Glycol methacrylate (GMA) embedding for light microscopy. II. Immunohistochemical analysis of semithin sections of undecalcified marrow cores

The Demonstration of Immunohistochemical Biomarkers in Methyl Methacrylate-Embedded Plucked Human Hair Follicles

Plucked human hair follicles have been proposed as a potential surrogate for tumour tissue for measuring the effect of drugs on pharmacodynamic biomarkers in drug intervention studies. We describe a new technique of embedding plucked hair follicles in the acrylic resin, methyl methacrylate, and the immunohistochemical demonstration of six potential biomarkers (Ki67, EGFR, phospho-p27, phospho-histone H3, phospho-MAPK and phospho-Rb) in de-plasticised sections. The advantages of this technique over those that have been used in support of clinical drug trials, such as skin and tumour biopsies, whole blood and whole hair samples is discussed.

A simple method for the immunocytochemical detection of proteins inside nuclear structures that are inaccessible to specific antibodies

It has been demonstrated elsewhere that a high concentration of an antigen within the nucleolus may prevent its proper recognition by specific antibodies. In this study, the authors found that a short proteinase treatment allowed for the detection of antigens in the nucleoli. The described approach is compatible with the simultaneous observation of proteins fused to fluorescent tags and with preembedding electron microscopy. It appears that the described method can be useful in situations when the proper recognition of antigens by specific antibodies is disturbed by a high density of cellular structures or a high concentration of antigens inside these structures.

Use of methyl methacrylate resin for embedding bone marrow trephine biopsy specimens

AIMS

To evaluate the use of methyl methacrylate resin as an embedding medium for undecalcified bone marrow trephine biopsy specimens.

METHODS

About 2500 undecalcified bone marrow trephine biopsy specimens were processed, and embedded in methyl methacrylate resin. Semithin sections (2-3 microns) were stained by routine tinctorial and immunocytochemical staining methods with a wide range of antibodies using a standard streptavidin biotin horseradish peroxidase technique. Different antigen retrieval pretreatments were evaluated.

RESULTS

Bone marrow trephine biopsy specimens are embedded routinely in methyl methacrylate at the Haematological Malignancy Diagnostic Service at The Leeds General Infirmary. Over 50 different primary antibodies are in current use; for the majority of these, microwave antigen retrieval or trypsin digestion, or both, is either essential or greatly enhances the results.

CONCLUSIONS

Embedding bone marrow trephine biopsy specimens in methyl methacrylate resin retains morphology and permits reliable, high quality immunocytochemistry. This is particularly desirable for the demonstration of neoplastic cells in regenerative marrow after chemotherapy, and in the detection of residual disease after treatment. The use of methyl methacrylate for routine use on bone marrow trephine biopsy specimens is advocated.

Immunohistochemical staining of plastic embedded bone marrow trephine biopsy specimens after microwave heating

AIMS

To investigate (1) whether adequate immunohistochemical staining can be achieved on sections cut from plastic embedded bone marrow trephine biopsy specimens after microwave heating in citrate buffer; and (2) whether this immunohistochemical staining is comparable with that achieved on routine sections cut from paraffin wax embedded trephine biopsy specimens after decalcification procedures.

METHODS

Sixty five consecutive bone marrow trephine biopsy specimens of more than 1 cm in length were divided transversely into two equal parts. One part was processed in paraffin wax followed by decalcification. The other part was embedded in the epoxyresin Polarbed 812 followed by the cutting of 1 micron sections. Both parts underwent immunohistochemical staining by an identical panel of antibodies. With Polarbed 812 plastic embedded sections, microwave heating in citrate buffer was undertaken before the application of antisera.

RESULTS

On sections cut from plastic embedded material, immunohistochemical staining was generally satisfactory, easy to interpret and comparable with that achieved with paraffin wax embedded material. Exceptions were antibodies to neutrophil elastase and CD61 where immunostaining was consistently negative on plastic embedded sections. Immunohistochemical staining for CD20 was consistently more reliable on plastic embedded sections.

CONCLUSIONS

The results provide evidence that, with few exceptions, satisfactory immunohistochemical staining is possible on plastic embedded bone marrow trephine biopsy specimens after microwave heating in citrate buffer. This, combined with the advantage of superior cellular morphology with semi-thin (1 micron) sections of plastic embedded material, make such embedding procedures the preferred method for the processing of bone marrow trephine biopsy specimens.

Proposal for a classification of acute myeloid leukaemia based on plastic-embedded bone marrow biopsy sections

Traditional approaches to haematological diagnosis of acute myeloid leukaemia (AML) include microscopic examination of peripheral blood (PB) and bone marrow (BM) cells studied in Romanowsky-stained, dry film smears. The routine evaluation of BM aspirates, however, may be disappointing in accurately assessing marrow activity because of the sampling error inherent in the BM aspiration technique, and occasionally may fail to provide a precise diagnosis because BM aspirates cannot be obtained due to packed or fibrotic marrows. Because of the advantages it offers over the conventional method of diagnosis, we have studied Romanowsky-stained, thin sections of plastic-embedded BM biopsies from 87 newly diagnosed AML patients. Based on our study, the patients were broadly grouped into four categories: (1) those with hypocellular marrow (haemopoietic cellularity less than 50%), hypoplastic AML; (2) those with some degree of marrow fibrosis, AML with marrow fibrosis; (3) those with homogeneous infiltration of marrow with blast cells; and (4) those with inhomogenous infiltration of marrow with blast cells. Our results show that the proposed classification of AML based on the evaluation of plastic-embedded BM biopsy sections may offer benefits over those afforded by conventional morphologic smear techniques. This may provide significant prognostic information and may have a major impact on patient management. It may also provide a meaningful stratification of the patient population when comparing treatment protocols for newly diagnosed AML patients.

Bone marrow trephine biopsy in lymphoproliferative disease

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Enzyme histochemistry and immunohistochemistry with freeze-dried or freeze-substituted resin-embedded tissue

Freeze-drying or freeze-substitution, combined with low-temperature resin-embedding, represents a new approach to the optimum preservation of tissue for enzyme histochemistry and immunohistochemistry. This method, which avoids tissue fixation, combines excellent tissue morphology with the preservation of enzyme activity and immunoreactivity and allows high-resolution enzyme histochemical and immunohistochemical studies to be performed. The activity of a wide range of enzymes can be demonstrated in sections of freeze-dried or freeze-substituted resin-embedded tissue. Enzymes are retained in situ with high activity, accurate localization and no diffusion. Immunohistochemical studies can also be performed on resin sections, and antigens--especially labile antigens--are immobilized in situ without denaturation and can be demonstrated with high sensitivity and accurately localized. This method allows the localization and distribution of enzymes and antigens to be studied in relation to excellent histological and cytological detail.

Immunohistochemical evaluation of bone marrow lymphoid nodules in chronic myeloproliferative disorders

One hundred and seventy bone marrow biopsies from patients with chronic myeloproliferative disorders (CMPDs) were evaluated for the presence of lymphoid nodules (LNs) and were immunostained using a panel of monoclonal antibodies (UCHL1, 4KB5 and L26) recognizing different lymphocyte antigens. LNs were found in 35% of cases of idiopathic thrombocythaemia, 24.6% of myelofibrosis/osteomyelosclerosis, 18.2% of polycythaemia vera 12.1% of chronic myeloid leukaemia and 19.2% of borderline cases. Varying degrees of immunohistochemical positivity for the three antibodies tested were found. LNs were always made up of variable proportions of both T- and B-lymphocytes with a prevalence of T-cells. This latter observation suggests that bone marrow LNs in CMPDs could be an expression of reactivity.

Plastic embedded core biopsy: a complementary approach to bone marrow aspiration for diagnosing acute myeloid leukaemia

Bone marrow aspirates and biopsy specimens were taken at diagnosis from 51 patients with acute myeloid leukaemia (AML). The diagnosis was based on morphological and cytochemical analyses, and the leukaemias were classified by FAB criteria. A considerable difference was observed between the results of bone marrow aspirates and the findings of plastic-embedded bone marrow biopsy specimens, particularly in marrow cellularity, extent of blast cell infiltration, and cell type involved in the leukaemic process. The myelomonocytic cell type seemed to predominate in the sections. In four cases there was considerable marrow infiltration with maturing, but dysplastic, granulocytic cells in the sections, but not in the aspirate smears. Features of potential prognostic importance, such as bone marrow infiltration with inflammatory cells, were easily recognised and quantified in the sections. These results indicate that plastic embedded bone marrow biopsy sections complement the findings of bone marrow aspiration in the diagnosis of AML and may also provide information of independent prognostic importance that cannot be obtained by other means.