Four of the 14 patients had no or low values of anti S1-RBD antibodies. last dose LP-935509 of rituximab 9?months earlier (group B 5 patients) and a group of patients who had received rituximab 12?months earlier (group C 5 patients). All patients received two doses of BNT162b2 mRNA COVID-19 vaccine 21?days apart. Patients underwent evaluation of the lymphocyte subpopulations with determinations of the B lymphocyte population (CD27???naive, CD27?+?memory, CD38?+?, CD20?+?, CD19?+) evaluated by flow cytometry (FACS CANTO II, BD LP-935509 Biosciences), before the vaccination and 3?weeks after the second dose of vaccine. The value of anti-SARS-CoV-2 Spike-RBD IgG antibodies (IgG antibodies against S1-RBD protein) quantified by FEIA (ThermoFisher, Uppsala Sweden) was decided 3?weeks after the second dose of vaccine. In addition, SARS-CoV-2-specific T cell responses were determined by incubating isolated T cells with a SARS-CoV-2-specific peptide mix (a peptide mix of the SARS-CoV-2 spike protein) and measuring the release of interferon by activated LP-935509 T cells using an ELISA system (IFN- release assay, IGRA) according to the protocol of the manufacturer (SARS-CoV-2-IGRA, Euroimmun, Lubeck, Germany). All patients were in clinical remission at the time of vaccination and discontinued methotrexate in the week of the first and second vaccine administration according to the published recommendations [4, 5]. Table ?Table11 shows the characteristics of the 14 patients. Four of the 14 patients had no or low values of anti S1-RBD antibodies. The evaluation of IFN- production by the IGRA test showed in the 4 patients a mediated CD8?+?T cell response with a value of? ?2500?mU/mL. Table 1 Summary of patients’ characteristics thead th align=”left” rowspan=”2″ colspan=”1″ Pt /th th align=”left” rowspan=”2″ colspan=”1″ Age /th th align=”left” rowspan=”2″ colspan=”1″ Number RTX cycle /th th align=”left” rowspan=”2″ colspan=”1″ RTX week before /th th align=”left” rowspan=”2″ colspan=”1″ Predn dose /th th align=”left” rowspan=”2″ colspan=”1″ MTX dose /th th align=”left” rowspan=”2″ colspan=”1″ CD3?+?cells/mcL /th th align=”left” rowspan=”2″ colspan=”1″ CD3?+?CD4?+?cells/mcL /th th align=”left” rowspan=”2″ colspan=”1″ CD3?+?CD8?+?cells/mcL /th th align=”left” rowspan=”2″ colspan=”1″ CD3???CD56?+?CD16?+?cells/mcL /th th align=”left” rowspan=”2″ colspan=”1″ CD19?+?cells/mcL /th th align=”left” rowspan=”2″ colspan=”1″ Pdgfb CD20?+?cells/mcL /th th align=”left” rowspan=”2″ colspan=”1″ CD27???naive cells/mcL /th th align=”left” rowspan=”2″ colspan=”1″ CD27?+?memory cells/mcL /th th align=”left” rowspan=”2″ colspan=”1″ CD38?+?cells/mcL /th th align=”left” rowspan=”1″ colspan=”1″ IgG SARS-CoV-2 RBD /th th align=”left” rowspan=”1″ colspan=”1″ IGRA IFN- /th th LP-935509 align=”left” rowspan=”1″ colspan=”1″ BAU/WHO mL /th th align=”left” rowspan=”1″ colspan=”1″ mU/mL /th /thead 15842451011235453462346246111223226152551013426345323429534121556934432451015466574322239621611356446626510678325286127328220.725005688372.512.5583395188350147131139661632676936512.5143911582934203125233316425007698442.510224519322904402.211017170.725008563382.5102037901109829117720019716164809526402.510148411103552543126254410.510333542.512.51560100351416552201762098011599562.5101548903606213183131109151131632125865451023391123109443838349147619236163213809565155304398219710777526529614436555108236122063136762931160.72500 Open in a separate window Literature data have shown a correlation between antibody response and circulating levels of CD19?+?B lymphocytes after vaccination against SARS-CoV-2 in patients with immune-mediated diseases. However, we can observe a T cell mediated immune response in patients with B cell depletion even. It has been observed also by other authors [6] recently. It isn’t yet very clear what degree of immunogenicity can be representative of vaccine effectiveness. We have no idea which degree of T cell response as well as for how lengthy it is sufficient to protect individuals against virus disease after vaccination, but initial studies are guaranteeing. Our data reveal that treatment with RTX might not preclude SARS-CoV-2 vaccination also, like a cellular defense response will be activated in the lack of circulating B lymphocytes actually. Declarations Turmoil of interestThe writers declare that zero turmoil is had by them appealing. Footnotes Publishers take note Springer LP-935509 Nature continues to be neutral in regards to to jurisdictional statements in released maps and institutional affiliations..