Preparation and investigation of P28GST-loaded PLGA microparticles for immunomodulation of experimental colitis.

The aim of this work was to prepare and characterize (in vitro and in vivo) PLGA-based microparticles loaded with an enzymatic protein derived from the helminth parasite Schistosoma haematobium: glutathione S-transferase P28GST (P28GST). This protein is not only a promising candidate vaccine against schistosomiasis, it also exhibits interesting immunomodulating effects, which can be helpful for the regulation of inflammatory diseases. Helminths express a regulatory role on intestinal inflammation, and immunization by P28GST has recently been shown to be as efficient as infection to reduce inflammation in a murine colitis model. As an alternative to the combination with a classical adjuvant, long acting P28GST microparticles were prepared in order to induce colitis prevention. PLGA was used as biodegradable and biocompatible matrix former, and a W/O/W emulsion/solvent extraction technique applied to prepare different types of microparticles. The effects of key formulation and processing parameters (e.g., the polymer molecular weight, drug loading, W/O/W phase volumes and stirring rates of the primary/secondary emulsions) on the systems' performance were studied. Microparticles providing about constant P28GST release during several weeks were selected and their effects in an experimental model of colitis evaluated. Mice received P28GST-loaded or P28GST-free PLGA microparticles (s.c.) on Day 0, and optionally also on Days 14 and 28. Colitis was induced on Day 35, the animals were sacrificed on Day 37. Interestingly, the Wallace score (being a measure of the severity of the inflammation) was significantly lower in mice treated with P28GST microparticles compared to placebo after 1 or 3 injections. As immunogenicity markers, increased anti-P28GST IgG levels were detected after three P28GST PLGA microparticle injections, but not in the control groups. Thus, the proposed microparticles offer an interesting potential for the preventive treatment of experimental colitis, while the underlying mechanism of action is still to be investigated.

The schistosome glutathione S-transferase P28GST, a unique helminth protein, prevents intestinal inflammation in experimental colitis through a Th2-type response with mucosal eosinophils.

Intestinal helminth parasites are potent inducers of T helper type 2 (Th2) response and have a regulatory role, notably on intestinal inflammation. As infection with schistosomes is unlikely to provide a reliable treatment of inflammatory bowel diseases, we have investigated the beneficial effect of a schistosome enzymatic protein, the 28-kDa glutathione S-transferase (P28GST), on the modulation of disease activity and immune responses in experimental colitis. Our results showed that immunization with recombinant P28GST is at least as efficient as established schistosome infection to reduce colitis lesions and expression of pro-inflammatory cytokines. Considering underlying mechanisms, the decrease of inflammatory parameters was associated with the polarization of the immune system toward a Th2 profile, with local and systemic increases of interleukin (IL)-13 and IL-5. Dense eosinophil infiltration was observed in the colons of P28GST-immunized rats and mice. Depletion of eosinophils by treatment with an anti-Siglec-F monoclonal antibody and use of IL-5-deficient mice led to the loss of therapeutic effect, suggesting the crucial role for eosinophils in colitis prevention by P28GST. These findings reveal that immunization with P28GST, a unique recombinant schistosome enzyme, ameliorates intestinal inflammation through eosinophil-dependent modulation of harmful type 1 responses, representing a new immuno-regulatory strategy against inflammatory bowel diseases.

Treatment of acute lymphoblastic leukemia in children with the BFM protocol. A cooperative pilot study.

From January 1981 through July 1983, 141 children with newly diagnosed acute lymphoblastic leukemia were registered in a cooperative clinical study whose objective was to evaluate the toxicity and the feasibility of the German Berlin-Frankfort-Münster (BFM) protocol. The results were comparable with those reported by the BFM group. For the 133 patients (94%) who achieved complete remission, the actuarial disease-free survival was 67% at 4 years. These results were obtained in spite of a high rate of deaths in complete remission during the initial year of the study. Subsequently, probably as a result of improved expertise in the handling of the protocol, the proportion of toxic deaths declined sharply. Although the current BFM protocol adjusts for aggressiveness of therapy according to the volume of the liver and spleen, splenomegaly (but not hepatomegaly) remained of prognostic significance. Moreover, for patients with bad risk features, an initial high hemoglobin level was found to represent an additional factor of negative significance.

Meningeal leukaemia in the blastic phase of chronic granulocytic leukaemia.

A 51/2-year-old boy is presented with chronic granulocytic leukaemia and blastic transformation whose clinical course is complicated by meningeal leukaemia. In the authors' opinion prophylactic central nervous system therapy should be part of the initial therapy of blastic transformation.

Oral BVDU treatment of varicella and zoster in children with cancer.

In the period June 1980-April 1983, 21 children with malignant disease were admitted because of an intercurrent varicella or zoster infection. They were treated with the new antiviral drug BVDU [(E)-5-(2-bromovinyl)-2'-deoxyuridine]. The drug was administered orally at a dose of 15 mg/kg per day for 5 days. All our patients responded promptly to BVDU treatment and recovered completely from their varicella or zoster infections without complications. No toxic side-effects due to the drug were observed.

Malignant otolaryngological tumors in children.

The details of 37 children presenting a malignant tumor in the ENT-region (period 1950-1983) are presented and discussed. The prevalence was higher in boys than in girls and the most common tumors were non-Hodgkin lymphoma (n = 14) and rhabdomyosarcoma (n = 13). The most common primary sites were the nasopharynx (9 cases), the paranasal sinuses (7 cases) and the soft tissue in the parotid region (7 cases). In 23 children the presence of a painless tumor was the first symptom, in 11 pain was predominant. Only a minority (5 children) presented a limited tumor; in 20 children there was a local extension of the tumor and in 10 children metastases were present at the first visit. The beneficial role of chemotherapy and the necessity of a good teamwork in the treatment of these children is outlined. Of the 37 children, 14, (38%) are surviving; of these 14 children, 12 are off therapy and cured. It is demonstrated that the prognosis improved considerably since the last 14 years.

Comparison of chemotherapy with immunotherapy for maintenance of acute lymphoblastic leukemia in children and adults.

Two hundred and seventeen patients, 1-50 yr old, with acute lymphoblastic leukemia in complete remission were randomized to receive a 1-yr consolidation chemotherapy of either type P, comprising 7 different drugs, or type M, consisting of methotrexate interspersed with prednisone and vincristine. Thereafter, they were randomized a second time to receive a 4-yr maintenance of either chemotherapy or immunotherapy, comprised of allogeneic blasts and bacillus Calmette-Guérin (BCG). Consolidation P caused more toxicity than consolidation M. However, comparison between the consolidation therapies P and M showed no significant difference, neither for disease-free interval nor for duration of survival. Chemotherapy showed more lethal toxicity in adults than in children. Comparison between chemotherapy (C) and immunotherapy (I) as maintenance treatment showed a significant (p = 0.016) superiority of C for disease-free interval (DFI). The difference was even more pronounced (p = 0.009) in the group with less than 8 g/dl of hemoglobin (Hb) at diagnosis before therapy. On the other hand, for patients with more than 8 g/dl Hb at diagnosis, presumably those with T-ALL, no difference in DFI was seen. No difference has been seen so far between maintenance therapies I and C concerning the duration of survival. The patients who were receiving maintenance I when they relapsed and who were consequently retreated by chemotherapy, survived longer from relapse than those patients retreated for relapse while receiving maintenance C.

Pentasomy 21 characterizing spontaneously regressing congenital acute leukemia.

Pentasomy 21 was found to characterize the proliferating cells in a case of transient congenital acute leukemia (or congenital acute leukemia) with spontaneous remission. The patient was phenotypically normal, and cytogenetically no evidence could be found for the existence of a mosaic with a normal cell line and one with more than two No 21 chromosomes. The importance of these findings is discussed.

[Skeletal changes in children with acute lymphoblastic leukemia]. / Skeletafwijkingen bij kinderen met acute lymfoblastenleukemie.

Children with acute lymphoblastic leukemia frequently show skeletal changes. We examined 50 children with acute lymphoblastic leukemia with reference for skeletal pain as well as the nature and the degree of skeletal changes. 14 children had bone pain. The pain did not correlate with the roentgenographic findings. Some children had characteristic bone changes without bone pain. Roentgenographic findings were observed in 35 of the 50 children (70%). The major lesions observed were: transverse metaphyseal lucent bands, osteolytic lesions, osteosclerotic lesions, periosteal reaction and osteoporosis. Different pathologic findings in leukemia have been given a prognostic value. This was also done for the bony changes but the literature is not coherent on this point. In the group of 17 children with evident skeletal changes, 15 had a non B- non T-cell leukemia. Also the age of the patient, apart from the immunological cell type, seems to be an important factor in the incidence of initial skeletal roentgenographic findings.