HLA typing

Contamination of blood products with lymphocytes can lead to transfusion-induced reactions ranging from a mild fever to severe reactions such as alloimmunization and graft versus host disease (GvHD), in which the transfused lymphocytes (graft) survive the defensive immune reaction of the patient (host) and start a reaction which destroys the cells of the host. The patient also may develop an immune response to the human leukocyte antigen (HLA) type of the graft s cells and reject all platelet transfusions that do not match their own HLA system. The HLA system, found on blood platelets and lymphocytes, is more compHcated than, but similar to, the ABO blood group system of red cells. 

Transfusion-induced autoimmune disease has been a significant complication in the treatment of patients who require multiple platelet transfusions. Platelets and lymphocytes carry their own blood group system, ie, the human leukocyte antigen (HLA) system, and it can be difficult to find an HLA matched donor. A mismatched platelet transfusion does not induce immediate adverse reactions, but may cause the patient to become refractory to the HLA type of the transfused platelets. The next time platelets with an HLA type similar to that of the transfused platelets are transfused, they are rejected by the patient and thus have no clinical efficacy. Exposure to platelets originating from different donors is minimized by the use of apheresis platelets. One transfusable dose (unit) of apheresis platelets contains 3-5 x 10 platelets. An equal dose of platelets from whole blood donation requires platelets from six to eight units of whole blood. Furthermore, platelets can be donated every 10 days, versus 10 weeks for whole blood donations. 

Allogeneic hematopoietic stem cell transplantation (HSCT) has been used in the treatment of pediatric AML in first complete remission. In most clinical trials, the availability of HLA-matched sibling donors determined whether patients underwent HSCT as postremission treatment. To facilitate this process, it is important to obtain HLA typing on all younger patients with AML and siblings shortly after diagnosis. Patients who do not have an HLA-matched sibling will proceed to postremission therapy. 

Transplant with umbilical cord blood (UCB) offers an alternative stem cell source to patients who do not have an acceptable matched related or unrelated donor. When allogeneic hematopoietic cells are obtained from UCB, the cord blood is obtained from a consenting donor in the delivery room after birth and delivery of the placenta.32 The cord blood then is processed, a sample is sent for HLA typing, and the cord blood... 

B3. Begovich, A. B., and Erlich, H. A., HLA typing for bone marrow transplantation. New polymerase chain reaction-based methods. JAMA, J. Am. Med. Assoc. 586-591 (1995). 

It is known that lympocytes are composed of two major subpopulations T-cell and B-cell, each of which plays an essential role in all of the immunological reactions in living systems. There are strong medical demands for the separation of T- and B-cells, which is essential for the therapy and diagnosis of autoimmune diseases and cancer, as well as for HLA typing in transplantation. 

The tissue type seems to be a factor, as there is a preponderance of the HLA-type DR4 in patients who develop the syndrome. Thus, in one study, an incidence of 73% for this HLA type was observed in patients suffering from the LE syndrome compared with an incidence of 33% in controls and 25% in patients not developing the LE syndrome. 

This is a vasodilator drug, which causes SLE in a significant proportion of patients. Several predisposing factors have been identified dose (>25 mg) duration of therapy (mean 18 months) acetylator phenotype (slow) HLA type (DR4) and gender (females males, 4 1). Antinuclear antibodies and antihydralazine antibodies are detected in serum. This causes a type III immune reaction. Mechanism is unclear but may involve interference with the development and maturation of T cells in the thymus, leading to an alteration of tolerance... 

Hansen, T. and Hannestad, K. (1989) Direct HLA typing by rosetting with immunomagnetic beads coated with specific antibodies. J. Immunogenet. 16,137—139. 

The high diagnostic accuracy of autoantibody tests for CD has questioned the need for intestinal biopsy [128], especially in pediatric populations [129]. Because histological and serological examination has limitations (and also HLA typing, an expensive procedure not suitable for routine diagnostic use), it is still advised to apply a combination to clarify the full breadth of the gluten-sensitive spectrum [130]. 

In a 46-year-old man taking olanzapine 10 mg/day, leukopenia and neutropenia were associated with HLA types A1 24, B7, B35, DRB1 15, DRB1 11, DRB3 01-03, DRB5 01-02, a haplotype distinct from that previously observed in clozapine-induced hemo-toxicity (213). 

HLA typing HLA-related inflammatory disease such as ankylosing spondylitis... 

The role of the immune system in the pathophysiology of Graves disease is well established. A considerable amount of information links the human major histocompatibility complex (human leukocyte antigen [HLA]) with Graves disease. For instance, several HLA types, such as HLA-B8 and HLA-DR3, are associated with this disorder. Graves disease in the Japanese has been found to be associated with HLA-B35, whereas in patients of Chinese... 

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