Vascular surveillance by haptotactic blood platelets in inflammation and infection

Breakdown of vascular barriers is a major complication of inflammatory diseases. Anucleate platelets form blood-clots during thrombosis, but also play a crucial role in inflammation. While spatio-temporal dynamics of clot formation are well characterized, the cell-biological mechanisms of platelet recruitment to inflammatory micro-environments remain incompletely understood. Here we identify Arp2/3-dependent lamellipodia formation as a prominent morphological feature of immune-responsive platelets. Platelets use lamellipodia to scan for fibrin(ogen) deposited on the inflamed vasculature and to directionally spread, to polarize and to govern haptotactic migration along gradients of the adhesive ligand. Platelet-specific abrogation of Arp2/3 interferes with haptotactic repositioning of platelets to microlesions, thus impairing vascular sealing and provoking inflammatory microbleeding. During infection, haptotaxis promotes capture of bacteria and prevents hematogenic dissemination, rendering platelets gate-keepers of the inflamed microvasculature. Consequently, these findings identify haptotaxis as a key effector function of immune-responsive platelets.

Breakdown of vascular barriers is a major complication of inflammatory diseases. However, the mechanisms underlying platelet recruitment to inflammatory micro-environments remains unclear. Here, the authors identify haptotaxis as a key effector function of immune-responsive platelets

Long-term disease-free survival of patients with advanced mantle-cell lymphoma following high-dose chemotherapy

In advanced stage mantle cell lymphoma, conventional chemotherapy yields a complete remission rate below 40%, and the median survival rate is only about 3 years. Between 1991 and 1996 we treated nine such patients (six male; three female) with high-dose chemotherapy (six of these also with 12 Gy fractionated total body irradiation (TBI)) and peripheral stem cell support (n = 8) or allogeneic bone marrow transplantation (n = 1). The median age was 47 years (range, 28-61). At the time of high-dose chemotherapy, five patients were in first complete remission (CR), two in first partial remission (PR) and two in second remission (CR = 1; PR = 1). High-dose chemotherapy included TBI (12 Gy), etoposide and cyclophosphamide (patients 1-5), TBI and cyclophosphamide (patient 7), busulfan, etoposide and cyclophosphamide (patients 6 and 9), cyclophosphamide and busulfan (patient 8). The patterns of toxicity according to the Bearman score were usually mild (mucositis grade 2, n = 7; renal grade I, n = 2) with no therapy-related fatality. Only one patient developed hepatic toxicity grade III (veno-occlusive disease) but recovered completely. The median time to neutrophil engraftment was 10 days (range, 8-15). After high-dose chemotherapy all patients achieved complete remission. After a median follow-up of 22 months (range, 9.4-64) all patients remain in continuous complete remission. These encouraging results suggest that high-dose chemotherapy can be applied safely and leads to long-term disease-free survival in otherwise incurable disease.

Busulfan, cyclophosphamide and etoposide as high-dose conditioning therapy in patients with malignant lymphoma and prior dose-limiting radiation therapy

Relapse after transplant for malignant lymphomas remains the main cause of treatment failure. Most conditioning regimens contain total body irradiation (TBI). We investigated the toxicity and efficacy of an intensified chemotherapy conditioning regimen without TBI in patients with relapsed or high-risk malignant lymphoma who had received prior radiation therapy and were therefore not eligible for TBI. Twenty patients with a median age of 38 (18-56) and relapsed or high-risk malignant non-Hodgkin's lymphoma (NHL, n = 16) or Hodgkin's disease (HD, n = 4) underwent high-dose chemotherapy consisting of busulfan (16 mg/kg), cyclophosphamide (120 mg/kg) and etoposide 30 mg/kg (n = 8) or 45 mg/kg (n = 12) followed by peripheral stem cell support (n = 14), autologous bone marrow (n = 3), allogeneic (n = 2) or syngeneic (n = 1) transplantation. All but two had chemosensitive disease before high-dose chemotherapy. The main toxicity -- according to the Bearman score -- was mucositis II in 18 (90%) patients; five patients (25%) suffered a grade I hepatic toxicity. GI toxicity I occurred in three (15%) and renal toxicity I in two patients (10%). Sixty percent of the patients developed transient dermatitis with erythema and three of them (15%) had skin desquamation; one patient experienced asymptomatic pancreatitis. Toxicity was slightly higher in patients treated with 45 mg/kg etoposide. One patient (5%) died of treatment-related venoocclusive disease. After a median follow-up of 50 months (24-84) the disease-free and overall survival were 50% and 55%. One of the nine relapsing patients developed secondary AML 18 months after transplant. High-dose busulfan, cyclophosphamide and etoposide is an effective regimen resulting in long-term disease-free survival in 50% of patients with relapsed malignant lymphoma and prior radiation therapy. The toxicity is moderate with a low treatment-related mortality (5%).

Allogeneic bone marrow transplantation for refractory mantle cell lymphoma

We report about a 28-year-old woman with relapsed mantle cell lymphoma (MCL, centrocytic lymphoma according to the Kiel classification) refractory to salvage chemotherapy. The patient underwent allogeneic bone marrow transplantation from a HLA-identical brother after myeloablative chemotherapy consisting of busulfan, etoposide, and cyclophosphamide. The patient experienced hepatic toxicity (grade I), mucositis (grade II) according the Bearman scale, and graft versus host disease of the skin (grade II) and showed stable engraftment with complete chimerism on day 15 after bone marrow transplantation. Eight years after transplantation, the patient is still disease free and in good condition without any late side effects. This report suggests a curative potential of allogeneic stem cell transplantation in MCL.

Experience with liposomal Amphotericin-B in 60 patients undergoing high-dose therapy and bone marrow or peripheral blood stem cell transplantation

60 patients undergoing bone marrow or stem cell transplantation were treated with liposomal Amphotericin-B for documented or suspected mycosis. 34 patients had a prior course of conventional Amphotericin-B with the following adverse effects: increasing creatinine above 1.4 mg/dl (n = 17), increasing creatinine below 1.5 mg/dl (n = 9), no response (n = 6), and clinical side-effects (n = 4). Liposomal Amphotericin-B failed in 6/7 patients with culture-proven mycosis who died from infection with Aspergillus (n = 2) and Candida (n = 4), respectively. One patient with Candida lambica sepsis was cured. No patient with clinically or serologically suspected or diagnosed infection died from mycosis. Liposomal Amphotericin-B was well tolerated in 57 patients, even after side-effects of the conventional formulation. Adverse effects occurred in three cases, requiring the withdrawal of the drug in one patient. Due to toxic side-effects of the high-dose therapy and transplant-related complications, it was difficult to evaluate the influence of liposomal Amphotericin-B on laboratory parameters. Eight patients showed a decrease of creatinine levels, which had increased above normal values under preceding therapy with conventional Amphotericin-B. Liposomal Amphotericin-B is well tolerated in patients undergoing high-dose therapy and bone marrow transplantation. The efficacy of liposomal Amphotericin-B needs to be investigated in randomized studies in comparison with conventional Amphotericin-B.

Cyclophosphamide/antithymocyte globulin conditioning of patients with severe aplastic anemia for marrow transplantation from HLA-matched siblings: preliminary results

Many approaches have been taken to reducing the rate of graft failure and the incidence of graft-versus-host disease (GVHD) in bone marrow transplantation (BMT) of patients with severe aplastic anemia (SAA). The combination of cyclophosphamide with irradiation has had unequivocal success in reconstituting a sustained engraftment, but this procedure has severe associated risks such as second malignancies. Recently, cyclophosphamide (CYC) plus antithymocyte globulin (ATG) has been shown to be an effective alternative to irradiation-based programs in retransplants. Based on these experiences, the current clinical trial was started to prepare patients suffering from SAA for marrow transplantation from HLA-identical siblings with ATG plus CYC. Nine patients have been enrolled into the study so far. They received a total dose of 200 mg/kg CYC and concomitantly 120 mg/kg or 90 mg/kg ATG, followed by cyclosporine plus methotrexate as post-transplantation GVHD prophylaxis. Eight of nine patients survived without any transplant-associated complications; i.e., they had a documented stable engraftment without rejection and without acute or chronic GVHD. One patient died due to an Aspergillus sepsis prior to a definite engraftment. Although our data are preliminary because of the small number of patients enrolled and a follow-up of only 30 months, CYC plus ATG appears to be an effective preparative regimen for BMT in patients with SAA, resulting in a favorable outcome.

Fatal outcome of disseminated candidosis after allogeneic bone marrow transplantation under treatment with liposomal and conventional amphotericin-B. A report of 4 cases with determination of the Mic values

Four patients undergoing allogeneic bone marrow transplantation were treated with liposomal (3 patients) and conventional (one patient) amphotericin-B for disseminated candidosis. Candida krusei was isolated from 3, and C. glabrata from 1 patient. The patients were treated with liposomal amphotericin-B in doses from 3 to 5 mg/kg. The fourth patient received conventional amphotericin-B in a reduced dose due to renal impairment. The patients died from multiorgan failure due to disseminated fungal infection. In 1 case, the switch to the conventional drug resulted in clearance before death. The 3 fungus isolates, together with the fourth strain obtained from patient no. 4 without any exposition to liposomal amphotericin-B were tested for their susceptibility to conventional, liposomal and discoidal amphotericin-B. All strains showed good sensitivity to the conventional and discoidal drug. The minimal inhibitory concentrations (MIC) of liposomal amphotericin-B were 1 to 3 titre steps higher indicating a reduced sensitivity of the tested strains to this preparation. We conclude that the use of liposomal amphotericin-B is recommended mainly on the base of the low incidence of side-effects. Intensive microbial resistance tests, pharmacokinetic investigations and randomized studies are necessary before the conventional drug is replaced as the gold standard for systemic antimycotic therapy.

Use of cryopreserved bone marrow in allogeneic bone marrow transplantation

Use of cryopreserved donor bone marrow may facilitate scheduling of allogeneic bone marrow transplantation (BMT) by affording independence of a fixed time for bone marrow donation. The potential risk of damage to hematopoietic stem cells by cryopreservation resulting in delayed engraftment or graft failure has to be taken into account, however. To address these issues, the outcome of 19 matched related BMT (1992-94) performed with cryopreserved donor bone marrow was analyzed and compared with 19 related BMT (1990-93) receiving fresh donor bone marrow (control group). Time to engraftment of patients receiving cryopreserved bone marrow was not different from the control group (ANC > 0.2 x 10(9)/l 15.5 +/- 3.8 days vs 15.8 +/- 5.0 days; ANC > 0.5 x 10(9)/l 17.3 +/- 4.1 days vs 17.9 +/- 5.0 days, respectively). We did not find the previously described trend toward a lower incidence of acute GVHD in patients receiving cryopreserved bone marrow compared with patients receiving fresh bone marrow (acute GVHD > or = II 78 vs 64%). Furthermore, the two groups did not differ in the incidence of chronic GVHD (55 vs 38%) or day 100 survival (74 vs 68%). We conclude that in allogeneic BMT cryopreserved bone marrow cells can be safely used without jeopardising or prolonging time to engraftment.

Use of cryopreserved bone marrow in unrelated allogeneic transplantation

Cryopreservation of donor bone marrow can facilitate scheduling allogeneic bone marrow transplantation (BMT) by affording independence of a preset time for donation. Previously, we and others have shown the feasibility of using cryopreserved related allogeneic bone marrow. Here, we report the results of the first 10 patients receiving cryopreserved unrelated bone marrow between 1992 and 1995. All evaluable patients (n = 9) engrafted. Time to reach an absolute neutrophil count (ANC) >0.2 x 10(9)/1 and ANC >0.5 x 10(9)/l was 21.4 +/- 9.1 days and 22.6 +/- 9.2 days, respectively. The incidence of acute GVHD > or = grade II and chronic GVHD was 75 and 20%, respectively. Five of nine evaluable patients were alive 100 days post-transplantation. We conclude that cryopreserved unrelated donor bone marrow may be used for allogeneic transplantation.

Bone marrow transplantation for Philadelphia-chromosome-positive acute lymphoblastic leukemia

The outcome of 14 bone marrow transplants (BMT) (autologous 4; allogeneic 10) for Philadelphia-chromosome (Ph1) positive acute lymphoblastic leukemia (ALL) was analyzed. Preparative regimens consisted of etoposide (VP16) (30 or 45 mg/kg BW) (n = 14), cyclophosphamide (CY)(120 mg/kg BW) (n = 14), and total body irradiation (TBI)(12 Gy) (n = 13) or busulfan (Bu)(16 mg/kg) (n = 1). All patients receiving autologous marrow were in complete remission (CR) (three patients in 1.CR, one patient in 2.CR) at the time of BMT. For allogeneic BMT (nine related, one unrelated donor), seven patients were in first CR, two patients in first refractory relapse, and one patient in second relapse. With a median follow-up of 503 days (range 93-1522 days), eight out of 14 patients are alive in remission (six out of 10 patients receiving allogeneic, and two out of four patients receiving autologous BMT). Disease-free survival for all patients is 46%. Causes of death were relapse (n = 3) and transplant-related toxicity (n = 3). All patients tested for the bcr/abl rearrangement by reverse transcriptase-polymerase chain reaction (RT-PCR) were negative 4 weeks post-BMT. Two of the three patients who subsequently relapsed were repeatedly RT-PCR positive prior to relapse (test not done in the third). Considering the negligible cure rate of Ph1-positive ALL with conventional chemotherapy regimens, our data support the concept of early (> or = 1 CR) BMT (allogeneic > autologous (purged) following triple therapy with TBI, VP16, and CY.

Early recurrence or persistence of autoimmune diseases after unmanipulated autologous stem cell transplantation

Autologous stem cell transplantation with or without in vitro lymphocyte depletion has been suggested as a new treatment option for severe autoimmune diseases. We describe five patients with autoimmune diseases (CREST syndrome, myasthenia gravis and Hashimoto's thyroiditis, systemic lupus erythematosus, atopic dermatitis, and rheumatoid arthritis) who underwent autologous bone marrow (n = 1) or peripheral blood progenitor cell (n = 4) transplantation with unmanipulated grafts as treatment for the autoimmune disease in one case or as treatment for a malignant disorder with a concomitant autoimmune disorder in four cases. In all patients serological and clinical signs of the autoimmune disease recurred early or persisted. These observations should be regarded as a cautionary note concerning the efficacy of high-dose therapy followed by transplantation of unmanipulated autologous stem cells for treatment of severe autoimmune diseases.