COVID-19 in a pediatric cancer patient with T-lymphoblastic lymphoma: Response to convalescence plasma and subsequent induction of SARS-CoV-2 specific humoral and cellular immunity despite strong B-cell lymphopenia

We report on an 11-year old pediatric cancer patient with T-lymphoblastic lymphoma who acquired a severe SARS-CoV-2 pneumonia immediately after the start of oral maintenance treatment with mercaptopurine. He was admitted to our hospital on day 7 after onset of symptoms (day 5 after diagnosis). Due to respiratory failure, he was transferred to the pediatric intensive care unit (from day 8 for 5 days) for high-flow-nasal cannula respiratory support. Treatment consisted of intravenous methylprednisolone and ceftriaxone. Because anti-SARS-CoV-2 antibodies were not detectable, he received two units of COVID-19 convalescence plasma containing high-titer neutralizing anti-SARS-CoV-2 antibodies (day 8 and day 9). Anti-SARS-CoV-2 antibodies increased to a maximum of 725 IU/L on day 10. Clinically, this was accompanied by a gradual decrease in oxygen demand and an overall clinical improvement. Remarkably, the patient started to mount a humoral immune response with continuously increasing anti-SARS-CoV-2 antibodies from day 15 up to 35.698 AU/ml on day 51 with extremely low (< 0.4%; < 0.01 x 109/L) detectible CD19-positive B-lymphocytes in his peripheral blood. Moreover, a strong SARS-CoV-2 specific CD4 and CD8 T cell response was induced with a predominance of CD8 T cells towards NCAP. This finding indicates that passive immunization facilitated active induction of both humoral and cellular immunity. This also suggests that active immunization may be feasible and effective in pediatric cancer patients despite B-lymphocytopenia.