Summary:Until recently, therapy for patients with severe congenital dyserythropoietic anemia (CDA) has been limited to blood transfusions and chelation therapy. Three children with transfusion-dependent CDA type I underwent allogeneic stem cell transplantation (SCT) from matched sibling donors. Conditioning was with cyclophosphamide 50 mg/kg/day for 4 days, busulphan 4 mg/kg/day for 4 days, and antithymocyte globulin (ATG) 30 mg/kg for four doses pre-SCT. All patients engrafted and are alive, and transfusion independent. To our knowledge, this is the first report of successful SCT in the management of CDA type I.

Summary.Several recent studies have demonstrated Kaposi's sarcoma-associated herpes virus (KSHV), also known as putative human herpes virus-8 (HHV-8), DNA in various epidemiologic forms of Kaposi's sarcoma (KS), including AIDS-associated, classic, and endemic types. Risk of developing KS in non-HIV-infected immunosuppressed hosts, such as patients following solid organ transplantation, is also significantly higher compared to normal individuals. We have retrospectively evaluated 28 organ transplant patients with KS (23 cutaneous and five visceral) for the presence of KSHV genome by polymerase chain reaction (PCR) amplification of DNA isolated from formalin-fixed, paraffinembedded archival tissue samples. 27/28 KS patients were positive for the presence of KSHV. In four KS patients, tissue samples with no histologic evidence of KS were also analysed for KSHV. No evidence of positivity in three samples was noted, but one patient had weak positive amplification products on DNA samples isolated from a gastric biopsy with chronic gastritis and lymph node with sinus histiocytosis. These data support the association of KSHV with KS developing in non-HIV-infected immunosuppressed patients, similar to other forms of KS, and suggest that KSHV may play a significant role in the development of all forms of KS.

T-lymphocyte phenotypes and human leukocyte antigen-DR expression (HLA-DR) expression in skin lesions and draining lymph nodes of zoonotic leishmaniasis caused by Leishmania major were studied. T lymphocytes were the dominant cells in the lymphocytic preponderance type of lesion. They were lowest when the parasitized macrophage was the dominant cell or when the reaction consisted of an equal admixture of lymphocytes, macrophages and plasma cells. Both inducer/helper and suppressor/cytotoxic T cells were present in varying proportions. The latter were thought to be suppressor rather than cytotoxic cells. Their late appearance in the host reaction was believed to play a major role in halting the inflammatory response. Low levels of cells expressing the suppressor/cytotoxic phenotype and the continued presence of antigen in macrophages was associated with persistence of the lesions even when parasites were largely eliminated after specific antileishmanial therapy. Such lesions healed after local or systemic steroid therapy. The majority of cells in the dermal infiltrate were HLA-DR positive. Keratinocytes also expressed HLA-DR antigen.AM El-Hassan, R Kubba, YM Al-Gindan, AS Omer, MK Kutty, MBM Saeed, Lymphocyte

JAK2 p.V617F was the most prevalent mutation detected among patients in this study. Non-p.V617F JAK2 mutations were identified in exons 12 and 13 corresponding to recently reported mutations, except for the novel p.I540_N542delinsM.

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4092 Background: The adhesion molecule CD11b, which associates with the beta2-integrin to form the Mac-1 complex, is expressed in monocytic leukemias as well as other myeloid leukemias. Its expression on the lekemic cells has been reported to correlate with more aggressive course in adult patients with AML. The clinical relevance of CD11b expression in pediatric AML is not known. More importantly, the clinical relevance of CD11b expression on pediatric AML when these patients are treated with allogeneic hematopoietic stem cell transplant (HSCT). We investigated whether HSCT can modify the expected adverse effects of CD11b expression in pediatric AML patients. Methods: Immunophenotype data of 62 pediatric patients with AML, all treated with allogeneic HSCT, was reviewed. The expression of the CD11b on the blast population as determined by flow cytometry was correlated with clinical data and outcome. The median age of patients was 8 years (range: 8 months–14 years) and included 47 (76%) patients transplanted in their first complete remission (CR1). Fourty six (74%) of all patients had intermediate-risk cytogenetics and the remaining (26%) had adverse-risk cytogenetic abnormalities. Results: Twenty five (40%) of all studied patients expressed CD11b on the surface of the blasts at diagnosis. Patients with CD11b expression had significantly shorter overall survival (P=0.038) with median survival of approximately 11 months while the median survival in the CD11b negative patients has not been reached. Similarly, CD11 positive patients had significantly shorter event free survival (EFS) (P=0.03). When we considered only patients treated with HSCT in CR1, the OS and EFS for the CD11b positive patients were both significantly shorter (P=0.04 and P=0.05, respectively). Multivariate analysis including CD11b expression and cytogenetic risk identified CD11b expression as an independent prognostic factor for survival and EFS, while cytogenetic-risk stratification became no longer a predictor. Conclusion: Our data suggests that the expression of CD11b in pediatric AML is a significant independent poor prognostic factor and HSCT does not change this trend. Most of the CD11b positive patients die in their first year after HSCT and the management of these patients should be modified to address the biological basis of this subset of AML that expresses CD11b adhesion molecule. Disclosures: No relevant conflicts of interest to declare.

BCR-ABL mutations are rare in early chronic phase and increases with CML disease progression. Therefore, search for other causes in resistant cases at this phase should be sought.

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