Marina Martinengo

Positive Selection and Expansion of Cytomegalovirus-specific CD4 and CD8 T Cells in Sealed Systems : Potential Applications for Adoptive Cellular Immunoreconstitution

Administration of pathogen-specific T-cell lines can reconstitute the cellular immune function of immunocompromised patients. Selection and expansion of specific T cells for reinfusion pose unique challenges owing to the fact that good manufacturing procedures must be implemented. Cytokine secretion-based methods can identify and select specific T cells. We showed here that it is possible to combine this method with procedures for cell handling performed in a sealed, unbreached system from start to end. Peripheral blood mononuclear cells, obtained from blood samples and processed in a sealed system, were stimulated in Teflon bags with a library of selected CD4 and CD8 peptides derived from the immunodominant cytomegalovirus protein pp65. The stimulated T cells were labeled with reagents for interferon-γ surface capture and selected on a magnetic column using a sealed system connected to the Teflon bags. Elution and final expansion were also performed with an unbreached protocol with preservation of sterility even if the steps were run on the bench top. Expanded cells exhibited the appropriate functions. The use of this unbreached procedure proves that safety of cellular products generated in a good manufacturing procedures facility can be further improved. Similar sealed protocols can also be applied for T-cell therapies directed against tumor antigens.

The first case of drug-induced immune hemolytic anemia due to hydrocortisone

BACKGROUND: Drug‐induced immune hemolytic anemia (DIIHA) is a well‐known complication of drug treatment. Sensitization can occur, due to interaction of the drug and/or its metabolites with cells of the immune system, after the first drug administration, while the hemolytic crisis generally occurs after repeated administration of a drug. This event occurred in the case described here of acute hemolysis due to the administration of corticosteroids.

Occult hepatitis B virus infection: a case of reactivation in a patient receiving immunosuppressive treatment for allogeneic bone marrow transplantation

The presence of hepatitis B virus (HBV) genome in HBsAg-negative subjects is known as occult HBV infection1. This particular form of hepatitis, already recognised in the 1980s, has been confirmed and studied using molecular biology techniques. In fact, occult infection is usually associated with the presence of anti-HBc and anti-HBs, but given the relatively high percentage (approximately 20%) of subjects who are negative for all markers1, the introduction of a test to detect HBV DNA was fundamental. Occult infection is related in some cases to mutant viruses that are not detectable by the commonly used tests; it has also been observed that the reactivation of HBV related to variants of the viral genome often has an unfavourable clinical prognosis2,3. Much more frequently, however, an occult infection is associated with strong suppression of viral replication, which is responsible both for the negativity for HBsAg and the undetectable or very low levels of HBV DNA in the serum, although this latter can be found in liver tissue4,5. An occult infection can have a important impact in various different clinical settings, including transmission through blood transfusion or organ transplants6,7 and reactivation following immunosuppressive therapy. Indeed, it has been shown that the hosts immune response, co-infections (e.g. with hepatitis C virus) and epigenetic factors all play significant roles in occult infection8. We present the case of a Georgian child negative for HbsAg who, after receiving an allogeneic bone marrow transplant and immunosuppressive therapy, was found to be positive for HBV. We then describe the investigations conducted in order to determine whether this was due to a new infection or reactivation of an occult infection.