An absence of human leukocyte antigen-DR and a decreased expression of beta 2-microglobulin on tumor cells of basal cell carcinoma: no influence on the peritumoral immune infiltrate

Interferon-gamma-induced ICAM-1 and CD40 expression, complete lack of HLA-DR and CD80 (B7.1), and inconsistent HLA-ABC expression in basal cell carcinoma: a possible role for interleukin-10?

Basal cell carcinomas (BCCs) of the skin show varying degrees of peritumoural inflammatory infiltrate consisting mainly of T cells, but lack an effective T-cell-mediated immune response. This may be caused by the absence of the major histocompatibility complex (MHC) class I and II antigens, intercellular adhesion molecule-1 (ICAM-1), CD40 and CD80 (B7.1). Interferon-gamma (IFN-gamma) is known to induce or up-regulate their expression on epithelial cells, whereas interleukin-10 (IL-10) down-regulates their expression. The induction and up-regulation of HLA-ABC, HLA-DR, ICAM-1, CD40, and CD80 in BCC and normal skin from BCC patients were investigated in a culture system using recombinant human IFN-gamma (rHuIFN-gamma). The levels of IL-10 were determined in the supernatants after culture. The results showed that only ICAM-1 expression was significantly up-regulated on BCC cells. However, in the normal epidermis of BCC patients and in the epidermis overlying the tumour nests, significant up-regulation of ICAM-1, and CD40, and CD80 and slight up-regulation of HLA-DR were observed. No changes in HLA-ABC expression were observed in either normal skin or BCC. High levels of IL-10 were present in the supernatants of BCC biopsies after culture. It may be concluded that it is highly likely that the presence of IL-10 in BCC is directly or indirectly responsible for the complete lack of expression of HLA-DR, ICAM-1, CD40 and CD80 and the inconsistent expression of HLA-ABC on BCC cells in situ and may be a way of escaping immune survillance.

Immune-associated cells in basal cell carcinomas of skin

Increased numbers of mast cells (MCs) and lymphocytes infiltrating in basal cell carcinomas (BCCs) have been observed. The presence of these infiltrating cells has been considered a sign of an immunologic anti-tumor response in the host, but the relationship of these two cell populations has not been examined. To elucidate this possible relationship, 30 non-ulcerated BCCs were analyzed. Frozen sections of the tumors were stained with monoclonal antibodies for Langerhans' cells, lymphocyte subsets and natural killer cells. Fluorescein isothiocynate (FITC)-avidin as well as anti-tryptase and anti-CD45RO monoclonal antibodies were used on formalin-fixed, paraffin-embedded sections for mast cell and T cell identification, respectively. B cells and natural killer cells were rarely observed in these tumors. MCs and T cells were quantified by direct enumeration and expressed as number of cells per high power field (hpf). FITC-avidin and anti-tryptase antibodies were equivalent in their ability to identify MCs. MC content in BCCs ranged from 1.0 to 31 cells/hpf. The number of T cells ranged from 0 to 50 cells/hpf with helper/suppressor cell ratios of 0.2 to 10. There was no correlation between helper/suppressor ratios and mast cell numbers; however, an inverse relationship was observed between the numbers of T cells and the number of mast cells in these tumors. These studies indicate that T cells and MCs are the primary immune cell populations responding to BCCs, and that decreased numbers of T cells are associated with more aggressive tumors.

HLA molecules in basal cell carcinoma of the skin

Fifty basal cell carcinomas (BCC) and 8 samples of healthy skin were studied for HLA class I and class II antigen expression and for the presence of mutations in codon 12 of the K-ras and H-ras genes. All samples of healthy skin and of epithelium near the tumor showed high levels of class I molecules, whereas 38% of the tumors showed complete absence. Sixty-two percent of the tumors presented positive class I expression with heterogeneous staining. These losses were due to the simultaneous lack of heavy chain and beta 2-microglobulin. Selective losses of HLA-A or HLA-B antigens were not detected. Class II antigens were absent in most of the tumors, only two tumors showing a few weakly positive cells with anti-HLA-DR mAb. The loss of class I expression correlated significantly with the degree of histological differentiation and aggressiveness. We were unable to correlate class I expression with clinical size, depth of invasion or the extent of leukocytic infiltrate surrounding the tumor. Analysis by PCR amplification of codon 12 of the K-ras and H-ras oncogenes detected H-ras mutations in 1 out of 50 cases, and no K-ras mutations in any of the tumors studied. Thus, a positive relationship between K-ras and H-ras mutations and BCC tumorigenesis or MHC alterations seems unlikely in this neoplasia.

Intralesional interferon alfa-2b in the treatment of basal cell carcinoma. Immunohistochemical study on cellular immune reaction leading to tumor regression

Four patients with basal cell carcinomas were treated with intralesional injections of interferon alfa-2b (1.5 million IU per injection) three times a week for 2 weeks. Histopathologic examination of biopsy specimens of the lesions confirmed the absence of basal cell carcinoma in all cases 4 weeks after completion of therapy. A dense mononuclear cell infiltrate and numerous ectatic blood vessels were present in the dermis at the sites of previous basal cell carcinoma. Immunohistologic analysis of the dermal infiltrate revealed a marked increase of Leu-4+ T cells with a slight predominance of Leu-3+ helper/inducer T cells over Leu-2+ suppressor/cytotoxic T cells. Most of the dermal infiltrate expressed HLA-DR antigen. In addition, Leu-11+ natural killer cells were observed in the dermal infiltrate. Immunohistologic changes in the skin lesions at the sites of previous basal cell carcinoma suggest that intralesional interferon alfa-2b acts on tumor cells by enhancement of local T-cell-mediated immune responses.

Biology of basal cell carcinoma (Part I)

Basal cell carcinoma is the most common malignancy in humans. Although rarely metastatic, it is capable of significant local destruction and disfigurement. This two-part article reviews the current understanding of basal cell carcinoma biology. Part I examines significant clinical, histologic, and ultrastructural features that relate to invasive potential. Genetic characteristics, including tumor growth rate, chromosomal abnormalities, and oncogene presence, are discussed, and expression of important cell and matrix proteins, including keratin, fibronectin, and HLA antigens, are reviewed. Further topics to be explored in Part II include host immunologic responses, theories of pathogenesis, and valuable second-line therapeutic regimens for treatment of multiple cancers.

Immunohistological evaluation of basal cell carcinoma immunoinfiltrate during intralesional treatment with alpha 2-interferon

We investigated the peritumoral and intratumoral immune infiltrate in 6 basal cell carcinomas (BCCs) treated with recombinant alpha 2b-interferon. Each BCC was injected intralesionally three times a week for 3 weeks with 1.5 x 10(6) IU of interferon per injection (total dose 13.5 x 10(6) IU). The immunohistological study was done before the start of interferon therapy and 15 days afterwards, using a series of monoclonal antibodies and an immunocytochemical technique. Before therapy the infiltrate consisted mainly of CD3+ (T) cells, with prevalence of CD4+ (helper/inducer) T cells. The percentage of T cells expressing interleukin-2 receptor (CD25+ cells) was higher in the tumor nests than in the peritumoral infiltrate (20% and 11% respectively). CD1+ (Langerhans) cells and CD14b+ cells (monocytes/macrophages) were present in the peritumoral infiltrate in all cases (9% +/- 5% and 14% +/- 7% respectively). Very few CD56+ (natural killer), CD15+ (granulocytes) and CD20+ (B) cells were observed in the peritumoral infiltrate and none at all in tumor nests. After 15 days of interferon therapy, we observed an increase in peritumoral and intratumoral CD4+ cells. There was a decrease in the number of CD25+ cells and of CD1+ cells in the peritumoral infiltrate. The number of intratumoral CD25+ increased. No variations were seen in CD14b, CD15, CD20, and CD56 positive cells. Eight weeks after completion of therapy, two BCCs were cleared and the remaining four showed clinical and histological improvement. These results may indicate a direct effect of interferon against BCC; in addition the immunohistological findings suggest that intralesional interferon enhances T cell mediated immune response, especially in tumor nests.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of the mononuclear infiltrate in Bowen's disease (squamous cell carcinoma in situ). Evidence for a T cell-mediated anti-tumour immune response

We investigated the dermal inflammatory infiltrate and the expression of HLA-DR and beta 2-microglobulin on the tumour cells in 8 Bowen's disease (BD) using a series of monoclonal antibodies. The inflammatory infiltrate was classified as mild, moderate or heavy. The infiltrate in all cases consisted mainly of T cells (55 +/- 21%) and where the T helper (TH) subset predominated over the T suppressor/cytotoxic (TS/C) subset (TH/TS/C ratio of 2.4 +/- 1.0). The mean percentage of HLA-DR positive cells was 58 +/- 18%, Langerhans cells (LC) 4 +/- 1% and Leu-M5 positive cells (monocytes/macrophages) 9 +/- 2%. The mean percentage of B cells and natural killer (NK) cells was 4 +/- 5% and 1 +/- 2% respectively. B cells and NK cells did not invade any of the tumours. In the 5 BD with moderate or heavy infiltrate, TH cells, TS/C cells and Leu-M5 positive cells did invade the tumour. In the tumour area where there was invasion, the number of LC was increased and HLA-DR was expressed on the cells. beta 2-microglobulin was generally expressed on the tumour cells of BD. We concluded that there is evidence for a T cell-mediated anti-tumour immune response which may account for the infrequent invasive growth in BD.