Abstract:

Objective: To evaluate the detection ability of nanopore-targeted sequencing (NTS) on granulomatous diseases in formalin-fixed paraffin-embedded (FFPE) tissues. Methods: According to inclusion criteria, clinical data of 82 patients admitted to Henan Provincial Chest Hospital from January to June 2023 who underwent lobectomy, lymph node dissection, and bone and joint surgical treatment due to therapeutic needs, and whose post-operative tissues were tested with traditional pathological tests which suggested granulomatous inflammation were collected (including the results of traditional pathological tests, etc.). NTS was applied on FFPE specimen from post-operative lesion tissue to compare its diagnostic value with traditional pathological methods on detecting granulomatous diseases, taking final clinical diagnosis as reference. Results: Of the 82 patients, histopathological test reported 73 cases (89.0%) of suspected tuberculosis, 4 cases (4.9%) of tuberculosis combined with aspergillosis, 3 cases (3.7%) of cryptococcosis, and 2 cases (2.4%) of granulomatous inflammation. The NTS detected 31 cases (37.8%) of Mycobacterium tuberculosis (MTB), 14 cases (17.1%) of Fungi, 9 cases (11.0%) of non-tuberculous mycobacterial (NTM), 5 cases (6.1%) of Nocardia, 2 cases (2.4%) of Brucella, 2 cases (2.4%) of MTB combined with Aspergillus niger, 16 cases (19.5%) of undetectable pathogens, and 1 case (1.2%) each of MTB combined with Pneumocystis carinii, Aspergillus polysporus, and M.avium. The final clinical diagnosis were 43 cases (52.4%) of tuberculosis, 13 cases (15.9%) of fungal disease, 9 cases (11.0%) of NTM disease, 5 cases (6.1%) of each nocardiosis and tuberculosis in combination with fungal disease, 2 cases (2.4%) of brucellosis, 1 case (1.2%) of tuberculosis in combination with NTM disease, and 4 patients (4.9%) with an unspecified diagnosis. With reference to the final clinical diagnosis, the sensitivities of pathological diagnosis and NTS for the detection of granulomatous inflammation were 60.3% (47/78) and 83.3% (65/78), with a Kappa value of 0.129 and 0.328, respectively; and the sensitivity of combing these two methods was 97.4% (76/78), with a Kappa value of 0.788; the specificities of three methods were all 4/4. Conclusion: NTS could detect granulomatous inflammation to strain level, with combination with traditional histopathological test, it can significantly improve the efficacy of diagnosing etiology of infectious diseases, thus could be recommended as a complementary method to traditional histopathological test.

Key words: Granulomatous disease, chronic, Paraffin embedding, Tissue fixation, Nanotechnology, Molecular diagnostic techniques, Comparative study