Multisystemic sarcoidosis-important lessons learnt from one of the great imitators

Hepatic Sarcoid-Like Reaction Mimicking Liver Metastases in a 36-Year-Old Female With Rheumatoid Arthritis

Hepatic and splenic sarcoidosis are still challenging issues for medical imaging, and in many cases, medical images can't exclude the most common mimic of sarcoidosis which is liver metastases; therefore, a liver biopsy is required. A young female patient who had rheumatoid arthritis presented to our hospital with abdominal pain, anorexia, and weight loss for the past three weeks. She was admitted to the acute medical ward and treated with intravenous fluid hydration for hypercalcemia. Her liver function tests were deranged (anicteric cholestasis picture), and her etanercept medication was stopped after being reviewed by the rheumatologist and gastroenterologist. She had a CT and MRI scan of the abdomen, an ultrasound (US) of the abdomen with enhanced contrast, and a positron emission tomography (PET) scan. The radiological findings could not exclude liver metastases, but an ultrasound-guided liver biopsy confirmed the finding of hepatic granulomatous changes of sarcoidosis. Her symptoms and hypercalcemia resolved, and her liver functions gradually normalized.

Imbalance of Lymphocyte Subsets and CD45RA-Expressing Cells in Intrathoracic Lymph Nodes, Alveolar Compartment and Bloodstream of Pulmonary Sarcoidosis Patients

Sarcoidosis is a systemic granulomatous disease mainly affecting the lungs and hilomediastinal lymph nodes. It is characterized by non-caseating epithelioid cell granulomas in lymph nodes and lungs. Our study aimed to evaluate and compare T, B and NK cell subsets in the alveolar compartment, lymph nodes and the bloodstream simultaneously in the same patients to elucidate the immune responses associated with the development and progression of sarcoidosis. A secondary aim was to evaluate the distribution of CD45RA-expressing cells in the different anatomical compartments. Patients suspected to have sarcoidosis and who underwent bronchoscopy with bronchoalveolar lavage (BAL), lung-draining lymph node (LLN) biopsy by EBUS-TBNA and peripheral blood (PB) sampling were included in the study. They were monitored at the Regional Referral Centre of Siena University Hospital and the Respiratory Diseases Unit of Perugia Hospital. Multicolour flow cytometry analysis through FASCLyric was performed to assess T, B and NK cell subsets. Thirty-two patients (median age (IQR) 57 (52-58) years) were consecutively and prospectively enrolled. Machine learning analysis created a model which selected CD56dim16bright, CD8, Tfc, Th17, Th12, Tfh17, Tfh2, Tc_emRA, Th_emRA, T naïve, Tc naïve, Breg, CD1d⁺CD5⁺, Th-reg, Tfh, Th1 and CD4 cells with an accuracy of 0.9500 (kappa 0.8750). Comparative analysis found 18 cell populations that differed significantly between the three anatomical compartments. The bloodstream was enriched in Th_emRA (p = 0.0416), Tfh2 (p = 0.0189), Tfh17 (p = 0.0257), Th2 (p = 0.0212), Th17 (p = 0.0177), Th-naïve (p = 0.0368), CD56dimCD16bright (p < 0.0001), CD8 (p = 0.0319), Tc_emRA (p < 0.0001) and Tfc cells (p = 0.0004) compared with the alveolar compartment, while Th-reg were lower in PB than BAL (p = 0.0329). The alveolar compartment was enriched in Breg (p = 0.0249) and CD1d⁺CD5⁺ (p = 0.0013) with respect to LLN samples and PB. Conversely, Tfh (p = 0.0470), Th1 (p = 0.0322), CD4 (p = 0.0486) and Tc-naïve (p = 0.0009) were more abundant in LLN than in BAL and PB. It has been speculated that changes in the relative contents of PB cells could be related to changes in production and to the selective redistribution of PB cells to granulomatous foci. This study further supports the fact that sarcoidosis is multisystemic in nature. However, the low level of immune cells in peripheral blood of patients with sarcoidosis is concerning. A re-expression of CD45RA on CD4⁺ and CD8⁺ cells could result in a reduction in peripheral immune activity. Thus, changes in the spectrum of the bloodstream may reflect both pathogenic and compensatory processes.