Hematopetik Kök Hücre Transplantasyonu Yapılan Hastalarda Bağışıklığın Yeniden Yapılanması

Abstract

Hematopoietic stem cell transplantation (HSCT) is widely used today in the treatment of many diseases. HSCT can completely cure malign diseases like leukemia as well as non-malign diseases like thalassemia. During allogeneic HSCT, complications such as graft versus host disease (GVHD) caused by immune interaction of patient and host cells, infections caused by suppression of the immune system, veno-occlusive disease (VOD), and graft failure may occur and these complications may lead to treatment failure. Delay in immune reconstitution after hematopoietic stem cell transplantation is thought to be associated with high morbidity due to infectious complications. In clinical trials, it has been shown that in patients receiving myeloablative regimens, neutrophil function returns to normal within weeks, natural killer (NK) cells function within one month, CD4(+) T cells function within years (1-5 years for memory cells, >5 years for T regulatory cells), CD8(+) T cells function within months (2-6 months for memory and effector cells), and B cells function within years and this duration is even longer for patients with GVHD. Complete functional recovery of these cells is variable and depends on the intensity and duration of immunosuppressive therapy, in the case of GVHD and also in the clinical course of some diseases. Other factors affecting immune reconstitution include underlying disease that require HSCT, history of chemotherapy or radiotherapy, nutritional condition, age of patient and donor, characteristics of conditioning regimens, total body radiation or use of anti-lymphocytic antibodies, stem cell source, procedures applied to the products, patient-donor HLA match, and infections after transplantation. In this retrospective study, lymphocyte subgroups were evaluated before transplantation and 1, 3, 6, 12, and 24 months after transplantation and whether there is an association between transplant related complications and immune reconstitution was investigated. xi Evaluation of absolute values of lymphocyte subgroups in 81 patients revealed that CD3(+) lymphocyte numbers returned to pre-HSCT levels at 3 months, CD4(+) T lymphocytes at 12 months, CD8(+) T lymphocytes at 3 months, CD19(+) B lymphocytes at 12 months and CD4/CD8 ratio at 24 months. Besides, CD3+4-8- double negative T lymphocytes returned to pre-HSCT levels at 6 months. CD16/56(+)CD3(+) NK-T and CD16/56(+)CD3(-) NK lymphocytes returned to pre-HSCT levels within a short time of 1 month. Association between lymphocyte subgroup and HSCT related complications were also investigated in our study. For this purpose, absolute values of activated T lymphocyte subgroups during GVHD and/or before the development of GVHD were evaluated using lymphocyte activation markers in patients with acute and chronic GVHD which are immunological complications of HSCT. When absolute levels of lymphocyte subgroups were compared in patients with and without acute GVHD, recovery of CD3(+) and CD4(+) lymphocytes were found to be delayed in patients with acute GVHD; CD3(+) lymphocyte counts returned to pre-HSCT levels at 6 months in patients with acute GVHD (3 months in those without acute GVHD) and CD4(+) lymphocyte counts returned to pre-HSCT levels at 24 months in patients with acute GVHD (12 months in those without acute GVHD). CD8(+) T lymphocytes returned to pre-HSCT levels at 3 months both in patients with and without acute GVHD. In patients with acute GVHD, CD8(+) T lymphocyte counts were found to be higher at 6, 12 and 24 months when compared to those of patients without acute GVHD (p≤0.05). Besides, CD19(+) B lymphocyte counts returned to pre-HSCT levels at 12 months in patients with acute GVHD and at 6 months in patients without acute GVHD. CD19(+) B lymphocyte count was also lower at 1,3, 6, 12 and 24 months in patients with acute GVHD when compared to those without acute GVHD (p≤0.05). CD4/8 ratio returned to pre-HSCT levels at 24 months in both groups. The absolute numbers of CD16/56(+)CD3(+) NK-T and CD16/56(+)CD3(+) NK lymphocytes returned to pre-HSCT levels within a short period of 1 month in both patients with and without acute GVHD. In order to evaluate the markers related to T lymphocyte activation in patients with acute GVHD, analysis of HLA-DR expression as a marker of CD3(+) T lymphocyte xii activation, CD8/57 for CD8(+) T lymphocyte activation, CD8/56 as a marker of NK cell activation, and CD4/25 and CD4/28 for CD4(+) T lymphocyte activation were performed. In patients with and without acute GVHD, the absolute values of activated CD3 (CD3/HLA-DR), activated CD8 (CD8/56) and activated NK (CD8/57) cells were found to be increased rapidly at an early stage after HSCT. This condition was thought to reflect lymphocyte activation; which occured after donor T lymphocytes, primarily cytotoxic T lymphocytes came across to the patient tissues at an early stage after HSCT. Besides, CD3/HLA-DR(+), CD8/56(+) and CD8/57(+) activated T lymphocytes were found to reach higher levels at 12 and 24 months in patients with acute GVHD when compared to those without acute GVHD (p≤0.05). CD3+4-8- ‘double negative’ T lymphocytes were also evaluated in our study. In patients with acute GVHD, CD3+4-8- ‘double negative’ T lymphocytes count was higher at 12 months than that of patients without acute GVHD (p≤0.05). First, CD4/25(+) activated T lymphocytes were found to be decreased after HSCT, but returned to pre-HSCT levels at 24 months in both patients groups with and without acute GVHD. Besides, in patients with acute GVHD, activated CD4/25(+) lymphocyte count was higher at 24 months (p≤0.05). CD4/28(+) activated T lymphocyte count decreased after HSCT in both groups; later, in patients without acute GVHD, their counts returned to pre-HSCT levels at 24 months while their counts still did not return to pre-HSCT levels at 24 months in patients with acute GVHD.When absolute levels of lymphocyte subgroups were compared in patients with and without chronic GVHD, CD3(+) lymphocyte count returned to pre-HSCT levels at 1 month in patients with chronic GVHD and at 6 months in patients without chronic GVHD. CD4(+) T lymphocyte count returned to pre-HSCT levels at 12 months both in patients with and without chronic GVHD. While CD8(+) T lymphocyte count returned to pre-HSCT levels as early as 1 month both in patients with and without chronic GVHD, CD8(+) T lymphocyte count was higher in patients with chronic GVHD at 1, 3, 6, 12, and 24 months when compared to those without chronic GVHD (p≤0.05). CD19(+) B lymphocyte count returned to pre-HSCT levels at 12 months both in patients with and without chronic GVHD, whereas CD19(+) B lymphocyte count was lower in patients with chronic GVHD at 3, 6, and 12 months (p≤0.05). CD4/8 ratio returned to pre-HSCT levels at 24 months in both groups. xiii CD16/56(+)CD3(+) NK-T and CD16/56(+)CD3(-) NK lymphocytes returned to pre-HSCT values within 1 month after HSCT in both groups. When specific subgroups reflecting lymphocyte activation were evaluated in patients with chronic GVHD, activated CD8/57(+) T lymphocyte count was higher at 1, 3, 6, 12, and 24 months, while activated CD8/56(+) NK lymphocyte count was higher at 12 and 24 months than those of patients without chronic GVHD (p≤0.05). Activated CD3/HLA-DR(+) T lymphocyte count was higher at 1, 6, 12, and 24 months in the chronic GVHD group. CD3+4-8- double negative T lymphocytes returned to pre-HSCT levels at 1 month in patients with chronic HSCT and at 6 months in patients without chronic GHVD. Activated CD4/25(+) T lymphocytes returned to pre-HSCT levels at 24 months in both groups, while CD4/28(+) activated T lymphocytes reached pre-HSCT values at 12 months in patients with chronic GVHD and at 24 months in patients without chronic GVHD. Besides, CD4/25(+) activated T lymphocyte count was higher at 1, 3, 6, and 24 months in patients with chronic GVHD. Higher counts of CD3(+) lymphocytes, CD8(+) T lymphocytes, CD4/25(+), CD8/56(+), CD8/57(+), CD3/DR(+) activated T lymphocytes in patients with chronic GVHD suggest that these lymphocyte subgroups play an important role in GVHD pathogenesis. If chronic GVHD does not take controlled, these lymphocytes were found to be at increased levels. In addition, low counts of CD19(+) B lymphocytes in patients with chronic GVHD at 3, 6, and 12 months suggests that development of chronic GVHD delays the reconstitution of B lymphocytes. Besides, high levels of CD3(+) lymphocytes, CD8(+) T lymphocytes, CD4/25(+),CD8/57(+), CD3/DR(+) activated lymphocytes at 1 month when chronic GVHD symptoms have not yet developed suggests that these lymphocyte subgroups may be used as a warning sign forchronic GVHD. Due to the association of delay in immune reconstitution and infectious complications after HSCT, lymphocyte subgroups were evaluated in patients with and without CMV reactivation. CD3(+) lymphocyte count returned to pre-HSCT levels at 6 months in patients with CMV reactivation and at 12 months in patients without CMV reactivation and CD3(+) lymphocyte count was higher at 3, 6, 12, and 24 months in patients with CMV reactivation (p≤0.05). CD4(+) T lymphocyte count xiv returned to pre-HSCT levels at 24 months both in patients with and without CMV reactivation. CD8(+) T lymphocytes reached pre-HSCT levels at 1 month in patients with CMV reactivation and at 3 months in those without CMV reactivation and CD8(+) lymphocyte counts were higher at 3, 6, 12, and 24 months in patients with CMV reactivation (p≤0.05). CD19(+) B lymphocyte count returned to pre-HSCT levels at 6 months in patients with CMV reactivation and at 12 months in those without CMV reactivation. CD4/8 ratio returned to pre-HSCT levels at 24 months in both groups. In addition, CD16/56(+)CD3(+) NK-T cells and CD16/56(+)CD3(-) NK lymphocytes returned to pre-HSCT levels within 1 month after HSCT in both groups. When specific subgroups reflecting lymphocyte activation were evaluated in patients with CMV reactivation, both CD8/57(+) activated T lymphocytes and CD3/HLA-DR(+) activated T lymphocytes counts were higher in patients with CMV reactivation at 6, 12, and 24 months than those without CMV reactivation (p≤0.05). CD8/56(+) activated NK lymphocyte profiles were similar both in patients with and without CMV reactivation. CD3+4-8- double negative T lymphocyte count was higher in patients with CMV reactivation at 12 months than those without CMV reactivation. CD4/28(+) activated T lymphocytes returned to pre-HSCT levels at 24 months both in patients with and without CMV reactivation and CD4/25(+) activated T lymphocytes returned to pre-HSCT levels at 24 months in patients without CMV reactivation while their counts still did not return to pre-HSCT levels at 24 months in patients with CMV reactivation. Higher CD3(+) and CD8(+) T lymphocyte counts at 3, 6, 12, and 24 months; CD8/57(+) and CD3/HLA-DR(+) activated T lymphocyte counts at 6, 12, and 24 months; CD4/25(+) activated T lymphocytes at 3 months; and CD3+4-8- double negative T lymphocyte counts at 12 months in patients with CMV reactivation when compared to those without CMV reactivation suggests that these lymphocyte subgroups may play an important role in CMV reactivation. In summary; return of CD3(+) lymphocyte count to pre-HSCT values at 3 months, CD4(+) T lymphocyte count at 12 months, CD8(+) T lymphocytes at 3 months, CD19(+) B lymphocytes at 12 months, CD4/CD8 cell ratio at 24 months, and xv CD16/56(+)CD3(+) NK-T and CD16/56(+)CD3(-) NK lymphocyte counts at 1 month after HSCT demonstrates that immune reconstitution may extend up to 2 years in patients underwent allogenic HSCT. Development of acute GVHD has been found to delay in immune reconstitution of especially CD3(+) lymphocytes, CD4(+) T lymphocytes, and CD19(+) B lymphocytes. Absolute numbers of activated CD3 (CD3/HLA-DR), activated CD8 (CD8/56) and activated NK (CD8/57) were found to be increased rapidly in early stages after HSCT both in patients with and without acute GVHD; this condition was thought to reflect lymphocyte activation; which occured after donor T lymphocytes, primarily cytotoxic T lymphocytes came across to the patient tissues at an early stage after HSCT. Since CD3(+) lymphocytes, CD8(+) T lymphocytes, CD4/25(+),CD8/57(+) and CD3/DR(+) activated T lymphocyte counts were found to be higher in patients with chronic GVHD as early as 1 month even when chronic GVHD symptoms were not evident, these lymphocyte subgroups may be used as a warning sign for the development of chronic GVHD.