Indeed, among individuals who performed a transplant for over 6 months only one experienced a spike IgG concentration below the cutoff. Conclusions Our Amisulpride data confirm reduced serological response in hematological individuals after anti-SARS-CoV-2 vaccination. evaluated after 30C45 days post second dose vaccine using chemiluminescent microparticle immunoassay technology. Results Individuals with hematological malignancies, compared with the control arm, experienced both a mean concentration of anti-SARS-CoV-2 IgG significantly lower and a seroconversion rate numerically lower. All chronic lymphatic leukemia individuals showed levels of antibody titer below the imply concentration, also in only medical monitoring individuals. Comparing serological response in hematological malignancies, only acute leukemia individuals who have been off therapy experienced the highest seroconversion rate among the individuals cohorts and a imply antibody concentration greater than the control arm. Individuals treated with steroids and rituximab showed a lower level of anti-SARS-CoV-2 spike IgG. Variations in anti-spike IgG levels among chronic myeloid leukemia individuals stratified relating to tyrosine kinase inhibitor therapy and molecular response were observed, and they could have interesting implications within the evaluation of the effects of these medicines on the immune system, but having not reached statistical significance at the moment. The cohort of individuals who received a stem cell transplant was very heterogeneous because it included different hematological malignancies and different types of transplant; however, a mean concentration of anti-SARS-CoV2 IgG greater than the control arm was reported. Indeed, among individuals who performed a transplant for over 6 months only one experienced a spike IgG concentration below the cutoff. Conclusions Our data confirm reduced serological response in hematological individuals after anti-SARS-CoV-2 vaccination. However, we found a great diversity of SARS-CoV-2 antibody response relating to types of pathologies and therapies. Keywords: SARS-COV-2, mRNA vaccination, anti-spike IgG, hematological malignancies, onco-hematology 1 Intro The novel coronavirus disease 2019 (SARS-CoV-2) pandemic emerged in Wuhan City, Hubei Province, China, on December 2019 which has Amisulpride spread throughout the world with over 4. 5 million deaths globally and more than 130,000 in Italy. Large variations in practice treatment strategies have emerged during these weeks; patients had been treated, because of lack of effective antiviral providers, with therapies targeted above all at counteracting the complications induced from the infection such as corticosteroids, low-molecular-weight heparin, oxygen therapy, interleukin-6 inhibitors, and antibiotics, but the results have often been disappointing (1C3). The use of SARS-CoV-2 convalescent plasma offers provided contrasting results (4). Anti-SARS-CoV-2 monoclonal antibodies that target different proteins of SARS-CoV-2 have been shown to have a clinical benefit in treating SARS-CoV-2 infection especially if administered within the 1st days of illness, but their use is still limited (5, 6). The only weapon to combat, on a large level, the spread of SARS-CoV-2 has been vaccination. This has been performed with fundamentally two different vaccine systems used in parallel: one based on SARS-CoV-2 mRNA (7, 8) and the other based on adenoviral vector (9, 10), both of which are capable of inducing the production of native viral spike proteins of SARS-CoV-2 and consequently neutralizing antibodies. In the beginning, also in Italy, both types of vaccines have been used; consequently, vaccines based on adenovirus, due Amisulpride to the event of severe atypical thrombotic phenomena, actually if limited to a few instances, have been reserved for men and women more than 60 years and then gradually left behind. Real-life results have confirmed those acquired by registration studies with demonstration of good immunization acquired in vaccinated subjects. In immunocompromised individuals, the mRNA vaccine has been used in Italy from the beginning of the vaccination marketing campaign, but several studies have shown the serological response of onco-hematological individuals was reduced compared to healthy subjects, due to the CLEC4M state of immunosuppression because of both underlying.