Polymerase chain reaction-Based clonality analysis of cutaneous B-cell lymphoproliferative processes

Introduction: The differential diagnosis of B-cell lymphoproliferative processes remains a challenge for pathologists, dermatologists and oncologists, despite advances in histology, immunohistochemistry and molecular biology. Objective: Evaluate aid and limitations of clonality analysis in the diagnosis of primary cutaneous B-cell lymphomas and B-cell pseudolymphomas. Methods: This study included 29 cases of B-cell lymphoproliferative processes classified as primary cutaneous B-cell lymphomas (13), B-cell pseudolymphomas (6) and inconclusive cases (10) using histology and immunohistochemistry. The clonality analysis was performed by polymerase chain reaction analysis of immunoglobulin light chain and heavy chain rearrangements. Results: DNA quality was shown to be generally poor; eight samples were inadequate for polymerase chain reaction analysis. The results showed monoclonality in eight of the primary cutaneous B-cell lymphomas and polyclonality in four of the B-cell pseudolymphomas. In addition, monoclonality was shown in two of the inconclusive cases by histology and immunohistochemistry, demonstrating the utility of polymerase chain reaction as an ancillary diagnostic tool for primary cutaneous B-cell lymphomas. Discussion: The low quality DNA extracted from these cases demanded the use of an IgH protocol that yielded small fragments and IgK. Both methods used together improved detection. Conclusion: Use of the two protocols, immunoglobulin heavy chain FR3-trad and immunoglobulin light chain-Kappa Biomed protocols for clonality analysis improved diagnostic accuracy.

A Case of Lambda-expressing Pulmonary MALT Lymphoma with Dual Clonal Rearrangements of Kappa and Lambda Immunoglobulin Light Chain Gene / 대한진단검사의학회지

A 70-yr-old woman was hospitalized with a history of dry cough. Bronchial endoscopy and transbronchial lung biopsy were performed. However, the findings of histopathology and immunohistochemistry were not sufficient to decide whether the lesion was benign or malignant, because of the presence of crush artifacts in the biopsy specimens. We performed B-cell clonality studies using BIOMED-2 multiplex PCR (InVivoScribe Technologies, USA) to detect clonal rearrangements in the immunoglobulin gene. The results of multiplex PCR showed clonal rearrangements of both kappa and lambda immunoglobulin light chain genes. The findings of immunochemistry revealed that the lesion expressed lambda light chain, but not kappa light chain. Based on the clinical, pathologic, and molecular findings, this case was diagnosed as pulmonary MALT lymphoma. We report the first case in Korea of lambda-expressing MALT lymphoma that is shown to have dual clonal rearrangements of kappa and lambda immunoglobulin light chain gene by multiplex PCR.

The V kappa III subgroup light chain proteins in AL amyloidosis & autoimmune diseases.

BACKGROUND & OBJECTIVES: Light chain associated amyloidosis (AL) is characterized by extracellular deposition of immunoglobulin light chain and its fragments. In vitro and in vivo studies have shown that some light chains are nonamyloidogenic and nonnephrotoxic, whereas others are potentially amyloidogenic. Some light chains are prone to be deposited as rheumatoid materials, and also as nodular amorphous aggregates (light chain deposition diseases). These findings suggest that specific sequence element(s) may control the various kinds of light chain associated diseases. In this study we tried to identify such sequence element(s). METHODS: Two Bence Jones proteins (BJPs), NIG93 and NIG2 of subgroup V kappa III, were characterized and compared with other members of the same subgroup whose sequences are available in the data base. RESULTS: Both NIG93 and NIG2 proteins had sequences characteristics of V kappa IIIa as distinguished from V kappa IIIb, subsubgroup proteins. They also contained several novel substitutions, such as Met-37, Leu-40, Val-58, and IIe-85 in NIG93, and Val-2, His-29, Arg-50, and Ile-72 in NIG2. The data accumulated at present indicate that all members of the V kappa IIIa subsubgroup are related to either AL amyloidosis or rheumatoid arthritis, whereas the V kappa IIIb proteins are related to autoimmune diseases. INTERPRETATION & CONCLUSION: These observations indicate that subgroup-specific residues might be critical for light chain pathogenesis, at least for the V kappa III proteins. Point mutations within these proteins may be another structural element controlling their conformation as well as their pathogenic aggregation.

Alotipos Gm y Km en una muestra de población urbana chilena / Gm and Km allotypes in a chilean urban population sample

The sample included 460 controls of a case control study of typhoid fever. The G1m-G2m-G3m most frequent haplotypes were: za,..;g or 1,17;(-);21=0.4493;fn;b or 3;23;5,13=0.2522;f-,..;b or 3;(-);5,13=0.1389; zax;..;g or 1,2,17;(-);21=0.0685;za;..;b or 1,17;(-);5,13=0.0454;za;n;g or 1,17;23;21=0.0207;f;..;g or 3;(-);21=0.0129. The frequencies of Km alleles were 0.2391 and 0.7609 for Km1 and km3 respectively. These frequencies are within those found in Amerindian and Caucasian populations as expected from the origin of the Chilean population. Gm haplotypes did not differ from Hardy-Weinberg equilibrium, while a significant lack of homozygous Km1/km1 was found in Km