N-Glycosylation of the Ig Receptors Shapes the Antigen Reactivity in Chronic Lymphocytic Leukemia Subset #201.

Subset #201 is a clinically indolent subgroup of patients with chronic lymphocytic leukemia defined by the expression of stereotyped, mutated IGHV4-34/IGLV1-44 BCR Ig. Subset #201 is characterized by recurrent somatic hypermutations (SHMs) that frequently lead to the creation and/or disruption of N-glycosylation sites within the Ig H and L chain variable domains. To understand the relevance of this observation, using next-generation sequencing, we studied how SHM shapes the subclonal architecture of the BCR Ig repertoire in subset #201, particularly focusing on changes in N-glycosylation sites. Moreover, we profiled the Ag reactivity of the clonotypic BCR Ig expressed as rmAbs. We found that almost all analyzed cases from subset #201 carry SHMs potentially affecting N-glycosylation at the clonal and/or subclonal level and obtained evidence for N-glycan occupancy in SHM-induced novel N-glycosylation sites. These particular SHMs impact (auto)antigen recognition, as indicated by differences in Ag reactivity between the authentic rmAbs and germline revertants of SHMs introducing novel N-glycosylation sites in experiments entailing 1) flow cytometry for binding to viable cells, 2) immunohistochemistry against various human tissues, 3) ELISA against microbial Ags, and 4) protein microarrays testing reactivity against multiple autoantigens. On these grounds, N-glycosylation appears as relevant for the natural history of at least a fraction of Ig-mutated chronic lymphocytic leukemia. Moreover, subset #201 emerges as a paradigmatic case for the role of affinity maturation in the evolution of Ag reactivity of the clonotypic BCR Ig.

Primary Hepatic Burkitt Lymphoma in a Kidney Transplant Recipient.

This is a case of a renal transplant recipient who developed a primary hepatic Burkitt lymphoma a few years after kidney transplantation. The past medical history of the patient was significant for anti-HCV positivity with liver histopathology showing minimal changes of grades 0 and 1, stage 0. She received a graft from a deceased donor, with rabbit antithymocyte globulin and methyl-prednisolone, as induction therapy, and was maintained on azathioprine, cyclosporine, and low dose methyl-prednisolone with normal renal function. Four years after KTx she presented with fatigue, hepatomegaly, and impaired liver function and the workup revealed multiple, variable-sized, low density nodules in the liver, due to diffuse monotonous infiltration of highly malignant non-Hodgkin lymphoma of B-cells, which turned out to be a Burkitt lymphoma. Bone marrow biopsy and spinal fluid exam were free of lymphoma cells. At time of lymphoma diagnosis she was shown to be positive for Epstein-Barr virus polymerase chain reaction. She received aggressive chemotherapy but died due to sepsis, as a result of toxicity of therapy.

The Significance of PET/CT in the Initial Staging of Hodgkin Lymphoma: Experience Outside Clinical Trials.

AIM: To examine the real-life impact of baseline positron-emission tomography/computed tomography (PET/CT) in Hodgkin lymphoma (HL). PATIENTS AND METHODS: A total of 162 consecutive patients with HL were retrospectively studied. RESULTS: Disease was up-staged in 26 patients (16%) and down-staged in 9 (6%). However, treatment strategy was modified in only 10 patients (6% of total). Involved field radiotherapy was delineated according to PET/CT in 36/66 patients (59%). These treatment modifications did not significantly affect outcome. Moreover, three potent prognostic parameters were identified: the number of involved sites, maximum standardized uptake value (SUVmax), and the product of SUVmax and maximal largest lesion diameter, as a surrogate of total lesion glycolysis. All three significantly correlated with 5-year freedom from disease progression p=0.004, p=0.009 and p=0.04, respectively). CONCLUSION: Baseline PET/CT findings may lead to treatment modification in <15% of patients with HL without a significant impact on outcome. Certain PET/CT parameters have potent prognostic significance.

Differential diagnosis of Waldenstrom's macroglobulinemia and other B-cell disorders.

Waldenstrom's macroglobulinemia (WM) is characterized by lymphoplasmacytic infiltration of bone marrow and/or other tissues and by the presence of serum monoclonal immunoglobulin M ([IgM], without cutoff limit). Differential diagnosis from other B-cell disorders (BCDs) is usually easy based on clinical, morphologic, histopathologic, immunophenotypic, and genetic features. However, all BCDs potentially produce monoclonal IgM. In this study we reviewed the medical files of 130 patients with IgM-secreting BCDs. Eighty-four patients were diagnosed with WM, 5 with IgM-monoclonal gammopathy of undetermined significance (MGUS), and 41 with other BCDs (9 with B-cell chronic lymphocytic leukemia, 5 with small lymphocytic lymphoma, 14 with marginal zone lymphoma, 5 with mantle-cell lymphoma, 2 with follicular lymphoma, 2 with diffuse large B-cell lymphoma, 2 with cryoglobulinemia, and 2 with low-grade lymphoma not otherwise specified). Median IgM levels were 3215 mg/dL in WM, 840 mg/dL in IgM-MGUS, and 285 mg/dL in other BCDs (5 had IgM levels > 1500 mg/dL). In 10% of non-WM BCDs, monoclonal IgM was found only when more sensitive immunofixation methods were used. Forty-four percent of patients with BCDs (splenic marginal zone lymphoma or small lymphocytic lymphoma) had diagnoses that corresponded to that of WM. Careful diagnosis requires the concomitant evaluation of all parameters of BCDs together. Marginal zone lymphoma is the most frequently overlapping entity. Special attention should be given to mantle cell lymphoma in its atypical forms. Research in this field should continue to further clarify the disease entities that overlap with WM. New technology such as gene-expression profile techniques may contribute to this purpose.

Tyrosine kinase inhibitors and interferon.

The use of interferon-a (INF) in chronic myeloid leukemia, when it started in the 80s, was considered as a breakthrough in the therapy of this disease; INF administered alone or in combination with aracytin was the standard choice for treatment for Chronic Myeloid Leukemia (CML) patients unfit for bone marrow transplantation. With the appearance of the first Tyrosine Kinase Inhibitor (TKI) (imatinib) and based on the results of the pivotal IRIS trial, imatinib monotherapy was the new treatment of choice for CML, according to the ELN recommendations. The possibility of combining INF with imatinib, for obtaining better therapeutic responses in CML patients has been already tested and reported. The current challenge is the combined use of second generation TKIs with pegylated -IFN, in order to minimize failures to therapy and increase the number of CML patients with deep molecular responses, who may be able to discontinue lifelong treatment.

Apoptotic and proliferative characteristics of proliferation centers in lymph node sections of patients with chronic lymphocytic leukemia.

We have analyzed the immunohistochemical expression of a wide range of molecules along with the proliferation rate separately in the proliferation centers (PCs) and in the rest of the tumor area, in lymph node or spleen sections of patients with chronic lymphocytic leukemia (CLL). Fas, FasL and c-FLIP were observed both within and outside the PCs in all cases. However, only the difference in FasL expression between the PCs and the non-PC areas attained statistical significance. Median survivin expression in the PCs was higher compared to the non-PC areas. Cleaved caspase 3 was expressed at very low levels both within and outside PCs, while BCL-2 protein was expressed at high levels in all cases in both tumor compartments. Multivariate analysis demonstrated that concurrent overexpression of Fas/FasL/c-FLIP in the PCs was correlated with worse outcome for progression-free survival as well as for overall survival.