[Is it necessary to revaccinate against hepatitis B virus when the titer of anti-HBs drops below 10 IU/L?]

Viral hepatitis B still represents a major epidemiological issue worldwide. After recombinant vaccine administration, a titer of anti-HBs antibodies ≥ 10 IU/L has long been considered to be seroprotective. Persons without this antibody level after complete vaccination are referred to as non-responders. A progressive decline in anti-HBs levels over years is also commonly seen in responders. Recently, there has been increasing evidence that the titer of anti-HBs ≥ 10 IU/L does not provide 100 % protection against infection and clinically manifest illness. Additionally, an important role of cellular immune memory has been demonstrated - without any correlation with anti-HBs titer. Based on current knowledge, there is no need for regular anti-HBs titer testing or booster vaccination in immunocompetent individuals with anti-HBs ≤ 10 IU/L. At present, regular serological testing and, if need be, revaccination to maintain anti-HBs ≥ 10 IU/L are recommended in immunocompromised persons and after liver transplantation.

[Treatment with rituximab as an opportunity for the prevention of infectious complications]. / Lécba rituximabem jako výzva k prevenci infekcních komplikací.

UNLABELLED: Rituximab, a monoclonal antibody against the surface antigen of B-lymphocytes CD20 is beeing used in the treatment of numerous hematological, hematooncological and autoimmune disorders. After administration of ritu-ximab, quick and almost complete depletion of B-lymphocytes with the exception of pre-B-lymphocytes and plasma cells occur. Neutropenia and low serum antibody levels in classes IgA, IgM and IgG may also develop. These changes usually persist for 6-12 months, rarely for several years. In the consequence, patients with the rituximab treatment are more prone to infections - usually of bacterial and viral origin. Concomitantly, rituximab treatment influences negatively postvaccination antibody production and therefore adequate preventive measures are necessary before the beginning of the treatment. The authors offer complex overview of actual literature, emphasize adequate education of patients as well as of healthcare providing staff and discuss the vaccination recommendation against preventable communicable diseases like influenza, pneumococcal diseases, tetanus, diphtheria and pertussis. KEY WORDS: autoimmune disease - immunosupression - infectious complications - prevention - rituximab - vaccination.