease requires education of both the general public and clinicians to allow for the early diagnosis of this disease.