Lymphoid stromal reaction in gastrointestinal lymphomas: immunohistochemical study of 14 cases

Molecular markers (PECAM-1, ICAM-3, HLA-DR) determine prognosis in primary non-Hodgkin's gastric lymphoma patients

AIM

To investigate the prognostic significance of PECAM-1, ICAM-3 and HLA-DR antigens in patients with primary non-Hodgkin's gastric lymphoma.

METHODS

We immunohistochemically studied PECAM-1, ICAM-3 and HLA-DR antigen expression in 36 B-cell MALT-type primary gastric lymphoma patients. Ten non-malignant and ten healthy gastric tissue specimens were used as controls. Clinicopathological and survival data were correlated with the staining results.

RESULTS

HLA-DR antigen expression was detected in 33 gastric lymphoma patients (91.7%) and 6 non-malignant patients (54.5%). PECAM-1 stained tumor cells of 10 patients (27.8%), endothelial cells of 9 patients (25%) and inflammatory infiltrate of 4 patients (40%) with benign gastric disease. ICAM-3 expression was observed on the tumor cells of 17 patients (47.2%), while 5 non-malignant patients (50%) were stained positive as well. None of the healthy controls was stained for any of the genes studied. In the multivariate analysis, HLA-DR antigen and PECAM-1 were proved to be statistically significant independent prognostic factors associated with a favourable and an unfavourable prognosis respectively (P=0.009 and P=0.003). In the univariate analysis, PECAM-1(+)/ICAM-3(-) and HLA-DR(-)/ICAM-3(-) patients exhibited a significantly decreased overall survival compared to those with the exactly opposite gene expression patterns (P=0.0041 and P=0.0091, respectively). Those patients who were HLA-DR(+)/ICAM-3(+)/PECAM-1(-) (n=8) had a significantly higher survival rate compared to the rest of the group (n=24) (P=0.0289).

CONCLUSION

PECAM-1, ICAM-3 and HLA-DR are representative markers of tumor expansion potential and host immune surveillance respectively. Their combined use may help us to identify high-risk patients who could benefit from more aggressive therapeutic protocols.

Immunohistocytochemical correlation of DAP IV-CD 26 reactivity with immunologic markers of lymphocyte activation in human lymphoid tissues

The topographic distribution of the dipeptidylaminopeptidase IV (DAP IV-CD 26) and II (DAP II) positive T-cell population in six reactive lymph nodes and seven follicular B-cell non-Hodgkin's lymphomas (NHL) was analysed with regard to the distribution of activated T-cells, as visualized by a panel of monoclonal antibodies including Tac-CD 25, HLA-DR, OKT 9-CD 71, ICAM-1-CD 54, LFA-1-CD 11a. For comparative studies serial frozen sections of the lymph nodes were tested by enzyme histochemistry and immunohistochemistry. In addition, cell suspensions obtained from 10 B-NHL and interleukin-2 (IL-2) activated T-cells were investigated by a combined cytochemical and immunological method for simultaneous visualization of DAP IV-CD 26 cytoplasmic activity and surface immunostaining for markers of lymphocyte activation. Both in reactive and lymphomatous lymph nodes the topographic distribution of DAP IV-CD 26+ and DAP II+ lymphocytes was rather similar to that of Tac-CD 25+ lymphocytes. On the contrary, the DAP IV-CD 26 and DAP II distribution pattern substantially differed from that of the other immunologic markers. In a cell suspension of IL-2 activated T-cells, more than 80% of the cells with a blastic morphology were DAP IV-CD 26+; DAP IV-CD 26+ cells coexpressing Tac-CD 25, OKT 9-CD 71, HLA-DR positivity, relative to the total number of DAP IV-CD 26 positive cells, were 90.5%, 70.5% and 87% respectively. Only small (not activated) lymphocytes expressed a focal cytoplasmic DAP II positivity. In cell suspensions from 10 cases of B-NHL the mean percentage of DAP IV-CD 26+ Tac-CD 25+ cells was 75.8. Only a small number of DAP IV-CD 26+ cells coexpressed HLA-DR, the mean percentage being 9.6. The results support the view that DAP IV-CD 26 may be considered as a marker of lymphocyte activation; this marker seems to be restricted to T lymphocytes that reside in the T dependent areas of reactive lymph nodes and to non malignant T-cells surrounding neoplastic follicles of follicular NHL.

Acute myeloid leukemia: immunohistologic findings in paraffin-embedded bone marrow biopsy specimens

Immunohistochemical investigations were performed on decalcified, paraffin-embedded iliac crest trephine biopsy specimens from 30 cases of acute myeloid leukemia (AML, as defined by the FAB classification) with antibodies against B cells (L26, 4KB5, MB1, Ki-B3), T cells (UCHL1, MT1), myeloid/histiocytic cells (anti-neutrophil elastase, MAC387, anti-S-100 protein, anti-alpha 1-antichymotrypsin, DAKO-M1), natural killer/killer cells (anti-Leu-7), and megakaryocytes (anti-factor VIII-related antigen). (1) The blast cells of all the cases reacted with from at least two to at most eight different antibodies. Each antibody reacted with blast cells in a minimum of two (maximum 30) cases. (2) MT1, Ki-B3, anti-alpha 1-antichymotrypsin anti-neutrophil elastase, anti-S-100 protein, and MAC387 stained blast cells in more than 50% of the cases; MB1, L26, UCHL1, 4KB5, and DAKO-M1 in 20% to 50% of the cases; and anti-Leu-7 and anti-factor VIII-related antigen in less than 20% of the cases. (3) In the majority of cases many T lymphocytes, a small-to-moderate number of B lymphocytes, and a few Leu-7-positive lymphoid cells were intermingled with the blast cells. In some cases, especially where only a minor proportion of the blast cells was immunostained, it was nearly impossible to distinguish the lymphocytes of the tumor's stromal reaction from small blast cells. Thus, AML exhibits a heterogeneous immunophenotype in trephine biopsy specimens. Immunohistologic diagnosis of this disease in such specimens may be extremely difficult. Since staining of the blast cells with one or more of the antibodies generally used to define B cells, T cells, or their neoplastic derivatives is not uncommon, misinterpretation as non-Hodgkin's lymphoma of high-grade malignancy could easily occur. These findings also suggest that mixed-type (hybrid) acute leukemias with coexpression of myeloid and lymphoid cell markers could be more common than generally realized.

Subsets of CD3+ (T cell receptor alpha/beta or gamma/delta) and CD3- lymphocytes isolated from normal human gut epithelium display phenotypical features different from their counterparts in peripheral blood

Intestinal intraepithelial lymphocytes (IEL) were studied, after isolation in humans, for their surface antigens with a large variety of monoclonal antibodies. They show peculiar characteristics when compared with peripheral blood lymphocytes and intestinal lamina propria lymphocytes. Although a majority of human intraepithelial lymphocytes (IEL) express an alpha/beta type of T cell receptor (TcR), 13% express a gamma/delta TcR, a percentage which was significantly higher than that found in blood and in lamina propria. In contrast to observations in mice, there was no evidence that normal human TcR gamma/delta+ intestinal IEL might use preferential variable segments of gamma genes. About 10% of human intestinal IEL expressed the alpha chain but not the beta chain of CD8, thus resembling a subset of CD8 alpha+beta- IEL, which was recently described in mice and found to be of thymoindependent origin. In addition, 10% of human IEL had a unique phenotype of immature T cells, as they bore only CD7, but no other T cell or natural killer cell markers. Finally, even the major population of IEL which expressed the usual markers of the T cell lineage (CD3, TcR alpha/beta, CD2, CD4 or CD8 alpha/beta) differed from peripheral blood T lymphocytes by their peculiar expression of surface antigens associated with activation. Indeed, 80% of IEL were CD45R0+, CD45A-, but co-expression of CD11a, CD29 and LFA-3 was inconstant. In addition, 90% of IEL expressed HML-1.

Dipeptidylaminopeptidase IV activity in T lymphocyte subsets in B cell non-Hodgkin's lymphomas

The total T cell population and T cell subsets in ten lymph nodes with reactive lymphoid hyperplasia (RLH) and 23 specimens (21 lymph nodes, one stomach, and one small bowel) involved by histologically and immunohistologically diagnosed B cell non-Hodgkin's lymphomas (NHLs) were determined by reactivity with monoclonal antibodies Leu 4-CD3, Leu 3-CD4, and Leu 2-CD8 in cytospin preparations from cell suspensions. T cell populations were also investigated for the coexpression of dipeptidylaminopeptidase IV (DAP IV) activity, which was visualized simultaneously with cell surface immunostaining by a combined cytochemical and immunocytochemical method. The mean absolute percentage of Leu 4-CD3+ (total T) and Leu 3-CD4+ cell populations was significantly lower in B cell NHL cases than in RLH cases (35% v 54%, P less than .001; 29.5% v 44.4%, P less than .01). No difference in the mean absolute percentage of the Leu 2-CD8+ T cell subset was found between the RLH cases and the B cell NHL cases classified as other than category A as described by the Working Formulation (WF) of NHLs. The relative percentage of Leu 4-CD3+ and Leu 2-CD8+ cells coexpressing DAP IV reactivity was lower in B cell NHL cases than in RLH cases (27.3% v 39.5%, P less than .05; 13.5% v 24.4%, P less than .10). There was no difference in the proportion of Leu 3-CD4+ cells expressing DAP IV reactivity between the NHL and RLH groups (34.5% v 36.1%). Since the mean relative percentage of Leu 2-CD8+ cells expressing DAP IV reactivity in the B cell NHL group in the other than category A according to the WF was lower than that of the RLH group (12.5% v 24.4%), and whereas the mean absolute percentage of total Leu 2-CD8+ cells was similar in the two groups (16.6% and 16.6%), a possible defective role of this Leu 2-CD8+ DAP IV+ subset, at least in B cell NHLs in the other than category A according to the WF, may be hypothesized.

Same peculiar subset of HML1 + lymphocytes present within normal intestinal epithelium is associated with tumoral epithelium of gastrointestinal carcinomas

The present study shows that the distribution of T lymphocytes in gastrointestinal carcinomas and their metastases mimic the distribution of T lymphocytes in normal intestine. The composition of the peritumoral reaction resembled that of normal lamina propria with a predominance of CD3 + CD4 + T cells. In contrast, lymphocytes located between carcinomatous cells showed phenotypical features similar to those of intraepithelial lymphocytes (IEL) in normal intestine; in particu(abstractlar they expressed the antigen defined by HML-1, a monoclonal antibody raised against normal human intestinal IEL which reveals 95% IEL but very few cells in lymphoid (abstractorgans and blood. As normal intestinal IEL, the majority of intratumoral lymphocytes had the CD3+ CD8+ phenotype. A panel of monoclonal antibodies and double immunostaining techniques permitted a better characterisation of minor subsets of IEL. Two subsets of HML1 + CD3 + CD4- CD8- and of HML1+ CD3- cells, representing 2% and 3% of normal intestinal IEL respectively, did not significantly increase in carcinomatous epithelium. In contrast, in carcinomatous epithelium, but not in normal intestinal epithelium, we observed the appearance of a few lymphocytes displaying the phenotype of activated T cells (CD25+) or of natural killer cells (NKHI+) or of suppressor cells (CD11+). Such cells may participate in antitumoral defence. Although a similar population of HML1+ lymphocytes is associated with normal and carcinomatous intestinal epithelium, some interactions between lymphocytes and epithelial cells may not be maintained in tumoral epithelium. It has previously been shown that HLA-DR expression by enterocytes is modulated by intraepithelial lymphocytes. In our study, no correlation could be shown between the degree of lymphocytic infiltration and the expression of HLA-DR antigens on carcinomatous cells.