Safe transplantation
Russian doctors have found out how to improve bone marrow transplantation
Scientists from the National Medical Research Center of Hematology have created a technique that quickly allows you to find genetic differences between a bone marrow donor and a patient. It will help make this procedure safer for the patient, scientists write in the journal Frontiers in Immunology (Romaniuk et al., Rapid Multiplex Genotyping of 20 HLA-A*02:01 Restricted Minor Histocompatibility Antigens).
"On the one hand, this will make it possible to predict the intensity of the immune response and the possible outcome of transplantation and adjust immunosuppressive therapy if necessary. On the other hand, we will be able to select optimal targets for each patient for immunotherapy, which is currently being developed in our laboratory," the scientists explain, whose words are transmitted by the press service of the Russian Science Foundation.
Bone marrow transplantation is a fairly widely used medical procedure that is used today to save the lives of a wide variety of patients, starting with HIV carriers whose immune system has been depleted to the limit, and ending with carriers of various forms of blood cancer, anemia and various forms of autoimmune diseases.
This procedure is not yet completely safe for patients – as in the case of other forms of transplantation, the patient's body may reject new tissue due to the fact that his immunity will begin to attack the transplanted tissues and bone marrow stem cells. In this regard, doctors are now spending a lot of time checking for compatibility, comparing how the genes responsible for the signals of "friend-foe" and other components of the immune system are arranged.
As scientists explain, it includes, in addition to the "main" set of genes responsible for the operation of this recognition system, the so-called main histocompatibility complex, and several dozen other genes. Their immune cells are used to distinguish "their" cells from "strangers".
A team of Russian scientists led by Grigory Efimov from the National Medical Research Center of Hematology has been studying the structure of these genes, the so-called secondary antigens of the complex, for several years. They are trying to find such features in their structure that could be used to fight cancer.
These searches helped them to solve another important task – to accelerate the analysis of the structure of these components of immunity in determining the compatibility between the patient's immunity and the cells of his donor.
As a rule, the appearance of even one small mutation in these DNA sites leads to the fact that the immune system begins to attack the "stranger". This greatly complicates the analysis and forces scientists to resort to very complex methods of extracting samples of proteins and genes from cells, sorting and comparing them. This greatly limits the possibilities for finding donors and checking their compatibility if the operation needs to be carried out very urgently.
According to the RNF press service, the method developed by Russian scientists makes it possible to identify differences in the genes of the donor and recipient within an hour, without resorting to more time-consuming and expensive methods.
In essence, it is an analogue of the so-called polymerase chain reaction, which is actively used in genetic analyses in any modern clinics. When it is carried out, doctors or scientists try to find the DNA segment they are interested in in the sample using special enzymes that recognize that set of nucleotides and "multiply" it.
To start this process, a so-called primer is needed - a special short chain of DNA "letters" that will attach to the necessary versions of the secondary antigens of the complex and start the reaction of copying them. Russian scientists have found out how it is possible to create such primers that simultaneously allow you to very accurately find specific versions of these genes, and at the same time look for not one, but many different variations in them.
This has significantly simplified and accelerated the verification of the compatibility of the donor and the patient – now doctors can simply mix their blood samples with primers, proteins and other reagents and determine in an hour how compatible their immune systems are. So far, Efimov and his colleagues have prepared two dozen similar labels, but their number can be easily expanded for a more complete compatibility assessment.
In addition, in a similar way, you can compare and look for other differences in the structure of different genes in cells. This will not only help scientists to make other types of organ transplants safe for patients, but also to study more quickly how cancer develops and how the immune system can be forced not to ignore tumor cells and fight them.
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