OBJECTIVETo investigate the frequencies and distribution of CD4+ T cells and CD8+ T cells as well as the changes of immune activation in gastric mucosa of HIV-infected individuals.

METHODS42 HIV-infected individuals were recruited into this investigation, and 36 patients had definite diagnosis of clinical stage. Biopsy of gastric mucosal tissues was performed by fiberoptic gastroscope including 10 normal people as a control group. Then, immunohistochemistry was used to detect expression of CD4, CD8 and CD38 in gastric mucosa, and the distinctions among three groups were analyzed with LEICA Qwin image analysis system.

RESULTS(1) Compared with asymptomatic HIV carriers and control group, CD4 T cells remarkably decreased in the gastric mucosa of AIDS patients (P < 0.01). In gastric mucosa of asymptomatic HIV carriers, there were still some CD4+ T cells in lymphoid follicles and stroma where CD4+ T cells were unevenly distributed, the frequency of CD4+ T cells was not significantly different between asymptomatic HIV carriers and control group (P > 0.05); (2) Phenomenon of CD8+ T cells infiltrating mucosal epithelium and gland was general in HIV-infected individuals. CD8+ T cells took on local excessive hyperplasia in gastric mucosa of some individuals. As compared with control group, CD8+ T cells markedly increased in gastric mucosa of infected individuals (P < 0.01), but the distinction of asymptomatic HIV carriers and AIDS patients was not significant (P > 0.05); (3) CD38-expressing cells mainly distributed over gastric mucosal surface to superficial layer(1/3-2/3 layer) of HIV-infected individuals, and was more intensive than control group (P < or = 0.01), but there was not noticeable difference between asymptomatic HIV carriers and AIDS patients (P > 0.05).

CONCLUSIONThe frequencies and distribution of gastric mucosal CD4+ T cells of HIV-infected individuals were closely correlated with progression of disease. Disfunction of mucosal immune system which was resulted from HIV infection and injury of CD4+ T cells could be an important cause of CD8+ T cells increasing and CD38-expressing enhancement.

ADP-ribosyl Cyclase 1 ; genetics ; immunology ; Adult ; CD4-Positive T-Lymphocytes ; cytology ; immunology ; CD8-Positive T-Lymphocytes ; cytology ; immunology ; Female ; Gastric Mucosa ; immunology ; Gene Expression ; HIV Infections ; genetics ; immunology ; HIV-1 ; immunology ; Humans ; Lymphocyte Count ; Male ; Middle Aged

CD99 is characteristically expressed in Ewing's sarcoma/primitive neuroectodermal tumor. Recently its immunoreactivity has also been reported in other tumors. However, the significance of CD99 isoforms expressed in these tumors has not been elucidated. In this study, we evaluated the expression of CD99 isoforms and its relationship with histopathologic parameters in gastric adenocarcinomas. Paraffin sections of 46 gastric adenocarcinomas were stained with an anti-CD99 monoclonal antibody, YG32. Twelve (26.1%) cases of 46 gastric adenocarcinomas showed immunoreactivity to YG32. The CD99 expression was also seen both in non-neoplastic foveolar epithelial cells and infiltrating lymphocytes. In addition, Western blot and RT-PCR analyses revealed that the type I is the predominant isoform of CD99 in non-neoplastic and neoplastic gastric tissues. The CD99 expression was usually seen in the intestinal type adenocarcinoma, while rarely in the diffuse type. The CD99 immunoreactivity decreased in MMP-2-overexpressing adenocarcinomas (p=0.028). Our results suggest that the type I is the major isoform of CD99 expressed in non-neoplastic gastric mucosa and gastric adenocarcinomas and its downregulation in gastric adenocarcinoma may be associated with cellular dedifferentiation and/or MMP-2 overexpression.
Adenocarcinoma/*immunology/pathology ; Adult ; Aged ; Antigens, CD/*analysis/genetics ; Cell Adhesion Molecules/*analysis/genetics ; Female ; Gastric Mucosa/cytology/immunology ; Humans ; Male ; Matrix Metalloproteinases/metabolism ; Middle Aged ; Protein Isoforms/analysis/genetics ; RNA, Messenger/genetics/metabolism ; Stomach Neoplasms/*immunology/pathology