[Trend of the CD23+ B cells in children with infectious mononucleosis caused by Epstein-Barr virus].

OBJECTIVE: Epstein-Barr virus (EBV) is a common causative agent of infectious mononucleosis (IM) and capable of efficiently immortalizing primary B cells into continuously growing lymphoblastoid cells in vitro. As B cell activation antigen, CD23 expression is induced by EBV infection of B cells and remains constitutively expressed at high levels in virtually all EBV-immortalized cells, which have been strongly linked to the development of B-cell lymphoproliferative disease and lymphoma. Whereas previous studies were performed in vivo in animals or ex vivo cultures, the present study aimed to explore the role of EBV-immortalized cells (CD23(+)/CD19(+)) in vivo analysis of children with EBV-IM. METHODS: In a prospective trial, a group of 30 patients with IM (18 boys and 12 girls) with mean age of 3.9 +/- 1.3 years (range 6 months to 8 years) were enrolled. Clinical diagnosis of IM was confirmed based on fever, lymphadenopathy, splenomegaly, lymphocytosis (> 50%), atypical lymphocytes (> 10%) in blood smears and the elevated levels of IgM antibody against EBV capsid antigen. The day of onset of fever was recognized as day 1 of illness. Blood samples taken during acute (3 - 5 days), early convalescent (about 11 - 15 days) and convalescent phase (about 30 - 45 days) were analyzed for expressions of CD19(+)/CD23(+), CD23, CD19 on peripheral blood mononuclear cells by flow cytometry (FCM) and was compared with those of control group. RESULTS: (1) The levels of CD23(+)/CD19(+) and CD23 expressions were markedly decreased in acute stage [CD23(+)/CD19(+) (2.22 +/- 1.47)%, (132 +/- 91)/mm(3); CD23 (3.12 +/- 1.88)%, (195 +/- 102)/mm(3)] and in early convalescent stage [CD23(+)/CD19(+) (4.51 +/- 2.25)%, (166 +/- 85)/mm(3); CD23 (5.55 +/- 2.76)%, (231 +/- 130)/mm(3)] in patients with IM as compared with those of the healthy controls [CD23(+)/CD19(+) (6.71 +/- 2.25)%, (215 +/- 68)/mm(3); CD23 (7.85 +/- 3.09)%, (249 +/- 86)/mm(3), respectively]. The earlier the history was, the lower the expressive levels were. The levels of CD23(+)/CD19(+) expressions returned to, but those of CD23 expressions exceeded, normal level in convalescent stage [CD23(+)/CD19(+) (6.72 +/- 2.16)%, (213 +/- 108)/mm(3); CD23 (9.46 +/- 2.73)%, (366 +/- 200)/mm(3)]. (2) There was a positive correlation in the expressions of CD23(+)/CD19(+) and CD23 among the three stages (P < 0.01). The positive correlation between the expressions of CD23(+)/CD19(+) and CD19 only occurred during acute stage (P < 0.01). There was no correlation between the expressions of CD23 and CD19 (P > 0.05). CONCLUSION: EBV-immortalized cells and CD23(+) cells were inhibited effectively during the acute and early convalescent stage of IM. With the recovery of the disease, they gradually recovered and the levels of CD23 expressions exceeded normal level in convalescent stage.

[The inhibition pathway of the EBV-immortalized cells in children with infectious mononucleosis].

OBJECTIVE: To explore the inhibition pathway of the EBV-immortalized cells (CD23(+)) in children with infectious mononucleosis (IM) caused by Epstein-Barr virus. METHODS: The expressions of CD23, CD19, CD95, Bcl-2 and the co-expressions of CD23CD95, CD19CD23 on peripheral blood mononuclear cell (PBMC) were analyzed by flow cytometry (FCM) during acute phase, early convalescent phase and convalescent phase of 34 EBV-IM children and compared with that of 24 healthy donors. RESULTS: (1) The levels of CD23(+) and CD23(+)CD19(+) cells decreased and CD95(+), CD95(+)CD23(+), Bcl-2(+) cells increased markedly in IM patients in acute phase [CD95(+) cells (19.43 +/- 8.46)%; CD95(+)CD23(+) cells (1.81 +/- 1.71)%; Bcl-2(+) cells (23.41 +/- 26.47)%] and early convalescent phase [CD95(+) cells (12.94 +/- 5.05)%; CD95(+)CD23(+) (1.05 +/- 1.20)%; Bcl-2(+) cells (10.54 +/- 9.68)%], as compared with those of healthy controls [CD95(+) cells (10.39 +/- 2.90)%; CD95(+)CD23(+) cells (0.50 +/- 0.46)%; Bcl-2(+) cells (7.25 +/- 2.88)%]. The earlier the course of IM, the more abnormal the expressive levels. All the abnormal results returned to normal in convalescent phase. (2) Positive relationships were observed between the expressions of CD95(+)CD23(+) cells and that of CD23(+) cells, CD23(+)CD19(+) cells during acute and early convalescent phase, the expressions of Bcl-2(+), CD3(+) cells and CD23(+), CD23(+)CD19(+) cells during acute phase, the expressions of CD95(+)CD23(+) cells and Bcl-2(+) cells during acute phase, and the expressions of CD95(+)CD23(+) cells and CD95(+) cells during convalescent phase. CONCLUSION: The results indicate that CD95L-CD95 mediated apoptosis plays an important role in eliminating EBV-immortalized cells, which is counteracted partly by Bcl-2.

[Role of the B lymphocytes in children with infectious mononucleosis caused by Epstein-Barr Virus].

OBJECTIVE: Infectious mononucleosis (IM) is a lymphoproliferative disease caused primarily by the Epstein-Barr virus (EBV) infection. The initial viral infection by EBV occurs in B lymphocytes and is followed by an extensive proliferation of T lymphocytes. Previous studies on immunity to EBV (including IM) have mainly focused on activation of peripheral blood T cells, which are responsible for the lymphocytosis in blood during acute IM. B cells, regarding CD23 as their activation marker, are the target cells of EBV infection. There are few reports on their effect in patients with IM. The role of them during acute IM is not known yet. The present study aimed to explore the action of B cells in patients with IM. METHODS: In a prospective trial, a group of subjects comprised 22 patients with IM (14 boys and 8 girls) with mean age of 3.48 +/- 0.81 years (range 7 months to 8 years). Clinical diagnosis of IM was confirmed based on fever, lymphadenopathy, splenomegaly, lymphocytosis (> 50%), atypical lymphocytes (> 10%) in blood smears and the elevated levels of IgM antibody against EBV capsid antigen. The day of onset of fever was recognized as day 1 of illness. Blood samples taken during acute (3 - 5 days) and convalescent phase (about 15 days) were analyzed for expressions of CD19, CD19(+)/CD23(+) on PBMC by flow cytometry (FCM) and was compared with those of control group. The number of the days with fever was recorded. RESULTS: (1) The levels of CD19 and CD19(+)/CD23(+) expressions were markedly decreased in acute stage [CD19 (5.63 +/- 2.91)%, (387 +/- 178)/mm(3), CD19(+)/CD23(+) (2.45 +/- 1.87)%, (160 +/- 99)/mm(3)] and in convalescent stage [CD19 (12.49 +/- 5.70)%, (428 +/- 156)/mm(3), CD19(+)/CD23(+) (5.05 +/- 2.79)%, (172 +/- 78)/mm(3)] in patients with IM as compared with those of the healthy controls [CD19 (16.20 +/- 2.80)%, (545 +/- 150)/mm(3); CD19(+)/CD23(+) (7.08 +/- 2.78)%, (249 +/- 136)/mm(3)]. The earlier the specimens were taken after onset, the lower the expressed levels were. (2) There was a positive correlation of the expressions of CD19 and CD19(+)/CD23(+) between acute and convalescent stage (P < 0.01);there was also a positive correlation between the expressions of CD19 and CD19(+)/CD23(+) during acute and convalescent stage (P < 0.01). (3) A negative correlation was found between the duration of fever and the level of CD19 and CD19(+)/CD23(+) in acute stage (P < 0.01). CONCLUSION: The results indicate that B cells and CD23(+) B cells were significantly inhibited during the onset of IM in the patients, that with the recovery of the disease, the condition was gradually improved, and that the more evidently the CD19 and CD19(+)/CD23(+) decreased, the more serious the clinical symptoms were and the longer time the recovery needed. The levels of CD19 and CD19(+)/CD23(+) expressions may be useful in diagnosis and predicting the severity.