CMV and HSV Pneumonia after Immunosuppressive Agents for Treatment of Cytokine Release Syndrome due to Chimeric Antigen Receptor-Modified T (CAR-T)-Cell Immunotherapy

Abstract

Pneumonia due to cytomegalovirus (CMV) and herpes simplex virus-1 (HSV-1) caused substantial morbidity after hematopoietic cell transplantation (HCT) before institution of preventative approaches. End-organ disease from herpesviruses is poorly described after chimeric antigen receptor–modified T (CAR-T)-cell immunotherapy. We report two cases of CMV pneumonia and one case of HSV-1 gingivostomatitis, esophagitis, and pneumonia after CAR-T-cell immunotherapy for treatment of hematologic malignancies.

Case 1

A 58-year-old, cytomegalovirus (CMV)-seropositive woman with non-Hodgkin’s lymphoma (NHL) was hospitalized 13 days after infusion of CD19-directed chimeric antigen receptor–modified T (CAR-T)-cells with dyspnea and cough. She had received fludarabine (30mg/m²/day) and cyclophosphamide (300mg/m²/day) from day −5 to day −3 prior to CAR-T-cell infusion (CTI) and had not undergone prior hematopoietic cell transplant (HCT). Serum immunoglobulin G (IgG) measured on day −14 prior to CTI was 131 mg/dL (reference range 610–1616 mg/dL).

On admission, her temperature was 37.3°C (99.1°F) and oxygen saturation was 94% on room air. Absolute neutrophil count (ANC) was 1.16 × 10⁹/L (reference range 1.8–7.0 × 10⁹/L) and absolute lymphocyte count (ALC) was 0.44 × 10⁹/L (reference range 1.0–4.8 × 10⁹/L). Chest x-ray showed diffuse airspace disease and a right middle lobe consolidation. This was unchanged from imaging prior to CTI and was attributed to lymphoma. Moxifloxacin was initiated for pneumonia. On day +15, she developed hypoxemic respiratory failure requiring intubation and new hypotension requiring vasopressors. Bronchoalveolar lavage fluid (BALF) testing showed an abnormal B-cell population by flow cytometry, consistent with lymphoma, and CMV shell vial culture was negative. A standard panel of BALF infectious studies (Table 1) showed no evidence of viral, bacterial, or fungal infection, and blood cultures had no growth. Given severe respiratory failure, two doses of dexamethasone 10mg and one dose of tocilizumab 8mg/kg were administered on day +15 for cytokine release syndrome (CRS). She was extubated to nasal cannula on day +19 after substantial diuresis and undergoing a thoracentesis for a right-sided pleural effusion, which revealed an abundance of CAR-T cells. On day +21 she was reintubated for hypoxemic and hypercarbic respiratory failure. Methylprednisolone 1 mg/kg/day was administered on days +21 to +28, but her respiratory status did not improve. A second bronchoscopy was performed on day +22 and BALF again showed evidence of lymphoma and no evidence of infection.

Table 1:

Infectious studies performed on bronchoalveolar lavage fluid collected with each bronchoscopy for all cases

Infectious studies
Bacterial culture with gram stain
Fungal culture with KOH stain
Nocardia culture with modified AFB stain
Legionella culture
Pneumocystis jirovecii direct fluorescent antibody
Galactomannan
Aspergillus fumigatus PCR
Zygomycetes PCR
Broad-range fungal PCR
Extended multiplex respiratory PCR for adenovirus, enterovirus, paraechovirus, bocavirus, metapneumovirus, parainfluenza 1–4, respiratory syncytial virus, influenza A, influenza B, rhinovirus, and coronavirus (excluding SARS-CoV-2)1

Abbreviations: acid-fast bacilli (AFB), potassium hydroxide (KOH), polymerase chain reaction (PCR), severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)

¹Cases 1 and 2 occurred prior to the identification of SARS-CoV-2; SARS-CoV-2 nasopharyngeal PCR was negative on day +29 in case 3

Computed tomography (CT) scan of the chest on day +26 showed increased bilateral upper lobe ground glass opacities compared to earlier in her hospitalization. BALF from a third bronchoscopy performed on day +27 was positive for CMV by shell vial culture and by PCR with a viral load of 35,000 IU/mL. CMV was detected in the plasma with a viral load of 2,700 IU/mL on day +29. She remained critically ill and was discharged on hospice on day +31 without CMV directed therapy. A summary of the cell counts, CMV studies and CRS treatment is shown in Figure 1. Testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was not performed as the case occurred prior to emergence of the virus.

Figure 1:

Summary of laboratory values, viral studies, cytokine release syndrome treatments, and clinical courses.

Abbreviations: Absolute lymphocyte count (ALC), absolute neutrophil count (ANC), bronchoalveolar lavage (BAL), cycle threshold (Ct), cytokine release syndrome (CRS), cytomegalovirus (CMV), chimeric antigen receptor-T (CAR-T), esophagogastroduodenoscopy (EGD), herpes simplex virus-1 (HSV-1), immunohistochemistry (IHC)

ANC reference range: 1.8–7.0 × 10⁹/L

ALC reference range: 1.0–4.8 × 10⁹/L

Case 2

A 63-year-old, CMV-seropositive man with NHL was hospitalized with neutropenic fever 10 days after infusion of CD19-directed CAR-T-cells. He had received fludarabine (30mg/m²/day) and cyclophosphamide (500mg/m²/day) on days −5 through −3 prior to CTI and had undergone autologous HCT six months prior to CTI. Serum IgG measured on day −29 prior to CTI was 592 mg/dL.

On admission, he was febrile to 38.1°C (100.6°F), and oxygen saturation was 98% on room air. He had no cough or dyspnea and chest X-ray showed clear lungs. ANC was 0.12 × 10⁹/L and ALC was 0.35 × 10⁹/L. Ceftazidime was initiated for neutropenic fever but he remained febrile despite antibacterials and underwent a CT scan of the chest on day +16 that showed new bilateral pulmonary nodules in the lower lobes with surrounding ground glass opacities. Isavuconazonium sulfate was initiated on day +18 for possible fungal infection but fevers did not resolve. On day +21, he developed encephalopathy, hypotension and hypoxemia and was treated with one dose of tocilizumab 8 mg/kg on day +21 and dexamethasone 10 mg every 6 hours on days +21 to +30 for CRS and immune effector cell-associated neurotoxicity syndrome (ICANS). Fever, hypotension, hypoxemia and mental status initially improved but subsequently worsened. On day +28, a chest CT showed new multifocal nodular densities, prompting bronchoscopy for evaluation of infectious processes. BALF recovered on day +28 was positive for CMV by PCR with a viral load of 6,700 IU/mL. All other BALF infectious studies were negative, including CMV shell vial culture, and CMV treatment was not initiated. On day +31, he developed hypotension requiring vasopressors and hypoxemia requiring supplemental oxygen. Methylprednisolone 1 g/day was administered on days +31 to +35 followed by 1 mg/kg/day on days +36 to +39; one dose of siltuximab 11 mg/kg on day +35 and anakinra 100 mg/day on days +31 to +39 were administered for refractory CRS.

On day +35, the patient was intubated for rapidly progressive respiratory failure. BALF on day +35 was positive for CMV by PCR with a viral load of 830,000 IU/mL, significantly increased from day +28, and CMV shell vial culture was positive. All other BALF infectious studies were negative. Transbronchial biopsy revealed persistent lymphoma, and CMV immunohistochemical stains were negative. Foscarnet was started on day +37 but discontinued two days later due to acute renal failure. He transitioned to comfort care and died on day +42 post-CTI. A summary of the cell counts, CMV studies and CRS treatment is shown in Figure 1. This case occurred prior to emergence of SARS-CoV-2 and therefore testing was not performed.

Case 3

A 66-year-old man with a history of refractory IgG lambda multiple myeloma was hospitalized with nausea, vomiting, and fever eight hours after receiving B-cell maturation antigen (BCMA)-directed CAR-T-cells. He had received fludarabine (25 mg/m²/day) and cyclophosphamide (300 mg/m²/day) from day −5 through day −3 and had undergone two autologous HCTs, one 12 years and one 8 years prior to CTI.

Two months prior to admission, he developed oral ulcers due to herpes simplex virus (HSV)-1, which occurred while taking 800 mg of acyclovir by mouth daily, rather than the prescribed dose of 800 mg twice-daily. The ulcers resolved after transitioning to valacyclovir 1 gram three times daily for one week. Valacyclovir was then reduced to prophylactic dosing at 500mg twice-daily until transitioning to intravenous acyclovir 400 mg twice-daily due to inability to tolerate oral medications after CTI. On day −13 prior to CTI, immunoglobulin G level was 529 mg/dL, as measured by subtracting the monoclonal M spike from total IgG.

On admission, his temperature was 39.0°C (102.2°F) and oxygen saturation was 93% on room air. There were no ulcers or vesicles on his lips or buccal mucosa, and he denied dysphagia or odynophagia. ANC was 1.0 × 10⁹/L and ALC was 0.03 × 10⁹/L. CT of the chest showed a left lower lobe consolidation, and blood cultures grew Selenomonas species, an anaerobic gram-negative bacillus. Cefepime and metronidazole were initiated for pneumonia, bacteremia, and neutropenic fevers. Given continued fevers, he was treated with two doses of tocilizumab 8mg/kg on days +3 and +6 and dexamethasone 10mg every 6 to 12 hours on day +3 and days +6 to +14 for CRS. Fevers resolved but he remained profoundly fatigued with anorexia leading to severe malnutrition.

On day +19 post-CTI, he developed odynophagia and ulcerations of his upper lip and buccal mucosa. Lesions were positive for HSV-1 by PCR with a cycle threshold (Ct) of 24.4, and plasma HSV-1 viral load was 1,200 copies/mL. Prophylactic acyclovir was switched to oral valacyclovir 1 g three times daily on day +19, which was subsequently changed to intravenous acyclovir 5 mg/kg every 8 hours on day +21 when lesions worsened. Esophagogastroduodenoscopy on day +24 demonstrated linear ulcerations in the esophagus, and histopathology revealed cytopathic changes with positive HSV-1 immunohistochemical stains (Figure 2). HSV-1 resistance testing demonstrated a frameshift mutation at position 146 and three point mutations (S23N E36K Q89R), consistent with acyclovir resistance. Intravenous acyclovir was changed to foscarnet 60 mg/kg every 12 hours on day +25, which resulted in slight improvement of his oral lesions and odynophagia.

Figure 2:

Esophageal tissue with herpes simplex virus-1 (HSV-1) esophagitis

1A: (Magnification 200x) Hematoxylin-eosin stain demonstrates ground glass nuclei (left arrow), nuclear molding, and multinucleated cells (right arrow). 1B: (Magnification 100x) Strong nuclear HSV-1 immunohistochemical staining.

The patient continued to receive foscarnet while hospitalized due to deconditioning and ongoing thrombocytopenia requiring frequent transfusions. On day +29, he developed progressive hypoxemia requiring intubation. CT of the chest showed progression of the left lower lobe consolidation with new right lower and middle lobe opacities. On day +29, HSV-1 was detected in BALF with a viral load of 6,500,000 copies/mL; plasma HSV-1 viral load was increased to 1,000,000 copies/mL. Other BALF infectious studies and a nasopharyngeal SARS-CoV-2 PCR were negative. Blood cultures showed no growth. The patient developed acute respiratory distress syndrome (ARDS) and hypotension prompting the addition of continuous infusion acyclovir 30mg/kg/day on day +32. Despite this, he continued to deteriorate and died on day +34 post-CTI. A summary of the cell counts, HSV studies and CRS treatment is shown in Figure 1.

Discussion

CAR-T-cell immunotherapy is an effective treatment for relapsed or refractory hematologic malignancies.¹ Infections are common after CAR-T-cell immunotherapy, occurring in 25%−40% of recipients within the first month.^{2, 3} Multiple factors likely contribute to this high incidence of early infection. In addition to lymphodepleting chemotherapy prior to CTI, most patients have previously received substantial cytotoxic chemotherapy and/or HCT. CAR-T-cells kill both malignant and healthy B-cells, resulting in B-cell aplasia and potential hypogammaglobulinemia. Thus, patients have defects in both T-cell and B-cell immunity, both of which are protective against CMV.^{4, 5} Infections are particularly common in patients with high-grade CRS,^{2, 3} which may predispose to infections via inflammatory cytokines, immunosuppression from corticosteroids and anti-cytokine therapies, and iatrogenic aspects of intensive care.²

The majority of viral infections after CD-19-directed CAR-T-cell immunotherapy are respiratory viruses. Although there are reports of CMV viremia, HSV gingivostomatitis, and herpes zoster,^{2, 3} there are no reports of end-organ disease due to herpesviruses in this setting to our knowledge. Pulmonary reactivation of both CMV and HSV in critically ill patients is well recognized and associated with increased mortality,⁵ and data suggest a causal role for CMV contributing to worse outcomes in ventilated patients.⁶ CMV pneumonia was the leading cause of death after HCT prior to routine monitoring and preemptive treatment.⁷ Importantly, routine surveillance or testing for CMV is not common practice after CAR-T-cell immunotherapy.

In the present cases, underlying malignancies and CRS were undoubtedly important causes of lung disease. However, subsequent reactivation of CMV and HSV-1 likely contributed to respiratory failure and death. In cases 1 and 2, BALF CMV viral loads were well-above 1,000 IU/mL, a cutoff with a >95% positive predictive value for CMV pneumonia in HCT recipients.⁷ Such results, combined with positive shell vial culture and supportive imaging, classify these cases as probable CMV pneumonia based on consensus definitions for CMV disease after HCT.⁸ While lung histopathology did not reveal cytopathogenic changes nor positive immunohistochemical staining in case 2, these tests have low sensitivity for CMV end-organ disease.⁹ In case 3, histopathologic confirmation of tissue-invasive HSV-1 in esophageal specimens illustrates evidence of end-organ disease due to herpesviruses after CTI.

All three patients in this series had prolonged lymphopenia and high-grade CRS requiring corticosteroids and anti-cytokine therapies. Lymphopenia and corticosteroids are established risk factors for CMV and HSV reactivation after HCT. Additionally, tumor necrosis factor-alpha (TNF-α), which is elevated in CAR-T-cell associated CRS,³ may induce CMV replication in latently infected cells,¹⁰ further promoting CMV reactivation. All three patients had some degree of hypogammaglobulinemia prior to CTI. While immunoglobulins were not measured after immunotherapy, CTI likely exacerbated pre-existing deficits in both humoral and cellular immunity, further increasing susceptibility to herpesvirus reactivation.⁴

This cases series highlights the potential for CMV and HSV to cause pneumonia in CAR-T-cell recipients. The incidence of herpesvirus infections in this patient population may be underrecognized given overlapping features with CRS and lack of routine testing. Pneumonia and other end-organ diseases due to herpesviruses should be considered after CAR-T cell therapy, particularly in the setting of high-grade CRS.