BACKGROUND: SARS-CoV-2 infected cancer patients (CP) show worse outcomes compared with non-cancer patients (NCP). The humoral immune response (HIR) of CP against SARS-CoV-2 is not well characterized. To better understand it, we conducted a serological study of hospitalized SARS-CoV-2 CP. MATERIALS AND METHODS: Unicentric, retrospective study enrolling adult SARS-CoV-2 patients admitted to a central hospital from March 15 to June 17, 2020, whose serum samples were quantified for anti-SARS-CoV-2 receptor-binding domain or spike protein immunoglobulin (Ig) M, G and A antibodies. The aims of the study were to assess the HIR to SARS-CoV-2, correlate it with different cancer types, stages and treatments, clarify the interplay between HIR of CP and clinical outcomes and to compare the HIR of SARS-CoV-2 CP and NCP. RESULTS: We included 72 SARS-CoV-2 positive subjects (19 CP, 53 controls). About 90% of controls revealed a robust serological response. Among CP, a strong response was verified in 57.9% of them, with 42.1% showing a persistently weak response. Treatment with chemotherapy within 14 days before positivity was the only factor statistically shown to be associated with persistently weak serological responses among CP. No significant differences in outcomes were observed between CP with strong and weak responses. All IgG, IgM, IgA and total Ig antibody titers were significantly lower in CP when compared with NCP. CONCLUSIONS: A significant part of CP develops a proper HIR. Recent chemotherapy treatment may be associated with weak serological responses among CP. CP have a weaker SARS-CoV-2 antibody response compared with NCP. IMPLICATIONS FOR PRACTICE: Our results place the spotlight on cancer patients, particularly the ones actively treated with chemotherapy. These patients may potentially be more vulnerable to SARS-CoV-2 infection, being important to provide oncologists further theoretical support (with concrete examples and respective mechanistic correlations) for the decision of starting, maintaining or stopping antineoplastic treatments (particularly chemotherapy) not only on non-infected but also on infected cancer patients in accordance with cancer type, stage and prognosis, treatment agents, treatment setting and SARS-CoV-2 infection risks.
Humoral immune response of SARS-CoV-2 infected cancer patients: influencing factors and its mechanisms