Our defense system (the immune system) is made up of cells, cellular receptors, intracellular proteins, soluble factors and different immune functions. This diversity of components explains why there are multiple pathologies that can affect it, as well as the ways of modulating the system, which we will call Immunotherapy globally.
The field of application of Immunotherapy ranges from lifelong preventive vaccines, through therapeutic vaccines for viral and bacterial infections, to the most recent cancer immunotherapy protocols applicable against check-points of the immune system.
Autoimmune diseases
Great progress has been made in the immunotherapy of inflammation and systemic autoimmune diseases, such as rheumatoid arthritis, inflammatory bowel diseases or for organ-specific diseases such as autoimmune diabetes. These are mostly monoclonal antibodies against different targets that have significantly improved the arsenal of therapies available to treat these pathologies. In addition, biomarkers (e.g., blood antibody levels) are emerging that allow the introduction of these biological therapies and some genetic markers that could be useful for locating the best candidates to respond to them.
Transplants
Immunotherapy agents are used in transplantation to prevent and treat graft rejection, and also to control severe infections.
On the other hand, considerable progress has been made in the evaluation of tolerogenic cell therapy. New forms of immunotherapy based on dendritic cells, regulatory T cells or regulatory B cells are being evaluated so that the transplanted patient can maintain a functioning graft without the need to use immunosuppressants.
In the field of prevention and treatment of serious infections in transplantation, the role of non-specific intravenous and subcutaneous immunoglobulins, but also specific immunoglobulins against cytomegalovirus, varicella or hepatitis B, is being evaluated. Adoptive T-cell-based immunotherapy has also been evaluated for the control of viral infections where cytomegalovirus is an important target.
Cancer immunotherapy
One of the most recent advances is the inhibition of immune check-points to enhance anti-tumor immune activity in some types of cancer.
The immune system has complex control mechanisms used to avoid exaggerated responses that can cause us harm. Tumor cells can use these control mechanisms to evade it.
New cancer immunotherapy agents include antibodies, peptides, proteins, cytokines or cells that can facilitate, enhance or reprogram the action of the innate and/or adaptive immune system against the tumor. One of the challenges will be to achieve adequate modulation of immune mechanisms, ultimately demonstrating therapeutic benefit with the least possible risk.
Allergic diseases
Other applications of immunotherapy are in the field of allergic diseases. In addition to increasingly well-designed vaccines, monoclonal antibodies have emerged that are useful for controlling complex cases of asthma, such as anti-IgE monoclonal antibodies.
Infectious diseases
Hyperimmune gamma globulins are being evaluated for the treatment of influenza A, and the role of similar products has been proposed for the treatment of Ebola patients. The field will also be explored in emerging infections such as those associated with the Zika virus. Preventive and therapeutic vaccines have also been tested to try to control AIDS.
For the control of frequent infections (such as those caused by bacteria), the concept of bacterial vaccines is being revived. The great potential of the mucous membranes as application sites for these vaccines is being rediscovered. The use of appropriate preparations by the right route can be a powerful tool for better infection control.
Abortion
Immunotherapy has also been introduced in other fields, such as human reproduction. This is the case of recurrent miscarriage, which can be related to immunological alterations such as lymphocyte activation, cytotoxicity of natural killer cells or changes in the receptor repertoire of these cells. Different immunotherapies are being evaluated to increase the live birth rate in these patients, including intravenous immunoglobulins.
Intravenous immunoglobulins have also been evaluated in women with obstetric antiphospholipid syndrome, in cases where a new miscarriage occurs despite the use of conventional therapy consisting of heparin and low-dose ASA.
Safety
Adequate immunological monitoring of the target components of the different forms of immunotherapy and their possible consequences in relation to patient safety is also a focus of attention on which many teams are focusing their research efforts in immunotherapy. It is necessary to remember that these therapies can produce adverse events in some patients, so one of the goals of the Immunology specialist is the identification of patients at risk of having these adverse events.
In summary, important advances are being made in the field of Immunotherapy for the control of different diseases, thanks to the progress in the knowledge of this complex system, and how to modulate it safely when necessary.