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CD Fei Academic | mNGS Technology Rapid Diagnosis of Cyanobacterium marneffei Infection in a Chinese Birth Immunodeficiency Cohort

Views: 0     Author: Fudan Pediatric Clinical Immunoallergy Department     Publish Time: 2022-12-14      Origin: 复旦儿科临床免疫过敏科


/ guide /


Recently, the team of Professor Wang Xiaochuan and Professor Hou Jia from the Children's Hospital of Fudan University, in cooperation with Datafei Medical, published 'Application of metagenomic next-generation sequencing technology in China's birth immunodeficiency cohort to rapidly Diagnosis of C. marneffei infection.This study reported the clinical and immunological characteristics of 6 neonates with T. marneffei infection, and explored the diagnostic value of metagenomic next-generation sequencing (mNGS) in T. marneffei infection.


/ Research Background /


T. marneffei is an opportunistic fungus mainly found in Southeast Asia.The majority of T. marneffei-infected individuals are AIDS patients, but have also been reported in other immunocompromised individuals, such as adult acquired immunodeficiency patients who produce IFN-γ autoantibodies, birth immunodeficiency (IEI), hematological malignancies, Diabetes and patients taking glucocorticoids or immunosuppressants.


In recent years, cases of T. marneffei infection with IEI have been reported one after another, involving mutations in STAT1, STAT3, CD40LG, CARD9 and IFNGR1 genes.Without timely and effective antifungal treatment, T. marneffei infection can lead to disseminated systemic infection and life-threatening.Therefore, early identification and rapid and accurate diagnosis of pathogenic microorganisms are particularly important for patients.The traditional diagnostic methods for T. marneffei infection mainly rely on fungal culture or microscopic examination, which is time-consuming and has a low positive rate.


We report the clinical and immunological features of 6 children with IEI infected by T.marneffei, and explore the diagnostic value of metagenomic next-generation sequencing (mNGS) in T.marneffei infection.


/ Research result /


1. Infection rate and clinical characteristics of C. marneffei in children with birth immunodeficiency


This study retrospectively analyzed 505 IEI patients admitted from January 2019 to June 2022, of which 402 (79.6%) were diagnosed with IEI for the first time.All patients underwent routine blood culture testing, 232 cases underwent mNGS detection, and 73 cases underwent histopathological examination.232 patients (45.9%) underwent both culture and mNGS testing.T. marneffei infection was detected in 6 patients, accounting for 1.2% (6/505).The causative genes of T. marneffei infected IEI patients included IL12RB1, IFNGR1, STAT3, STAT1, and CD40LG (Fig. 1A).


Figure 1 Distribution of pathogenic genes in IEI patients infected by C. marneffei


Table 1 Clinical characteristics of 6 cases of IEI children with C. marneffei infection



Fig. 2 Histopathological staining and mNGS results of P1 and P5.P1 Right axillary lymph node enlargement (A).The mNGS results of P1 cervical lymph node aspiration showed 108,380 reads specific to T. marneffei, with a genome coverage of 18.93% (B).Histopathological examination of a P1 cervical lymph node biopsy showed granulomatous inflammation (C), with fungal spores (arrowheads) visible on PAS staining (× 400) (D).Histopathological examination of P5 abdominal lymph node biopsy showed a large number of neutrophil infiltration, and histiocytes were distributed in patches.Fungal spore-like substances dispersed or aggregated in some tissue cells (×400) (E), PAS staining showed fungal spores (arrow) (×400) (F).


Fig. 3 Imaging findings of IEI children with C. marneffei infection.P1 Chest CT showed enlarged axillary and mediastinal lymph nodes (A.1). After oral itraconazole and anti-tuberculosis treatment for 2 months, follow-up chest CT showed that axillary and mediastinal lymph nodes were still enlarged (A.2), 2022 Lymph node biopsy was performed on April 19, 2010, and T. marneffei was detected by mNGS.Intravenous amphotericin B was given for 2 weeks, followed by itraconazole, and lymph node shrinkage was reexamined one month later (A.3).P3 Chest CT showed partial consolidation of the left lung with a small amount of pleural effusion (B.1), oral itraconazole combined with anti-tuberculosis treatment, reexamination of the chest after 3 months (B.2) and 8 months (B.3) CT significantly improved.Abdominal CT at the beginning of P5 disease showed hepatosplenomegaly and multiple abnormal signals (C.1). After 25 days of intravenous voriconazole treatment and continuous oral voriconazole, multiple abnormalities occurred after 2 weeks (C.2) and 3.5 months (C.3) The signal has improved.


2. Diagnostic value of mNGS for C. marneffei infection in patients with IEI


Traditional diagnostic methods for T. marneffei infection include culture and histopathological examination.We analyzed 232 patients who underwent both conventional diagnostic methods and mNGS testing.Both mNGS and traditional diagnostic methods were positive in 3 cases, and both were negative in 226 cases.Only mNGS was positive in 3 patients, while traditional diagnostic methods were negative.In this cohort, the sensitivity and specificity of mNGS in diagnosing T. marneffei infection were 100% and 98.7%, and the positive likelihood ratio and negative likelihood ratio were 76.9 and 0, respectively.


Twelve samples from 6 patients were cultured and tested by mNGS at the same time, 2 samples (16.7%, 2/12) were detected by culture method, and 8 samples (66.7%, 8/12) were detected by mNGS method.One cervical lymph node biopsy sample was positive for both histopathological staining and mNGS (Fig. 4).Further analyzing the reporting time of different diagnostic methods in this cohort, the median reporting time of mNGS was 26 hours (21.5-30 hours).The reporting time of 3 culture-positive samples was 3 days, 10 days and 14 days respectively, and the reporting time of 2 lymph node pathology results was 6 days and 11 days.The reporting time of mNGS is significantly shorter than that of traditional diagnostic methods.



3. Literature review of C. marneffei infection in patients with IEI


We searched Pubmed for literature review and reported 28 cases of IEI patients with T.marneffei infection. The median age of infection was 3 years old (5 months to 34 years old), 82% were Chinese (23/28), and the others were from Thailand.Twenty cases (71%) were disseminated T. marneffei infection involving blood or bone marrow, lung, colon, skin, lymph nodes, and liver.Immunodeficiency genes include CD40LG (35%), STAT1 (29%), STAT3 (22%), CARD9 (7%) and IFNGR1 (7%).We reported for the first time two cases of IEI children infected with T. marneffei with mutations in the IL12RB1 gene (Fig. 1).


A total of 46 clinically positive samples were collected from 28 patients (Figure 4).Nearly half (12/28) of patients received amphotericin B followed by itraconazole or voriconazole, and the remainder received itraconazole (5/28), voriconazole (2/28) or amphotericin B alone (3/28) treatment, 1 patient was treated with intravenous amphotericin B plus oral flucytosine, and the treatment methods of 5 patients were unknown.Except for 1 case lost to follow-up, most patients (21/28) improved after effective antifungal treatment, 6 patients (6/28) still died, 2 died of multiorgan failure and 1 died of disease Respiratory failure due to rapid progression, 1 died of pulmonary hemorrhage at age 16, 2 others died of unknown cause.


/ in conclusion /


People suffering from T. marneffei infection need to be alert to the potential immune function damage of the host.We reported for the first time two cases of IEI children with IL12RB1 gene mutations infected with T. marneffei, expanding the spectrum of immunodeficiency diseases infected by T. marneffei.mNGS has high diagnostic sensitivity and specificity for T.marneffei infection, and has rapid diagnostic value, which is of significance for timely clinical diagnosis and treatment and improvement of prognosis.


References: Lipin Liu, Bijun Sun, Wenjing Ying, Danru Liu, Ying Wang, Jinqiao Sun, Wenjie Wang, Mi Yang, Xiaoying Hui, Qinhua Zhou, Jia Hou, Xiaochuan Wang. Rapid diagnosis of Talaromyces marneffei infection by metagenomic next-generation Sequencing technology in a Chinese cohort of inborn errors of immunity. Front. Cell. Infect. Microbiol., 08 September 2022 Sec. Clinical Microbiology

https://doi.org/10.3389/fcimb.2022.987692


Text: Hou Jia Sun Bijun Liu Lipin Reviewer: Wang Xiaochuan Hou Jia

Source: Department of Immunoallergy, Pediatrics, Fudan



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