Lenalidomide in the management of eosinophilic dermatosis of hematological malignancy

Eosinophilic dermatosis of hematological malignancy is a paraneoplastic skin eruption associated with chronic lymphocytic leukemia and other B‐cell malignancies. It clinically resembles an insect bite reaction and it can precede the symptoms of the hematological malignancy or be related to a more aggressive course. Different treatments have been proposed, but partial response and recurrence are frequent. Herein, we describe a case of eosinophilic dermatosis associated with mantle cell lymphoma with remission after lenalidomide therapy.     

Interleukin 2 stimulates the T-cells from patients with eosinophilia to produce CFU-Eo growth stimulating factor

Patients with immune thrombocytopenia have an increased percentage of microthrombocytes/platelet fragments and megathrombocytes. It has been suggested that increased levels of platelet associated IgG (PA-IgG) found in these patients might be related to the presence of this abnormal platelet size distribution. In this study we used flow cytometry to investigate the distribution of PA-IgG within a population of platelets and, in particular, we examined the relationship between platelet size and PA-IgG determined simultaneously on individual platelets. Platelet samples from 10 normals and 31 thrombocytopenic patients were studied. PA-IgG was estimated using immunofluorescent FITC anti-IgG antibody. Binding of FITC anti-IgG to the platelets was quantitated in the flow cytometer as relative mean fluorescence (RMF) which was calibrated against values (in fg/plt of FITC anti-IgG) obtained by spectrofluorometry after solubilization of the platelets. A high correlation (r = 0.89) was found between flow cytometric RMF value and spectrofluorometric FITC anti-IgG values. The flow cytometric studies showed that platelet samples with abnormally elevated levels of FITC anti-IgG (greater than 1.7 fg/plt) not only have a higher percentage of platelets with elevated FITC anti-IgG, but that these platelets also have increased levels of FITC anti-IgG as compared to platelets from normal samples. Platelet size was measured by the amount of forward light scatter in the flow cytometer. A low but significant correlation (r = 0.33 +/- 0.12) was found between size (FALS) and fluorescent signals in samples with elevated FITC anti-IgG. The contribution of 10% of the smallest platelets by FALS and 10% of the largest platelets by FALS to the total levels of flow cytometer platelet fluorescence in these samples was only 4.4% and 19.4% respectively which was not higher than obtained with samples with normal levels of FITC anti-IgG. In conclusion, this study showed that increased levels of PA-IgG found among thrombocytopenic patients were not confined to any particular size class of platelets.     

Heterogeneity of in vitro growth pattern of megakaryocyte progenitors (CFU-M) in myeloproliferative disorders

In groups of 26 patients with myeloproliferative disorders (MPD), 8 with chronic myelogenous leukaemia (CML); 8 with polycythaemia vera (PV); 10 with essential thrombocythaemia (ET); and 6 patients with reactive thrombocytosis (RT), we studied the growth characteristics of bone marrow CFU-M in agar culture. The bone marrows from all the patients with MPD formed so called endogenous CFU-M colonies, in the absence of PHA-LCM, that increased in a dose-dependent manner with the addition of increasing concentrations of normal human AB-citrated plasma (NH-ABCP), while the bone marrows from all the patients with RT and from healthy controls formed few or no endogenous CFU-M colonies. In MPD, the endogenous CFU-M growth was enhanced by normal T cells in a dose-dependent fashion, and was decreased with the depletion of T cells from the marrow cells. These results suggest that the formation of endogenous CFU-M colonies is caused by hypersensitivity of CFU-M in MPD to NH-ABCP, which may contain a small amount of Meg-CSF, and/or by in vitro T cell stimulation. Among MPD, the endogenous CFU-M growth in ET was significantly lower than that of other MPD patients; however, the total number of ET CFU-M grown in the presence of PHA-LCM was the highest. These data show that the bone marrow CFU-M in MPD are heterogeneous with respect to in vitro growth pattern or sensitivity to exogenous Meg-CSF.