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Minocycline is an oral antibiotic widely used for the long-term treatment of acne vulgaris. Unusual side effects of this medication include two overlapping autoimmune syndromes: drug-induced lupus and autoimmune hepatitis. In addition, in a few patients livedo reticularis or subcutaneous nodules have developed in association with arthritis and serum perinuclear antineutrophil cytoplasmic antibodies (P-ANCA) during long-term minocycline therapy. We report the cases of two young women receiving long-term minocycline therapy (>3 years) in whom P-ANCA-positive cutaneous polyarteritis nodosa developed. Both patients presented with a violaceous reticulated pattern on the lower extremities. Histologic examination of biopsy specimens from a reticulated area and a subcutaneous nodule showed necrotizing vasculitis of medium-sized arteries in the deep dermis, consistent with the diagnosis of polyarteritis nodosa. The cutaneous lesions rapidly resolved on discontinuation of minocycline and initiation of prednisone therapy. A high index of suspicion and testing for antineutrophil cytoplasmic antibody in addition to the standard antinuclear antibody panel can facilitate diagnosis of minocycline-related autoimmune disorders.

Predicting the biologic behavior of melanocytic neoplasms (benign versus malignant) based on histology is one of the most difficult challenges in surgical pathology and dermatology. Success in the field of melanocytic neoplasia can be achieved by two means: performing excisions or biopsies that maximize the obtainable histologic information and providing sufficient history.

Cutaneous B-cell infiltrates showing a prominent follicular growth pattern with germinal centers are thought by some authors to represent either marginal zone lymphomas with reactive germinal centers or pseudolymphomas. To establish whether a true primary cutaneous follicular lymphoma exists, we studied biopsies from 15 patients with skin lesions characterized histopathologically by the presence of B-cell infiltrates with follicular pattern. Staging investigations, including bone marrow biopsy, were negative in all patients. All were negative for bcl-2 protein expression and did not present the t(14;18). In all biopsy specimens neoplastic follicles showed 1 or more morphologic or immunophenotypic criteria of malignancy (presence of a reduced mantle zone, absence of tingible body macrophages, reduced proliferation rate). In 9 specimens a monoclonal rearrangement of J(H) genes could be detected by polymerase chain reaction analysis. After laser beam microdissection, a band of the same length could be observed in 6 probes from different follicles from the same specimen, indicating the presence of the same monoclonal population of follicle center cells. Follow-up examinations in all patients revealed no evidence of extracutaneous spread (mean follow-up, 48.7 months). Our study demonstrates that primary cutaneous follicular lymphoma represents a distinct entity of the cutaneous B-cell lymphomas. (Blood. 2000;95:3922-3928)

TNF activates endothelial cells to express cell surface molecules that are necessary to recruit a local infiltrate of leukocytes. Because the actions of this proinflammatory cytokine are not species restricted, we investigated whether human TNF can up-regulate porcine endothelial adhesion molecules to elicit human T cell infiltration and damage of pig skin xenografts in a chimeric immunodeficient mouse model. We have previously demonstrated the vigorous rejection of human skin allografts and the absence of injury to porcine skin xenografts in human PBMC-SCID/beige mice. Intradermal administration of human TNF at high doses (600 or 2000 ng) caused nonspecific inflammatory damage of pig skin grafts, whereas low concentrations of TNF (60 or 200 ng) resulted in human PBMC-dependent injury of porcine endothelial cells. There was a strong correlation among pig skin xenograft damage, human T cell infiltration, and the TNF-induced up-regulation of swine MHC class I and class II molecules, VCAM-1, and, in particular, the de novo expression of porcine E-selectin. The microvascular damage and leukocytic infiltration elicited by TNF were enhanced by porcine IFN-gamma, suggesting that xenografts may be less prone to cytokine-mediated injury due to the species-restricted effects of recipient IFN-gamma. Our results indicate that maintenance of a quiescent endothelium, which does not express E-selectin or other activation-dependent adhesion molecules, is important in preventing human anti-porcine T cell xenoresponses in vivo and that TNF signaling molecules and TNF-responsive gene products are appropriate therapeutic targets to protect against human T cell-mediated rejection of pig xenografts.

The newly described apoptosis inhibitor survivin is expressed in many human cancers and appears to play a critical part in both apoptosis regulation and cell cycle progression. Its potential role in malignant melanoma is unknown. In a panel of 30 malignant melanomas, survivin was strongly expressed in all cases (15 of 15) of metastatic malignant melanomas and 13 of 15 cases of invasive malignant melanomas by immunohistochemistry. In invasive malignant melanomas, survivin was also expressed in the in-situ component of the lesion. Survivin expression was found in all cases (11 of 11) of nevi, but not in melanocytes in sections of normal skin. The apoptosis inhibitor bcl-2 was expressed in 26 of 30 cases, but generally at lower levels than that of infiltrating lymphocytes. The mitotic index, as assessed by MIB-1 staining, was consistently higher in metastatic than invasive malignant melanomas. Assessment of apoptotic index by in situ end-labeling revealed extremely low rates of apoptosis in most malignant melanomas. Survivin expression by western blotting was detected in four human metastatic malignant melanoma cell lines but not in cultured normal human melanocytes. Transfection of both YUSAC-2 and LOX malignant melanoma cells with green fluorescence protein-conjugated survivin anti-sense or green fluorescence protein-conjugated survivin dominant negative mutant (Cys84Ala) [corrected] resulted in increased apoptosis in the absence of other genotoxic stimuli. Two-color flow cytometry confirmed that YUSAC-2 cells transfected with survivin anti-sense expressed less endogenous survivin and exhibited an increased fraction of cells with sub-G1 DNA content. These data demonstrate that apoptosis inhibition by survivin may participate in the onset and progression of malignant melanomas, and suggest that therapeutic targeting of survivin may be beneficial in patients with recurrent or metastatic disease.

The recently described apoptosis inhibitor survivin is expressed in many human cancers, thus potentially contributing to disease progression and resistance to therapy. Its potential role in nonmelanoma skin cancer is unknown. By immunohistochemistry, survivin was expressed in 81% (17 of 21) of basal cell carcinomas (BCC) of both nodular and morpheaform subtypes, and in 92% (24 of 26) of cutaneous squamous cell carcinomas (SCC). Survivin was also expressed in 19 premalignant lesions of Bowen's disease (SCC in situ) and hypertrophic actinic keratosis (HAK), suggesting that its appearance occurs early during keratinocyte transformation. Survivin expression was detected by Western blotting in a model keratinocyte cell line, HaCat. Transfection of HaCat cells with green fluorescent protein (GFP)-conjugated survivin antisense or GFP-conjugated survivin dominant negative mutant (Cys84Ala) resulted in spontaneous apoptosis in the absence of other genotoxic stimuli. In GFP-conjugated survivin antisense transfectants, a decreased level of endogenous survivin was confirmed by flow cytometry. This was associated with a five-fold increase in the sub-G0/G1 fraction corresponding to apoptotic cells and a decrease in proliferating cells with 4N DNA content. These data demonstrate that apoptosis inhibition by survivin may participate in the onset and progression of both BCC and SCC, and suggest that therapeutic targeting of survivin may be beneficial in patients with recurrent or advanced disease.

Morphea (localized scleroderma) is a disease of unknown etiology, presenting as circumscribed areas of indurated skin. Histologically, most cases of morphea feature thickened collagen bundles in the deep reticular dermis, sometimes also extending into the superficial dermis or into the subcutis. We present six cases of morphea in which typical histologic features were restricted to the superficial dermis and contrast these with 27 additional biopsies of conventional morphea seen during the same time period. Sections were stained for elastic fibers, and dermal dendritic cells were labeled with antibodies to CD34 and Factor XIIIa. All six cases showed thickened collagen bundles restricted to the superficial dermis, sparing the deep dermis and without associated evidence of lichen sclerosus et atrophicus (LSA). Dermal elastic fibers were not appreciably decreased in number. There was loss of CD34-positive dermal spindle cells in each of our six superficial examples of morphea, which was restricted to the area of altered collagen in four of the six cases. This report highlights the distinctly uncommon phenomenon of morphea presenting solely as alteration of the superficial reticular dermis, without features of LSA. The selective loss of CD34-labeled spindle cells may provide information regarding the role of these putative immune accessory cells in morphea. Recognition of this manifestation of morphea may be helpful diagnostically.

Graft versus host disease, an alloimmune attack on host tissues mounted by donor T cells, is the most important toxicity of allogeneic bone marrow transplantation. The mechanism by which allogeneic T cells are initially stimulated is unknown. In a murine allogeneic bone marrow transplantation model it was found that, despite the presence of numerous donor antigen-presenting cells, only host-derived antigen-presenting cells initiated graft versus host disease. Thus, strategies for preventing graft versus host disease could be developed that are based on inactivating host antigen-presenting cells. Such strategies could expand the safety and application of allogeneic bone marrow transplantation in treatment of common genetic and neoplastic diseases.

Basaloid follicular hamartoma (BFH) is one of several benign skin tumors that may occur in multiple and solitary forms. While the histologic findings of BFH may be observed in a variety of clinical settings, familial multiple BFH represents a distinct clinical entity characterized by tiny flesh-colored papules scattered predominantly over the face. We present two sisters with this rare condition and review the clinical and histologic differential diagnosis of familial multiple BFH.

The term cutaneous T-cell lymphoma was originally coined to encompass the spectrum of mycosis fungoides and Sézary syndrome. It has become increasingly evident that the histopathologic diagnosis of CTCL can be exceedingly challenging. A series of recent studies, however, have helped clarify the nature of the histologic findings in CTCL. Recently reported histologic data on mycosis fungoides, Sézary syndrome, and their variants is emphasized in this article, with special focus given to the findings in early lesions. A brief summary of lymphocyte immunophenotyping and the role of T-cell reception gene rearrangements in CTCL is included.

Thymidine phosphorylase/platelet-derived endothelial cell growth factor (TPase/PD-ECGF) is a catabolic enzyme that has been shown to be chemotactic for endothelial cells in vitro and angiogenic in vivo. TPase/PD-ECGF expression is increased in a variety of tumors. In the skin, TPase is active in normal keratinocytes in vitro and in vivo. Our objective was to study the expression and localization of TPase/PD-ECGF by immunohistochemical analysis in normal skin and cutaneous tumors and to correlate this information with enzymatic activity of TPase. TPase/PD-ECGF expression was observed in keratinocytes with intense staining of the infundibulum of hair follicles but no staining of hair bulbs. Expression localized primarily to the nucleus of keratinocytes in the basal layer but was more intense and cytoplasrmic in suprabasal keratinocytes. Increased expression of TPase/PD-ECGF in differentiated cells was confirmed by in vitro studies of TPase activity. In cutaneous tumors, there was positive staining for TPase/ PD-ECGF in squamous cell carcinomas (10/10), eccrine poromas (3/4), eccrine syringomas (4/4), trichoepitheliomas (1/3), and tumors of the follicular infundibulum (2/3) and melanomas (5/8). There was no staining of any intradermal nevi (0/2), basal cell carcinomas (0/10) or Merkel cell carcinoma (0/1). We conclude TPase/PD-ECGF is found throughout the epidermis and its expression increases with differentiation of keratinocytes. In cutaneous tumors, expression of TPase/PD-ECGF may be linked to the cell of origin of the tumor as well as the tumor's degree of differentiation.

Integrin alpha4beta7 has been associated with tissue-specific homing of malignant and inflammatory lymphocytes to gastrointestinal mucosa, whereas integrin alphaEbeta7 has been associated with intraepithelial lymphocytes in both the gut and the skin. This prompted us to examine the expression of alpha4beta7 on skin-infiltrating lymphocytes in 12 cases of patch/plaque stage cutaneous T cell lymphoma (CTCL) and in 4 cases of spongiotic dermatitis, which also display intraepidermal T cell accumulation. alpha4beta7 was found to be expressed on 64.8+/-7.4% of intraepidermal and 39.1+/-5.0% of intradermal T lymphocytes in CTCL. There was a significant positive correlation (r=0.58) between the degree of epidermotropism and the percentage of intraepidermal T cells expressing alpha4beta7. Similar findings were observed in spongiotic dermatitis, indicating that this result is not unique to malignant T cells. We evaluated staining of T cells in the same specimens for presence of alphaEbeta7 and observed a strong correlation between the expression of both beta7 integrins in each specimen. Staining with antibodies directed against the known ligands of alpha4beta7 was also performed on skin biopsies from CTCL patients. There was significantly increased dermal microvascular endothelial expression of vascular cell adhesion molecule-1 in lesional compared with nonlesional skin, and in nonlesional skin compared with skin of normal control subjects. Dermal and epidermal expression of the CS-1 domain of fibronectin was present but not increased in lesional biopsies compared with nonlesional or normal controls, whereas expression of mucosal addressin cell adhesion molecule-1 was not detectable in any skin biopsy specimens. In summary, alpha4beta7, like alphaEbeta7, is expressed at high levels on epidermotropic T cells and may interact with endothelial cell vascular cell adhesion molecule-1 as part of stepwise recruitment of lymphocytes from the blood to the epidermis.

WNT signalling orchestrates a number of developmental programs. In response to this stimulus, cytoplasmic beta-catenin (encoded by CTNNB1) is stabilized, enabling downstream transcriptional activation by members of the LEF/TCF family. One of the target genes for beta-catenin/TCF encodes c-MYC, explaining why constitutive activation of the WNT pathway can lead to cancer, particularly in the colon. Most colon cancers arise from mutations in the gene encoding adenomatous polyposis coli (APC), a protein required for ubiquitin-mediated degradation of beta-catenin, but a small percentage of colon and some other cancers harbour beta-catenin-stabilizing mutations. Recently, we discovered that transgenic mice expressing an activated beta-catenin are predisposed to developing skin tumours resembling pilomatricomas. Given that the skin of these adult mice also exhibits signs of de novo hair-follicle morphogenesis, we wondered whether human pilomatricomas might originate from hair matrix cells and whether they might possess beta-catenin-stabilizing mutations. Here, we explore the cell origin and aetiology of this common human skin tumour. We found nuclear LEF-1 in the dividing tumour cells, providing biochemical evidence that pilomatricomas are derived from hair matrix cells. At least 75% of these tumours possess mutations affecting the amino-terminal segment, normally involved in phosphorylation-dependent, ubiquitin-mediated degradation of the protein. This percentage of CTNNB1 mutations is greater than in all other human tumours examined thus far, and directly implicates beta-catenin/LEF misregulation as the major cause of hair matrix cell tumorigenesis in humans.

Cutaneous lymphadenoma is an uncommon basaloid epithelial tumor of uncertain histogenesis, most recently classified as a variant of trichoblastoma. Because characteristic immunohistochemical findings have been reported in trichoblastomas, we evaluated the staining patterns of five cutaneous lymphadenomas and compared the results to those of ten trichoblastomas and ten nodular basal cell carcinomas (BCCs), using antibodies to cytokeratin 20 (CK20), bcl-2, and CD34. In addition, because lymphadenomas contain intraepithelial S100-positive putative Langerhans cells, we compared staining of all tumor groups for S100 protein and CD1a. We also attempted to corroborate recent reports of CD30-positive activated lymphocytes in lymphadenomas. We identified CK20-positive Merkel cells in 3/5 lymphadenomas, 7/10 trichoblastomas, and none of the BCCs. Staining for bcl-2 accentuated the peripheral epithelial layer in all lymphadenomas and in 3/10 trichoblastomas, while the remaining trichoblastomas and all BCCs stained diffusely. There was stromal staining with CD34 in two lymphadenoma, 4 trichoblastomas, and 3 BCCs. All lymphadenomas featured numerous intraepithelial S100-positive cells which were also positive for CD1a in three cases tested. In addition, 8/10 trichoblastomas and 2/10 BCCs contained modest numbers of cells labelling for S100 and CD1a. Two of three lymphadenomas contained rare single cells resembling histiocytes faintly positive for CD30, and similar cells labelled for CD68. We conclude that the similar staining patterns of lymphadenomas and trichoblastomas support the classification of lymphadenoma as a variant of trichoblastoma. Staining with CD34 does not reliably distinguish between these tumors and BCCs. Lymphadenomas, trichoblastomas, and BCCs may all contain Langerhans' cells. The relationship between these cells and the striking lymphoid infiltrates seen in lymphadenomas is not clear. In our cases, the CD30-positive cells in lymphadenomas appear to represent histiocytes rather than activated lymphocytes.

Epithelioid cell histiocytoma (ECH) is an unusual and still poorly recognized variant of benign fibrous histiocytoma. Epithelioid cell histiocytoma differs from most benign fibrous histiocytomas in five important ways: the predominance of epithelioid cells, relative lack of secondary elements (such as giant cells, foamy, or hemosiderin-laden macrophages), relative sharp circumscription, prominent vascularity, and centering in the papillary dermis in most cases. A strong resemblance to melanocytic and vascular lesions has been noted, and a recent case was reported with features suggesting endothelial origin. Fifteen new cases of ECH, including one example of the rare deep cellular variant, are presented herein, with emphasis on features mimicking vascular and melanocytic neoplasms. Labeling with endothelial markers, including previously unreported CD-31 labeling, showed abundant vascular staining, which may be challenging to interpret, but which does not indicate an endothelial origin of ECH.

We have analyzed the mechanism of human endothelial injury in a human peripheral blood lymphocyte-severe combined immunodeficient (huPBL-SCID) mouse/human skin graft model of allograft injury and examined the effect of immunosuppressive drugs on this process. In this model, split-thickness human skin containing the superficial dermal microvessels was grafted onto immunodeficient C.B-17 SCID or SCID/beige mice and allowed to heal. Human peripheral blood mononuclear cells (PBMCs) allogeneic to the skin, when subsequently introduced by intraperitoneal injection, caused destruction of the human dermal microvasculature by day 16, evident as endothelial cell sloughing and thrombosis. In the same specimens, mouse microvessels that invaded the human skin graft were uninjured. Human microvascular cell injury was accompanied by a mononuclear cell infiltrate consisting of approximately equal numbers of human CD4+ and CD8+ T cells, some of which contained perforin-positive granules. We found no evidence of human natural killer cells and noted occasional human, but not mouse, macrophages at a frequency indistinguishable from that resident in skin on animals not receiving human PBMCs. These human T cell infiltrates did not extend into adjacent mouse skin. Human immunoglobulin G antibody was detected in the blood and was diffusely present throughout mouse and human tissues in SCID mice receiving PBMCs. Mouse C3 was detected on human dermal vessels in both unreconstituted control animals and those that received PBMCs. Blood and tissues from mice injected with PBMCs depleted of B cells showed no human immunoglobulin, but circulating CD3+ cells were detected by flow cytometry at levels comparable with those of animals receiving whole PBMCs. Significantly, skin graft infiltration by human T cells and human dermal microvascular injury were equivalent in the B cell-depleted and whole-PBMC-reconstituted mice. Mice inoculated with PBMCs depleted of CD8+ T cells developed microvascular injury and infiltrates containing perforin-expressing CD4+ T cells. These data suggested a cytolytic T cell-dependent mechanism of microvessel injury. We then tested the ability of T cell immunosuppressants, cyclosporine and rapamycin, to attenuate vessel damage. Neither cyclosporine nor rapamycin alone effectively reduced either mononuclear cell infiltration or vascular injury. However, a combination of the two agents reduced both parameters. We conclude that the huPBL-SCID/skin allograft model may be used both to study cytolytic T cell-mediated rejection and to test the effect of immunosuppressive drug strategies in vivo in a small-animal model of human immune responses.

There has been ongoing debate about the nature of Woringer-Kolopp disease (unilesional pagetoid reticulosis). Despite the histologic resemblance to mycosis fungoides, these lesions are typically solitary and indolent. Recently, cutaneous plaques of epidermotropic lymphocytes restricted to acral sites resembling Woringer-Kolopp disease were reported to show T-cell clonality, leading to the designation mycosis fungoides palmaris et plantaris. We describe a similar case of recurrent plaques on palms and soles of a 45-year-old man that persisted for >14 years without other cutaneous or systemic disease. Histologically, the lesions were comprised of epidermotropic atypical lymphocytes with sparse dermal infiltrates. Immunohistochemically, the majority of intraepidermal lymphocytes labeled as CD8-positive suppressor/cytotoxic T cells and expressed alphaE beta7 (CD103), an integrin associated with epitheliotropism. Polymerase chain reaction studies revealed similar clonal gene rearrangements of T-cell receptors beta and gamma in tissue from both palm and sole. In view of these findings, the diagnosis of mycosis fungoides palmaris et plantaris may be appropriate. To date, however, the lesions have remained localized and continue to resolve spontaneously. As such, the behavior is similar to what has been described as pagetoid reticulosis. Long-term follow-up will be necessary to determine the biologic potential of this disease.

We evaluated the in vivo anti-metastatic activity of recombinant Ancylostoma caninum Anticoagulant Peptide (rAcAP), a potent (Ki = 265 pM) and specific active site inhibitor of human coagulation factor Xa originally isolated from bloodfeeding hookworms. Subcutaneous injection of SCID mice with rAcAP (0.01-0.2 mg/mouse) prior to tail vein injection of LOX human melanoma cells resulted in a dose dependent reduction in pulmonary metastases. In order to elucidate potential mechanisms of rAcAP's anti-metastatic activity, experiments were carried out to identify specific interactions between factor Xa and LOX. Binding of biotinylated factor Xa to LOX monolayers was both specific and saturable (Kd = 15 nM). Competition experiments using antibodies to previously identified factor Xa binding proteins, including factor V/Va, effector cell protease receptor-1, and tissue factor pathway inhibitor failed to implicate any of these molecules as significant binding sites for Factor Xa. Functional prothrombinase activity was also supported by LOX, with a half maximal rate of thrombin generation detected at a factor Xa concentration of 2.4 nM. Additional competition experiments using an excess of either rAcAP or active site blocked factor Xa (EGR-Xa) revealed that most of the total factor Xa binding to LOX is mediated via interaction with the enzyme's active site, predicting that the vast majority of cell-associated factor Xa does not participate directly in thrombin generation. In addition to establishing two distinct mechanisms of factor Xa binding to melanoma, these data raise the possibility that rAcAP's antimetastatic effect in vivo might involve novel non-coagulant pathways, perhaps via inhibition of active-site mediated interactions between factor Xa and tumor cells.

Studies were conducted on the hypothesis that melanoma metastasis might be initiated through the generation of hybrids comprised of cells of the primary tumor and tumor-infiltrating leukocytes. Fusion hybrids were generated in vitro between weakly metastatic Cloudman S91 mouse melanoma cells and normal mouse or human macrophages. Hybrids were implanted s.c. in the tail and mice were monitored for metastases. Controls included parental S91 cells, autologous S91 x S91 hybrids, and B16F10 melanoma cells. Of 35 hybrids tested, most were more aggressive than the parental melanoma cells, producing metastases sooner and in more mice. A striking characteristic was heterogeneity amongst hybrids, with some lines producing no metastases and others producing metastases in up to 80% of mice. With few exceptions, hybrids with the highest metastatic potential also had the highest basal melanin content whereas those with the lowest metastatic potential were basally amelanotic, as were the parental melanoma cells. A spontaneous in vivo supermelanotic hybrid between an S91 tumor cell and DBA/2J host cell was one of the most metastatic lines. Hybrids with the highest metastatic potential also exhibited markedly higher chemotaxis to fibroblast-conditioned media. Histologically, the metastatic hybrids demonstrated vascular invasion and spread to distant organs similar to that of metastatic melanomas in mice and humans. Thus previous findings of enhanced metastasis in leukocyte x lymphoma hybrids can now be extended to include leukocyte x melanoma hybrids. Whether such hybridization is a natural cause of metastasis in vivo remains to be determined; however the fusion hybrids with genetically-matched parents described herein so closely resembled naturally-occurring metastatic melanoma cells that they could serve as useful new models for studies of this complex and deadly phenomenon.

Murine lupus in MRL mice has been strongly attributed to alphabeta T cell-dependent mechanisms. Non-alphabeta T cell-dependent mechanisms, such as gammadelta T cells, have been shown to drive antibody and autoantibody production, but they have not been considered capable of inducing end-organ disease. Here, we have expanded upon the findings of such previous work by examining the mechanism and extent of end-organ disease attainable via gammadelta T cells and/or non-alphabeta T cell-dependent mechanisms, assessing two prototypical lupus lesions, renal and skin disease, in TCR alpha -/- MRL mice that possessed either functional or defective Fas antigen (Fas + or lpr). Observed to 1 year of age, TCR alpha -/- MRL mice developed disease characterized by increased mortality, overt renal disease and skin lesions. While delayed in onset and/or reduced in severity compared with TCR alpha +/+ MRL/lpr animals, renal and skin lesions in alphabeta T cell-deficient animals were clearly increased in severity compared with age-matched control non-autoimmune mice. In contrast to TCR alpha +/+ MRL mice, whose disease reflected pan-isotype immune complex deposition with significant complement fixation, renal disease in TCR alpha -/- MRL animals reflected predominantly IgG1 immune complex deposition, with poor complement fixation. Thus, this study demonstrates conclusively that non-alphabeta T cell-dependent mechanisms can induce renal and skin injury in murine lupus, but at least in the kidney, only via humoral autoimmunity of a relatively non-pathological isotype which results in the delayed onset of end-organ damage.

Purpose: To describe the ophthalmic findings of patients with discoid lupus erythematosus., Method: We describe two women who originally were thought to have asymmetric posterior blepharitis; however, the involved eyelid also had an erythematous, scaly cutaneous lesion., Result: In both patients, histology and immunofluorescence studies performed on cutaneous biopsy specimens established the diagnosis of discoid lupus erythematosus., Conclusions: It is important to diagnose discoid lupus of the eyelids because misdiagnosis can delay treatment and thus lead to deformities of the eyelid margin. Misdiagnosis can also lead to a complicated full-thickness eyelid biopsy and delay the diagnosis of systemic lupus erythematosus.

Split-thickness pig skin was transplanted on severe combined immunodeficient mice so that pig dermal microvessels spontaneously inosculated with mouse microvessels and functioned to perfuse the grafts. Pig endothelial cells in the healed grafts constitutively expressed class I and class II major histocompatibility complex molecules. Major histocompatibility complex molecule expression could be further increased by intradermal injection of pig interferon-gamma (IFN-gamma) but not human IFN-gamma or tumor necrosis factor. Grafts injected with pig IFN-gamma also developed a sparse infiltrate of mouse neutrophils and eosinophils without evidence of injury. Introduction of human peripheral blood mononuclear cells into the animals by intraperitoneal inoculation resulted in sparse perivascular mononuclear cell infiltrates in the grafts confined to the pig dermis. Injection of pig skin grafts on mice that received human peripheral blood mononuclear cells with pig IFN-gamma (but not human IFN-gamma or heat-inactivated pig IFN-gamma) induced human CD4(+) and CD8(+) T cells and macrophages to more extensively infiltrate the pig skin grafts and injure pig dermal microvessels. These findings suggest that human T cell-mediated rejection of xenotransplanted pig organs may be prevented if cellular sources of pig interferon (e.g., passenger lymphocytes) are eliminated from the graft.

Photochemotherapy employing 8-methoxypsoralen and long-wavelength ultraviolet radiation (UVA, 320-400 nm) is widely used in the treatment of psoriasis. The photoactivation of psoralens in skin cells leads to formation of DNA photoadducts which may be responsible, at least in part, for the efficacy of these photochemotherapies. However, mutations arising from these adducts may also lead to the well-characterized increased incidence of squamous cell carcinoma. Mutations in the p53 tumor suppressor gene have been detected in many human cancers. To determine whether p53 mutations occur in squamous cell carcinomas in PUVA patients, PCR was used to amplify the exons (5-9) in which other studies have found a high frequency of point mutations. Gel electrophoresis was used to detect single-strand conformational polymorphisms. Aberrantly migrating bands were excised, reamplified and sequenced. Thirty-four specimens from 10 patients were examined. Specimens from one patient who had received no phototherapy as well as from normal controls were also analyzed. Five of the 10 patients showed at least one p53 mutation. In contrast to previously reported psoralen-induced p53 mutations in mice, the expected psoralen type mutations at alternating AT sites were not detected. All but two of the altered sequences occurred at dipyrimidine sites which is typical of solar type mutations. Two C-->T mutations and two dipyrimidine mutations (CC-->TT) were found. Other mutations included: C-->G, G-->T, C-->A and an 18 bp deletion. A review of therapeutic history of these patients showed that some had also received UVB phototherapy. Furthermore, because sunlight is thought to be beneficial for psoriasis, nontherapeutic, casual UVB exposure cannot be excluded. Our observations suggest that the SCC may have arisen from the solar mutations and that PUVA may enhance tumor progression or immune suppression.

A human skin allograft injury model in immunodeficient mice, engrafted with human peripheral blood mononuclear cells from a different donor, has been used to test whether reagents that block human T cell CD2 interactions with its principal ligand, LFA-3 (CD58), can inhibit immune reactions in vivo. In this model, human skin grafts show a reproducible pattern of progressive human T-cell infiltration and human graft microvascular injury that resembles human first-set skin graft rejection. Murine Mab to human LFA-3 or human LFA-3-IgG1 fusion protein, but not isotype-matched control antibodies, each markedly protected skin grafts from leukocyte infiltration and injury. These data provide the first evidence that LFA-3 functions in vivo and establish the ability of this new model to test human-specific immune modulators.

A chronologic study of ischemic changes in the mouse intestinal muscularis was done to delineate the morphologic alterations occurring within 24 hours of ischemia. The muscle cells initially contracted with segmental condensation of myofilaments. Subsequently, increasing degeneration and lysis of myofilaments resulted in the formation of dense degenerative bands and nodules alternating with clear segments in the muscle cells. Eventually, the myofilaments disintegrated. Mitochondria were initially swollen and subsequently condensed, shrunken, and fragmented. The plasma membrane showed progressive dissolution and eventually disappeared. These ultrastructural changes were represented by discernible changes in the histologic sections.

Changes in the fine structure of the gastric mucosa following exposure to graded concentrations of ethanol were studied in dogs. 300 ml of 12.5, 20, and 40%, vol/vol, were instilled intragastrically for 30 min. Mucosa from the midbody and midantrum along the greater curvature was examined by light and electron microscopy. Ethanol produced a gradation of changes in the surface epithelial cells and in the lamina propria without affecting the parietal cells and chief cells. 12.5% ethanol produced widened and irregular intercellular spaces while 20 and 40% disrupted the apical cell membrane with concomitant exudation of mucin into the gastric lumen. These changes were more severe after 40% ethanol. The tight junction between cells remained intact following exposure to the lower concentrations of ethanol, but focal separation of cell junctions was observed in severely damaged areas. Quantitation of protein, sodium, and potassium concentrations in the gastric contents revealed marked increases following exposure to ethanol which correlated with the concentration. These studies provide additional morphological data on the relationship between structural changes and functional abnormalities induced by agents which break the gastric mucosal barrier.

The purpose of this study was to examine the morphologic changes that occur in the early stages of intraalveolar edema. Anesthetized rabbits were intravenously administered a bolus of 40 mg/kg of ethchlorvynol, a mild hypnotic known to induce respiratory distress syndrome in humans and laboratory animals when given intravenously. After 15 min their lungs were fixed for transmission electron microscopy. Examination revealed variable amounts of irregularly distributed intraalveolar edema with erythrocytes and fibrin strands that coexisted with modest or nonexisting interstitial edema suggesting that primary hemorrhagic alveolar flooding had taken place. Most alveolar epithelial and endothelial cells appeared normal except in localized areas. In lungs fixed by vascular perfusion, in which normal capillaries were flushed, obstructions were noticed in alveolar corner capillaries. These areas were identified by light microscopy and selectively sectioned for electron microscopy. They contained intravascular cell-fibrin aggregates consisting of plugs of degranulated platelets, fibrin, erythrocytes, and leukocytes. Endothelial and epithelial cells in the vicinity of the plugs showed variable degrees of injury. In places the damage was so severe that vascular and alveolar spaces were separated only by the basal lamina. Our work shows the previously unnoticed existence of capillary microemboli or microthrombi in a well-known experimental model of respiratory distress syndrome and suggests extravasation of blood elements through discrete sites of cell injury associated with the fibrin-platelet aggregates rather than diffuse increase of permeability as cause of early alveolar flooding.

We slowly administered a bolus of 10 micrograms/kg of angiotensin II in saline to anesthetized rabbits. Their lungs are fixed by vascular perfusion of fixatives 2-3 minutes after the end of the infusion. Electron-microscopic examination of the lung parenchyma did not reveal signs of hemodynamic edema, but several epithelial alterations were observed that could be interpreted as the result of incorporation of plasmalemmal vesicles into the plasma membrane: these included undulating membrane profiles, transcellular channels formed by coalescing vesicles, and/or deep infoldings of the cell membrane. These appear to have the capability of causing demarcations in the cellular cytoplasm of Type I epithelial cells, which result in cell fractionation and localized destruction of the squamous alveolar epithelium, which leads to denudation of the basement membrane from the air side. These epithelial lesions were often associated with intracapillary platelet-fibrin aggregates, and cell destruction was most apparent in the presence of substantial amounts of fibrin. Morphologic signs of damage of the capillary endothelial cells existed but were less pronounced; in particular, there was no endothelial denudation under the platelet aggregates.