419. Diagnostic Performance of Immunohistochemistry Test to Differentiate Aspergillosis from Mucormycosis with Formalin-fixed tissue specimens
Session: Poster Abstract Session: Fungal Disease: Management and Outcomes
Thursday, October 4, 2018
Room: S Poster Hall

Background: Distinguishing aspergillosis from mucormycosis is clinically important as different antifungal agents are required. However, the sensitivity of fungal culture is suboptimal and histomorphologic diagnosis is not always accurate due to morphologic similarities. We investigated the diagnostic performance of immunohistochemistry (IHC) test for diagnosis of aspergillosis and mucormycosis.

Methods: Patients who met the criteria for mycologically proven aspergillosis or mucormycosis and in whom formalin-fixed, paraffin-embedded tissues were available were enrolled at a tertiary hospital from January 1992 to October 2017. Mycologically proven invasive fungal infections were defined as there were the histologic evidence of tissue invasion of hyphae and the recovery of Aspergillus species or agents of mucormycosis (Rhizopus spp., Cunninghamella spp., Apophysomyces spp., Saksenaea spp., Absidia spp., Mucor spp.) by culture from sterile specimens. Anti-Aspergillus mouse monoclonal antibody (1:50; clone WF-AF-1; LSBio, WA, USA) and anti-Rhizopus arrhizus mouse monoclonal antibody (1:100; clone WSSA-RA-1; LSBio, WA, USA) were used for IHC test, and we evaluated the diagnostic performance of IHC test using sensitivity and specificity.

Results: A total of 32 invasive fungal infection including 12 proven mucormycosis and 20 proven aspergillosis were analyzed. The fungal species from sterile sites and diagnostic performance of IHC test for these 30 patients were shown in Table 1.

Conclusion: The IHC test seems to be useful in compensating the limitations of histomorphologic diagnosis in distinguishing between aspergillosis and mucormycosis.

Keywords: Aspergillosis; Mucormycosis; Histomorphology; Immunohistochemistry


Table 1. Diagnostic Performance of Mucormycosis and Aspergillosis Immunohistochemistry Tests in Proven Mucormycosis and Proven Aspergillosis

IHC Test Result

Proven Mucormycosis,

No. of Cases (n=12)

Proven Aspergillosis,

No. of Cases (n=20)

Diagnostic Performance

% (95% CI)

Mucormycosis

 

 

 

Positive

12

0

Sensitivity: 100

(70 - 100)

Negative

0

0

Specificity: 100

 (80 - 100)

Aspergillosis

 

 

 

Positive

0

18

Sensitivity: 90

(67 - 98)

Negative

0

2

Specificity: 100

(70 - 100)

Abbreviations: CI, confidence interval; IHC, immunohistochemistry.

 

Ji Hyun Yun, MD1, Sungim Choi, M.D2, Jung Wan Park, MD3, Kyung Hwa Jung, MD4, Kyeong Min Jo, M.D2, Jiwon Jung, MD5, Min Jae Kim, MD2, Yong Pil Chong, MD, PhD2, Sang-Oh Lee, MD, PhD2, Sang-Ho Choi, MD, PhD2, Jun Hee Woo, M.D6, Yang Soo Kim, MD, PhD2, Joon Seon Song, M.D7, Young Soo Park, M.D7 and Sung-Han Kim, MD, PhD2, (1)Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Songpa-gu, Seoul, Korea, Republic of (South), (2)Department of Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea, Republic of (South), (3)Department of Infectious Disease, Asan medical center, University of Ulsan College of Medicine, Seoul, Korea, Republic of (South), (4)Departments of Infectious Diseases, Departments of Infectious, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea, Republic of (South), (5)Internal Medicine, Ulsan University Hospital, Ulsan, Korea, Republic of (South), (6)Infectious Diseases, Asan Medical Center, University of Ulsan College of Medicine, Songpa-gu, Seoul, Korea, Republic of (South), (7)Pathology, Asan Medical Center, University of Ulsan College of Medicine, Songpa-gu, Seoul, Korea, Republic of (South)

Disclosures:

J. H. Yun, None

S. Choi, None

J. W. Park, None

K. H. Jung, None

K. M. Jo, None

J. Jung, None

M. J. Kim, None

Y. P. Chong, None

S. O. Lee, None

S. H. Choi, None

J. H. Woo, None

Y. S. Kim, None

J. S. Song, None

Y. S. Park, None

S. H. Kim, the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI): Investigator , Grant recipient .

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