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Dive into the research topics where Haluk Koç is active.

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Featured researches published by Haluk Koç.


British Journal of Haematology | 2002

Mobilization of peripheral blood stem cells with chemotherapy and recombinant human granulocyte colony-stimulating factor (rhG-CSF): a randomized evaluation of different doses of rhG-CSF.

Taner Demirer; Meltem Ayli; Muhit Ozcan; Nazan Günel; Rauf Haznedar; Mehmet Daglı; Turgay Fen; Yasemin Genç; Suleyman Dincer; Onder Arslan; Gunhan Gurman; S. Demirer; Gülsüm Özet; Akin Uysal; Nahide Konuk; Osman Ilhan; Haluk Koç; Hamdi Akan

Summary. To date, no randomized study has compared different doses of recombinant human granulocyte colony‐stimulating factor (rhG‐CSF) following submyeloablative mobilization chemotherapy. Therefore, we evaluated the effect of different doses of rhG‐CSF following mobilization chemotherapy on yields of CD34+ peripheral blood stem cells (PBSC). Fifty patients were randomized to receive 8 (n = 25) versus 16 µg/kg/d (n = 25) of rhG‐CSF following mobilization chemotherapy. The median number of CD34+ cells collected after 8 µg/kg/d of rhG‐CSF was 2·36 × 106/kg (range, 0·21–7·80), compared with 7·99 (2·76–14·89) after 16 µg/kg/d (P < 0·001). Twenty out of 25 (80%) patients in the low‐dose and 23 out of 25 (92%) in the high‐dose rhG‐CSF arm underwent high‐dose chemotherapy (HDC) and autologous stem cell transplantation (ASCT). Median days to white blood cell engraftment in patients mobilized with 8 µg/kg and 16 µg/kg of rhG‐CSF were 12 (10–20) and 9 (8–11) respectively (P < 0·001). There was no difference between the two groups regarding the other parameters of peritransplant morbidity: days to platelet engraftment (P = 0·10), number of red blood cell (P = 0·56) and platelet transfusions (P = 0·22), days of total parenteral nutrition requirement (P = 0·84), fever (P = 0·93) and antibiotics (P = 0·77), and number of different antibiotics used (P = 0·58). These data showed that higher doses of rhG‐CSF following submyeloablative mobilization chemotherapy were associated with a clear dose–response effect based on the collected cell yields. Based on the parameters of peritransplant morbidity, 8 µg/kg/d was as effective as 16 µg/kg/d except for a rapid neutrophil engraftment in the high‐dose arm. Therefore, in routine clinical practice, despite some advantage in the use of higher doses of rhG‐CSF, lower doses may be used for PBSC collections following chemotherapy‐based mobilization regimens in this cost‐conscious era.


Bone Marrow Transplantation | 1997

Hepatitis B virus infection in allogeneic bone marrow transplantation

C. Üstün; Haluk Koç; S Karayalçın; Gülen Akyol; Gunhan Gurman; Osman Ilhan; Hamdi Akan; Muhit Ozcan; Onder Arslan; Nahide Konuk; Akin Uysal; Meral Beksac

Fourty-four patients who underwent allogeneic bone marrow transplantation (alloBMT) were studied for hepatitis B virus (HBV)-related complications. The mean follow-up period was 15.3 months. Positivity for HBV surface antigen (HBsAg) was observed in 10 patients (22.7%) throughout the study. Four of the 10 patients were HBsAg carriers before alloBMT, while the remaining six became HBsAg(+) after alloBMT. During the follow-up period (from 6 months to 45 months), an elevation in serum ALT activity was observed in the four carriers when immunosuppression was reduced or withdrawn. All of the four HBsAg carriers developed hepatitis, but none of them died of liver failure due to HBV. Only one death due to GVHD and diabetic ketoacidosis was observed in this group. Two of the four carriers received marrow from anti-HBs positive donors and one of them cleared HBsAg from his serum via adoptive immunity 8 months after transplantation. The remaining six patients acquired HBV after alloBMT, but we were unable to demonstrate the source of HBV. Five of them had a moderate increase in serum ALT activity while the other patient had a normal ALT. Two patients seroconverted to anti-HBs spontaneously. Two patients died during the follow-up, one due to intracranial hemorrhage and the other due to GVHD and accompanying pulmonary infection. The rest of the study group (34 patients) remained HBsAg(−) throughout the study. Two of them had an HBsAg(+) donor, but neither developed HBV infection in their follow-up period. The acquisition rate of HBV infection was relatively low in recipients who were positive for anti-HBs compared to those who were negative for anti-HBs (8 vs 19%). Anti-HBs positivity remained for a longer period in recipients who received marrow from anti-HBs positive donors compared to those recipients who had anti-HBs negative donors (median 12 vs 3 months). We think that HBV is a frequent cause of liver dysfunction in alloBMT patients where HBV infection is endemic. Whether the disease is in the form of reactivation of HBsAg-positive recipients, or is acquired from unknown sources in recipients who never had contact with the virus, the course of the disease is not fatal. Silent serologic changes can be demonstrated if viral serologic markers are sought serially. Among them, the disappearance of serum anti-HBs may be important as it increases the risk of HBV contamination in recipients.


Bone Marrow Transplantation | 1999

Autoimmune thrombocytopenia in a patient with small cell lung cancer developing after chemotherapy and resolving following autologous peripheral blood stem cell transplantation.

Taner Demirer; Harika Çelebi; Mutlu Arat; C. Üstün; S Demirer; Imdat Dilek; Muhit Ozcan; Osman Ilhan; Hamdi Akan; Gunhan Gurman; Haluk Koç

A 46-year-old white male with small cell lung cancer (SCLC) limited to the thorax developed autoimmune thrombocytopenic purpura (AITP), following a cyclophosphamide, paclitaxel and G-CSF-containing regimen for peripheral blood stem cell (PBSC) mobilization. AITP associated with small or non-small cell lung cancer has been reported. We considered that the AITP in this case may be a part of paraneoplastic syndrome, which is frequently seen in patients with SCLC. The patient received HDC and autologous PBSC transplantation (APBSCT) for SCLC and the AITP resolved following transplantation, thus supporting the concept of HDC + APBSCT for the treatment of autoimmune diseases.


Transfusion Science | 1999

The impact of the CD34+ cell dose on engraftment in allogeneic peripheral blood stem cell transplantation.

Osman Ilhan; Onder Arslan; Mutlu Arat; Meral Beksac; Hamdi Akan; Muhit Ozcan; Gunhan Gurman; Nahide Konuk; Akin Uysal; Haluk Koç

Forty-five patients who underwent allogeneic peripheral blood stem cell transplantation (PBSCT) were evaluated in order to investigate any relationship between CD34+ cell dose given and hematological recovery. Granulocyte counts > 1.0 x 10(9)/L and platelet > 50 x 10(9)/L were considered as hematological recovery. Three different regimens were used for mobilization, by adjusting the recombinant granulocyte colony stimulating factor (rhG-CSF, Roche) dose. The first group (n = 3), whose donors mobilized with 5 micrograms/kg/d s.c. rhG-CSF received a mean of 5.9 x 10(6)/kg (95% confidence interval for mean (CI); 2.4-9.3) CD34+ cells. The second group (n = 37), mobilized with 10 micrograms/kg/d s.c. rhG-CSF and the third group (n = 5) mobilized with 15 micrograms/kg/d s.c. rhG-CSF, received a mean of 5.7 x 10(6)/kg (95% CI; 4.6-6.75) and 6.56 x 10(6)/kg (95% CI; 4.57-8.55) CD34+ cells, respectively. CD34+ cell dose was 5.82 x 10(6)/kg (95% CI; 4.97-6.68) for all the patients. All patients received rhG-CSF from day +1 until attaining granulocyte count > 1.0 x 10(9)/L for three consecutive days. Median granulocyte and platelet engraftment days for the whole group was 15 (range; 11-44) and 14 (11-54) days respectively. There was a close correlation (r = -0.301, p < 0.05) between the CD34+ cell dose and granulocyte recovery for the whole group. When these analyses were performed separately within groups, this correlation was also found significant for the first group (r = -0.99, p < 0.05) for granulocyte recovery. On the contrary the same analysis did not reach significance for the other groups, nor for platelet recovery for the whole group (r = 0.039, p = 0.821). We calculated a minimum dose of 4 x 10(6)/kg CD34+ cells for a safe alloPBSCT. There was no difference between patients who received more than 5 x 10(6)/kg CD34+ cells, and those who received more than 2 x 10(6)/kg and less than 5 x 10(6)/kg CD34+ cells. In conclusion, we have demonstrated a correlation between the CD34+ cell dose given and faster hematological recovery for alloPBSCT patients.


Bone Marrow Transplantation | 2001

Recombinant human granulocyte colony-stimulating factor (rh-G-CSF) may accelerate hematopoietic recovery after HLA-identical sibling allogeneic peripheral blood stem cell transplantation.

Muhit Ozcan; C. Üstün; E. Akcaglayan; Hamdi Akan; Onder Arslan; Osman Ilhan; Meral Beksac; Gunhan Gurman; Taner Demirer; Mutlu Arat; Harika Çelebi; Nahide Konuk; Akin Uysal; Haluk Koç

We studied the effects of recombinant human granulocyte colony-stimulating factor (G-CSF) on hematopoietic recovery and clinical outcome in patients undergoing allogeneic peripheral blood stem cell (PBSC) transplantation. Fifty-six patients with hematological malignancies who underwent allogeneic PBSC transplantation between 1995 and 1998 were entered into this study. Twenty-eight patients who received daily G-CSF from day +1 after allogeneic PBSC transplantation until the absolute neutrophil count (ANC) reached >0.5 × 109/l for 3 consecutive days were compared with 28 patients (control group) who did not receive G-CSF in a non-randomized manner. The study group and the control group were comparable with respect to baseline patient and transplantation characteristics. Median times to ANC of >0.5 × 109/l and 1 × 109/l with or without G-CSF were 12 days (range 8–21), 13 days (10–32) (P = 0.04) and 13 days (9–21), 15 days (11–44) (P = 0.02), respectively. Median times to reach a platelet count of >20 × 109/l with and without G-CSF were 11 days (0–20) and 13 days (9–26), respectively (P = 0.03). The incidence of febrile episodes was significantly lower with G-CSF, 75% vs 100% (P = 0.008). Patients receiving G-CSF had less grade III–IV mucositis than those who did not receive G-CSF (P = 0.01). There was also no increase in the incidence and severity of acute GVHD in patients using G-CSF (P = 0.22). Although the number of relapsing patients was greater in the G-CSF group (seven vs three patients), this was not statistically significant (P = 0.24). Disease-free and overall survival rates did not differ between the two groups (P = 0.58 and 0.53, respectively). The administration of G-CSF after allogeneic PBSC transplantation provided faster neutrophil and platelet engraftment associated with less severe mucositis and less febrile episodes. Bone Marrow Transplantation (2001) 27, 499–505.


Leukemia & Lymphoma | 1998

Acute myeloblastic leukemia associated with hyperleukocytosis and diabetes insipidus

Imdat Dilek; Akin Uysal; Taner Demirer; Haluk Koç; Muhit Ozcan; Numan Numanogl; Celalettin Uustün; Ercüment Cliftç

Two cases with acute myeloblastic leukemia (AML M4-FAB) associated with diabetes insipidus (DI) are presented here. Both patients presented with hyperleucocytosis. One had a white blood cell count (WBC) of 150 x 10(9)/L and the second patient had 200 x 10(9)/L. One of these patients was a 40 year-old male and MRI of the hypophysis showed an infindibuler mass. This patient did not respond to remission induction chemotherapy and reinduction chemotherapy was given. The other patient was a 16-year-old male with a normal CT scan of the head. Both patients had DI with typical clinical and laboratory findings. The first patient died early on during reinduction chemotherapy and the second patient died of intracranial bleeding before induction chemotherapy was given. These findings are consistent with the data in the literature suggesting that the prognosis of AML associated with DI is poor and that these cases generally present with hyperleucocytosis.


Bone Marrow Transplantation | 1998

Acquired ichthyosis associated with chronic graft-versus-host disease following allogeneic peripheral blood stem cell transplantation in a patient with chronic myelogenous leukemia

Imdat Dilek; Taner Demirer; C. Üstün; Mutlu Arat; Haluk Koç; Meral Beksac; H. Erdi; Anadolu R; Muhit Ozcan; Osman Ilhan; Hamdi Akan

Acquired ichthyosis (AI) has rarely been described following bone marrow transplantation (BMT). We report a 29-year-old male, who underwent allogeneic peripheral blood stem cell transplantation (alloPBSCT) for chronic myelogenous leukemia, and who developed AI associated with chronic graft-versus-host disease (cGVHD). Both of these disorders were treated successfully with cyclosporin A. We conclude that AI may be related to an autoimmune process on the basis of cGVHD, and dermathopathologic evaluation must be performed in patients with skin changes suggesting AI following allogeneic bone marrow transplantation.


Leukemia & Lymphoma | 2002

An Unusual Presentation of Plasma Cell Dyscrasias: Cardiac Tamponade due to Myelomatous Infiltration

Mutlu Arat; Vasfi Ulusoy; Taner Demirer; Akin Uysal; Muhit Ozcan; Süleyman DinÇer; Osman Ilhan; Haluk Koç

Pericardial involvement, a rare complication of multiple myeloma (MM), is caused by amyloidosis, infections, bleeding abnormalities or plasma cell infiltration, usually at a late or terminal stage of the disease. Three cases of MM with pericardial involvement are reported here and discussed in the light of current literature. In a retrospective review of all patients with MM at two institutions, three cases of pericardial involvement were identified. In one case, we were able to obtain cytospin preparations of the pericardiocentesis fluid. In the remaining two patients, the pericardial biopsy specimen was obtained via a pericardial window. All patients had progressive dyspnea and signs of pericardial tamponade. The pericardiocentesis fluid showed infiltration with plasma cells in one of the three patients, who had a progressive and fatal course. In the second patient pericardial invasion was proven by biopsy and the third was diagnosed with a plasma cell leukemia but developed a pericardial effusion demonstrated by pericardial biopsy. All these three patients died of progressive disease without any response to chemotherapy and supportive measures. In conclusion, optimal treatment for malignant involvement of the pericardium by myeloma cells has not yet been established and is often fatal.


Bone Marrow Transplantation | 2002

A randomized trial of assessment of efficacy of leukapheresis volumes, 8 liters vs 12 liters

Taner Demirer; M Daglı; Osman Ilhan; M Aylı; Rauf Haznedar; T Fen; N Gunel; Y Genc; Mutlu Arat; Muhit Ozcan; Onder Arslan; E Seyrek; S Dincer; T Ustun; N Ustael; Haluk Koç; O Muftuoglu; Hamdi Akan

It is logical to expect that large-volume leukapheresis may be able to collect adequate numbers of PBSC with fewer procedures. To date, there is no agreement on the optimal volume of leukapheresis. Therefore, in this study we compared 8 l volume with 12 l and assessed whether a 50% increase in the blood volume processed would decrease the number of leukaphereses each patient needed to collect ⩾2.5 × 106 CD34+ cells/kg in normal mobilizers. PBSC mobilization was done with cyclophosphamide etoposide followed by rhG-CSF in all patients. Forty patients were randomized to undergo 8 l leukaphereses (n = 20 patients) or 12 l leukaphereses (n = 20). The median numbers of leukaphereses required in order to collect ⩾2.5 × 106 CD34+ cells/kg in patients processed with 8 l and 12 l were 1 (range 1–5) and 1 (1–4), respectively (P = 0.50). The median number of total nucleated cells (TNC) collected per patient was greater for the 12 l group (7.47 × 108/kg vs 3.90 × 108/kg, P < 0.001), as was the median number of total mononuclear cells (TMNC) (4.26 × 108/kg vs 2.16 × 108/kg, P < 0.001), whereas there was no difference between the two groups for the median number of CD34+cells collected per patient (8.94 × 106/kg vs 8.60 × 106/kg, P = 0.85). The TNCs and TMNCs collected per leukapheresis were again greater for the 12 l group (3.64 × 108/kg vs 1.91 × 108/kg, P = 0.001 and 2.17 × 108/kg vs 0.88 × 108/kg, P < 0.001), whereas there was no difference between the two groups for the median number of CD34+ cells collected per leukapheresis (3.98 × 106/kg vs 3.26 × 106/kg, P = 0.90). This study showed that there is no difference between 8 l and 12 l volumes in regard to collected CD34+ cells/kg and also the use of a 12 l leukapheresis volume did not decrease the number of leukaphereses performed compared with a 8 l leukapheresis volume. In fact, the use of the larger leukapheresis volume had the disadvantage of adding 60 min to the time the patient was on the machine.


Transfusion and Apheresis Science | 2001

The effect of G-CSF on lymphocyte subsets and CD34+ cells in allogeneic stem cell transplantation

Gunhan Gurman; Imdat Dilek; Onder Arslan; Mutlu Arat; Meral Beksac; Osman Ilhan; Muhit Ozcan; Hamdi Akan; Klara Dalva; Nahide Konuk; Akýn Uysal; Haluk Koç

The effect of granulocyte colony-stimulating factor (G-CSF) on peripheral blood lymphocytes (PBL) and CD34+ cell frequency in the apheresis product has been determined in 25 healthy stem cell donors. Peripheral blood mononuclear cells (PBMNC) were collected after five days of G-CSF 10 microg/kg/day s.c., which was well tolerated. The median number of leukocytes increased eight-fold over that of pretreatment levels. Collection of PBMNC lasted a median of two (range, 1-3) days. The mean mononuclear cell (MNC) count and total lymphocyte percentage were 6.69 x 10(8)/kg and 59.08%, respectively, and the frequency of CD34+ cell expression was 2.1% in the apheresis product. The frequency of CD3+, CD4+, CD25+, NK and CD122+ cell expressions in mobilized PBMNC and PBL showed no significant difference. However, the frequency of CD8+, CD8+28+, CD3+DR+, CD19+, CD20+ and CD22+ B cells expression in the apheresis product increased significantly compared to steady-state PBL. In contrast, the frequency of the CD11 a+ and CD8+38+ cell expressions in the apheresis product was decreased compared to the steady-state PBL. The mean yield of CD34+ and CD3+ cells were 13.6 x 10(6) and 2.69 x 10(8)/kg of recipient body weight (RBW), respectively. Following allograft all patients engrafted with >0.5 x 10(9)/l neutrophil and < or = 20 x 10(9)/l platelets on a median of day 13 and 12, respectively. Nine patients had grade II-IV acute GVHD and chronic GVHD occurred in eight patients. Four patients died due to transplant-related complications. There was one late engraftment failure which occurred on the fifth month. Thirteen patients are still alive. In conclusion, these results indicate that administration of G-CSF at 10 microg/kg/day in normal donors alters the lymphocyte subsets and there are significant differences in the lymphocyte contents of the recipients before apheresis and in apheresis product.

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