Practical Issues and Challenges in the Diagnosis and Treatment of Pulmonary Sarcoidosis

Value of different bronchoscopic sampling techniques in diagnosis of sarcoidosis: a prospective study of 151 patients

BACKGROUND

The exact position of routine bronchoscopic sampling techniques in diagnostic workup of sarcoidosis is often debated. Herein, we ascertain the role of transbronchial needle aspiration (TBNA), endobronchial ultrasound-guided TBNA (EBUS-TBNA), transbronchial lung biopsy (TBLB), and endobronchial biopsy (EBB) in diagnosis of sarcoidosis.

METHODS

Consecutive patients with suspected sarcoidosis who underwent fiberoptic bronchoscopy were studied. TBLB, EBB, TBNA, or EBUS-TBNA was performed as indicated in a standardized manner. A diagnosis of sarcoidosis was established based on the finding of non-necrotizing granulomas or on clinical grounds at 6-month follow-up. Individual and cumulative yield of various procedures and their correlation with clinicoradiologic parameters was analyzed.

RESULTS

Of the 164 patients studied, 151 were finally diagnosed as sarcoidosis. Granulomas were demonstrated in 127 (84.2%) patients. Diagnostic yield of TBLB, EBB, TBNA, and EBUS-TBNA was 68.7%, 49.6%, 22.43%, and 57.1%, respectively. Cumulative yields of various procedures were: EBB+TBLB 81.4%; TBLB+TBNA 73.7%; TBNA+EBB 62.9%; TBLB+EBB+TBNA 86.9%; and TBLB+EBB+EBUS-TBNA 86.4%. In those with visible mucosal abnormalities, TBLB+EBB conferred the highest diagnostic yield (92.8%). Clinical findings or radiologic stage had no impact on diagnostic yield.

CONCLUSIONS

TBLB is an important tool in bronchoscopic diagnosis of sarcoidosis. If endobronchial abnormalities are seen during bronchoscopy, TBLB with EBB gives the best results otherwise TBLB combined with conventional TBNA and EBB or EBUS-TBNA are required to maximize the diagnostic yield.

Utility of B-cell epitopes based peptides of RD1 and RD2 antigens for immunodiagnosis of pulmonary tuberculosis

Tuberculosis (TB) continues to be a major health problem due to lack of accurate, rapid, and cost-effective diagnostic tests. Serodiagnostic tests incorporating highly specific region of difference (RD) antigens (early secretory antigenic target 6 [ESAT-6], culture filtrate protein 10 [CFP-10], culture filtrate protein 21 [CFP-21], and mycobacterial protein from species tuberculosis 64 [MPT-64]) have recently been shown to be promising for specific diagnosis of TB in our lab. However, only few studies have reported the use of synthetic peptides of RD antigens, and none has used them to differentiate TB from sarcoidosis, a close mimic of smear-negative pulmonary TB (PTB) with entirely different management. The present study was conducted with an aim to study the utility of B-cell epitopes based peptides of RD1 (ESAT-6, CFP-10) and RD2 (CFP-21, MPT-64) antigens for immunodiagnosis of PTB for which sputum smear-positive PTB patients, sputum smear-negative PTB patients, sarcoidosis patients, and healthy controls (n = 24/group) were recruited. Bioinformatic software Bcepred was used to predict linear B-cell epitopes, using physico-chemical properties on a non-redundant dataset. Seven peptides as representative B-cell epitopes of ESAT-6, CFP-10, CFP-21, and MPT-64 were evaluated as targets of the antibody responses in TB patients and controls by enzyme-linked immunosorbent assay (ELISA). The current study showed sensitivity with individual peptides ranging from 37.5% to 83.3% for smear positive, 25% to 58.3% for smear negative as compared to 4.16% to 20.8% for sarcoidosis. Four out of 7 peptides that showed higher reactivity with TB patients and better discrimination from sarcoidosis patients representing ESAT-6, CFP-10, CFP-21, and MPT-64 were selected for multiepitope ELISA. The combination of peptides yielded 83.3% sensitivity for smear positive, 62.5% for smear negative, and only 4.16% for sarcoidosis. The specificity, however, for all the peptides/combination was 100%. Combination of peptides has proven to be better than individual peptides as per the latest criteria of the World Health Organization according to which a test that can replace smear microscopy with sensitivity of >90% for smear-positive patients and >65% for smear-negative TB patients with a specificity >95%, and thus, the present study suggests that a test based on combination of peptides selected from mycobacterial RD1 and RD2 antigens could be important for promoting an early diagnosis and management of otherwise difficult to diagnose smear-negative PTB patients. Moreover, it can also be used to discriminate sarcoidosis from PTB, thus preventing the misdiagnosis and mismanagement.

Pharmacotherapy for pulmonary sarcoidosis: a Delphi consensus study

BACKGROUND

Most issues concerning pharmacotherapy of pulmonary sarcoidosis have not been resolved in clinical trials. The objective was to survey sarcoidosis experts concerning the treatment of pulmonary sarcoidosis and attempt to reach a consensus by these experts using a Delphi method.

METHODS

A 6-item questionnaire was developed. Experts were identified at the Diffuse Lung Disease Network at the annual CHEST meeting in October 2008. Three rounds of questionnaires were presented to the experts. Respondent feedback and supporting literature was incorporated into the questionnaires of subsequent rounds.

RESULTS

Experts reached a consensus concerning the following issues: (a) corticosteroids are the initial therapy of choice; (b) initial use of inhaled corticosteroids are not recommended; (c) methotrexate was the preferred second-line drug; (d) 40mg of daily prednisone equivalent was the maximum dose recommended for the treatment of acute pulmonary sarcoidosis; (e) tapering to 10mg of daily prednisone equivalent for chronic pulmonary sarcoidosis was considered a successful taper. The experts could not resolve the following issues: (a) the initial corticosteroid dose for the treatment of acute pulmonary sarcoidosis; (b) the decision and timing of corticosteroid therapy in a patient with mild, Stage 2 pulmonary sarcoidosis.

CONCLUSIONS

This Delphi study revealed that sarcoidosis experts reached a consensus concerning several aspects of the treatment of pulmonary sarcoidosis; these could be considered as appropriate approaches to therapy. Other issues concerning the therapy of pulmonary sarcoidosis remain unresolved by experts, and are areas where further clinical research could be directed.