Preventive effect of ultraviolet radiation on murine chronic sclerodermatous graft-versus-host disease.

Although previous studies have demonstrated the efficient modulatory effects of ultraviolet radiation B (UVB) on cutaneous graft-versus-host disease (GVHD), most animal research on GVHD has been performed in murine models of acute GVHD. Here, we studied the preventive effect of UVB radiation on the occurrence of chronic sclerodermatous (Scl) GVHD in a murine model. Scl GVHD was induced by transplanting lethally irradiated BALB/c mice with B10.D2 bone marrow and spleen cells. Recipient mice were exposed to UVB before or after bone marrow and spleen cell infusion. Histological and clinical evaluation of GVHD was performed, in association with the characterization of epidermal Langerhans cells. UVB irradiation of recipients after, and more remarkably before, transplantation induced a decrease of Scl GVHD severity associated with epidermal Langerhans cells depletion. We conclude that UVB irradiation of recipient before or after transplantation has a preventive effect on cutaneous Scl GVHD and may represent an effective strategy for prevention of Scl GVHD.

Association of mixed hematopoietic chimerism with elevated circulating autoantibodies and chronic graft-versus-host disease occurrence.

BACKGROUND: Use of a reduced-intensity conditioning regimen before an allogeneic hematopoietic cell transplantation is frequently associated with an early state of mixed hematopoietic chimerism. Such a coexistence of both host and donor hematopoietic cells may influence posttransplant alloreactivity and may affect the occurrence and severity of acute and chronic graft-versus-host disease (GVHD) as well as the intensity of the graft-versus-leukemia effect. Here we evaluated the relation between chimerism state after reduced-intensity conditioning transplantation (RICT), autoantibody production, and chronic GVHD (cGVHD)-related pathology. METHODS: Chimerism state, circulating anticardiolipin, and antidouble stranded DNA autoantibody (Ab) titers as well as occurrence of cGVHD-like lesions were investigated in a murine RICT model. RESULTS: We observed a novel association between mixed chimerism state, high levels of pathogenic IgG autoantibodies, and subsequent development of cGVHD-like lesions. Furthermore, we found that the persistence of host B cells, but not dendritic cell origin or subset, was a factor associated with the appearance of cGVHD-like lesions. The implication of host B cells was confirmed by a host origin of autoantibodies. CONCLUSION: Recipient B cell persistence may contribute to the frequency and/or severity of cGVHD after RICT.

Differential sensitivity of T lymphocytes and hematopoietic precursor cells to photochemotherapy with 8-methoxypsoralen and ultraviolet A light.

The combination of 8-methoxypsoralen (8-MOP) and long wave ultraviolet radiation (UV-A) has immunomodulatory effects and might abolish both graft-vs-host and host-vs-graft reactions after allogeneic hematopoietic stem cell transplantation. In the present study, we have confirmed the sensitivity of T lymphocytes to 8-MOP treatment plus UV-A exposure as evidenced by the abrogation of the alloreactivity in mixed lymphocyte cultures as well as the inhibition of the response to phytohemagglutinin A. However, the clonogenic capacity of the bone marrow hematopoietic progenitors was inhibited with UV-A doses lower than the doses needed to inhibit T-lymphocytes alloreactivity. Moreover, long-term bone marrow cultures showed that 8-MOP plus UV-A treatment had detrimental effects on the more immature bone marrow stem cells. These data were confirmed when murine bone marrow graft was treated with 8-MOP, exposed to UV-A, then transplanted into semiallogeneic recipient mice. The treated cells could not maintain their clonogenic capacity in vivo resulting in death of all animals. Taken together, these data show that ex vivo 8-MOP plus UV-A treatment of the marrow graft cannot be used to prevent post-bone marrow transplantation alloreactivity.

c-Flip protein expression in Burkitt's lymphomas is associated with a poor clinical outcome.

The World Health Organization Classification of Lymphoid Neoplasms identifies Burkitt's lymphoma/leukaemia (BL) as a single entity, characterized by unique clinical and genetic features that require specific high intensity chemotherapy regimens. Although remarkable successes in the treatment of the disease have been observed, when compared with paediatric patients, adults are less likely to reach stable complete remission. We investigated 32 BL cases, composed in equal part by adults and children that were treated with the French LMB regimen, for factors that may be implicated in chemoresistance. Immunohistochemical detection of procaspase-8, caspase-3a, survivin, p53, CD95, c-Flip and Phospho-RelA (Ser536) was investigated on paraffin-embedded tissues. The expression of c-Flip was found highly related to a poor prognosis, mostly characterized by adults with a chemoresistant disease, resulting in a high death rate within the first year of diagnosis. The 2-year overall survival with c-Flip expression was 24% compared with 93% in the absence of this marker (P = 0.04). All c-Flip-positive BL cases presented a nuclear Phospho-RelA (Ser536) localization, suggesting the presence of an active nuclear factor (NF)-kappa B transcription pathway. These findings show that c-Flip could be a reliable prognostic factor in BL, suggesting new therapeutic approaches that target the NF-kappa B pathway.

A single intravenous infusion of apoptotic cells, an alternative cell-based therapy approach facilitating hematopoietic cell engraftment, did not induce autoimmunity.

Previously, we reported that intravenous infusion of apoptotic leukocytes facilitated bone marrow (BM) engraftment across major histocompatibility barriers. This cell-based therapeutic approach is of great interest for stem cell therapy across histocompatibility barriers. Autoimmunity associated with apoptotic cell administration may, however, limit the use of this approach. Indeed, autoantigens are concentrated on the surface of apoptotic cells, and defective clearance of apoptotic bodies is associated with the occurrence of systemic autoimmune disease. In consequence, we assessed the autoimmune responses raised against ubiquitous double-stranded DNA (dsDNA) and cardiolipin autoantigens following a single intravenous infusion of apoptotic cells simultaneously to allogeneic BM administration. No difference was observed between levels of natural circulating immunoglobulin M (IgM) (anti-dsDNA and anti-cardiolipin) autoantibodies found in mice receiving allogeneic BM alone and those found in mice receiving apoptotic cells also. Pathogenic IgG autoantibody titers after apoptotic cell infusion were 9- to 200-fold lower than autoantibody titers found in lupus-prone mice and not different from titers detected in BM grafted mice. Kinetic analysis of autoantibodies after transplantation did not demonstrate any immunization against tested autoantigens after apoptotic cell infusion. Finally, neither immune complex deposition nor specific lesions were observed in the renal glomeruli of mice infused with apoptotic cells 9 months post-BM transplantation. Overall, these results show no specific toxicity of a single infusion of apoptotic cells administrated simultaneously to BM and may also shed light on factors influencing the immunogenic properties of apoptotic cells.

Hepatosplenic gammadelta T-cell lymphoma is a rare clinicopathologic entity with poor outcome: report on a series of 21 patients.

We report on the characteristics of 21 patients with hepatosplenic gammadelta T-cell lymphoma (HSgammadeltaTCL), an entity recognized since 1994 in the Revised European American Lymphoma (REAL) classification. Median age was 34 years. Patients had splenomegaly (n = 21), hepatomegaly (n = 15), and thrombocytopenia (n = 20). Histopathologic findings were homogeneous and showed the presence of medium-sized lymphoma cells within the sinusoids of splenic red pulp, liver, and bone marrow. Marrow involvement was usually mild but could be demonstrated by phenotyping in all patients. Cells were CD3+CD5-, expressed the gammadelta T-cell receptor, and had a nonactivated cytotoxic cell phenotype (TIA-1+, granzyme B-). Most patients were CD4-/CD8- (16 of 18); CD56+ (15 of 18), expressed the Vdelta1epitope (Vd1+/Vd2-/Vd3-) (9 of 12); and were negative for Epstein-Barr virus (EBV) (18 of 20). Isochromosome arm 7q was documented in 9 of 13 patients. Eight patients had previously undergone kidney transplantation or had a history of systemic lupus, Hodgkin disease, or malaria. Prognosis was poor; median survival time was 16 months, and all but 2 patients ultimately died despite consolidative or salvage high-dose therapy. In conclusion, HSgammadeltaTCL is a disease with distinctive clinical, histopathologic, and phenotypic characteristics. Bone marrow biopsy with combined phenotyping is sufficient for diagnosis, and splenectomy is therefore unwarranted. Current treatment modalities appear to be ineffective in most patients.

Human bone marrow angiogenesis: in vitro modulation by substance P and neurokinin A.

We have previously described a culture system for human bone marrow endothelial cells that organize into capillary tubes associated to pericytes. In the present work, we used this model to assess the angiogenic properties of tachykinins, which have been demonstrated to be involved in neuro-immuno-haematopoietic interactions. The substance P (SP) and neurokinin A (NKA) were similarly potent at increasing in vitro angiogenesis, via NK1 and NK2 receptors respectively. These mediators were not produced by cells in culture, suggesting that in vivo they may be released by nerve fibres in the bone marrow. Therefore, we looked for in situ innervation of the human bone marrow, unknown to date, using immunohistochemistry techniques. As in rodents, arterioles were largely innervated, associated with between one and 10 nerve fibres. Capillary innervation was more restrictive as a unique thin nerve fibre was found in the vicinity of only 6% of these vessels. Finally, no nerve fibres were observed in the vicinity of sinus walls. In conclusion, both in vitro results and the anatomical display of nerve fibres suggest a role in human bone marrow for the vasoactive neuropeptides SP and NKA, which were secreted into a perivascular location. These neural mediators might modulate blood flow in the bone marrow both in the short term by adjusting vascular tone and in the long term by inducing angiogenesis.

Danger of systemic cyclosporine for corneal graft.

PURPOSE: To report a case of posttransplant lymphoproliferative disorder (PTLD) in a patient receiving oral cyclosporine (CS) for immunosuppression in a high-risk keratoplasty. METHODS: A systemic CS therapy was given to prevent graft rejection of a keratoplasty. Risk rejection was high in regard to a previous graft rejection and persistence of a corneal vascularization. One year after the keratoplasty, the patient developed a gastric Epstein-Barr virus (EBV)-induced B cell lymphoma. The outcome was favorable after chemotherapy. CONCLUSIONS: This unique case of lymphoma (PTLD) in the course of corneal graft management questions the indications and the follow-up of patients with CS therapy and raises the issue of topical CS treatment.