An assessment of the usefulness of immunohistochemical stains in the diagnosis of hairy cell leukemia

Annexin-1 and T-bet are recently described immunohistochemical stains that reportedly assist in the diagnosis of hairy cell leukemia (HCL). Our objective was to assess the sensitivity and specificity of a panel of immunohistochemical stains in distinguishing HCL from other B-cell neoplasms, particularly splenic and extranodal marginal zone lymphomas (SMZL and ENMZL, respectively). The study included 234 bone marrow biopsy specimens: 101 HCL, 13 SMZL, and 10 ENMZL cases were assessed with CD20, tartrate-resistant acid phosphatase (TRAP), DBA.44, a-1, T-bet, and cyclin D1, and 110 control cases were assessed with annexin-1 and T-bet. Our study showed that annexin-1 is a specific and sensitive marker for HCL; however, interpretation is limited by positivity within myeloid precursors. T-bet, DBA.44, and TRAP immunohistochemical stains lack sufficient sensitivity and specificity to differentiate HCL from either form of marginal zone lymphoma. However, our data suggest that the addition cyclin D1 to the immunostaining panel will increase the sensitivity and specificity of HCL diagnosis.     

Reaction patterns of TRAP and DBA.44 in hairy cell leukemia, hairy cell variant, and nodal and extranodal marginal zone B-cell lymphomas.

CONTEXT: The differential diagnosis of hairy cell leukemia (HCL) includes HC variant (HC-V) and marginal zone lymphoma (MZL). There is a high sensitivity of combined DBA.44/TRAP-positivity (+) in confirming HCL. A previous study of mucosa-associated lymphoid tissue lymphoma showed DBA.44+ in 10%, TRAP+ in 29%, and DBA.44+/TRAP+ in 5%. OBJECTIVE: We now study nodal MZL (NMZL) and HC-V. DESIGN: Two HCL, 2 HC-V, 3 MZL of bone marrow (BM), 2 MZL versus B-cell lymphoma, not otherwise specified (BCL, NOS) of BM, and 4 NMZL and 5 extranodal MZL (EMZL) were stained with DBA.44 and TRAP and reviewed for staining pattern/intensity. RESULTS: DBA.44 intensely stained all cells in 2/2 HCL, 1/2 HC-V, and 1 EMZL; intensely stained >20% of neoplastic cells (NCs) in 7 MZLs (1 BM, 3 NMZL, and 3 EMZL); and was negative/stained <10% of NCs in 1/2 HC-V, the remaining MZLs (2 BM, 1 NMZL, and 1 EMZL), and 2/2 MZL versus BCL, NOS-BM. TRAP intensely stained all cells in 2/2 HCL, the DBA.44+ HC-V, and 1 MZL versus BCL, NOS-BM; intensely stained >20% of NCs in 1 MZL versus BCL, NOS-BM, 1 MZL-BM, and 1 EMZL; and was negative in the remainder (1 HC-V, 2 MZL-BM, 1 MZL vs. BCL, NOS-BM, the 4 NMZL, 3 EMZL) in which it was able to be performed. There was combined DBA.44+/TRAP+ in 2/2 HCL, 1/2 HCV, 1/3 MZL-BM, and 1/5 EMZL. Only 1 case (MZL vs. BCL, NOS-BM) was TRAP+/DBA.44-. CONCLUSIONS: Although combined intense, diffuse TRAP+/DBA.44+ is highly sensitive for HCL, it is not entirely specific, and may be observed in HC-V and EMZL, further supporting a histogenetic relationship between these entities.     

Hairy cell leukemia and variant in Taiwan: report of a variant case and literature review

Hairy cell leukemia (HCL) is characterized by leukemic cells with abundant "hairy" cytoplasm, strong cytoplasmic positivity for tartrate-resistant acid phosphatase (TRAP), characteristic immunophenotype and sensitivity to treatment with purine nucleoside analogs. HCL-variant (HCL-v) encompasses chronic B-cell leukemias resembling classical HCL but exhibiting variant cytomorphology, variant immunophenotype and resistance to conventional HCL therapy. We present the case of a 67-year-old Taiwanese male with HCL-v who had leukocytosis and splenomegaly. His hairy leukemic cells were weakly positive for TRAP and expressed CDllc and CD103 but not CD25. He received oral chemotherapy with chlorambucil and in complete hematological remission in 9 months but relapsed 2 months later. Literature review revealed 9 cases of HCL and 3 cases of HCL-v including current case from Taiwan. All patients were adults with splenomegaly. The HCL patients had a significantly higher frequency of leukopenia (p = 0.024) and monocytopenia (p = 0.008) and a lower frequency of leukocytosis (p = 0.018) than HCL-v patients. All 8 HCL patients responded favorably to 2-chlorodeoxyadenosine with or without splenectomy. The 3 HCL-v patients had leukocytosis and received chemotherapy with variable outcome. HCL and HCL-v are rare in Taiwan and their pathological and immunophenotypical features were not fully characterized. A multimodality approach incorporating hematological findings, cytomorphology, histopathology, cytochemistry, complete immunophenotyping and clinical features is needed to identify and characterize such cases in Taiwan.     

Immunohistochemical analysis using a BRAF V600E mutation specific antibody is highly sensitive and specific for the diagnosis of hairy cell leukemia

Hairy cell leukemia (HCL) is usually diagnosed by morphology and flow cytometry studies. However, it is challenging sometimes to distinguish HCL from its mimics. Recently, the BRAF V600E mutation has been described as a disease-defining molecular marker for HCL which is present in nearly all cases of HCL but virtually absent in mimics of HCL. In this study, we investigated the possibility of using immunohistochemical detection of the BRAF V600E mutant protein to differentiate HCL from its mimics. A total of twenty-eight FFPE tissue specimens were studied, including HCL (n=12), HCL variant (HCL-v, n=3), splenic marginal zone lymphoma (SMZL, n=6), and other marginal zone lymphomas (MZL, n=7). Immunohistochemical studies were performed using a mouse monoclonal antibody (clone VE1, Spring Bioscience, CA) specific for BRAF V600E mutation. Molecularly confirmed BRAF V600E mutation positive and negative cases were used as the positive and negative controls respectively. All 12 cases of HCL showed cytoplasmic BRAF V600E protein expression in leukemia cells by immunohistochemical study regardless of tumor burden, whereas all cases of HCL mimics including HCL-v, SMZL, and MZL were negative for BRAF V600E protein. Using this BRAF V600E mutation specific antibody, this immunohistochemical study has 100% sensitivity and 100% specificity for the diagnosis of HCL in our cohort. In conclusion, immunohistochemical detection of the BRAF V600E mutant protein is highly sensitive and specific for the diagnosis of HCL. Compared to PCR or sequencing-based methodologies, immunohistochemistry is a relatively rapid and inexpensive alternative for the differential diagnosis between HCL and its mimics.     

Impact of p53 and Ki-67 in predicting recurrence and progression of superficial (pTa and pT1) urothelial cell carcinomas of urinary bladder

In predicting the aggressive behavior of bladder tumors, the histopathological characteristics of grade and invasive stage are of principal importance. However, for predicting tumor recurrence and progression, these are sufficient only to a limited extent, particularly in the case of superficial (pTa and pT1) urothelial cell carcinomas. New prognostic factors are therefore needed to avoid either insufficient or excessive treatment. In this retrospective study, we investigated the prognostic value of the p53 and Ki-67 immunoreactivity indices. The present study included 118 superficial urinary bladder tumors consisting of 58 recurrent and 60 non-recurrent cases. Twenty of the recurrent tumors progressed into a higher grade and/or invasive stage. Paraffin immunohistochemical analysis was carried out using anti-p53 and anti-Ki-67 antibodies on the initial tumor tissues. We concluded that there is a highly significant relationship between the p53 and Ki-67 immunoreactivities and the histological grade and pathological stage of the tumors (P < 0.0001). We observed a significant relationship between the presence of recurrence and progression and the p53 immunoreactivity index (P < 0.01 and P = 0.017, respectively) and Ki-67 immunoreactivity index (P < 0.0001 and P = 0.046, respectively). Positivity for p53 and Ki-67 can demonstrate the risk of recurrence (p53: sensitivity = 76%, specificity = 58%; Ki-67: sensitivity = 86%, specificity = 48%) and progression (p53: sensitivity = 80%, specificity = 46%; Ki-67: sensitivity = 85%, specificity = 36%; ). We believe that both of these immunohistochemical markers can be considered valuable in addition to classical histopathological prognostic parameters for predicting recurrence and progression risks.     

Tartrate-resistant acid phosphatase as a marker of bone metastases in patients with breast cancer and prostate cancer

Serum activity of tartrate-resistant acid phosphatase 5b (TRAP 5b) in patients with breast cancer and prostate cancer having bone metastases was much higher than in healthy donors and patients without skeletal injuries. TRAP 5b activity in patients with breast cancer and multiple bone metastases surpassed that in patients with single bone metastases. The mean activity of TRAP 5b and range of enzyme activity in women treated with bisphosphonates were significantly lower than in patients not receiving antiresorptive therapy. Diagnostic sensitivity and specificity of TRAP 5b as a marker of skeletal metastases in patients with breast cancer were 82 and 87%, respectively. In patients with prostate cancer these indexes were 71 and 83.4%, respectively. Detection of this marker in tumor patients holds much promise for early diagnostics of bone metastases, estimation of the severity of skeletal metastases, and monitoring of the efficiency of bisphosphonate therapy.     

Pitfalls in TRAP assay in routine detection of malignancy in effusions

Telomerase has been found to be reactivated in a majority of cancers but is inactive in most somatic cells. Our principal goal was to determine the potential use of the telomeric repeat amplification protocol (TRAP) assay as marker for malignancy in cytological effusions. The simple selection criterion was the cytological diagnosis, and routine samples were classified into malignant (58 samples) and nonmalignant (233 samples). Of the malignant samples, 44/58 (76%) were positive by TRAP assay. Of the 14 telomerase-negative cytology-positive samples, RNA integrity was poor in 9, indicating suboptimal sample conservation for molecular analysis. In 3 of the remaining 5 samples with a negative TRAP assay, a high number of malignant cells was observed, and these cells might have been telomerase-negative. Thus, the sensitivity of TRAP assay for the presence of malignant cells was about 76%. In the cytologically nonmalignant effusions, the presence of telomerase activity was observed in 24% (55/233). Of these, 6% were highly suspicious for malignancy, 9% were doubtful, and 9% were cytologically nonmalignant effusions confirmed by a follow-up of 12 mo or more. According to these data, the specificity of the TRAP assay to detect tumor cells in effusions ranged only between 82-91%. Our results indicate that, although the TRAP assay is positive in 6-15% of putative malignant effusions, the relatively high number of TRAP false-negative and false-positive cases renders this test unsuitable for routine diagnostic purposes.     

Rapid detection and quantitation of BRAF mutations in hairy cell leukemia using a sensitive pyrosequencing assay

BRAF protooncogene is an important mediator of cell proliferation and survival signals. BRAF p.V600E mutation was recently described as a molecular marker of hairy cell leukemia (HCL). We developed and validated a pyrosequencing-based approach that covers BRAF mutational hotspots in exons 11 (codon 468) and 15 (codons 595 to 600). The assay detects BRAF mutations at an analytical sensitivity of 5%. We screened 16 unenriched archived bone marrow aspirate samples from patients with a diagnosis of HCL (n = 12) and hairy cell leukemia-variant (HCL-v) (n = 4) using pyrosequencing. BRAF p.V600E mutation was present in all HCL cases and absent in all HCL-v. Our data support the recent finding that BRAF p.V600E mutation is universally present in HCL. Moreover, our pyrosequencing-based assay provides a convenient, rapid, sensitive, and quantitative tool for the detection of BRAF p.V600E mutations in HCL for clinical diagnostic testing.     

Quantitative detection of telomerase activity by real-time TRAP assay in the body fluids of cancer patients

Real-time TRAP assay was developed to improve the sensitivity and quantitative detection of telomerase activity in the body fluids of cancer patients. The sensitivity and clinical significance of the real-time TRAP assay was investigated. Real-time PCR protocol was modified by using ACX primer and SYBR green mixture from the process of TS primer extension. Real-time TRAP showed high correlation (r2=0.843, p=0.001) and sensitivity (25 times higher) compared to conventional TRAP. Of 164 samples, there were 8 positives in cytology (4.9%), 7 (4.3%) using the conventional TRAP, and 41 (25%) using real-time TRAP. In cytology positive samples, real-time TRAP showed a higher positivity than conventional TRAP (75% vs 63%) suggesting a higher sensitivity in the body fluids. There was a tendency towards a longer progression-free duration in telomerase negative patients than in positive patients, as determined by conventional and real-time TRAP. The diagnostic interval between the first positivity documentation and clinical progression was short in the order of real-time TRAP, conventional TRAP and cytology. In conclusion, real-time TRAP assay can detect telomerase activity at an earlier phase of cancer progression and can replace conventional TRAP assay for detecting the telomerase activity in body fluids.     

Minimal residual disease detection in hairy cell leukemia. Comparison of flow cytometric immunophenotyping with clonal analysis using consensus primer polymerase chain reaction for the heavy chain gene

We studied 86 specimens from 24 patients with hairy cell leukemia (HCL) to determine the sensitivity of routine flow cytometry (FC) and consensus primer PCR (cpPCR) in this disease. FC was more sensitive, detecting HCL in 48 (56%) of 86 specimens, while clonal B-cell populations were detected by cpPCR in only 23 (27%) of 86 specimens. FC and cpPCR were both more sensitive than morphologic examination. A positive cpPCR result is associated with higher tumor cell numbers than a negative cpPCR result, as determined by FC (P = .0017). We determined cutoff values for number of tumor cells at which cpPCR is consistently positive. At 6.8 tumor cells per microliter, cpPCR would be expected to be positive in at least 90% of the samples. FC was adequate in 86 cases (100%), while cpPCR was adequate in 74 cases (86%). FC is superior to cpPCR for detecting minimal residual HCL. It is more sensitive and more specific and permits quantitation of tumor cell number.     

Utility of CD10 and RCCma in the diagnosis of metastatic conventional renal-cell adenocarcinoma by fine-needle aspiration biopsy

The cytologic diagnosis of primary conventional renal-cell adenocarcinoma (cRCC) is usually straightforward; however, metastatic cRCC must be distinguished from a variety of neoplasms with clear-cell features. CD10, a cell membrane-associated neutral endopeptidase, and renal-cell carcinoma marker (RCCma), an antibody against human proximal tubular brush border antigen, have recently been shown to be useful in the diagnosis of cRCC. We compared CD10 and RCCma in cell block material from fine-needle aspiration biopsies (FNABs) to assess their utility in the diagnosis of metastatic cRCC, in cytologic specimens. Seven primary and sixteen metastatic cRCCs were immunostained with CD10 and RCCma. The immunoreactivity results were compared with those of a variety of neoplasms originating from other sites such as the liver, lungs, breast, and the gastrointestinal tract. The sensitivity and specificity of CD10 for cRCC were 100% and 59%, respectively. The sensitivity and specificity of RCCma for cRCC were 35% and 100%, respectively. We conclude that CD10 has limited value in confirming the diagnosis of cRCC because of its low specificity. RCCma, when positive, is highly specific for cRCC, but its low sensitivity hinders its diagnostic usefulness.     

Tartrate-resistant acid phosphatase as a marker of bone metastases in patients with breast cancer and prostate cancer

Serum activity of tartrate-resistant acid phosphatase 5b (TRAP 5b) in patients with breast cancer and prostate cancer having bone metastases was much higher than in healthy donors and patients without skeletal injuries. TRAP 5b activity in patients with breast cancer and multiple bone metastases surpassed that in patients with single bone metastases. The mean activity of TRAP 5b and range of enzyme activity in women treated with bisphosphonates were significantly lower than in patients not receiving antiresorptive therapy. Diagnostic sensitivity and specificity of TRAP 5b as a marker of skeletal metastases in patients with breast cancer were 82 and 87%, respectively. In patients with prostate cancer these indexes were 71 and 83.4%, respectively. Detection of this marker in tumor patients holds much promise for early diagnostics of bone metastases, estimation of the severity of skeletal metastases, and monitoring of the efficiency of bisphosphonate therapy. Translated fromByulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 138, No. 7, pp. 91–93, July, 2004     

Clinical usefulness of immunohistochemistry for plakoglobin,N-cadherin,and connexin-43 in the diagnosis of arrhythmogenic right ventricular cardiomyopathy

Diagnosing arrhythmogenic right ventricular cardiomyopathy (ARVC) is often challenging because no single diagnostic tool is available to detect the disease. We evaluated whether analysis of plakoglobin, N-cadherin, and connexin-43 immunoreactivity can be used as a significant test in diagnosis of ARVC. We selected subjects with suspicion of ARVC (n=22) in patients who underwent endomyocardial biopsy (EMB) in Kyungpook National University Hospital (n=1326). The patients (n=22) were classified into definite ARVC patients (n=17) and borderline ARVC (n=5). We selected control subjects (n=20) who were autopsied and died of non-cardiac disease. Hematoxylin-eosin, Masson’s trichrome, and immunohistochemical stains for plakoglobin, N-cadherin, and connexin-43 were used for all specimens. Reduced immunoreactivity of plakoglobin was observed in 13 (76%) of the 17 patients with a definite ARVC and in 4 (80%) of the 5 patients with a borderline ARVC. All subjects displayed no significant reduction of the immunoreactivity for connexin-43 as well as for N-cadherin. Our investigation revealed that the immunohistochemical analysis for plakoglobin had an accuracy of 81%, 76% sensitivity, and 84% specificity in diagnosis of ARVC. Results of our study showed that the immunohistochemical analysis of plakoglobin had a relatively high sensitivity and specificity in ARVC, but immunohistochemistry for plakoglobin alone could not be relied upon as a diagnostic test for ARVC. We confirmed that N-cadherin and connexin-43 had no diagnostic value in ARVC.     

Bone marrow changes in patients with hairy cell leukemia treated by recombinant alpha2-interferon

Bone marrow specimens from 21 patients with hairy cell leukemia (HCL) who were entered into a program to study the efficacy of treatment with recombinant alpha 2-interferon were evaluated. Patients were treated with the interferon, 2 X 10(6) U/m2 subcutaneously three times weekly, and were scheduled to undergo bone marrow aspiration and biopsy at study entry and after three (21 patients) and six (16 patients) months of treatment. Bone marrow samples after three months of treatment showed an overall decline in cellularity, from an average of 77 +/- 20 to 57 +/- 22 per cent, with a marked decrease in the percentage of neoplastic mass (from 87 +/- 9 to 59 +/- 24 per cent). The bone marrow changes were associated with significant improvement in hematologic values, including hemoglobin levels and granulocyte and platelet counts. The bone marrow changes and improved hematologic values remained stable with continuation of interferon therapy. However complete bone marrow remission did not occur in any of the patients after three or six months of interferon therapy. The HCL cell mass in more than 60 per cent of the patients remained at or above 50 per cent of the marrow cellularity and dropped to less than 25 per cent in 14 per cent of the patients. In all of the patients increased amounts of reticulin fibers were identified in the bone marrow prior to therapy, and 89 per cent of bone marrow aspirations failed (dry tap). The amounts of reticulin fibers remained increased in most of the patients (91 per cent), with a high incidence of dry taps (73 per cent), after therapy. Interferon therapy also changed the tartrate-resistant acid phosphatase(TRAP)-positive HCL cells to TRAP-negative, suggesting inhibition of activity and/or production of TRAP in HCL cells.     

Atypical cells in effusions: Diagnostic value of cell image analysis combined with immunocytochemistry

The reliable identification of tumor cells in populations of atypical cells occurring in body cavity effusions is a well-known diagnostic problem. In order to improve tumor cell detection and to predict disease progression, we developed a cell scoring strategy based on a combination of DNA cytophotometry and immunocytochemistry. For this purpose, morphologically atypical cells obtained from 33 effusion samples were submitted to DNA content analysis and tested for Ber-EP4 immunoreactivity. It turned out that elevated DNA content alone has a low specificity (true negative ratio) and sensitivity (true positive ratio) in predicting disease outcome, whereas Ber-EP4 immunoreactivity alone has a high specificity (100%) but a low sensitivity (56%). In contrast, the use of a scoring system combining the two techniques and relating scores to the previous disease state and the cytomorphology of the atypical cells results in highly specific and sensitive prediction of the disease outcome. We therefore suggest that this approach is a valuable tool for reliably identifying tumor cells in effusions containing populations of cytologically suspect cells. Diagn Cytopathol 1996;15: 263–269. © 1996 Wiley-Liss, Inc.     

毛细胞白血病脾脏的临床病理学研究

目的 探讨毛细胞白血病(HCL)脾脏的临床病理学特征、诊断与鉴别诊断及脾切除预后.方法 回顾性分析15例HCL脾切除患者的临床资料,脾脏常规石蜡切片,HE及免疫组织化学染色(EliVision二步法)后光镜观察,并进行随访.结果 (1)15例患者,男11例,女4例,男:女为2.75:1,中位年龄47(36～68)岁.均以脾大为主要临床表现,B症状(发热、盗汗、体重减轻)不明显.多伴血红蛋白降低(80.0%)、血小板降低(60.0%)和白细胞升高(53.3%),少数全血细胞减少(20.0%).(2)特殊检查:外周血和骨髓毛细胞比例为(14.6±7.2)%和(47.3±23.8)%;骨髓细胞耐酒石酸酸性磷酸酶(TRAP)阳性率62.5%,咐醇酯(TPA)诱导附壁试验阳性率85.7%,毛细胞透射电镜核糖体板层复合体(RLC)检出率25%;骨髓活检HCL累及率100%.(3)15例患者脾脏重量(3012±1974)g,镜下白血病细胞呈弥漫性增生,淋巴滤泡完全消失或严重萎缩(14/15),红髓窦-索结构不清.3例可见"血湖"形成,白血病细胞胞质丰富淡染,免疫组织化学示CD45RA、CD20和PAX-5、CD25、CD11c、Annexin A1、cyclinD1阳性,CD3、CD43阴性.(4)随访13例目前均存活.随访时间5年以上的9例,10年以上的7例.结论 该病以中老年缓慢起病,脾大为首发症状,结合脾脏组织形态、免疫组织化学及相关检杳确诊.脾切除后可长期缓解.     

Purification and seroreactivity of pneumococcal surface adhesin A (PsaA).

Pneumococcal surface adhesin A (PsaA) is a 37-kDa common protein antigen of Streptococcus pneumoniae. In the present study, the protein was purified so that its immunoreactivity could be determined. PsaA was released and purified from cells by lysis in the presence of n-laurylsarcosine; this was followed by ammonium sulfate precipitation and subsequent preparative isoelectric focusing. A capture antibody enzyme-linked immunosorbent assay was used to determine the immunoreactivity of purified PsaA. The assay had a 67% sensitivity for sera from patients with bacteremic pneumococcal pneumonia. A specificity of 97% was estimated on the basis of a lack of reactivity with sera from patients with pneumonia caused by other organisms. PsaA is a potential vaccine candidate and may be useful as an antigen in a diagnostic assay for pneumococcal disease.     

血清标本中HBsAg免疫复合物对检测HBsAg的影响

０．５ｍｏｌ／Ｌ ＨＣｌ处理１ｈ后解离ＨＢｓＡｇ－抗ＨＢｓ免疫复合物，并变性抗ＨＢｓＡｇ抗体而对ＨＢｓＡｇ免疫反应性无影响，３４例临床抗ＨＢｓ＾＋血清样品经ＨＣｌ处理前后，常规ＥＬＩＳＡ检测ＨＢｓＡｇ比较，结果；酸处理前ＨＢｓＡｇ阳性率为１１．７６％，处理后增加至４１．１８％，实验表明血清样品经酸处理后能明显提高临床乙肝ＨＢｓＡｇ检出率。     

Reactivity and assay restriction profiles of monoclonal and polyclonal antibodies to acid phosphatases: a preliminary study

The development of secure diagnostic immunoassays requires, among others, rigorous characterisation of potential antibody reagents. The reactivity profiles of seven antibodies (six monoclonal [MAb] and one polyclonal [PAb]) with putative specificity for tartrate-resistant acid phosphatase (TRAP) and/or osteoclasts were evaluated in enzyme-linked immunosorbent assay (ELISA) and/or immunocytochemistry. MAbs 2H1, 4E6 and 5C1 demonstrated assay restriction: exhibiting reactivity only in ELISA. The remaining three MAbs (G211D, G312G and V35B) and the PAb 8023 recognised recombinant TRAP (rTRAP) in ELISA and native acid phosphatases in selected tissues and cell lines. The latter were cytochemically assessed for both tartrate-sensitive acid phosphatase (TSAP) and TRAP. V35B showed reactivity against the monocytic leukaemia cell line U937 and guinea pig kidney tissue (both TSAP+ and TRAP+) and ECV304 (TSAP+) cells. Interestingly, the reactivity of MAb G211D co-localised with TRAP activity in the membrane of osteoclasts but also detected cytoplasmic components in U937 cells and human embryonic lung fibroblasts (TRAP+ and TRAP+). G211D exhibited immunoreactivity against placental trophoblasts (positive for total AP). Intriguingly, MAbs 2H1, 4E6, 5C1 and PAb 8023 cross-reacted with potato acid phosphatase in ELISA, suggesting reactivity to conformationally similar epitopes. Thus, some of these reagents could be used in the development of standardised diagnostic immunoassays or as drug-targeting agents for conditions in which the pathological process involves bone resorption, the MAbs G211D, 2H1, 4E6, 5C1 and PAb 8023 being useful in ELISA but not immunocytochemical detection of TRAP.     

The identification of ganglion cells in Hirschsprung disease by the immunohistochemical detection of ret oncoprotein

The absence of ganglion cells (GCs) is the primary anatomic abnormality in Hirschsprung disease. Light microscopy is the mainstay in establishing this diagnosis. However, establishing a condition of aganglionosis may be challenging on routine H&E-stained sections of colonic biopsies and resections. We studied the identification of GCs by retinoblastoma oncoprotein (ret) immunoreactivity and routine H&E light microscopy by evaluating 53 blocks from 34 patients demonstrating GCs on original H&E-stained sections and 55 blocks from 38 patients lacking GCs on original H&E-stained sections. All blocks demonstrating GCs on H&E-stained sections also were positive for GCs on ret staining (100%). In 3 blocks that were negative for GCs by H&E staining (5%), GCs were shown on ret-stained sections. Immunoreactivity for ret has comparable specificity but slightly higher sensitivity to routine light microscopic evaluation in identifying GCs. GCs are identified more readily by ret immunoreactivity than by routine morphologic examination.