The effect of absolute lymphocyte count during engraftment period on progression free survival and its relation with rituximab use in the patients diagnosed as lymphoma and autologous stem cell transplantation performed

SUMMARYObjective: Hematopoietic stem cell transplantation is the process of infusion of hematopoiteic stem cells colllected from bone marrow or peripheral blood. Hematopoiteic stem cell transplantation (HSCT) can be classified as autologous stem cell transplantation, allogenic stem cell transplantation and syngenic stem celltransplantation according to donor site of stem cells. HSCT takes place in treatment schemes of solid organ tumors, autoimmune diseases, chronic inflammatory diseases and many other diseases in addition to hematologic malignancies. In the treatment of many diseases HSCT provides cure possibility but also causes significant morbidity and mortality. In this study in autologous stem cell transplantation performed (ASCT) patients we aimed to evaluate the effects of age, stage at the time of diagnosis, disease subtypes, chemotherapy cyclus numbers, and in patients who used rituximab; number of cycluses and time from last course to time of ASCT, radiotherapy, disease status before ASCT, after transplant 15th and 100th days and 1st year absolute lymphocyte lymphocyte count and their relation with progression free survival.Materials and methods: Total 53 patients followed by DEUSM Hematology Department between the dates January 2003 and December 2011 dignosed as Hodgkin and Non-Hodgkin lymphoma to whom ASCT was performed were included in the study. The datas of patients included was obtained from DEUSM data base and patient files.Results: From the patients who were included to study 26 patients (49,1%) were diagnosed as Non-Hodgkin lymphoma whereas 27 patients (50,9) were diagnosed as Hodgkin Lymphoma. According to gender 39 patients (73,58%) were male, 14 patients (26,42%) were female. Median age was 41,7(±14,98) (21;69). In 20 (37,74) out of 53 patients rituximab was used. In 33 patients (62,26) rituximab wasn?t used. 27 patients (81,8%) out of these 33 patients were diagnosed as Hodgkin lymphoma. In 18 patients out of 53 patients progression was observed after transplantation whereas in 35 patients(66,04%) pogression wasn?t observed. In our study the median time to progression was 8 months (1-90). 28 (%52,83) of the patients survived whereas the 25 (%47,17) of the patients died. The 13(%52)of these deaths were caused by infection while in the 12(%48) of the deaths disesase progression was dedected. The median of lymphocyte in the stem cell mobilization was 865/mm³ (100-4600/mm³), ASCT 15th day median of lymphocyte was 300/mm³ (1-5300/mm³), ASCT 100th day median of lymphocyte was 1800/mm³ (300-7800/mm³), ASCT 1st year median of lymphocyte was 1950/mm³ (600-8700/mm³). The progression was dedected in 13(50%) of the Non-Hodgkin lymphoma patients and 5 (%18,5) of the Hodgkin lymphoma patients. In the Non-Hodgkin lymphoma patients without progression survival time was 29,3 months, in Hodgkin lymphoma patients it was 64,74 months and when all the patients were evaluated the total survival time was determined as 44,23 months. When the patients were evaluated alltogether there was no statistically significant difference (p=0,488) was dedected between the patients who used rituximab and the patients did not use rituximab.In the Non-Hodgkin lymphoma patients ASCT 15th day lymphocyte numbers being less then 500(>500) does not have a statiscally important effect (p=0,210)on progression free survival. In the Hodgkin lymphoma patients ASCT 15th day lymphocyte numbers being less than 500 (>500) does not have a statiscally important effect (p=0,014)on progression free survival. In the Non-Hodgkin lymphoma patients who used rituximab, using rituximab does not have statistically significant difference (p=0,011). In the patients whose ASCT 15th day lymphocyte numbers were less than 500, the progression free survival was 34,44 months while in the patients whose lymphocyte number was less than 500 it is 52,73 months (Table 3). When all patients were evaluated It was deteced that the ASCT 15th day lymphocyte number does not have statistically important difference (p=0,459).Comment: As it is a retrospective study and the amount of patienets respectively less this study is restricted. In this study although there was not statistically important relation between ASCT 15th and 100th day lymphocyte number and use of rituximab, when the 15th and 100th day lymphocyte numbers were examined it was detected that the negative effect of rituximab on B lymphocytes started to descrease on the 100th day. The better progression free survival results of ASCT 15th day lymphocyte count <500 can be attributed to the continuing antichemothereupotic effect of rituximab. As a result we believe for better understanding of after transplant immunremodelition, because of recent routine use of ritıximab in some subtypes of lymphoma learning the role of rituximab in this process, learning which lymphocyte subtypes and which cytokines derived from these lymphocytes takes place in this process, multicenter, prospective and larger studies are needed.Keywords:ASCT,rituximab,NHL,HL, ASCT 15th day lymphocyte count