A couple interesting articles about B-cell depletion, ITP, vaccines and Covid-19.
ashpublications.org/blood/article/122/11/1946/31886/The-effect-of-rituximab-on-vaccine-responses-in
In discussion:
The impact of rituximab on the immune response to vaccination has been examined in patients with malignancy and rheumatic disease. In patients with lymphoma previously treated with high-dose chemotherapy, rituximab was associated with an inadequate antibody response to pneumococcal vaccine but a preserved response to tetanus toxoid and Hib vaccines.44 The addition of rituximab to chemotherapy in 11 patients with hematological malignancies resulted in a failure to respond to the H1N1 vaccine,14 and low rates of seroconversion were observed in 14 patients with lymphoid malignancies; however, responses were not significantly different from control patients who did not receive rituximab.45 In one study of patients with rheumatoid arthritis (n = 14), rituximab was not associated with an impaired antibody response to 2 of 3 influenza virus antigens even during profound B-cell depletion15 ; whereas in another study (n = 17) a poor response to the influenza vaccine was observed.10 Cellular immune responses to influenza vaccination was preserved in rituximab-treated patients with rheumatoid arthritis while humoral immunity was severely impaired.46 In another report, both humoral and cellular responses were found to be compromised.47 In summary, previous studies have focused on patients with underlying hematological malignancies who had received rituximab in addition to myelosuppressive chemotherapy14,17,44,45 or patients with rheumatoid arthritis10,11,15 in the context of biologic agents and other immunosuppressant medications. In general, these studies suggested that antibody responses were compromised. Ours is the first study to assess the impact of rituximab on immune responses in ITP controlling for disease stage and timing of rituximab exposure.
In summary, rituximab was associated with an impaired antibody response to pneumococcal and Hib vaccines during the period of B-cell depletion. Antibody levels against Hib did not indicate functional bactericidal activity for all patients. B-cell depletion resulted in a loss of the “burst” in preplasma cell blasts that is expected after vaccinations, which may explain why specific antibody production was reduced. The overall reduction in antigen presenting cells may result in impaired T-cell function. Our findings provide insight into the mechanisms of humoral and cellular immune suppression caused by rituximab in patients with ITP.
onlinelibrary.wiley.com/doi/full/10.1111/cei.13495
This suggests that it may be possible to undertake dose interruption to maintain inflammatory disease control, while allowing effective vaccination against SARS‐CoV‐29, if and when an effective vaccine is available.
It appears that the innate immune response, and perhaps later anti‐viral CD8 T cell responses, could eliminate the SARS‐CoV2 before significant antibody responses have developed [20, 28, 33] (Fig. 1), suggesting that most MS treatments that largely exhibit limited persistent effects on the innate immune and CD8 T cell responses would have limited influence on COVID‐19. SARS‐CoV‐2 is eliminated by the majority of people with MS and other autoimmunities on immunotherapies, without significant consequences
….the vast majority of people treated with CD20 B cell‐depleting agents in MS recover from COVID‐19
It is evident that there is a lower frequency of seroconversion and reduced titre to 23‐valent pneumococcal polysaccharide vaccine (23‐PPV) (Fig. 2a,b) with or without a booster vaccine (Fig. 2c), keyhole limpet haemocyanin (KLH) neoantigen (Fig. 2d), tetanus toxoid vaccine (Fig. 2e,f) and seasonal influenza vaccines ….The relatively poor vaccine response in people treated with ocrelizumab was predictable, and consistent with that seen following vaccination in people treated with rituximab, suggesting that this is an issue for all classes of anti‐CD20 antibodies used in the treatment of cancer and autoimmune diseases.