**2. Case Report**

A 55-year-old female with advanced chronic obstructive pulmonary disease (COPD) underwent a successful bilateral LTX 5 months earlier. Induction therapy (basiliximab) was used, and the patient was started on a standard immunosuppressive regime (cyclosporine—C2 target level 1200–1500 μg/L after 48 h), 1.0 g bid mycophenolate mofetil, and i.v. methylprednisolone according to our standard protocol. In March 2020 she presented with vomiting, diarrhea and a 38.9 ◦C fever in our emergency department. In the recent months and weeks, she had an uneventful post-transplant course except for a switch from cyclosporine to tacrolimus because of strongly variable trough levels. A recent surveillance bronchoscopy showed no evidence of acute cellular rejection and a stable allograft function with an FEV1 of 104% predicted based on standard triple immunosuppressive therapy (tacrolimus, mycophenolate and prednisolone). At the time of presentation, she had a new onset of mild respiratory symptoms consisting of a dry cough and rhinorrhea. Due to the fever, respiratory symptoms and ongoing SARS-CoV-2 pandemic, diagnostic sampling included blood, feces, and urine and a nasal swab for SARS-CoV-2. The nasopharyngeal swab for SARS-CoV-2 was positive, prompting hospitalization on a special isolation ward. Feces were positive for norovirus after having been negative 2 months earlier. The stool specimen tested negative for SARS-CoV-2. The serological antibody test for SARS-CoV-2 IgG und IgM was negative 14 days after the positive nasopharyngeal swab test. The main results at presentation included CRP 77 mg/L, leukocytosis (9.9 g/L), neutrophilia (8.96 g/L) and a marked declining lymphocytopenia (0.52 g/L, previously 1.3 g/L). The arterial blood gas analysis was within normal limits, thus no oxygen supplementation was given initially. Initial serum interleukin (IL-)6 was slightly elevated 4.5 pg/mL (Ref < 3.1) and decreased subsequently. Soluble IL-2-receptor (sIL-2R) was 394 pg/mL (Ref < 477) at presentation, increased up to 2778 on day 6 and decreased to normal levels (327) on day 15. IgG was in the lower normal range with 7.1 g/L (7–16). Five days after admission, CRP dropped to 5.7 mg/L (Ref < 5 mg/L). Bronchoalveolar lavage was not performed due to the favorable clinical evolution and the lack of respiratory deterioration. Chest computed tomography (CT) imaging revealed, at initial presentation, three small new solid nodular consolidations without predominant ground-glass opacities or pleural effusions (Figure 1a−c). These findings had not been observed 3 months earlier in a routine CT examination. The consolidations diminished over time and some of them disappeared completely in a follow up chest CT 6 weeks later (Figure 1d–f).

(**a**) **Figure 1.** *Cont.*

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(**c**)

(**d**) **Figure 1.** *Cont.*

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(**f**)

**Figure 1.** (**a**–**c**) new pulmonary consolidations in the chest computed tomography (CT) on March 18th that were not visible in a chest CT 3 months before. (**d**–**f**): All of the consolidations resolved partially or completely in the follow-up chest CT 6 weeks later.

The patient was treated empirically with intravenous piperacillin/tazobactam 4.5 g every 8 h for 10 days. We administered neither lopinavir/ritonavir nor hydroxychloroquine, the drug regimen for COVID-19 used predominantly in China and Italy at that time and also the drug regimen for severe cases at our hospital then. This treatment was withheld due to the fairly stable condition of the patient without signs of respiratory deterioration in the first hours of hospitalization and due to concerns about potential drug interactions in this LTX recipient. The clinical evolution was favorable, with the normalization of temperature, stool frequency and no further vomiting. The dry cough and rhinorrhea were resolved within a week. Spirometry remained stable throughout. After three consecutive negative nasal and pharyngeal swabs for SARS-CoV-2, the patient was discharged on day 12 and quarantined at home, with additional empiric amoxicillin/clavulanic acid for 7 days. Lung function continues with steadily increasing allograft function with an FEV1 of 113% predicted on day 201 posttransplant.
