SARS-COV-2 INDUCED REMISSION OF DIFFUSE LARGE B-CELL LYMPHOMA: A CASE REPORT

INTRODUCTION: Diffuse Large B-cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma, which accounts for approximately 30% of all non-Hodgkin lymphoma cases. Spontaneous remission of DLBCL is exceedingly rare, with only a handful of case reports that describe the phenomenon present in the literature. Specialists are investigating similar cases to find out whether the SARS-CoV-2 infection triggered an antitumor immune response, as has been described with other infections in the context of high-grade non-Hodgkin lymphoma. We report one case of an elderly woman with EBV positive DLBCL diagnosed with PCR-positive SARS-CoV-2 pneumonia in the course of the disease and their outcomes. Case report: A 81 years-old woman, was referred to the consult ambulatory of intern medicine with progressive cervical, axillary and inguinal lymphadenopathy with local pain, fever and weight loss. The biopsy of an axillary lymph node demonstrated diffuse atypical lymphoid infiltrate. Immunohistochemistry stains showed positive CD20, CD30, Bcl-2 and MUM-1. It was negative for CD3, CD10, Bcl-6, c-Myc and CMV. The Ki-67 proliferation index was 80%. Epstein-Barr virus (EBV) stain were positive. These findings were consistent with DLBCL, EBV positive, clinical Stage IIIB and R-IPI 4 (poor prognosis and high risk). Since PET-CT was unavailable, thorax and abdomen computed tomographies were performed and revealed enlarged lymph node on pulmonary hilum, pathological lymph node enlargement in the axillary and supraclavicular chains bilaterally and peri aortocaval adenomegaly, extending along the bilateral femoral iliac vessels (larger lymph nodes of 2.5cm). She was treated with 4 cycles of R-CVP (rituximab with cyclophosphamide, vincristine and prednisone). When an interim PET-CT was performed, disease progression was revealed (Lugano score 5). Therefore, considering patient age and clinical status, treatment scheme was changed to R-mini-CHOP (rituximab with reduced doses of cyclophosphamide, doxorubicin, vincristine and prednisone), achieving partial response after 4 cycles (Lugano score 4). A month after this evaluation, she was admitted to the Emergency Department with diarrhea, fever and was diagnosed with PCR-positive SARS-CoV-2 pneumonia. After 6-days hospitalization with no significant ventilatory impairment, she was discharged. No corticosteroid or immunochemotherapy was administered. Two months later, she had no palpable lymphadenopathy and a PET/CT scan revealed widespread resolution of the lymphadenopathy and reduced metabolic uptake throughout (Lugano score 1). After a 7-months follow-up, the patient still has no clinical relapse. DISCUSSION: The putative mechanisms of action include cross-reactivity of pathogen-specic T cells with tumour antigens and natural killer cell activation by inammatory cytokines produced in response to infection. It is important to consider that the more cases of SARS-CoV-2 infection in patients with non-Hodgkin lymphoma, the more likely it is to analyze lymphoma remissions and demonstrate the exact mechanism of pathogen-specific T cells with tumor antigens. CONCLUSION: Because spontaneous remission of DLBCL associated with SARS-CoV-2 infection is a new event, careful investigation of these cases is important, because the information gained may lead to new therapeutic targets or treatment strategies for future patients.