[Large granular lymphocyte leukemia]

Transplantation and immunosuppression: a review of novel transplant-related immunosuppressant drugs

Immunosuppressive drugs used in the transplantation period are generally defined as induction and maintenance therapy. The use of immunosuppressants, which are particularly useful and have fewer side effects, decreased both mortality and morbidity. Many drugs such as steroids, calcineurin inhibitors (cyclosporine-A, tacrolimus), antimetabolites (mycophenolate mofetil, azathioprine), and mTOR inhibitors (sirolimus, everolimus) are used as immunosuppressive agents. Although immunosuppressant drugs cause many side effects such as hypertension, infection, and hyperlipidemia, they are the agents that should be used to prevent organ rejection. This shows the importance of individualized drug use. The optimal immunosuppressive therapy post-transplant is not established. Therefore, discovering less toxic but more potent new agents is of great importance, and new experimental and clinical studies are needed in this regard.Our review discussed the mechanism of immunosuppressants, new agents' discovery, and current therapeutic protocols in the transplantation.

T Cell Large Granular Lymphocyte Leukaemia with Cutaneous Infiltration

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Good syndrome presenting with CD8⁺ T-Cell large granular lymphocyte leukemia

Good Syndrome is an adult-onset combined immunodeficiency defined by hypogammaglobulinemia, low or absent number of B cells, T cell deficiency and thymic tumor. We have characterized CD8+ T cells from a patient with Good syndrome that presented with CD8+T-cell large granular lymphocytic leukemia (LGL). Characterization of peripheral blood CD8+ T cells revealed that majority of CD8+ T cells were terminally differentiated effector memory phenotype (T_EMRA; CD8+CCR7-CD45RA+), and were PD-1^high (CD279), ICOS^low (CD278), and granzyme^high. Almost all CD8+ T cells were IFN-γ+. CD8 Treg (CD8+CD183+CCR7+CD45RA-) were decreased. T_EMRA phenotype along with CD279^high, demonstrates that these are exhausted CD8+ T cells. This phenotype along with CD278^low may also explain severe T cell functional deficiency in our patient. In the present patient, T-LGL appears to be a clonal expansion of CD279+granzyme+IFN-γ+CD8+T_EMRA cells. To best of our knowledge this is the first case of CD8+T-cell LGL leukemia associated with Good syndrome.

Guidelines for an integrated diagnostic approach of chronic lymphoproliferative disorders in the routine laboratory of haematology in Belgium

This paper summarizes the minimal workout of chronic lymphoproliferative disorders in a routine laboratory of haematology as recommended by a team of experienced laboratory supervisors in Belgium, taking into account the specific organisation of healthcare in Belgium, the innovations in the field of molecular analyses and related reimbursement. The starting point was essentially based upon clinical and/or haematological indications and it is emphasized that conclusions should be drawn in close dialogue with the clinician and experts in cytogenetics and histopathology. Reports made in the laboratory should be based upon an integration of cytomorphological, immunophenotypical and molecular data. These guidelines are not intended to be used as universal 'diagnostic pathways', but should be useful in developing local diagnostic pathways. It is well understood that this consensus, being valid anno 2009, may rapidly change with new technologies being introduced and new targets discovered.

Platelet-derived growth factor mediates survival of leukemic large granular lymphocytes via an autocrine regulatory pathway

Large granular lymphocyte (LGL) leukemia results from chronic expansion of cytotoxic T cells or natural killer (NK) cells. Apoptotic resistance resulting from constitutive activation of survival signaling pathways is a fundamental pathogenic mechanism. Recent network modeling analyses identified platelet-derived growth factor (PDGF) as a key master switch in controlling these survival pathways in T-cell LGL leukemia. Here we show that an autocrine PDGF regulatory loop mediates survival of leukemic LGLs of both T- and NK-cell origin. We found high levels of circulating PDGF-BB in platelet-poor plasma samples from LGL leukemia patients. Production of PDGF-BB by leukemic LGLs was demonstrated by immunocytochemical staining. Leukemic cells expressed much higher levels of PDGFR-beta transcripts than purified normal CD8(+) T cells or NK cells. We observed that phosphatidylinositol-3-kinase (PI3 kinase), Src family kinase (SFK), and downstream protein kinase B (PKB)/AKT pathways were constitutively activated in both T- and NK-LGL leukemia. Pharmacologic blockade of these pathways led to apoptosis of leukemic LGLs. Neutralizing antibody to PDGF-BB inhibited PKB/AKT phosphorylation induced by LGL leukemia sera. These results suggest that targeting of PDGF-BB, a pivotal regulator for the long-term survival of leukemic LGLs, may be an important therapeutic strategy.

Outcomes of splenectomy in T-cell large granular lymphocyte leukemia with splenomegaly and cytopenia

OBJECTIVE

T-cell large granular lymphocyte leukemia (T-LGL) is a chronic clonal lymphoproliferation of cytotoxic T cells often complicated by cytopenia. Because the outcomes of splenectomy in patients with T-LGL have been only reported sporadically, we objectively assessed the outcomes of splenectomy.

MATERIALS AND METHODS

When a cohort of 56 T-LGL patients was analyzed, patients with splenomegaly (n = 34) and had higher frequency of bi- and pancytopenia than patients with no splenomegaly (70% vs 27%; p = 0.001). We identified 15 patients who, in their clinical course, underwent splenectomy and studied their hematological and clinical outcomes.

RESULTS

Indications for splenectomy included symptomatic splenomegaly and/or severe refractory cytopenia. Median spleen weight was 1300 g, consistent with diagnosis of splenomegaly; T-cell receptor (TCR)-gamma rearrangement and typical T-LGL were detected by immunophenotype in all specimens. There was no surgery-related mortality, with the median follow-up and survival of 719 and 498 days, respectively. Two patients died due to causes possibly related to the splenectomized state and/or primary disease. All patients showed lineage-specific hematologic response and achieved transfusion independence; however, precise molecular analysis of TCR and variable chain Vbeta flow cytometry showed persistence of the LGL clones.

CONCLUSION

We conclude that splenectomy constitutes a viable and safe therapeutic option for patients with T-LGL, splenomegaly, and refractory cytopenia.