Chronic lymphocytic leukemia presenting with symptomatic central nervous system involvement.

Leukemic infiltration of the central nervous system (CNS) resulting in neurological manifestations is a rare complication of chronic lymphocytic leukemia (CLL). Furthermore, symptomatic CNS involvement as the initial presentation of previously undiagnosed CLL is extremely rare. In the present report, the authors describe a case of an 89-year-old female previously diagnosed with Alzheimer's disease who suddenly developed rapidly worsening mental changes. Cytological and immunocytological examinations of the lymphoid cells present on the cerebrospinal fluid (CSF) revealed CNS involvement by a clonal B-cell lymphoproliferative disorder, most consistent with de novo B-CLL expressing kappa light chain restriction. Subsequently, flow cytometric analysis done on the peripheral blood lymphocytes confirmed the diagnosis of B-CLL in this patient. Thus, this study shows the potential usefulness of immunocytological evaluation in detecting monoclonal lymphoid populations on CSF samples in adult patients presenting with altered mental status and CSF pleocytosis of lymphocytes.

Primary nodal marginal zone B-cell lymphoma arising from more than one clonal neoplastic population.

Primary nodal marginal zone B-cell lymphoma is an uncommon monoclonal B-cell lymphoproliferative disorder. We report a case of a 79-year-old woman who presented with generalized lymphadenopathy. Histologic and immunohistochemical examinations of biopsy sections from an axillary lymph node were consistent with nodal marginal zone B-cell lymphoma. Flow cytometry analysis showed 2 distinct clonal B-cell populations expressing lambda or kappa light chain restriction. Subsequently, genomic deoxyribonucleic acid (DNA) isolated from a paraffin-embedded lymph node section was analyzed for the presence of gene rearrangements. Polymerase chain reaction (PCR) analysis of immunoglobulin heavy chain genes revealed 3 rearranged DNA bands, confirming the presence of more than one clonal B-cell population. These immunophenotypic and genotypic findings have not been previously described in association with this type of lymphoma. To our knowledge, this represents the first reported case of biclonal nodal marginal zone B-cell lymphoma.

Mutation in the gene encoding the alpha chain of platelet glycoprotein Ib in platelet-type von Willebrand disease.

Platelet-type von Willebrand disease (PT-vWD) is an autosomal dominant bleeding disorder characterized by abnormally enhanced binding of von Willebrand factor (vWF) by patient platelets. Although the platelet glycoprotein (GP) Ib/IX complex is known to constitute the platelet's ristocetin-dependent receptor for vWF, a unique structural abnormality within this complex has not previously been identified in PT-vWD. Using the polymerase chain reaction to amplify genomic DNA coding for the alpha chain of GP Ib (GP Ib alpha) and then sequencing the amplified DNA following cloning into M13mp18 and M13mp19 phage vectors, we have found a single point mutation in the GP Ib alpha coding region of PT-vWD DNA resulting in the substitution of valine for glycine at residue 233. This substitution within the vWF-binding region of GP Ib alpha is likely to exert a significant influence on the conformation of the resulting protein. Competitive oligonucleotide primer assay for this mutation showed a homozygous wild-type pattern in genomic DNA from the 161 normal volunteers studied and from 6 phenotypically normal members of a PT-vWD family. All 7 affected members of this family studied were heterozygous for the mutant allele. Platelet GP Ib alpha mRNA reverse-transcribed and studied by competitive oligonucleotide primer assay showed similar expression of the mutant and wild-type alleles in the affected PT-vWD patients. Absence in the normal population, tight linkage with phenotypic expression of disease, and absence of any additional abnormality of GP Ib alpha in these patients identify the glycine-to-valine substitution as a point mutation underlying functional abnormality of the vWF receptor in PT-vWD.

Evidence that an abnormality in the glycoprotein Ib alpha gene is not the cause of abnormal platelet function in a family with classic Bernard-Soulier disease.

The underlying molecular basis for Bernard-Soulier Disease (BSD) is currently unknown. Platelets from patients with this autosomal recessive bleeding disorder have multiple abnormalities, including a markedly reduced von Willebrand factor-dependent adhesiveness due to a deficiency of the platelet membrane glycoprotein (GP) Ib/IX complex. In the present studies, we have used an intragenic restriction fragment length polymorphism (RFLP) for Taq I in the GPIb alpha gene to study linkage between this gene and the inheritance of BSD in a family with two affected siblings. Whereas the proband was heterozygous, showing both the 0.7 and 4.0 kb bands of this polymorphism (A/B), her affected brother was homozygous for the 0.7 kb band (A/A). Accordingly, these siblings did not inherit the same pair of GPIb alpha alleles from their parents. Additionally, one child of the proband was A/A, while the second studied child was A/B, with neither showing any evidence of BSD. No construct of heterozygosity or homozygosity for GPIb alpha alleles in this family is consistent with a model in which one or more defective GPIb alpha alleles could produce BSD. RFLP analysis with BamHI or HindIII showed entirely normal patterns in the patients, indicating the absence of any gross deletion of the GPIb alpha gene. GPIb alpha mRNA from patient platelets was reverse transcribed and subsequently amplified by the polymerase chain reaction, demonstrating the presence of GPIb alpha transcript. Furthermore, trace amounts of GPIb could be shown on the surface of patient platelets. Based on these results, a defect in the GPIb alpha gene is unlikely to be the cause of BSD in this family.