Comparison of in situ hybridisation and polymerase chain reaction in the diagnosis of B cell lymphoma

Analysis of clonality in cutaneous B-cell lymphoma and B-cell pseudolymphoma using skin flow cytometry: Comparison of immunophenotyping and gene rearrangement studies

To identify clonal neoplastic cells in skin affected by B-cell lymphoma using skin flow cytometry (FCM) techniques, we investigated light-chain restriction using skin FCM with clonality assessed by polymerase chain reaction and light-chain restriction by in situ hybridization (ISH). We retrospectively analyzed 16 cases of B-cell lymphoma with cutaneous involvement: primary cutaneous diffuse large B-cell lymphoma, leg type (pcDLBCL-LT) (n = 7), DLBCL-not otherwise specified (DLBCL-NOS) (n = 6), primary cutaneous follicle center lymphoma (pcFCL) (n = 1), and follicular lymphoma (n = 2), as well as cutaneous B-cell pseudolymphoma (n = 9). Results of skin FCM light-chain restriction analyses were compared with immunoglobulin H (IgH) gene rearrangement and κ/λ ISH findings. Skin FCM detected light-chain restriction in 11 of 14 B-cell lymphoma patients but none of the B-cell pseudolymphoma patients. The sensitivity of skin FCM for distinguishing B-cell lymphoma and B-cell pseudolymphoma was 79%, and the specificity was 100%. Eleven of 13 B-cell lymphoma patients exhibited gene rearrangement (sensitivity 85%), whereas six of seven pseudolymphoma patients were negative (specificity 86%). ISH was positive in three of 16 B-cell lymphoma cases (sensitivity 19%) but none of the B-cell pseudolymphoma cases (specificity 100%). ISH sensitivity was 29% for pcDLBCL-LT, 17% for DLBCL-NOS, and 0% for pcFCL and follicular lymphoma. Skin FCM therefore appears to be more sensitive than ISH in detecting light-chain restriction in DLBCL and follicular lymphoma, and as sensitive as IgH gene rearrangement analysis in detecting clonality. Skin FCM is thus a promising diagnostic tool for identifying monoclonal neoplastic B-cell populations.

Virus-infected peripheral blood plasmablasts in a patient with severe fever with thrombocytopenia syndrome

Severe fever with thrombocytopenia syndrome (SFTS) is a tick-borne viral hemorrhagic disease with a high fatality rate. It is caused by the SFTS virus and is endemic in East Asian countries such as China, South Korea, and Japan. Previous studies have shown that plasmablasts appear transiently in peripheral blood during the acute phase of SFTS, but do not specify the characteristics of these plasmablasts. In this report, we describe the features of peripheral blood plasmablasts in a patient with SFTS. Immunohistochemical and immunofluorescence staining detected a small number of atypical lymphocytes expressing the SFTS virus antigen among peripheral leukocytes in a blood sample. The phenotype of the virus-infected cells was CD27+, CD38+, MUM1+, and CD138+, which is consistent with that of plasmablasts. This novel study demonstrates that plasmablasts in the peripheral blood of patients with SFTS are targets of the SFTS virus.

In situ hybridisation: Technologies and their application to understanding disease

In situ hybridisation (ISH) is unique amongst molecular analysis methods in providing for the precise microscopic localisation of genes, mRNA and microRNA in metaphase spreads, cell and tissue preparations. The method is well established as a tool to guide appropriate therapeutic intervention in breast, gastric and lung cancer. With the description of ultrasensitive ISH technologies for low copy mRNA demonstration and the relative ease by which microRNA can be visualised, the applications for research and diagnostic purposes is set to increase dramatically. In this review ISH is considered with emphasis on recent technological developments and surveyed for present and future applications in the context of the demonstration of genes, mRNA and microRNA in health and disease.

The differentiation of idiopathic inflammatory pseudotumor from lymphoid tumors of orbit: analysis of 319 cases

PURPOSE

To analyze the clinical, morphologic, immunophenotypic, and molecular genetic differences between idiopathic inflammatory pseudotumor and lymphoid tumors of the orbit.

METHODS

209 patients with IOIP and 110 patients with lymphoid tumors seen between January 1, 1978 and December 31, 1999 in Zhongshan Ophthalmic Center, Sun Yat-sen University were evaluated retrospectively.

RESULTS

More patients with lymphoid tumors had palpable mass than patients with idiopathic orbital inflammatory pseudotumor (IOIP) (P < 0.0001), with the percentage of 90% and 65%, respectively, whereas more patients with IOIP had swollen eyelid, eyelid or conjunctival congestion, pain, retinal folds or hamorrhage, and optic nerve atrophy than patients with lymphoid tumors, with the percentage of 55% and 40% (P = 0.014), 42% and 24% (P = 0.001), 24% and 1% (P < 0.0001), 14% and 4% (P = 0.004), 7% and 2% (P = 0.043), respectively. Ultrasound and computed tomography/magnetic resonance image (CT/MRI) scan usually could not differentiate IOIP from lymphoma. Nearly one third of patients with IOIP could not be easily differentiated pathologically from lymphoid tumor. Immunophenotypic, and molecular genetic analyses can differentiate IOIP from lymphoid tumor based on polyclonal or monoclonal proliferation of lymphocytes with the IOIP being polyclonal and lymphoma monoclonal.

CONCLUSIONS

Idiopathic orbital inflammatory pseudotumor and lymphoid tumor showed distinguishing clinical, morphologic, immunophenotypic, and molecular genetic characteristics.

Determination of light chain restriction in fine-needle aspiration-type preparations of B-cell lymphomas by mRNA in situ hybridization

The purpose of this study was to investigate whether B-cell clonality could be demonstrated in fine-needle aspiration (FNA)-type preparations by using automated and manual in situ hybridization (ISH) systems. FNA-like preparations were made from 10 cases of B-cell lymphoma and 5 cases of reactive lymphoid hyperplasia. Kappa/lambda expression was determined using an automated mRNA ISH assay or a manual ISH system. Other variables tested included type and length of fixation, protease digestion, and time in chromogen. Clonality data were corroborated by either flow cytometry or tissue-based analysis. Optimal conditions required formalin fixation, strong protease digestion, and prolonged hybridization and chromogen times; under these conditions, monoclonality was demonstrated by in situ in 8 of 10 cases. Each of the five cases of reactive lymphoid hyperplasia showed polyclonal light chain expression by automated mRNA ISH. In situ kappa/lambda mRNA analysis of FNA-type specimens allows direct determination of monoclonality in cytologic preparations.

A single primer pair immunoglobulin polymerase chain reaction assay as a useful tool in fine-needle aspiration biopsy differential diagnosis of lymphoid malignancies

BACKGROUND

Different polymerase chain reaction (PCR) assays have proved to be useful tools for the detection of clonal immunoglobulin heavy chain (IgH) gene rearrangements in frozen or paraffin-embedded tissues. However, the usefulness of a single primer pair PCR assay on fine-needle biopsy aspirates has not been proven yet.

METHODS

The authors conducted a wide prospective study of 148 lymph nodes and extranodal lymphoid infiltrates obtained by fine-needle aspiration biopsy (FNAB). The power of a single primer pair PCR amplification of the hypervariable CDRIII region IgH genes was evaluated using a pair of consensus primers. The PCR cytologic results were compared with the final clinicopathologic diagnosis of each case assessed by combining cytologic and/or immunophenotypic data and histologic features or clinical follow-up.

RESULTS

Among the 139 cases with an evaluable PCR result, 35 of 40 (87%) B-cell non-Hodgkin lymphomas were detected as a monoclonal band. Monoclonal IgH bands also were detected in two of the five (40%) T-cell lymphomas, two of the seven (29%) Hodgkin lymphomas, and 5 of the 87 (6%) reactive lymphoid disorders. These results are similar to those obtained by other authors using seminested PCR or combining different PCR tests in each sample obtained by FNAB or excisional biopsy.

CONCLUSIONS

The results of the current study demonstrate the convenience of a single primer pair PCR amplification over seminested methods in terms of lower cost and workload. The existence of PCR false-negative and false-positive results for lymphoma makes it necessary to combine the information obtained by PCR with cytologic and/or immunophenotypic data to optimize the number of lymphoid malignancies correctly diagnosed by FNAB.

Automated colorimetric in situ hybridization (CISH) detection of immunoglobulin (Ig) light chain mRNA expression in plasma cell (PC) dyscrasias and non-Hodgkin lymphoma

Immunohistochemistry (IHC) is frequently used to detect plasma cell (PC) or B cell monoclonality in histologic sections, but its interpretation is often confounded by background staining. We evaluated a new automated method for colorimetric in situ hybridization (CISH) detection of clonality in PC dyscrasias and small B cell lymphomas. Cases of PC dyscrasia included multiple myeloma (MM; 31 cases), plasmacytoma (seven cases), or amyloidosis (one case), while cases of lymphoma included small lymphocytic (three cases), marginal zone (four cases), lymphoplasmacytic (three cases), and mantle cell lymphomas (three cases). Tissue sections were stained for kappa and lambda light chains by IHC and for light chain mRNA by automated CISH using haptenated probes. Twenty-eight of 31 MM cases had detectable light chain restriction by IHC. Thirty of 31 MM cases demonstrated light chain restriction by CISH, including 2 cases with uninterpretable IHC and one case of nonsecretory myeloma, which was negative for light chains by IHC. Seven of 7 plasmacytoma cases had detectable light chain restriction by CISH, including one case of nonsecretory plasmacytoma in which IHC was noninformative. Automated CISH demonstrated monoclonality in 9 of 13 cases of B cell non-Hodgkin lymphoma and had a slightly higher sensitivity than IHC (6 of 13 cases), especially in cases of lymphoplasmacytic and marginal zone lymphoma. Overall, there were no discrepancies in light chain restriction results between IHC, CISH, or serum paraprotein analysis. Automated CISH is useful in detecting light chain expression in paraffin sections and appeared superior to IHC for light chain detection in PC dyscrasias and B cell non-Hodgkin lymphomas, predominantly due to lack of background staining.

Analysis of immunoglobulin H gene rearrangement by polymerase chain reaction in primary central nervous system lymphoma

OBJECT

Diagnosing primary central nervous system lymphoma (PCNSL) may be difficult either because of a paucity of tumor cells in the brain biopsy specimens or a failure to demonstrate monoclonality on immunomorphological studies. Monoclonality can also be demonstrated by amplification of the rearranged immunoglobulin H genes by polymerase chain reaction (PCR) to the framework region (FR)3 and FR2 complementarity determining region (CDR)-III and CDR-II of these genes. The PCR method is feasible with formalin-fixed, paraffin-embedded biopsy material and has proven to be helpful in the diagnosis of non-Hodgkin lymphoma on biopsy samples obtained from various locations in the body. Nevertheless, few studies have addressed the value of this method in the context of PCNSL. In the present study, the contribution of both FR3 single and FR2 seminested PCR procedures for confirming the diagnosis of PCNSL was estimated retrospectively in 30 cases of PCNSL and in three cases of epidural lymphoma.

METHODS

Twenty-eight cases of immunophenotypically confirmed PCNSL and two of suspected lymphoma were studied. Tissue specimens obtained in 22 cases of other cerebral diseases, among which were various inflammatory conditions. were used as negative controls. In 18 (60%) of 30 cases the results of FR3 PCR demonstrated monoclonality, whereas FR2 PCR showed monoclonality in 12 cases (40%). In 11 cases FR3 PCR yielded monoclonal patterns and FR2 PCR did not, whereas reversibly in five cases FR2 PCR proved monoclonality and FR3 PCR failed to do so. Adding the results of FR3 to those of FR2 PCR, monoclonal patterns were obtained in 23 (77%) of 30 cases. In both cases in which lymphoma was suspected but not proven immunomorphologically, FR3 PCR revealed monoclonality, as did FR2 PCR in one case. In all 22 control lesions either polyclonal patterns were seen or no consistent patterns were obtained. In the PCNSL group, older age of patients and multifocal presentation of lesions on neuroimaging were significantly associated with worse survival. No correlation between histological subtype and clinical outcome was elucidated.

CONCLUSIONS

The application of FR3 and FR2 PCR is a useful additional tool in making the diagnosis of PCNSL. Moreover, in some cases the PCR method may be essential in distinguishing neoplasia from reactive conditions.

Thyroid transcription factor-2 gene expression in benign and malignant thyroid lesions

Thyroid transcription factor-2 (TTF-2) is a recently cloned thyroid-specific gene and is central to the development and differentiation of the thyroid follicular cell. Information regarding transcript levels in normal and diseased adult human thyroids is lacking. We have investigated TTF-2 gene expression in various thyroid pathologies and assessed its potential in preoperative diagnosis of thyroid nodular disease, which is a common clinical problem. We have used reverse transcription-polymerase chain reaction (RT-PCR) and in situ hybridization (ISH) and detected TTF-2 transcripts in 60% of 125 samples of adult human thyroids tested by RT-PCR (64% of 35) or ISH (59% of 90). In normal thyroid tissues TTF-2 transcript levels are low, 18 of 36 were weakly positive and 18 of 36 negative when tested by ISH. In the benign lesions, TTF-2 transcripts were detected either by RT-PCR or ISH in 8 of 8 Graves disease; 3 of 7 Hashimoto's; 2 of 2 follicular hyperplasia; 15 of 21 follicular adenoma; 11 of 13 multinodular goiters and 0 of 1 hyalinizing trabecular adenoma. In the malignant thyroid lesions, TTF-2 transcripts were detected in 8 of 18 follicular cancers; 0 of 2 anaplastic carcinoma, and 11 of 17 papillary cancers. Compared with normal thyroids, transcripts were more abundant in 24% of thyroid lesions tested by ISH. In conclusion, we report for the first time on TTF-2 gene expression in normal and diseased adult human thyroids.

Megacystis-microcolon-intestinal hypoperistalsis syndrome and the absence of the alpha3 nicotinic acetylcholine receptor subunit

BACKGROUND & AIMS

The megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS) is a rare disease of childhood that presents early with intestinal hypoperistalsis, hydronephrosis, and hydroureters. Transgenic mice that lack the alpha3 subunit containing nicotinic acetylcholine (nAChR) have a phenotype similar to that of MMIHS.

METHODS

We examined the expression of this subunit in control and MMIHS tissue derived from patients using in situ hybridization (ISH) and immunocytochemistry (ICC).

RESULTS

In controls, both techniques showed a wide distribution of alpha3 nAChRs present in ganglion cells, muscle, and epithelium. By contrast, most MMIHS tissue gave negative staining with ISH and variable results with ICC.

CONCLUSIONS

These observations are consistent with a lack of alpha3 nAChRs contributing to the pathogenesis of MMIHS.

Evaluation of lymphoid cell populations in cytology specimens using flow cytometry and polymerase chain reaction

Differential diagnosis between lymphomas and reactive lymphoid proliferations often requires ancillary techniques and morphologic evaluation. Flow cytometry (FCM) and polymerase chain reaction (PCR) can aid the detection of monoclonal B-cell populations. In the present study, the sensitivity and specificity of these two methods in the study of cytology specimens were compared. Eighty-six cytologic specimens from 81 patients (lymph nodes, solid organs, and body cavities) were evaluated. These specimens were taken from three groups of patients: those who underwent an initial evaluation for suspected lymphoma; those who were previously diagnosed with B-cell lymphoma and were now evaluated for possible disease recurrence; and those who were diagnosed with a nonhematologic malignancy. Histologic diagnosis was available for 51 samples. All samples were tested by FCM for the detection of monoclonality using kappa:lambda ratio and for clonal immunoglobulin heavy chain (IgH) gene rearrangements using a single-round PCR after cytologic evaluation. Tissue morphology, FCM and PCR results, and clinical findings in specimens without histologic diagnosis were correlated. Histologic evaluation (N = 51) revealed 44 specimens with B-cell malignancy. Twenty of the 44 lymphoma specimens (45%) were accurately diagnosed in cytologic smears, 18 (41%) were classified as suspicious of lymphoma, and 6 (14%) were diagnosed as reactive. FCM had superior sensitivity compared with PCR (77% vs. 64%). Fifty-six percent of specimens with B-cell malignancy were FCM+/PCR+, 23% were FCM+/PCR-, 14% were FCM-/PCR+, and 7% were FCM-/PCR-. The combined use of FCM and PCR resulted in a diagnosis of B-cell lymphoma in 41 (93%) of 44 B-cell lymphoma specimens and increased the sensitivity of fine needle aspiration by 48%. Both FCM and PCR aid in the diagnosis of lymphoid lesions in cytology specimens, and both can detect monoclonal B-cell populations that may be interpreted in cytology smears as reactive, even by experienced cytologists. Although FCM had higher sensitivity than PCR test in the present study, their combined use should be considered because of a relatively large number of specimens that were detected as monoclonal only with PCR.