Upper and Lower Respiratory Tract Infections By Respiratory Viruses in Adult Recipients of Allogeneic Hematopoietic Stem Cell Transplantation (Allo-HSCT)

Introduction: Respiratory viruses are known to be the major causes of morbidity and mortality in recipients of Allo-HSCT. In this study, we evaluated the results of respiratory viral panel in the patients after Allo-HSCT, having the symptoms and/or findings of upper or lower respiratory infections.

Patients&Methods: In our center, the examination of the respiratory viral panel has been routinely performing in the patients having the symptoms and/or findings of upper or lowers respiratory infection since January 2013. We retrospectively evaluated the results of respiratory viral panel in 39 patients (24 M/ 15F) who underwent allo-HSCT for benign (n=4) or malign (n=35) hematological disease. Median age was 39 years (range, 20-67). Nasopharyngeal aspirates were used for obtaining upper respiratory specimens for respiratory viral panel. Viral panel was studied with PCR method, Seeplex RV 15 ACE Detectionkit (Seegene, Korea). Adenovirus A/B/C/D/E, Coronavirus 229E/NL63, Coronavirus OC43/HKU1, Parainfluenza virus 1,2,3,4, Rhinovirus A/B/C, Influenza A ve B virus, Respiratory Syncytial virus (RSV) A ve B, Boca virus 1/2/3/4, Metapneumovirus and Enterovirus can be detected with this technique. The sensitivity of the method is 5500 copies per ml.

Results: We detected the viral panel positivity in 25 patients with median 140 days (range: 3-617 days) after the transplantation. The most frequent viral agent disclosed was RSV and parainfluenza (32 %; n=7) followed by Coronavirus (n=6), Rhinovirus (n=5), Influenza (n=3),H1N1 (n=1), Metapneumovirus (n=1) and Adenovirus (n=1). In five patients two viruses were detected concurrently (1 Rhinovirus plus influenza; 2 RSV plus Coronovirus; 1 Rhino plus RSV; 1 Parainfluenza plus Rhino; and 1 Parainfluenza plus Coronovirus). Although CMV reactivation was occurred in 4 patients at the time of viral panel positivity, there was no statistical correlation between CMV reactivation and respiratory viral panel positivity (p=0.11). Most of the patients (n=20) with viral panel positivity were under immunosuppressive therapy for graft versus host disease prophylaxis or treatment. In 7 of 25 viral panel positive patients, bacterial infections were accompanied. 15 viral panel positive patients were diagnosed as pneumonia by radiological imaging. In addition, viral panel positive patients have significantly lower lymphocyte counts (p=0.013)(Table 1).

Conclusion: Parainfluenza and RSV are the most common viral agent detected similar to prior studies. Although viral panel positive patients have lower neutrophil count accompanied by higher CRP, the difference was not found to be statistically significant. CMV reactivation is not related with viral panel positivity. But the lymphocyte count was lower in the patients having positive results. In viral panel negative patients, high CRP levels might show infections rather than virus in etiology. The limitations of our study were that few patients were able to be evaluated in, and also the evaluations had both early and late time-period of the transplantation. Nevertheless, we thought that the results should give an opinion about the development of respiratory viral infections to the clinicians.