A6--a new 45RO monoclonal antibody for immunostaining of paraffin-embedded tissues

Bilateral testicular lymphoma treated with chemotherapy and radiation without orchiectomy: complete response relapsed at 52 months in the vitreous humor

We report the first detailed case of testicular lymphoma managed with chemotherapy and radiation without orchiectomy. A 60-year-old man with Stage II extralymphatic bilateral testicular lymphoma refused orchiectomy, but underwent cyclophosphamide, doxorubicin, vincristine, and prednisone chemotherapy and radiation. He remained disease free for 52 months, when a solitary central nervous system relapse to the vitreous humor was diagnosed. The optimal therapy for testicular lymphoma is unclear but often includes orchiectomy with adjuvant chemotherapy and radiation. Stage I testicular lymphoma can be cured by surgery alone; however, the relapse rates for all stages of testicular lymphoma are high despite systemic therapy. For Stage II disease and higher, chemotherapy/radiation is recommended; orchiectomy may not be mandatory.

Pagetoid reticulosis (Woringer-Kolopp disease): an immunophenotypic, molecular, and clinicopathologic study

Pagetoid reticulosis (PR), also known as Woringer-Kolopp disease, is a form of cutaneous T-cell lymphoma that demonstrates striking epidermotropism on histologic examination. We present the histologic, immunologic, and molecular findings for seven patients who had PR. The patients ranged in age from 33 to 67 years. All patients presented with one or several thick plaques involving the distal extremities except for one patient, who presented with a tongue lesion. Immunohistochemical staining of the atypical lymphoid cells demonstrated a T-cell phenotype in all cases. In one of four frozen cases, the neoplastic cells were of T-helper cell phenotype (CD4 positive). Four of seven cases demonstrated a T-cytotoxic/suppressor cell phenotype (CD8 positive). The T-cell subset for the remaining two cases could not be determined. CD30 positivity and a high growth fraction as indicated by staining with Ki-67 were seen in three of seven and three of four cases, respectively. Genotypic analysis performed on three of our cases revealed T-cell receptor (gamma and/or beta) rearrangement, indicating a clonal proliferation. The clinical follow-up ranged from 15 months to 13 years. Four of seven patients are alive and free of disease after treatment with excision or local irradiation. One patient relapsed twice after treatment with radiation and photochemotherapy with 8-methoxypsoralen and UVA and was then lost to follow-up. The lesions of another patient resolved spontaneously but recurred at the same and in an additional site 5 years later. One patient recurred after electron beam therapy. The recurrent lesion improved with radiation therapy and local wound care but never resolved completely. The patient died of unrelated causes. Our findings suggest that PR is a distinct clinicopathologic entity, separate from unilesional mycosis fungoides, demonstrating a slow disease course. The disease is a clonal cutaneous T-cell lymphoma with relatively consistent clinical and histopathologic findings but a heterogeneous immunophenotypic profile.

Imaging of Hand-Schüller-Christian syndrome by a monoclonal antibody

PURPOSE

Multifocal eosinophilic granuloma (Hand-Schüller-Christian syndrome) consists of localized lesions of histiocytosis X originating from proliferating Langerhans' cells involving male children and young adults.

MATERIALS

The authors present the first case of multifocal eosinophilic granuloma that was imaged by Tc-99m monoclonal antibody BW250/183 recognizing NCA-95 antigen on granulocytes. A 30-year-old man had a diagnosis of histiocytosis X for 16 years.

RESULTS

All active known lesions were visualized. The previous radiotherapy fields were also accurately demonstrated as areas with no antibody accumulation. Bone marrow biopsy taken 30 hours after injection showed no infiltrations, but mild hypoplasia suggesting chronic disease was demonstrated. Retrospectively, the authors performed digital autoradiography from tissue samples and found specific targeting with the same BW250/183 antibody.

CONCLUSION

Their results indicate that antibody targeting is possible in multifocal eosinophilic granuloma, probably even allowing radioimmunotherapy.

Identification of amino acids at the junction of exons 3 and 7 that are used for the generation of glycosylation-related human CD45RO and CD45RO-like antigen specificities

The CD45 transmembrane protein tyrosine phosphatase plays an essential role in lymphocyte activation. In humans, CD45 is composed of five isoforms that are generated by alternative splicing of three exons of a common precursor mRNA. Expression of the smallest molecular mass 180-kD CD45 isoform (CD45-O) results from splicing out of exons 4(A), 5(B), and 6(C), which encode peptide regions near the NH2 terminus, and is regulated during T cell maturation and activation. Two monoclonal antibodies (mAb), UCHL1 (anti-CD45RO) and A6 (anti-CD45RO-like), were studied that selectively bind to murine transfectant cells expressing the human CD45-O isoform. The anti-CD45RO-like A6 mAb, but not the anti-CD45RO UCHL1 mAb, also weakly reacted with transfectant cells expressing the human CD45 isoforms that contained exons 4 and 5(AB), or exon 5(B) encoded sequences. The structural basis of the antigen specificities of these two different human anti-CD45RO mAbs was investigated at the molecular level by using potential glycosylation-defective CD45-O isoform variants containing amino acid substitutions at the junction of exons 3 and 7. Replacement of the threonine residue at position 8 (last amino acid encoded in exon 3 and a putative O-linked carbohydrate anchorage site) by an alanine, completely abrogated the reactivity of the UCHL1 mAb, but did not affect that of the A6 mAb. Conversely, replacement of either the asparagine at position 174 or the serine at position 176 (the first two putative carbohydrate anchorage sites in exon 7) by alanine, abrogated the reactivity of the A6 mAb, but not that of the UCHL1 mAb. Both the UCHL1 and A6 epitopes were dependent on the presence of O-linked carbohydrates; and the UCHL1, but not the A6 epitope, was dependent on the presence of sialic acid. These results demonstrate a pivotal role for the amino acids encoded at the junction of exons 3 and 7 for the generation of glycosylation-related CD45RO epitopes that are expressed in a cell lineage- and activation-regulated fashion.

Epstein-Barr virus-infected T lymphocytes in Epstein-Barr virus-associated hemophagocytic syndrome

The clonal composition of EBV-infected cells was examined in three cases of EBV-associated hemophagocytic syndrome by analysis of the heterogeneity of terminal repetitive sequences in the EBV genome, indicating monoclonal expansion of EBV-infected cells in all cases. Involvement of T lymphoid cells was determined by in situ hybridization using 35S-labeled RNA probes specific for the small EBV-encoded nuclear RNAs, EBER1 and EBER2, in combination with immunostaining for the TCR-beta chain, CD45RO, CD20, CD30 and CD68 antigens in these three cases. The majority of lymphoid cells showing EBER transcripts were stained by antibodies against CD45RO and T cell receptor-beta. In contrast, EBER-specific signals were not detectable on B cells or hemophagocytic cells. These data support the concept that EBV-associated T cell proliferation is a primary feature of EBV-AHS.

Immunohistochemical examination of lichen nitidus suggests that it is not a localized papular variant of lichen planus

BACKGROUND

Lichen nitidus is believed, by some, to be a variant of lichen planus, and by others to be a distinct entity.

OBJECTIVE

We examined five cases of lichen nitidus with immunohistochemical reagents designed to characterize the dermal inflammatory infiltrate in an attempt to resolve the uncertainty.

METHODS

We stained formalin-fixed, paraffin-embedded tissue sections with the following antibodies: L26, A6, KP1, BerH2, OPD4, and HECA-452.

RESULTS

The inflammatory infiltrate was 90% A6+, with few L26+ cells. In contrast to lichen planus, KP1+ macrophages were seen and fewer of the lymphocytes demonstrated HECA-452. Fifty percent to 80% of lymphocytes were OPD4 positive, similar to that usually seen in lichen planus. Rare Ki-1+ cells were seen in one case.

CONCLUSION

We believe that the pattern of a mixed cellular infiltrate characterized by macrophages and a helper T cell response with few HECA-452+ cells is somewhat different from the pattern seen in lichen planus, wherein almost all of the cells are CD4+/HECA-452+ lymphocytes. This suggests a different immunologic pathogenesis.

Incidence and histological features of bone marrow involvement in malignant lymphomas

Bone marrow biopsy (BMB) is a routine investigation in the diagnosis and staging of Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL), and there is evidence supporting its prognostic importance in some histological varieties. The histological characteristics of BMB in 433 NHL and 155 HD patients were reviewed for clinicopathological correlations; 36 of these cases were also studied by means of immunohistochemistry. BM infiltrates were discovered in 171 NHL patients. In 36 cases, the diagnosis of NHL was directly established by BMB; a discordance between lymph node and BM histology was observed in 38 of the other 135 cases. BM-positive centroblastic and immunoblastic NHL were significantly associated with larger infiltrates, BM fibrosis, and megakaryocytic hyperplasia. Leukemization at diagnosis was more frequent in low-malignancy NHL. No correlation was found between histology and prognosis, although immunohistochemistry revealed a B-cell phenotype in all but two cases. BMB was positive in 18 of the 155 HD patients and directly diagnostic in two; Reed-Sternberg and Hodgkin cells were CD-30 positive and surrounded by T-cell infiltration. The concordance between BM and lymph node histology was fairly satisfactory, although the relationships between BM infiltration and other histological parameters may reflect peculiar interactions with BM microenvironmental factors. The usefulness of BMB in the diagnosis of malignant lymphomas has been demonstrated, and further progress can be expected from the availability of reliable immunohistochemical markers of clonality reacting on paraffin-embedded BM sections.

Nodular sclerosing Hodgkin's disease and large cell lymphoma. Immunophenotypic characterization of a composite case

Composite lymphomas have rarely been reported in Hodgkin's disease (HD), except in the lymphocyte predominance sub-type, and immunohistochemical investigations have been performed in only few cases. We describe the histological and immunophenotypical findings in a case of composite nodular sclerosing HD and high-grade, large cell non-Hodgkin's lymphoma (NHL). In our case HD and NHL cells displayed striking morphological and immunophenotypical divergence, suggesting a lack of correlation between the two neoplasms.