Receptor Gamma Chain Gene Research Articles

A new Hu-PBL model for the study of human islet alloreactivity based on NOD- scid mice bearing a targeted mutation in the IL-2 receptor gamma chain gene

Immunodeficient NOD-scid mice bearing a targeted mutation in the IL2 receptor common gamma chain (Il2rgamma(null)) readily engraft with human stem cells. Here we analyzed human peripheral blood mononuclear cells (PBMC) for their ability to engraft NOD-scid Il2rgamma(null) mice and established engraftment kinetics, optimal cell dose, and the influence of injection route. Even at low PBMC input, NOD-scid Il2rgamma(null) mice reproducibly support high human PBMC engraftment that plateaus within 3-4 weeks. In contrast to previous stocks of immunodeficient mice, we observed low intra- and inter-donor variability of engraftment. NOD-scid Il2rgamma(null) mice rendered hyperglycemic by streptozotocin treatment return to normoglycemia following transplantation with human islets. Interestingly, these human islet grafts are rejected following injection of HLA-mismatched human PBMC as evidenced by return to hyperglycemia and loss of human C-peptide. These data suggest that humanized NOD-scid Il2rgamma(null) mice may represent an important surrogate for investigating in vivo mechanisms of human islet allograft rejection.

Lymphoma-like Lesion of the Uterine Cervix

Lymphoma-like lesion of the female genital tract is rare. We report 12 cases of lymphoma-like lesions of the cervix in patients ranging from 27-54 years of age (mean 41). The commonest clinical presentation was post-coital bleeding (8), which was followed by vaginal bleeding (2) and leukorrhagia (4). Grossly, the lesions were either polypoid (8) or ulcerated (4). On histological examination, the lesions were eroded and involved the superficial mucosa 2-12 mm (mean 4 mm) in depth. They comprised sheets of dense populations of predominantly large lymphoid cells admixed with small lymphocytes, plasma cells, and neutrophils. Follicle formation was occasionally seen. Immunostaining revealed the majority of the large cells were B cells (CD20(+), CD79a(+)) with no aberrant CD5 and CD43 expression. The lymphoid cells in the follicle were CD10(+) and bcl6(+) but negative for bcl-2. Cyclin D1 was negative. There was no immunoglobulin light chain restriction and polymerase chain reaction for T cell receptor-gamma chain gene and immunoglobulin heavy chain gene demonstrated polyclonal patterns. In situ hybridization for EBER and high risk HPV 6/11 and 16/18 were negative. All patients were well with one case developing local recurrence in the follow-up period up to 7 years.

Simultaneous occurrence of peripheral T-cell lymphoma unspecified and B-cell small lymphocytic lymphoma. Report of 2 cases

We report on 2 composite lymphomas occurring in elderly patients, morphologically characterized by the combination of peripheral T-cell lymphoma (PTCL) unspecified and B-cell small lymphocytic lymphoma. Immunohistochemistry provided objective confirmation of the coexistence of the 2 malignancies, as did molecular biology by revealing clonal T-cell receptor gamma and immunoglobulin heavy chain gene rearrangements. One of the patients had no history of indolent lymphoma either at the personal and family level, whereas the other showed a strong familial predisposition, his mother and sister having suffered from B-cell chronic lymphocytic leukemia. Epstein-Barr virus was detected in the PTCL component of 1 case, but was negative in the other. To the best of our knowledge, the simultaneous occurrence of PTCL unspecified and B-cell small lymphocytic lymphoma is an exceptional event; the possible pathogenetic correlations between the 2 neoplasms are discussed.

Phage ϕC31 integrase‐mediated genomic integration of the common cytokine receptor gamma chain in human T‐cell lines

X-linked severe combined immunodeficiency (SCID-X1, X-SCID) is a life-threatening disease caused by a mutated common cytokine receptor gamma chain (gammac) gene. Although ex vivo gene therapy, i.e., transduction of the gammac gene into autologous CD34(+) cells, has been successful for treating SCID-X1, the retrovirus vector-mediated transfer allowed dysregulated integration, causing leukemias. Here, to explore an alternative gene transfer methodology that may offer less risk of insertional mutagenesis, we employed the phiC31 integrase-based integration system using human T-cell lines, including the gammac-deficient ED40515(-). A phiC31 integrase and a neo(r) gene expression plasmid containing the phiC31 attB sequence were co-delivered by electroporation into Jurkat cells. After G418 selection, integration site analyses were performed using linear amplification mediated-polymerase chain reaction (LAM-PCR). ED40515(-) cells were also transfected with a gammac expression plasmid containing attB, and the integration sites were determined. IL-2 stimulation was used to assess the functionality of the transduced gammac in an ED40515(-)-derived clone. Following co-introduction of the phiC31 integrase expression plasmid and the plasmid carrying attB, the efficiency of integration into the unmodified human genome was assessed. Several integration sites were characterized, including new integration sites in intergenic regions on chromosomes 13 and 18 that may be preferred in hematopoietic cells. An ED40515(-) line bearing the integrated gammac gene exhibited stable expression of the gammac protein, with normal IL-2 signaling, as assessed by STAT5 activation. This study supports the possible future use of this phiC31 integrase-mediated genomic integration strategy as an alternative gene therapy approach for treating SCID-X1.

Combined Therapy with Alemtuzumab and Pentostatin Is Feasible and Effective in T- Lymphoprolifertive Disorders.

Mature T-cell lymphoid neoplasms are clonal proliferation of post-thymic T-cells, which are generally refractory to traditional chemotherapy regimens. The prognosis for most patients with these disorders, particularly those with relapsed disease, is poor. New treatment strategies are urgently needed. Alemtuzumab and pentostatin have been used as single agents in various T-cell neoplasms with response rates of up to 75% and 50%, respectively. Immunosuppression and opportunistic infections are the principal overlapping toxicities. We have treated 9 patients with T-lymphoid malignancies (5 T-PLL, 1 ATL, 1 γδ-T-cell hepatosplenic lymphoma, 2 T-LGL) on a phase II study of alemtuzumab 30 mg IV three times weekly for up to 3 months with concomitant pentostatin 4 mg/m2 weekly x 4 followed by alternate weekly administration for up to 6 months. Prophylactic antibiotics including valcyclovir, trimethoprim/sulfamethoxazole, and fluconazole were administered during therapy and for 2 months after completion. Median age of patients was 57 years (range 25–80 years), median WBC was 78.5 x 109/L (range 0.7 – 279.5 x109/L), median serum β2M was 4.1 mg/L (2.7 – 10.8 mg/L). Six patients had splenomegaly (1 – 6 cm), and 3 lymphadenoapthy. Six had received prior therapy (median 5, range 1 to 6 regimens). To date, 6 of 8 evaluable patients have responded (5 CR, 1PR). One patient who had failed both single agent pentostatin and single agent alemtuzumab achieved CR with the combination. Monoclonal T-cell receptor gamma chain gene rearrangements were detected by PCR in all patients and became negative in 3 of 5 evaluable responding patients. Median response duration is 5+ months (range 2 – 6+ months). Two patients proceeded to an allogeneic stem cell transplant, 2 (1 with ATL and 1 with T-LGL) have died from disease progression after a response, 2 are alive and disease-free, and 2 were refractory to therapy. Opportunistic infections have included reactivation of CMV and HSV in one patient, recurrence of pre-existing Serratia pneumonia in 1 patient and Aspergillus pneumonia in 1 patient. We conclude that the combination of alemtuzumab and pentostatin is effective in T-cell neoplasms; infections can be prevented with prophylactic antibiotic therapy and close monitoring of patients.

Long-Term Follow-Up of Patients with T-Large Granular Lymphocyte Leukemia (T-LGL); Experience in a Single Institution.

T-LGL is a clonal indolent lymphoid leukemia characterized by accumulation of large granular T-cells and cytopenias. We have identified 21 patients with T-LGL who were seen at the MD Anderson Cancer Center between 1997 and 2005. The median age at diagnosis was 53.5 years (range 34 to 72) without a male or female predilection. Fourteen patients (67%) were asymptomatic at diagnosis. Five patients (24%) presented with fatigue secondary to anemia; 1 (5%) had symptomatic splenomegaly and 1 presented with a diverticular abscess. Eighty percent of the patients presented with anemia with median hemoglobin of 9.9g/dl (range 7.4 to12.9 g/dl), 47% with neutropenia with a median absolute neutrophil count of 975/ul (range 110 to 5600/ul), and 38% had thrombocytopenia with a median platelets count of 61.5 x 109/l (range18 to 135 x 109/l). Six patients (29%) had splenomegaly, 3 (14.2%) had hepatomegaly and 1 had retroperitoneal lymph node enlargement on CT. During the course of follow-up (median 19 months, range 2–78 months), 11 patient (52%) developed constitutional symptoms. Six patients had recurrent infections including upper respiratory infections, pneumonia, and folliculitis unrelated to initiation of treatment. Associated autoimmune conditions included rheumatoid arthritis in 3 patients (14%) and hemolytic anemia in one patient. Only two patients had cytogenetic abnormalities, both including abnormalities involving chromosome 6. Monoclonal T cell receptor gamma chain gene rearrangements were detected by PCR analysis in 17 of 18 evaluable patients. Immunophenotypic studies revealed 16 patients to be CD4−/CD8+, 3 CD4−/CD8−, 1 CD4+/CD8+, and 1 CD4+/CD8−. CD56 was positive in 1 patient and none expressed CD26. Five patients (24%) have required no therapy, and remain asymptomatic with a median follow up of 67 months (range 5 to 78). Three patients received erythropoietin or G-CSF with some improvement. Nine patients (43%) were treated with cyclosporine, 2 achieving a response, 2 with stable disease, 3 with progression, and 2 were lost follow up. One of the 3 patients with disease progression had splenectomy and 1 was treated with infliximab; both responded. Combination of pentostatin and alemtuzumab was used in 2 patients with no improvement in the cytopenias; therapy was discontinued in both due to worsening of cytopenias and infections. Other treatment modalities included alemtuzumab alone in 1 patient with no improvement, fludarabine in 1 with minor response, combination of fludarabine and cyclophosphamide in 1 with minor response, methotrexate in 2 with no response and splenectomy in 3 with response and no requirements for further intervention. We conclude that T-LGL generally has an indolent course with no need for active therapy; patients with progressive cytopenias or refractory disease may benefit from splenectomy. New treatment modalities are needed.

Analysis of T-Cell Receptor Gene Rearrangement for Predicting Clinical Outcome in Patients With Cutaneous T-Cell Lymphoma

To extend previous observations regarding the prognostic value of analyzing lymph node DNA from patients with cutaneous T-cell lymphoma for the presence of a monoclonal T-cell population by Southern blot vs polymerase chain reaction (PCR) methods. Inception cohort study from 1982 to 1998. Recruitment of new patients ended in 1994. A tertiary care referral center in Seattle, Wash. Patients Fifty-five uniformly staged patients with the diagnosis of cutaneous T-cell lymphoma who underwent a lymph node biopsy, 21 with clinically abnormal nodes and 34 with normal nodes. Interventions Lymph nodes were evaluated for T-cell receptor (TCR) gamma-chain gene rearrangement by 2 PCR methods: capillary electrophoresis and denaturing gradient gel electrophoresis. The same lymph nodes were evaluated by Southern blot analysis for TCR beta-chain gene rearrangement and examined histopathologically on the basis of the National Cancer Institute lymph node classification system. Patients were observed clinically for a mean of 9.5 years. Skin stage, clinical lymph node examination, lymph node histologic examination, Southern blot analysis, and PCR analyses were evaluated as potential prognostic predictors by univariate and multivariate analyses. The statistical association of TCR analysis and clinical outcome was determined among all patients. Hazard ratios (HRs) by Cox proportional hazards regression analysis were used to estimate the risk of a poor clinical outcome. Cumulative survival rates were analyzed by the Kaplan-Meier method. A skin stage of T3 (tumors) or T4 (erythroderma) was the most powerful predictor of a poor clinical outcome (HR, 31.3 vs T1; P<.001). Patients with detectable TCR gamma-chain gene rearrangement in lymph node DNA by PCR also were more likely to have a poor outcome (HR, 5.1; P<.001), but it was a less powerful predictor than skin stage. Even when the skin stage, presence or absence of lymphadenopathy, and histologic lymph node score were known for the patient, Southern blot analysis still added to prediction of a poor outcome (HR, 9.3; P = .007), whereas PCR provided no statistically significant additional information on outcome. Detection of a monoclonal T-cell population by PCR in lymph nodes of patients with cutaneous T-cell lymphoma does not enhance prediction of clinical outcome and probability of survival beyond what can be determined from clinical examination and histologic lymph node scores. Skin stage and the presence or absence of lymphadenopathy remain the most important determinants of clinical outcome.

Proliferation rate and outcome in children with T-cell rich B-cell lymphoma: A clinicopathologic study from the NHL-BFM-study group

T-cell rich B-cell lymphoma (TCRBCL) is considered a rare variant of aggressive B-cell lymphoma characterized by few neoplastic cells and a large reactive infiltrate with striking similarities to nodular lymphocyte predominant Hodgkin's lymphoma (NLPHL). In childhood, these tumors occur even less frequently. Biopsy specimens at diagnosis from 16 children (13 boys) with a median age of 12 years (range, 7 to 18) were immunophenotyped. The proliferation rate was assessed with monoclonal antibodies against Ki-67 and repp86 antigens and additional clonality analyses were performed. Ten patients had localized disease and only two had B symptoms. All patients showed high Ki-67 expression (median: 80%, range 40% to 90%), but low repp86 expression (median: 25%, range 10% to 50%). PCR-based clonality studies of the hypervariable CDR III region of the immunoglobuline heavy chain and the T-cell receptor gamma-chain genes demonstrated predominant clones in nine and five patients, respectively. Three patients had previous or concomitant NLPHL and two of them received initial treatment for Hodgkin's disease. All patients achieved remission after a brief polychemotherapy regimen. Two patients subsequently relapsed and one was rescued by salvage therapy including autologous stem cell transplantation. At a median follow-up of 23 months, 15 patients (94%) are alive. The striking contrast between the proliferation rates determined by Ki-67 and repp86 expression points to a possible arrest in the G1 cell cycle phase because repp86 expression is restricted to the S, G2 and M cell cycle phases. This G1 arrest may explain the paradoxon of high Ki-67 expression in a paucicellular lymphoma with a favorable prognosis in young patients.

The usefulness of clonality for the detection of cases clinically and/or histopathologically not recognized as cutaneous T-cell lymphoma

The determination of clonality has proven to be a useful adjunct to the diagnosis of cutaneous lymphocytic infiltrates. It is considered particularly helpful for the distinction of mycosis fungoides (MF) and inflammatory dermatoses. To verify the sensitivity of the polymerase chain reaction (PCR)-heteroduplex analysis of T-cell receptor gamma-chain gene (TCRgamma) rearrangements in patients with MF and to establish whether a clinicopathological re-evaluation of lesions previously unclassified or considered to be non-neoplastic entities but found to be monoclonal allowed the recognition of additional cases of MF. Included in the study were 116 patients, seen at our Institute from April 2002 to September 2003 and tested for TCRgamma rearrangements. Thirty-six patients were affected by clinically and histopathologically proven MF, while the remaining 80 cases had not been classified or had been classified as non-neoplastic entities. The sensitivity of the molecular analysis was determined on the basis of the results obtained in the 36 patients with MF. The 29 cases of the second series of patients found to be monoclonal were clinically and histopathologically re-evaluated. Clonal rearrangements were found in 87.5% of patients with plaque stage MF and in 20% of those with patch stage MF. The clinicopathological re-evaluation allowed us to reclassify 15 of 29 monoclonal cases of the second series of patients as MF. The study showed that the PCR-heteroduplex technique can determine a high percentage of monoclonality only in plaque stage MF. However, in spite of the low sensitivity of the method, several cases previously unrecognized could be reclassified as MF when their clinical and histopathological features were re-evaluated taking into account the clonality of the lymphocytic infiltrate.

HHV-8-Associated T-Cell Lymphoma in a Lymph Node With Concurrent Peritoneal Effusion in an HIV-Positive Man

Primary effusion lymphoma (PEL) is an uncommon large cell lymphoma, usually seen in human immunodeficiency virus (HIV)-infected patients. PEL is characterized by various clinical, histomorphologic, and immunophenotypical features, and is associated with the human herpes virus 8 (HHV-8). PEL may present as either a body cavity-based lymphomatous effusion or a solid tumor mass. Most so-called "solid PEL" usually have an extranodal location; exceptionally rarely, they occur in lymph nodes. The majority of PEL consist of malignant cells of B-cell genotype; seldom they are of T-cell origin. We report a rare case of HHV-8-associated "solid PEL" of T-cell type in a 41-year-old HIV-seropositive man with a concomitant peritoneal effusion. The T-cell lymphoma was diagnosed on the basis of morphologic, immunophenotypic, and molecular findings of a lymph node biopsy. The tumor cells strongly expressed CD45R0, CD7, CD43, MUM1/IRF4, CD30, HHV-8, and EBER, and demonstrated a clonal rearrangement of T-cell receptor-gamma chain gene. The following case provides another example of a lymph node-based "solid" PEL, demonstrating the variety within the spectrum of HHV-8-associated lymphoma.

High-dose chemotherapy with autologous blood stem cell transplantation for aggressive subcutaneous panniculitis-like T-cell lymphoma

High-dose chemotherapy with autologous blood stem cell transplantation for aggressive subcutaneous panniculitis-like T-cell lymphoma

Composite B-Cell and T-Cell Non-Hodgkin Lymphoma of the Tibia

We report a unique case of de novo composite lymphoma in the tibia of a 35-year-old man who presented with increasingly frequent and intense pain in the right upper leg. He was otherwise healthy without significant medical history. A plain radiograph of the right leg showed a permeative lesion with alternating areas of radiolucency and radiodensity in the upper third of the tibia. Magnetic resonance imaging showed a large, heterogeneous enhancing lesion involving the medullary and cortical bone of the proximal tibia with cortical disruption and extension into the adjacent soft tissue. A biopsy showed sheets and clusters of large cells, punctuated by clusters of small, irregular lymphocytes. Flow cytometry and immunohistochemical analysis showed composite lymphoma: diffuse large B-cell lymphoma (DLBCL) and peripheral T-cell non-Hodgkin lymphoma with predominantly small cell morphologic features. The DLBCL expressed CD19, CD20, CD79a, CD5, CD10, CD23, CD38, CD117, bcl-2, and bcl-6, with monotypic expression of immunoglobulin kappa light chain. The T cells expressed CD2, CD3, CD5, CD7, and CD8, with partial loss of CD4. Clonal rearrangement of T-cell receptor gamma chain gene was found. Neither the large B cells nor the small T cells expressed Epstein-Barr virus-encoded RNA. Physical examination and radiologic studies showed no evidence of lymphadenopathy, organomegaly, or other mass lesions in the body. No peripheral lymphocytosis or bone marrow involvement was present.

Peripheral T-Cell Lymphomas Expressing CD30 and CD15

Coexpression of CD30 and CD15 is typically associated with classic Hodgkin's lymphoma (HL). Peripheral T-cell lymphomas (PTCLs) can often display histologic features that simulate classic HL. However, reports of PTCLs coexpressing both CD30 and CD15 have been infrequently described. We report 11 cases of PTCL in which at least a subset of the neoplastic cells coexpressed CD30 and CD15. The patients included 4 women and 7 men and age ranged from 43 to 83 years (median, 62 years). Nine of 10 patients had advanced stage III or IV disease at presentation. Nodal involvement predominated in 8 of 11 patients, whereas 2 patients presented primarily with skin involvement. Two distinct groups were identified based on morphologic and immunophenotypic features. The first group of 5 cases had histologic features mimicking classic HL with CD30+, CD15+ Reed-Sternberg (RS)-like cells in an inflammatory background of varied extent and composition. The background lymphoid cells showed minimal cytologic atypia. The RS-like cells were negative for CD20 and CD79a in all cases, and CD45 expression was absent in 4 of 5 cases. The RS-like cells expressed CD25 and at least one T-cell-associated marker in all cases. The background T-cell population showed convincing subset predominance in 4 of 5 cases and loss of T-cell-associated antigens in 3 of 5 cases and coexpression of CD30 and CD15 in one case. The second group of 6 cases had morphologic features more in keeping with PTCL than classic HL. The proportion of neoplastic cells coexpressing CD30 and CD15 varied. Loss of T-cell antigens was noted in all cases and CD4 predominated in 4 of 5 cases. Three of the 6 cases expressed CD45. PCR analysis revealed clonal T-cell receptor gamma (TCR-gamma) chain gene rearrangements in 9 of 11 cases, but no immunoglobulin heavy (IgH) chain gene rearrangements. In situ hybridization studies for Epstein-Barr virus were negative in all cases. In some PTCL cases, the overlap with classic HL can be striking, and combined immunophenotypic and molecular studies are often necessary to confirm the diagnosis.

Diagnostic validation of capillary electrophoresis analysis of T-cell receptor gamma-chain gene rearrangements: prediction of malignant transformation of cutaneous T-cell lymphoproliferative disorders.

T-Cell lymphoproliferative disorders of the skin constitute in themselves a unique area of diagnostic difficulty for the clinician and the pathologist. Hence, although T-cell clonality analysis by PCR and capillary electrophoresis (CE) has been used extensively in lymphoproliferative disorders in general, there are very few reports describing their application to the differential diagnosis of cutaneous T-cell lymphoma (1)(2) or to cases of cutaneous lymphoproliferative disorders with less conclusive histology, where their superior resolution properties have provided strong confirmatory evidence of evolving lymphoma development (3). We present here our validation data of the use of CE in the analysis of T-cell receptor γ-chain (TCRγ) gene rearrangements for clinical use. We also present a report of a case that was judged to be benign based on clinical and pathologic grounds but was found to have the clonal molecular fingerprint that could have predicted malignant transformation at an early stage. This predictive value, in our opinion, enhances the diagnostic value of this test in the clinical setting. Pathologists are aware that distinction between benign and malignant T-cell lymphoproliferative disease by use of morphologic criteria can often be difficult, even with the aid of immunotyping. The best marker of T-cell malignancy is T-lymphocyte monoclonality, which is rarely encountered in nonneoplastic disease. Rearrangements of TCR genes in a rapidly proliferating neoplastic lymphoid cell population derived from a single progenitor cell are identical, involving unique combinations of specific variable (V), joining (J), diversity (D), and constant (C) gene segments, and thus serve as unique clonal markers (3)(4). In contrast, nonneoplastic and reactively proliferating T-cells yield different, polyclonal TCR gene rearrangements. TCR gene rearrangements can be …

Florid CD4+, CD56+ T-Cell Infiltrate Associated with Herpes Simplex Infection Simulating Nasal NK-/T-Cell Lymphoma

We report a case of Herpes simplex virus (HSV) infection of the nasopharynx associated with a dense CD4+, CD56+ T-cell infiltrate that simulated lymphoma on clinical, histologic, and immunophenotypic grounds. Histologic examination showed a tumorlike lymphoid infiltrate with extensive necrosis. Multinucleated giant cells with “ground-glass” nuclei characteristic of HSV were observed in necrotic areas but were not prominent. Immunohistochemical studies of the lymphoid infiltrate revealed a predominance of T cells, positive for CD3, CD4, CD5, and CD56. Immunohistochemical staining with HSV antibody was focally positive in the multinucleated giant cells. Molecular studies using PCR and Southern blot were positive for HSV Type II. PCR studies for T-cell receptor gamma and immunoglobulin heavy chain gene rearrangements showed no evidence of a clonal population. In situ hybridization studies for Epstein–Barr virus (EBV) were negative. The clinical presentation of a large fungating mass, the extent of the lymphoid infiltrate, and the expression of CD56 all raised the possibility of a nasal NK/T cell lymphoma. However, the presence of HSV, lack of angioinvasion and angiodestruction, absence of EBV, and polyclonal T-cell nature of the infiltrate argued against this diagnosis. Although prior studies have not fully characterized the immunophenotypic features of the lymphocyte response to HSV in infected tissues, we postulate that the CD56+, CD4+ T-cell reaction represents a florid antiviral immune response.

Prevalence of mycosis fungoides and its association with EBV and HTLV-1 in Pakistanian patients.

Mycosis fungoides (MF) is an indolent T cell lymphoma that is distinguished from other lymphomas by its initial appearance on the skin. The histologic diagnosis of MF may be difficult because there is significant overlap in the histologic features of neoplastic T-cell infiltrates and inflammatory dermatoses. This T-cell neoplasm commonly occurs in a mixed, reactive background and can show only a subtle degree of cytologic atypia, rendering histologic diagnosis difficult. In this study MF constituted 0.86% of all non-Hodgkin s lymphoma (NHL) both T and B, as compared to the Western studies which have reported 0.5% prevalence for MF of all NHL. Polymerase chain reaction (PCR) technique was used to assess T-cell clonality in paraffin-embedded skin biopsies clinically and pathologically suspicious for early MF. Out of the 14 cases diagnosed as MF, amplifiable DNA was isolated from 6 cases, which were further studied for T-cell receptor (TcR) beta, gamma, and delta chain gene rearrangements. Clonal product was seen in 4 out of 6 cases for beta, gamma, and delta TcR chain genes. Association for Epstein Barr virus (EBV) was observed in 3 out of 6 cases (50%) of MF. Although these 3 cases were positive for EBV by PCR, but were negative by in-situ hybridization (ISH). No heterogeneity was noted in these 3 cases of MF for BamHI E, K, N, and Z regions of EBV. All six cases were negative for HTLV-1 (tax region) by PCR. It was concluded that the prevalence of MF in Pakistani population is comparable to the Western data, and that EBV association to MF cases was higher than in Western studies.

The value of molecular analysis by PCR in the diagnosis of cutaneous lymphocytic infiltrates.

The diagnosis and classification of cutaneous lymphomas remain a challenge for the clinician and dermatopathologist. This diagnostic dilemma is mainly encountered in the distinction between an early malignant lymphoma and a benign reactive lymphocytic infiltrate (pseudolymphoma). Until the beginning of the 1980s, our diagnostic tools were limited to the clinical presentation, course, and histopathology in diagnosis and classification of lymphocytic infiltrates. Advances in immunology and, in particular, in molecular genetics with the introduction of the Southern blot technique and the polymerase chain reaction (PCR) have revolutionized the diagnosis of lymphocytic infiltrates by determination of clonality. In some series, more than 90% of cutaneous T-cell lymphomas have a clonal rearrangement of the T-cell receptor gamma-chain gene, as opposed to very low percentages of rearrangement in T-cell pseudolymphomas. However, the presence of clonality does not necessarily imply malignancy. Cases of pseudolymphomas, lichen planus and pityriasis lichenoides et varioliformis acuta were reported with clonal lymphocytic proliferations. Therefore, care should be exercised in the evaluation of the results of molecular analysis, and these should always be correlated with the clinical, histological and immunophenotypic picture to arrive at the correct diagnosis. It may be expected that the molecular methods for diagnosis of lymphocytic infiltrates will be improved and refined in future, and that sensitivity and specificity will increase.

Clonal T cell receptor gamma-chain gene rearrangement by PCR-based GeneScan analysis in the skin and blood of patients with parapsoriasis and early-stage mycosis fungoides.

Cutaneous T cell lymphoma (CTCL) and reactive T cell skin diseases represent opposite ends of a spectrum of diseases ranging from overtly malignant to persistently benign. Within this spectrum, the parapsoriasis group is not clearly defined regarding malignant potential. In contrast to consistent findings in advanced-stage CTCL, clonality analysis of parapsoriasis has produced conflicting results in previous studies. As T cell receptor gamma-chain polymerase chain reaction GeneScan analysis (TCR-gamma-PCR-GSA) stands out by its sensitivity, its accuracy in size determination of PCR products, its capacity to identify false positives by repeated analysis and its easy applicability, this approach was used to analyse the clonality status of 41 patients with borderline T cell lymphoproliferative skin diseases, including parapsoriasis (n=27) and early-stage mycosis fungoides (MF) (n=14). A monoclonal T cell infiltrate was demonstrated by repeated TCR-gamma-PCR-GSA in lesional skin specimens in 19.2% of parapsoriasis patients and in 66.6% of early-stage MF cases (p=0.013). In peripheral blood, a monoclonal T cell population was found in a similar percentage of parapsoriasis and of early-stage MF patients (26.7% versus 12.5%; p=0.611). A detailed analysis of parapsoriasis subentities, namely small and large plaque parapsoriasis, and parapsoriasis lichenoides, revealed monoclonality in 2(6)/2(5), 3(14)/2(8) and 0(6)/0/(3) of the skin and peripheral blood specimens, respectively. The high detection rate of false positive cases by repeated analysis (20-37.5%) provides a corrected perspective for the high rates of dominant T cell clones found by others in the peripheral blood of such patients. From the results obtained, three major conclusions can be drawn: firstly, CTCL is clearly associated with detection of monoclonality, even in its early stages; secondly, monoclonality is not a prerequisite for potential CTCL precursor entities; and thirdly, recirculating malignant T cells identical to the skin clone are not readily detected in parapsoriasis or early-stage MF, but may rather indicate disease progression.

T Cell Receptor γ-Chain Gene Polymerase Chain Reaction to Diagnose Central Nervous System Involvement by Cutaneous T Cell Lymphoma

The authors describe a patient who was suspected of having cutaneous T cell lymphoma involvement of the brain despite repeatedly negative cerebrospinal fluid (CSF) cytology, inconclusive flow cytometry, and no discrete lesion for brain biopsy. The diagnosis was made by polymerase chain reaction (PCR) analysis that showed a monoclonal T cell receptor gamma-chain gene rearrangement in the CSF, identically sized to that present in a skin biopsy specimen. Thus, PCR could be used early and routinely to diagnose central nervous system spread of T cell lymphomas, because of its potentially superior sensitivity and specificity to CSF cytology.

Hypopigmented mycosis fungoides: frequent expression of a CD8+ T-cell phenotype.

Hypopigmented mycosis fungoides (MF) is a form of cutaneous T-cell lymphoma in which hypopigmentation occurs in the absence of classic lesions of MF. Hypopigmented MF predominantly affects people with dark complexions. The natural history of this variant of cutaneous T-cell lymphoma is similar to that of conventional MF, although the disease onset is usually in childhood or adolescence. In a retrospective study we evaluated the clinical, histopathologic, immunohistochemical, and molecular characteristics of hypopigmented MF in 15 patients. Similar to other reports, the disease onset occurred in childhood and adolescence in most of the cases. The survival rate was comparable with that of classic MF. We did not observe progression to systemic disease or lymph node involvement. Histopathologically hypopigmented lesions were indistinguishable from hyperpigmented or erythematous patches. On immunohistochemical analysis a predominantly CD8+ infiltrate was detected in the majority of cases (nine of 15 patients). To determine whether epidermotropic CD8+ T cells represent the malignant T-cell clone or whether these cells are innocent, tumor-infiltrating T lymphocytes, we performed microdissection of epidermotropic CD8+ T cells and analyzed T-cell receptor-gamma chain gene for rearrangements. The epidermotropic CD8+ T lymphocytes showed clonal T-cell receptor gene rearrangement and therefore represented the malignant T-cell clone. We conclude that hypopigmented MF tends to occur in young people and that it belongs to the group of CD8+ cutaneous T-cell lymphomas in the majority of cases.