高橋 清

<P>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.</P>

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.

We have attempted to clarify the characteristics of monoclonal antibodies (MAbs) detecting lymphocyte subsets in fixed materials. We examined by means of flow cytometric technique influences of fixatives and reactivity with malignant lymphomas (MLs). Specific markers for T-cells were UCHL1 and OPD4, which reacted especially with helper/inducer T-cells. MT1 recognized almost all of T-cells from peripheral blood and tonsils, but reacted with a part of B-MLs. As for B-cell markers, L26 was the most reliable marker for B-MLs. L26 and MB1 antigens could not be detected on living cells flow cytometrically. LN1 reacted with a part of T-cells as well as B-cells, but fluorescent intensity of the former was apparently stronger than that of the latter. Although LN2 antigen was located mainly in the cytoplasm close to the nuclear membrane immunohistochemically, it could be detected on living cells flow cytometrically. LN2 positive cells belonged to B-cells in peripheral blood and tonsils. When fixed for relatively short time, B5 and buffered formalin were better for examining MAbs than non-buffered formalin and ethanol.

Anti-IgE-induced histamine release from basophils was examined in 46 asthmatic subjects using a whole blood method. Basophils from subjects less than 30 years old released more histamine than those from subjects aged 41 to 50. The age at onset of the disease also affected the reactivity of basophils to anti-IgE: basophils showed a high response in subjects whose age at onset was between 0 and 10 years, and low response in the subjects whose age at onset was between 41 and 50 years. There was a correlation between histamine release and serum IgE levels. However, individual dose-response curves of histamine release varied greatly in whom serum IgE levels were low.

Seventy-one cases of bronchial asthma were classified into three types: bronchospasm, bronchospasm-hypersecretion and bronchiolar obstruction types. The characteristics of each type were studied in relation to patient age and age at onset of the disease. In the 71 subjects studied, the most frequent type was the bronchospasm type followed by the bronchospasm-hypersecretion type and bronchiolar obstruction type. Intractable asthma was most frequently observed in the bronchiolar obstruction type and least in the bronchospasm type. Most of the patients under 50 years of age showed the bronchospasm type. The bronchospasm-hypersecretion type was characteristically accompanied by blood eosinophilia when the patient age was under 50 years. In the bronchospasm-hypersecretion type, the incidence of intractable asthma was high in patients under 50 years of age, but not remarkable in those over 50. A large proportion of the patients over 50 years of age were of the bronchiolar obstruction type. There was no difference in the incidence of intractable asthma between the two groups classified by age at onset.

The correlation between blood eosinophilia and anti-IgE-mediated histamine release was investigated in 22 bronchial asthma patients with peripheral eosinophilia (over 8%). In the cases (Group A-1 and Group A-2) in which house dust was the specific antigen, significant histamine release from basophils was induced by anti-IgE and house dust. The result indicates a relationship between eosinophilia and the IgE-mediated mechanism of disease onset. In the cases (Group A-3) with RAST scores of 0+ and 1+ to house dust, the anti-IgE-induced histamine release varied from low to high percentages, and the participation of the IgE-mediated pathway was indicated in some cases. In the cases (Group B) with negative skin reactions, few patients had a family history of allergic disease. Their ages at onset were higher, and they demonstrated lower total IgE levels. These cases showed an extremely low percent of histamine release from basophils, which indicated the absence of a correlation between eosinophilia and IgE-mediated mechanisms.

IgE-mediated histamine release from whole blood was analyzed in 44 patients with bronchial asthma by observing maximum present release and dose-response curves of histamine release induced by anti-IgE and house dust extract. The maximum histamine release from whole blood induced by anti-IgE correlated with total serum IgE levels. There was a close correlation between allergen-induced release from whole blood and the serum levels of specific IgE antibodies. In the maximum histamine release from whole blood induced by both anti-IgE and allergen, the interaction with a serum factor was not clearly recognized. Effect of a serum factor was shown in the dose-response curves of anti-IgE-induced histamine release, but not in those of allergen-induced histamine release. The dose-response curves caused by anti-IgE showed that basophils from cases with a high serum IgE level require much more anti-IgE to produce maximum histamine release than basophils from cases with a low serum IgE level. The results showed that IgE molecules contained in the serum participate in anti-IgE-induced histamine release from whole blood.