Application of polymerase chain reaction (PCR) to the microscopically identified cells on the slides: evaluation of specificity and sensitivity of single cell PCR.

The sensitivity and specificity of single cell polymerase chain reaction (PCR) were studied. Its high sensitivity enabled detection of a single-copy gene, such as human T-lymphotropic virus type I genome in paraffin sections. The rate of obtaining positive signals with this method was affected by the number of copies of the gene in the target cell. Specificity was satisfactory if the procedure was properly and carefully followed. Since the single cell PCR is a time-consuming method which requires skill and experience to pick up the target cells accurately, the applicability of this method is limited. It works best when it is used to analyze a single or a few copy genes in histologically identified cells.</p

Detection of Epstein-Barr virus RNA and related antigens in non-neoplastic lymphoid lesions.

To elucidate the latent state and reactivation of Epstein-Barr virus (EBV) in non-neoplastic lymphoid lesions, we investigated 144 non-neoplastic lymphoid lesions by in situ hybridization (ISH) to detect the expression of EBV-encoded small RNAs (EBER)-1 and BCRF-1 and by immunostaining for latent membrane protein (LMP)-1 and ZEBRA. ISH for EBER-1 detected EBER-1-positive cells (EPC) in 31 of the 144 examined lesions (22%). EPC were detected in 4 of 49 cases of nonspecific lymphoid hyperplasia, in 16 of 20 abscess-forming granulomatous lymphadenitis (AFGL), 5 of 25 Kikuchi's disease, and in 3 of 3 infectious mononucleosis. LMP-1 was expressed in 6 of 124 non-neoplastic lymphoid lesions (4.8%). LMP-1-positive cells were observed in 6 of the 31 EBER-1-positive cases (19%). EPC were detected significantly more frequently in LMP-1- and ZEBRA-positive specimens than in the LMP-1- and ZEBRA-negative specimens. BCRF-1 was expressed in 4 of 11 cases examined: 2 of 3 AFGL, 1 of 2 Kikuchi's disease, and in the 1 case of atypical lymphoid hyperplasia. This study suggests that Epstein-Barr virus is prevalent and can be reactivated in the lymph nodes effaced by destructive inflammation, such as AFGL. Such inflammation may provide a local milieu that is conducive for EBV to enter the lytic cycle.</p

Variable expression of Epstein-Barr virus latent membrane protein I in Reed-Sternberg cells of Hodgkin's disease.

&#60;P&#62;Reed-Sternberg cells (RS cells) of Hodgkin's disease (HD) are frequently infected with Epstein-Barr virus (EBV) and express EBV-encoded nonpolyadenylated RNA transcripts (EBER)-1. EBV latency has been classified into three distinct forms: Latency I, expressing only one of the latent proteins, EBV nuclear antigen (EBNA)-1, latency II, coexpressing EBNA-1 and LMPs, and latency III, expressing all latent viral proteins. RS cells express LMP-1 in addition to EBNA-1 and are considered to be EBV latency II frequently encountered in nasopharyngeal carcinoma. We examined 13 cases of EBV-infected HD by combined EBER-1 in situ hybridization and immunostaining for LMP-1. All of the RS cells expressed EBER-1, but a substantial number of EBER-1+ RS, cells were negative for LMP-1. The percentage of LMP-1+ RS cells out of EBER-1+ RS cells varied from 7% to 100% (average 69%). In this study, we showed that all EBV-infected RS cells were not restricted to latency II, and some belonged to latency I.&#60;/P&#62;</p