This is a prospective biological study evaluating the persistence of COVID-19 vaccine and other vaccines' (zoster, diphtheria and tetanus)-induced immunity in a subgroup patient affected by Follicular Lymphoma requiring treatment undergoing frontline induction immuno-chemotherapy and anti-CD20 maintenance within the prospective FIL_FOLL19 study (NCT05058404).

Blood samples from patients will be collected before and at planned timepoints during treatment to evaluate humoral and cellular immunity against SARS-COV-2, VZV, tetanus and diphtheria and T-cell markers characterization.

Patients (pts) with follicular lymphoma (FL) were reported to be at high risk for hospitalization and death from COVID-19 infection, especially if exposed to anti-CD20 monoclonal antibodies (mAbs)-based therapy. A large amount of studies unequivocally demonstrated that anti-CD20 mAbs-containing therapies typically impair the development of protective levels of neutralizing anti-spike antibodies after immunization with full course of approved mRNA-based COVID-19 vaccines (up to 12 months after last anti-CD20 infusion). Moreover, booster doses seem to induce seroconversion only in a minority of such pts. On the contrary, preliminary findings seem to suggest that a substantial proportion of vaccinated pts with B-cell lymphoma (B-NHL) mount detectable SARS-CoV-2-specific T-cell responses (as measured by assays evaluating IFN-Y secretion after stimulation with SARS-CoV-2 peptides), independently from humoral response status.

For newly diagnosed FL pts current guidelines suggest to complete the vaccination with booster dose(s) before treatment initiation, as anti-CD20 mAbs seems to spare pre-established humoral immunity to COVID-19 vaccine, although data supporting this finding are scanty.5 Furthermore, data about long term persistence of pre-established cellular immunity in this setting are lacking, although preliminary findings in unselected immunosuppressed pts suggest that it decline over time without significant difference with respect to the general population.

The novel adjuvanted recombinant zoster vaccine demonstrated lower humoral immune response in pts with B-NHL with respect to other pts, probably due to anti-CD20 therapy, while cellular immunity was not affected, although the small number of pts requires further investigation.

Very few data concerning persistence of immunity to childhood vaccines after anti-CD20-based therapy are available and suggest that humoral immunity to diphtheria and tetanus may be significantly impaired after therapy.

This is a prospective biological study evaluating the persistence of COVID-19 vaccine and other vaccines' (zoster, diphtheria and tetanus)-induced immunity in a subgroup of FL patients undergoing frontline induction immuno-chemotherapy and anti-CD20 maintenance within the prospective FIL_FOLL19 study (NCT05058404).

After the signature of a specific informed consent, eligible patients will receive a questionnaire evaluating vaccination history, past infection history and treatment, and passive immune prophylaxis (e.g. tixagevimab/cilgavimab administration). A baseline blood sample will be collected before the initiation of treatment and will be sent to the central laboratory, where specific analyses evaluating vaccine-induced cellular and/or humoral immunity against COVID-19, VZV, diphtheria and tetanus will be performed.

COVID-19 cellular and humoral immunity will be evaluated in all patients at all available timepoints.

Humoral and cellular immunity for VZV will be evaluated for all patients at study entry. In the subgroup of patients with a detectable serologic response at study entry, humoral and cellular immunity will be also evaluated at all available later timepoints.

Humoral immunity for diphtheria and tetanus will be evaluated for all patients at study entry. In the subgroup of patients with a detectable serologic response at study entry, humoral immunity will be also evaluated at all available later timepoints.

T-cell immunological parameters will be evaluated at study entry and 12 months after EOI (or early withdrawal).

Inclusion Criteria:

1. Enrolment in FIL_FOLL19 study
2. Previous vaccination for COVID-19 (at least 3 doses)
3. Availability of informations about COVID-19 and other vaccines previously administered (vaccination records)
4. Willingness to comply with blood collection timepoints required for vaccination immunity evaluation
5. Signature of specific informed consent form

Exclusion Criteria:

None

Patients affected by Follicular Lymphoma undergoing frontline induction immuno-chemotherapy and anti-CD20 maintenance within the prospective FIL_FOLL19 study