Molecular analysis of sarcoidosis lymph nodes for microorganisms: a case–control study with clinical correlates

Abstract

IntroductionSarcoidosis is an incurable, chronic granulomatous disease primarily involving the lungs and lymph nodes of unknown aetiology, treated with non-specific anti-inflammatory/immunosuppressive drugs. Persistently symptomatic patients worsen with a disabling, potentially fatal clinical course. To determine a possible infectious cause, we correlated in a case-control study the clinical information with the presence of bacterial DNA in sarcoidosis mediastinal lymph nodes compared with control lymph nodes resected during cancer surgery.MethodsWe retrospectively studied formalin-fixed, paraffin-embedded, mediastinal lymph nodes from 30 patients with sarcoidosis and 30 control patients with lung cancer. Nucleic acids were extracted from nodes, evaluated by ribosomal RNA PCR for bacterial 16S ribosomal DNA and the results were sequenced and compared with a bacterial sequence library. Clinical information was correlated.Results11/30 (36.7%) of lymph nodes from patients with sarcoidosis had detectable bacterial DNA, significantly more than control patient lymph nodes (2/30, 6.7%), p=0.00516. At presentation, 19/30 (63.3%) patients with sarcoidosis were symptomatic including all patients with detectable bacterial DNA. Radiographically, there were 18 stage I and 12 stage II patients. All stage II patients were symptomatic and 75% had PCR-detectable bacteria. After a mean follow-up of 52.8±32.8 months, all patients with PCR-detectable bacteria in this series were persistently symptomatic requiring treatment.Discussion36.6% of patients with sarcoidosis had detectable bacterial DNA on presentation, all of these patients were quite symptomatic and most were radiographically advanced stage II. These findings suggest that bacterial DNA-positive, symptomatic patients have more aggressive sarcoidosis that persists long term and might benefit from antimicrobial treatment directed against this presumed chronic granulomatous infection.

Is there any association between Sarcoidosis and infectious agents?: a systematic review and meta-analysis

“…With regard to the infectious agents investigated, 36 studies evaluated the presence of mycobacteria [20–55] (Table 1), 11 evaluated P. acnes [19, 22, 24, 25, 31, 35, 38, 56–59] (Table 2), seven evaluated human herpesvirus-8 (HHV-8) [22, 40, 60–64] (Table 3), and six evaluated Borrelia species [4, 65–69] (Table 4). Other infectious agents were investigated in some of the studies included, but there were insufficient cases to perform a meta-analysis.…”

“…)CountryMolecular techniqueSarcoidosis patientsNon-sarcoidosis controlsOR (95% CI)n/NType of microorganismsn/NType of microorganismsBocart, 1992 [23]FrancePCR of 65 kDa mycobacterial antigen and IS61102/22MTBC0/22-5.49 (0.25–121.18)Hofland, 2014 [20]NetherlandsNAAT for Mycobacteria and Culture0/32-2/861 MTBC, 1NTM0.52 (0.02–11.13)Robinson, 2013 [24]USAPCR for 16S rDNA, hsp65 and rpoB2/30NTM1/30NTM2.07 (0.18–24.15)Oswald-Richter, 2012 [25]USAMALDI-IMS for ESAT-65/15Mycobacterium spp0/4-4.71 (0.21–104.49)Svendsen, 2011 [26]DenmarkBD ProbeTec IS6110 amplification1/52MTBC0/50-2.94 (0.12–73.93)Mootha, 2010 [27]IndiaPCR of 65 kDa mycobacterial antigen and IS611013/2710 MTBC, 3 NTM2/40NTM17.64 (3.53–88.25)Zhou, 2008 [28]ChinaReal-time PCR of IS986 and human β-blobin gene20/104MTBC7/55MTBC1.63 (0.64–4.14)Dubaniewicz, 2006 [29]PolandBD ProbeTec IS6110 amplification3/50MTBC0/10-1.55 (0.07–32.27)Fite, 2006 [30]SpainPCR of IS6110 and Southern blot hybridisation9/23MTBC1/23MTBC14.14 (1.61–124.11)Yasuhara, 2005 [31]JapanPCR of IS61100/6-0/6--Song, 2005 [32]USAPCR of MTB 16S rRNA6/16MTBC0/16-20.43 (1.04–401.67)Marcoval, 2005 [33]SpainNAAT for rR...…”

“…There was a positive signal rate of 68.54% for P. acnes (366 positive samples from 534 patients). When accounting for the source of biological samples studied, we found that nine of the 11 studies [19, 22, 24, 25, 35, 38, 56–58] evaluated the presence of P. acnes in lymph node samples, of which seven evaluated this location exclusively [19, 24, 35, 38, 57, 58]. This could justify the low heterogeneity among studies, contrary to what was observed in the forest plot of mycobacteria, where the studied biological samples were more heterogeneous.

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“…Regarding sarcoidosis and mycobacteria, there was a strong and significant association (OR 4.33; CI:2.06–9.10) in subgroup analysis of geographic locations when we restricted to studies performed in countries with low burden of tuberculosis [24, 30, 35, 38, 40, 42, 44–46, 49, 51, 53]. There was low heterogeneity among these studies (I 2 test 45.7%; p  = 0.042) (Table 5).…”

“…Most of the studies included in our meta-analysis used biological samples from different locations, including the skin, lymph nodes, and lungs. However, when we restricted the analysis to include only studies that performed PCR on biological samples of the same type, the associations were also significant in both lung samples [30, 40, 45] (OR 2.93; CI:1.09–7.86; I 2  = 56.9%) and lymph node samples [24, 35, 38, 40, 46] (OR 3.82; CI:1.53–9.49; I 2  = 4%), but not skin biological specimens [37, 40] (OR 11.58; CI:0.06–2016.91; I 2  = 81.3%). Once again, the heterogeneity among studies was low to moderate except in two studies performed on skin biopsies (Table 5).…”