Expression and Role of Integrin Receptors in Sézary Syndrome

Activity of proximal promoter of the human beta(1)-integrin gene was increased in Sézary syndrome

Changes in beta1-integrin expression have been involved in abnormal cellular interactions between malignant lymphocytes from Sézary (Sz) patients and keratinocytes. In this paper, we compare the activity of both distal and proximal promoters of the beta1-integrin gene in malignant lymphocytes from Sz patients with human normal lymphocytes. Activity of both beta1-integrin promoters was also analysed in human normal keratinocytes. Northern blot analysis shows that beta1-integrin mRNA expression is higher in malignant Sz lymphocytes than in normal lymphocytes. CAT assays show that the activity of proximal beta1-integrin promoter is markedly increased (up to 6-fold) in malignant lymphocytes from Sz patients, in comparison to normal lymphocytes. These results suggest that changes in activity of the proximal promoter of beta1-integrin subunit could be, in part, responsible for the abnormal cellular interactions between malignant lymphocytes and keratinocytes observed in Sz syndrome.

Aberrant expression of adhesion molecules by Sézary cells: functional consequences under physiologic shear stress conditions

Although aberrations in adhesion molecule expression by lymphoma cells have been reported, the functional consequences of these changes are unclear. Herein, we report a patient with Sézary syndrome whose malignant peripheral blood T cells were TCRVbeta17+. Malignant T cell adhesion molecule abnormalities included an 80% downregulation of LFA-1 compared with normal controls and no detectable expression of alpha4 integrin. Under shear stress conditions, malignant T cells failed to arrest on recombinant ICAM-1 in the presence of chemokines and displayed an 80% decrease in the ability to arrest on TNF-alpha activated dermal microvascular endothelial cells compared with normal CD4+ memory T cells. Cutaneous lymphocyte-associated antigen expression was detected in approximately 25% of malignant T cells in the peripheral blood, but was substantially less than this in TCRVbeta17+ T cells in the dermis. By contrast, > 95% of malignant T cells in peripheral blood expressed L-selectin (CD62L), and L-selectin ligand was detected in dermal blood vessels at affected skin sites. Compared with normal CD4+, malignant T cells attached and rolled 6-fold more efficiently on L-selectin ligand (p < 0.0001). Thus, despite aberrant expression of LFA-1 and functional defects in the ability to arrest on activated endothelial cells, malignant T cells in this patient entered skin and produced significant clinical disease. We propose a mechanism by which the upregulated expression of L-selectin and L-selectin ligands may partially compensate for altered LFA-1 function.

Skewed expression of activation, differentiation and homing-related antigens in circulating cells from patients with cutaneous T cell lymphoma associated with CD7- T helper lymphocytes expansion

Mycosis fungoides and Sézary syndrome represent the most frequent forms of cutaneous T cell lymphoma. Both are characterized by skin infiltrating and/or circulating malignant cells displaying a CD4+CD7- phenotype in the majority of cases. Because an expansion of CD4+CD7- cells may also be found in inflammatory dermatoses or in the aging process, we evaluated, by flow cytometry, the relationship between CD7 expression and the distribution of differentiation/activation or homing antigens on peripheral blood lymphocytes from 36 cutaneous T cell lymphoma patients and from healthy donors. CD4+CD7- cells were increased in all patients with cutaneous T cell lymphoma. As a consequence, the CD7+/- ratio was reduced in stage I-II mycosis fungoides (3.96 vs 6.55 in healthy donors), and inverted in stage III-IV MF and Sézary syndrome (0.28 and 0.12 respectively). In the late stage of disease, the CD7+/- inverted ratio was strictly related to the expression of CD15s, CD60, and CD45R0, and the lack of expression of CD26 and CD49d. Interestingly, in leukemic patients, this phenotype was also associated with peculiar morphologic (large size) or phenotypical (CD3dim expression) characteristics. Furthermore, a progressive reduction of circulating CD8+ cells was also seen throughout all stages of disease. The presence of these populations in cutaneous T cell lymphoma at late phases of disease and Sézary syndrome suggests that all of these molecules may play an important part in the activation pathway and skin homing of circulating T cells in lymphoproliferative disorders. Therefore, this may constitute a distinctive feature in cutaneous T cell lymphoma patients with more aggressive characteristics.

The prevention and treatment of cutaneous injury secondary to chemical warfare agents. Application of these finding to other dermatologic conditions and wound healing

Chemical warfare agents are easily and inexpensively produced and are therefore potentially accessible to even underdeveloped nations and are a threat to civilian populations as well as advancing troops. Sulfur mustard is by far the most significant chemical warfare agent that produces cutaneous injury. Significant advances over the past few years have been made in understanding the pathophysiology of the lesions produced by sulfur mustard, as well as development of barrier creams and pre and post exposure therapies to moderate the damage and accelerate healing. Not only have these advances improved our understanding of the sulfur mustard injury and the care of the patients, these are potentially numerous applications for these findings in other dermatologic conditions including the treatment of chronic wounds.

T lymphocytes from Sézary syndrome patients express beta1 integrins whose beta(1-6)-branched N-linked oligosaccharides reflect their adhesive capacity

Sézary syndrome (Sz), characterized by slowly progressing clonal proliferation of CD4+, CD45 RO+ T cells, has several forms that are distinguished according to the epidermotropic properties of the pathological cells. In a recent paper (Derappe C, Haentjens G, Lemaire S, Feugeas JP, Lebbe C, Pasqualetto V, Bussel A, Aubery M, Néel D. Leukemia 1996;10:138), we observed that T lymphocytes from most of the Sézary patients [Szbeta(1-6)+] expressed high levels of beta(1-6)-GlcNAc-branched N-linked oligosaccharides while T lymphocytes from other patients [Szbeta(1-6)-] did not. Because this observation suggests the possibility of two forms of Sz, distinguished according to the expression rate of these glycans, we looked for a possible relationship between this expression rate and T-cell adhesiveness. Using an original protocol (Braut-Boucher F, Pichon J, Rat P, Adolphe M, Aubery M, Font J. J Immunol Methods 1995;178:41), we observed that T lymphocytes obtained from the Szbeta(1-6)+ patients adhered less to normal keratinocyte monolayers than T lymphocytes from Szbeta(1-6)- patients and normal donors. As assessed by FACS analysis, all the integrin-subunits studied were more expressed on Szbeta(1-6)-, especially alpha4, alpha5, beta1 and beta2, than on Szbeta(1-6)+ and normal lymphocytes. Although these results suggest that beta1- and beta2-integrin expression is involved in the adhesive properties of these T-cells, other factors, such as glycosylation, may also contribute. To demonstrate this possibility, we sought the presence of beta(1-6)-GlcNAc-branched N-linked oligosaccharides on beta1 integrins expressed by T lymphocytes from Sz patients. Immunoblot experiments, performed using the specific lectin from Phaseolus vulgaris (Leukoagglutinin form), showed that only the beta1 integrin subunit expressed by T lymphocytes from Szbeta(1-6)+ patients carried these glycans, supporting the concept of the involvement of T-cell glycosylation in the evolution of Sz.

Prognostic factors in Sézary syndrome: a multivariate analysis of clinical, haematological and immunological features

BACKGROUND

Sézary syndrome (SS) prognostic factors are not well defined because of the rarity of this disease. The specific goal of this prospective study was to assess by multivariate analysis the predictive value with respect to survival of a series of clinical, haematological and immunological parameters taken at SS diagnosis.

PATIENTS AND METHODS

A cohort of 62 SS patients diagnosed and followed since 1975 was examined, and 51 were included in the multivariate analysis model.

RESULTS

The median survival time was 31 months (range: 1 month-15.7+ years), and the five-year survival rate 33.5%. The following variables were found by univariate analysis to be associated with a poor prognosis at the time of SS diagnosis: previous history of mycosis fungoides (P = 0.013), high number of circulating leukocytes (P = 0.001), Sézary cells (SC) (P < 0.001) and CD4+ cells (P < 0.001), presence of large circulating SC (P < 0.001), above normal range LDH serum levels (P = 0.015), presence of PAS-positive inclusions in the cytoplasm of circulating SC (P < 0.001), high CD4/CD8 ratio (P = 0.004) and a CD7 negative circulating SC phenotype (P < 0.001). Among them, the stepwise multivariate analysis selected as adverse independent prognostic factors: PAS-positive cytoplasmic inclusions (P = 0.001), CD7 negative phenotype (P = 0.018) and presence of large circulating SC (P = 0.045).

CONCLUSIONS

Two low-/high-risk groups have been singled out on the basis of the risk index. Patients with no or one adverse prognostic feature(s) (risk index < or = 1; n = 31) share a slow disease course and a relatively favorable prognosis (five-year survival: 58%); on the other hand, patients with 2 or 3 adverse prognostic feature (risk index > 1; n = 20) are characterized by an aggressive disease course not modifiable by traditional therapies (five-year survival: 5%).

Histopathologic and immunohistochemical features in human skin after exposure to nitrogen and sulfur mustard

N-methyl-2,2'-dichlorodiethylamine (HN2)is a topical chemotherapeutic agent used as therapy for cutaneous T-cell lymphomas (CTCL). Di(2-chloroethyl)sulfide (SM), and less often HN2, have been used as chemical weapons, with the skin being a principle target. The mechanisms by which these chemicals produce their therapeutic and toxic effects in skin, however, are not clearly defined. We exposed human skin explants to two doses of HN2 and SM. At 18 hours after exposure, histopathologic features were compared. In addition, immunohistochemical markers to basement membrane proteins were used to evaluate the effects of both chemicals on the basement membrane zone. Gross vesication was not seen. Pyknotic nuclei with or without dyskeratotic changes within epidermal keratinocytes were present at both doses. These changes varied more between skin specimens than they did between doses. Ballooning degeneration was more marked after SM exposures. Diffuse dermal-epidermal separation was present only at high-dose exposures and did not appear to correlate with the degree of changes locally in the overlying epidermis. Antibodies to laminin-5 showed decreased immunoreactivity after exposure to HN2 and SM. Immunoreactivity for laminin- was decreased to a lesser extent, and immunoreactivity for collagen IV and VII was unchanged. HN2 and SM produce similar histopathologic and immunohistochemical features after cutaneous exposure. These features suggest that part of mechanism of action of HN2 and SM is a direct effect on the basement membrane zone. Understanding the effects of HN2 and SM separate from their effect on DNA may be important in designing therapies and in advancing our understanding of the pathophysiologic changes induced by these chemicals when delivered topically.

CD44 variant expression in cutaneous T-cell lymphoma

Expression of the lymphocyte homing receptor CD44 and its splice variants have been linked to tumour dissemination and poor prognosis in non-Hodgkin's lymphoma. Specifically, the in vitro expression of variant exon V6 confers metastatic potential in rat pancreatic carcinoma cell lines. In this study, we investigated the expression of CD44 splice variants in cutaneous T-cell lymphomas, including patients with mycosis fungoides (MF), Sezary syndrome (SS), large-cell anaplastic lymphoma (LCAL) and HTLV1-associated cutaneous lymphoma. In addition, 4 involved lymph nodes from 2 patients with MF and 1 patient with SS were examined. Inflammatory dermatoses, lichen planus and psoriasis, and normal skin were also studied. Immunohistochemistry was performed using a panel of monoclonal antibodies, including those with specificity for CD44H (standard isoform) and variant exons V3, V6 and V8-9. Normal epidermal keratinocytes were consistently CD44H and CD44 V3, V6 and V8-9 positive. In all the different clinicopathological subtypes and stages of cutaneous T-cell lymphomas, including involved lymph nodes, tumour cells consistently expressed CD44H, but were CD44 V3 and V6 negative. CD44 V8-9 was expressed on a majority of tumour cells in 2/5 LCAL and on occasional tumour cells in 2/5 LCAL. Occasional V8-9 positive tumour cells were also identified in 6/13 MF, 1/4 SS and 3/4 HTLV1. In 2/3 lymph node samples from 2 patients with tumour-stage MF, CD44 V8-9 expression was found on a small percentage of atypical mononuclear cells. Scattered V8-9 positive dermal mononuclear cells were present in sections of lichen planus and psoriasis. We have found no evidence to suggest that the metastasis-associated CD44 variant exon (V6) is expressed in cutaneous T-cell lymphoma, or that CD44H expression is associated with an adverse prognostic group. It is not clear whether the strong expression of CD44 V8-9 in 2 patients with CD30 positive LCAL reflects activation status or metastatic potential.

Utility of bone marrow and liver biopsies for staging cutaneous T-cell lymphoma

BACKGROUND

The wide use of staging procedures, looking for visceral involvement in patients with cutaneous T-cell lymphoma (CTCL), is controversial, especially in the early stages. In this study, we analyzed the results of bone marrow biopsy and laparoscopy with liver biopsy in a series of 43 patients with CTCL.

METHODS

Clinicopathologic stages were established by a modification of the TNM system proposed in 1979. Results of staging procedures were correlated with blood cell counts and laboratory tests. The usefulness of the staging procedures was analyzed particularly in patients without clinical or biologic evidence of extracutaneous disease.

RESULTS

The patient's median age was 66 years; 35 patients were men and eight women. The clinicopathologic stages were as follows: T1: 3 cases; T2: 15; T3: 14; T4: 11; N0: 15; N1: 28; M0: 38; M1: 5; B0: 37; and B1: 6 cases. Internal lymph node disease, diagnosed by lymphangiography and/or abdominal scanning, was demonstrated in 37% of patients. Bone marrow infiltration was seen in 12% of patients and was the only form of visceral involvement. All liver biopsies were negative. Serum lactate dehydrogenase (LDH) levels were raised in patients with lymph node disease; it was the only laboratory test that correlated with extracutaneous involvement. Staging procedures changed three of the nine patients with a clinical T1-T2N0M0B0 stage (33%) to a more advanced stage. The abdominal lymph node evaluation allowed a reclassification from N0 to N1 in two of nine cases (22%); one of the remaining cases was reclassified from M0 to M1 on the basis of bone marrow biopsy results.

CONCLUSIONS

Our results indicate that bone marrow biopsy is a useful investigational procedure for determining extracutaneous disease in CTCL. Peritoneoscopy with liver biopsy rarely is informative; however, as our study does not include a very large number of patients, these preliminary conclusions must be confirmed in the future by including more cases.