IMMUNOHISTOCHEMICAL STAINING OF PLASTIC-EMBEDDED BONE-MARROW TREPHINEBIOPSY SPECIMENS AFTER MICROWAVE-HEATING

Aims-To investigate (1) whether adequate immunohistochemical staining can be achieved on sections cut from plastic embedded bone marrow trep hine biopsy specimens after microwave heating in citrate buffer; and ( 2) whether this immunohistochemical staining is comparable with that a chieved on routine sections cut from paraffin wax embedded trephine bi opsy specimens after decalcification procedures. Methods-Sixty five co nsecutive bone marrow trephine biopsy specimens of more than 1 cm in l ength were divided transversely into two equal parts. One part was pro cessed in paraffin wax followed by decalcification. The other part was embedded in the epoxyresin Polarbed 812 followed by the cutting of 1 mu m sections. Both parts underwent immunohistochemical staining by an identical panel of antibodies. With Polarbed 812 plastic embedded sec tions, microwave heating in citrate buffer was undertaken before the a pplication of antisera. Results-On sections cut from plastic embedded material, immunohistochemical staining was generally satisfactory, eas y to interpret and comparable with that achieved with paraffin wax emb edded material. Exceptions were antibodies to neutrophil, elastase and CD61 where immunostaining was consistently negative on plastic embedd ed sections. Immunohistochemical staining for CD20 was consistently mo re reliable on plastic embedded sections. Conclusions-The results prov ide evidence that, with few exceptions, satisfactory immunohistochemic al staining is possible on plastic embedded bone marrow trephine biops y specimens after microwave heating in citrate buffer. This, combined with the advantage of superior cellular morphology with semi-thin (1 m u m) sections of plastic embedded material, make such embedding proced ures the preferred method for the processing of bone marrow trephine b iopsy specimens.