LAUSR

We read with interest the letter by Roeker et al., on SARSCoV-2 antibody responses in twenty-one patients with chronic lymphocytic leukemia (CLL), reporting that 67% generated antibodies to the SARS-CoV-2 Nucleoprotein antigen [1]. Their report highlighted the need to characterise the serological response to SAR-CoV-2 in immune compromised patients, particularly those with haematological malignancies, to help inform patient management and public health strategies. Patients with acute leukemia also represent a particularly high-risk group, who are reported to have some of the poorest outcomes of COVID-19 [2] and are hypothesised to have impaired immune SARS-CoV-2 responses due to either diseaseor treatment-associated immune dysfunction. This has resulted in recommendations to reduce the risk of COVID-19 in these patients, including restructuring of clinical services, shielding and alterations in therapy to minimise their immune suppressive consequence [3]. Here we report SARS-CoV-2 antibody responses in a cohort of patients with acute leukemia and COVID-19 receiving systemic anti-cancer therapy (SACT) at University College London Hospital during the first wave of the pandemic. Longitudinal serum samples were collected from nine patients with acute leukaemia, of whom eight had PCRconfirmed SARS-CoV-2 infection and one had a clinical diagnosis of COVD-19. Five patients had AML, three BALL and one T-ALL. Four patients commenced SACT prior to developing COVID-19 and five presented with leukemia and COVID-19. All patients received SACT within 28 days of developing COVID-19. Four patients received less myelosuppressive regimens (venetoclax azacitdine or gilteritinib) in accordance with NICE/NCRI COVID-19 guidance for acute leukaemia. COVID-19 symptoms were assigned from mild to severe [4], with two patients requiring ITU and mechanical ventilation. The median time between symptom onset and PCR diagnosis was 2.5 days (IQR 8.25), median duration of PCR positivity was 18.5 days (IQR 22) (Supplementary Fig. 1) and four patients received a potential COVID-19 modifying agent (tocilizumab, anakinra, remdesivir or dexamethasone). All patients survived and were discharged from hospital, with a median duration of illness of 30 days (IQR 30). Further patient demographics are described in Table 1. Serum samples were taken a median of 9.5 days after positive PCR test for SARS-CoV-2 (range 1–25 days) and subsequent longitudinal serum samples taken between 2 and 103 days post onset of symptoms (POS). These were screened for anti-SARS-CoV-2 antibodies using ELISA to the external Spike glycoprotein (S1 subunit) and internal Nucleoprotein (N) [4–6]. Total serum IgG was within in the normal range in each case, excluding hypogammaglobinaemia. Seven of eight patients (88%) with PCR-confirmed SARS-CoV-2 had IgG responses to S1 and N (Fig. 1a, b and appendix). Classifying patient samples into 7-day intervals POS (Supplementary Fig. 2) showed that seroconversion to S appeared to precede N, with only two patients seroconverting to both by day 30 (Supplementary Fig. 2 and Supplementary Tables 1–3). Overall seroconversion rates of 88% were similar to the general population [4, 6, 7] and higher than that reported by * J. O’Nions [email protected]