Pathology, immunopathology, and immunohistochemistry in cutaneous lupus erythematosus

Assessment of Clinical and Laboratory Use of the Cutaneous Direct Immunofluorescence Assay

Importance

Dermatologists submit direct immunofluorescence (DIF) biopsies on a daily basis, using an assay detecting immunoreactant deposition with a panel that has traditionally comprised immunoglobulin (Ig) G, IgA, IgM, C3, and fibrin, with or without albumin antibodies.

Objectives

To evaluate and compare the frequency of immunoreactants in DIF biopsies submitted over an 8-year period and assess use by dermatologists based on clinical impression.

Design, Setting, and Participants

A quality improvement study was conducted in a community outreach reference laboratory associated with a large academic medical center. Results of 2050 consecutive DIF skin biopsies submitted to the laboratory between April 1, 2012, and June 12, 2020, were analyzed by final pathologic diagnosis and antibody subtype positivity, in comparison with clinical impression. Biopsies in which the submitting physician had not performed the biopsy were excluded.

Main Outcomes and Measures

Histopathologic findings and the results of DIF biopsies using the standard 6-antibody panel were evaluated in correlation with the submitted clinical diagnosis to assess immunoreactivity of the assay.

Results

Of 2050 DIF biopsies submitted, 367 (17.9%) were positive; IgG, IgA, and C3 alone identified all primary immunobullous disease cases (pemphigoid, pemphigus, linear IgA, and dermatitis herpetiformis), and IgA, C3, and fibrin antibodies alone identified all vasculitis cases. A panel of IgG, IgA, IgM, and fibrin identified all cases of lupus erythematosus. DIF results were positive in less than half of cases of hematoxylin and eosin biopsy-confirmed lupus erythematosus (23 of 47 [49%]). A total of 247 biopsies were submitted for clinical diagnoses not optimally supported on DIF: lichen planus, porphyria, and connective tissue disease.

Conclusions and Relevance

The findings of this study suggest that there is a knowledge gap among dermatologists relating to the opportunity for high-value, cost-conscious use of DIF. The practice of reflexive antibody testing using a 6-antibody panel for all DIF biopsies is likely unnecessary. DIF protocols tailored to the clinical diagnosis may enhance cost-effectiveness without loss of test sensitivity or specificity.

Cutaneous Manifestations of "Lupus": Systemic Lupus Erythematosus and Beyond

Lupus, Latin for "wolf," is a term used to describe many dermatologic conditions, some of which are related to underlying systemic lupus erythematosus, while others are distinct disease processes. Cutaneous lupus erythematosus includes a wide array of visible skin manifestations and can progress to systemic lupus erythematosus in some cases. Cutaneous lupus can be subdivided into three main categories: acute cutaneous lupus erythematosus, subacute cutaneous lupus erythematosus, and chronic cutaneous lupus erythematosus. Physical exam, laboratory studies, and histopathology enable differentiation of cutaneous lupus subtypes. This differentiation is paramount as the subtype of cutaneous lupus informs upon treatment, disease monitoring, and prognostication. This review outlines the different cutaneous manifestations of lupus erythematosus and provides an update on both topical and systemic treatment options for these patients. Other conditions that utilize the term "lupus" but are not cutaneous lupus erythematosus are also discussed.

Cutaneous lupus erythematosus in dogs: a comprehensive review

Since the first description of discoid lupus erythematosus (LE) in two dogs in 1979, the spectrum of canine cutaneous lupus erythematosus (CLE) variants has expanded markedly.

In this review, we first propose an adaptation of the Gilliam-Sontheimer classification of CLE for dogs. We then review the signalment, clinical signs, laboratory and histopathology and treatment outcome of the currently recognized variants of canine CLE, which are vesicular CLE, exfoliative CLE, mucocutaneous LE and facial or generalized discoid LE. We end with a short description of the rare cutaneous manifestations of systemic LE in dogs.

Canine CLE variants are heterogeneous, some of them mirror their human counterparts while others appear—thus far—unique to the dog. As most CLE subtypes seem to have a good prognosis after diagnosis, veterinarians are encouraged to become familiar with the spectrum of often-characteristic and unique clinical signs that would permit an early diagnosis and the rapid implementation of an effective treatment.

Scarring alopecia in discoid lupus erythematosus: a clinical, histopathologic and immunopathologic study

Scarring alopecia is a very frequent feature of chronic discoid lupus erythematosus (DLE). So far in the literature, only clinic-pathologic features or histopathologic-immunopathologic traits of DLE scarring alopecia (DLESA) have been reported. We describe the most significant features of clinical morphology, histopathology, serum and tissue immunopathology of 36 DLESA patients (41.9% of all our scarring alopecia patients). Clinically, 33.3% presented a single lesion and 52.7% presented multiple lesions of scarring alopecia, while 13.8% exhibited a picture resembling Pseudopelade of Brocq, with the classic ‘footprints in the snow’ appearance. The most frequent morphologic features were sclero-atrophy (80.5%) and erythema (63.8%). The main histopathologic aspects appeared to be fibrosis (100%), follicular hyperkeratosis (91.4%), epidermal atrophy (88.5%), lymphocytic infiltrate (88.5%), thickened basement membrane (77.1%) and basal vacuolar degeneration (74.2%). Antinuclear antibodies were present in 42.8% of patients and antigastric mucosa, antithyroid and anticardiolipin antibodies in 17-21% of patients. A positive lupus band test was demonstrated in 81.8% of cases and perivascular deposit in 30.3% of patients. Histopathology alone allowed a correct diagnosis only in 68.5% of cases; in the other cases, the diagnosis was assessed also taking into account immunopathologic findings. Our study defines the clinic, histopathologic and immunopathologic features of DLESA patients and points out that a multiparametric approach is mandatory to assess the diagnosis of DLESA.

[Cutaneous panniculitis]

Panniculitis is an inflammation of the subcutaneous fat. Skin biopsy plays a critical role in the differential diagnosis of panniculitis. The most common approach to diagnosis relies on the differentiation between predominantly septal or lobular panniculitis, followed by the distinction between lesions with and without vasculitis. It is also very important to submit a part of the skin biopsy for microbiological analysis and for T-cell clonal expansion if T-cell lymphoma is suspected. Erythema nodosum, the most frequent septal panniculitis, has many causes and in its typical clinical presentation, does not require skin biopsy. In other panniculitis, diagnosis is based on the integration of the clinical and histological data, which renders a deep cutaneous biopsy necessary. Periarteritis nodosa, a septal panniculitis with vasculitis characterized by subcutaneous nodules and livedo racemosa, can be associated with systemic involvement. Nodular thrombophlebitis needs search for associated coagulopathy, Behçet's disease, periarteritis nodosa or Buerger's disease. Lobular panniculitis are classified according to the nature of cells present in the inflammatory infiltrate. If there is a lymphocytic infiltration, lupus panniculitis is difficult to differentiate from subcutaneous panniculitis-like T-cell lymphoma. If there are histiocytes, it can be a sarcoidosis, a cytophagic histiocytic panniculitis or, in newborn, a subcutaneous fat necrosis. Neutrophilic panniculitis needs careful clinic-pathologic correlation. Treatment of panniculitis can be challenging and is based on the histopathological findings. Frequently, the precise cause of panniculitis cannot be established from the outset, so it is important to follow-up patients and not hesitate to repeat the skin biopsy.

Kutaner Lupus erythematodes

The diagnosis of cutaneous lupus erythematosus (CLE) requires a specific diagnostic approach to identify subtypes, to address differential diagnostic considerations, and to rule out systemic organ involvement. In addition to a detailed patient's history and clinical evaluation of the skin, histopathologic and immunofluorescent examination of a skin biopsy as well as laboratory screening are recommended. Photoprovocation tests can be performed to confirm the diagnosis of CLE and to assess photosensitivity in these patients. Recently, a scoring system for the activity of the cutaneous manifestations in CLE has been developed and validated which involves anatomical areas and morphologic signs of the skin lesions. In all subtypes of CLE, antimalarials are still the treatment of choice. Advances in biotechnology have led to the development of several novel agents for the treatment of autoimmune diseases; however, controlled trials have not been performed in patients with CLE. Furthermore, there is need for specific immunointervention, especially for patients who fail to respond to standard therapies. The second part of this review will enable the reader to differentiate CLE from other diseases and to suggest specific diagnostic procedures and treatment approaches.

Lupus erythematosus: considerations about clinical, cutaneous and therapeutic aspects

Systemic Lupus Erythematosus is a chronic inflammatory disease with multifactorial etiology. Although clinical manifestations are varied, the skin is an important target-organ, which contributes to the inclusion of skin lesions in 4 out of the 17 new criteria for the diagnosis of the disease, according to the Systemic Lupus International Collaborating Clinics. The cutaneous manifestations of lupus are pleomorphic. Depending on their clinical characteristics, they can be classified into Acute Cutaneous Lupus Erythematosus, Subacute Cutaneous Lupus Erythematosus, Chronic Cutaneous Lupus Erythematosus and Intermittent Cutaneous Lupus Erythematosus. Treatment is based on preventive measures, reversal of inflammation, prevention of damage to target organs and relief of adverse events due to pharmacological therapy. The most commonly used treatment options are topical, systemic and surgical treatment, as well as phototherapy. The correct handling of the cases depends on a careful evaluation of the morphology of the lesions and the patient's general status, always taking into consideration not only the benefits but also the side effects of each therapeutic proposal.

Neonatal lupus syndrome in a Nigerian child

Neonatal lupus is a rare syndrome resulting from passively transferred maternal autoantibodies during pregnancy. A male infant was delivered at term to a 29-year-old primiparous woman who was diagnosed of systemic lupus erythematosus 2 years earlier and had detectable levels of autoantibodies (antinuclear antibody (ANA), anti-dsDNA, anti-Ro and anti-La/SSB) in second trimester. However, the pregnancy was otherwise uneventful. He presented at the age of 8 week with a widespread hypopigmented macular rash on the trunk and patchy alopecia involving the hair line and the occipito-parietal regions of 3 weeks duration, anaemia and symptomatic thrombocytopaenia. Serologic test for autoantibodies was positive for ANA and anti-La/SSB. Further evaluation was normal. He was managed conservatively with blood products and topical corticosteroids. Mother was also advised to avoid direct exposure to sunlight and fluorescent light. Haematological parameters gradually normalised over 2 months and the skin lesions resolved completely by the age of 6 months.

Prolonged urticaria and fever in a toddler

We describe a 14-month-old girl who initially presented with 8 days of fever, conjunctival injection, rash, and irritability, admitted with a presumptive diagnosis of Kawasaki disease. Further history revealed intermittent urticarial-like rash since 3 months of age and pathological evaluation showed a perivascular infiltrate of neutrophils and lymphocytes. Here, we discuss the key points surrounding her diagnostic workup and our therapeutic approach.

Immunohistochemistry of ultrastructural changes in scarring lupus erythematosus

BACKGROUND

The various clinical types of lupus erythematosus (LE) show an essentially similar histological picture, and the subsets of LE cannot easily be distinguished by histology alone. However, there is an important clinical difference: lesions of discoid LE (DLE) cause scarring, particularly on the scalp, whereas lesions of subacute and acute LE heal without scarring. The focal thickening of the basement membrane zone (BMZ) in DLE lesions represents an important histopathological finding, and there is little known about the nature of these alterations at the BMZ level.

AIM

To investigate BMZ alterations in the basement membrane zone (BMZ) in cutaneous LE (CLE) by immunohistochemistry.

METHODS

Skin biopsies from 30 patients with CLE [DLE and subacute CLE (SCLE)] and from 10 controls were studied using antibodies to cytokeratin 5, cytokeratin 14, bullous pemphigoid (BP)180, BP230, plectin, laminin 5, collagen IV and collagen VII. Results.  There was increased expression of components of the lamina lucida, lamina densa and anchoring fibrils in active DLE, whereas expression was normal in SCLE and control tissues, and in areas of scarring in DLE. In addition, higher expression of the hemidesmosome-associated antigens (BP230 and plectin) was found in active DLE. The expression of other antigens was similar in all tissues examined.

CONCLUSIONS

These alterations in the BMZ suggest that the BMZ may react in a different way in active DLE than in SCLE, and that the BMZ may remodel in different ways. These immunohistochemical differences may provide a new method of histological differentiation between the various LE subtypes.

High Ro52 expression in spontaneous and UV-induced cutaneous inflammation

Ro52 is an E3 ubiquitin ligase with a recently identified regulatory role in inflammation. The protein is targeted by autoantibodies in rheumatic diseases, and Ro52 autoantibodies are specifically associated with cutaneous lupus erythematosus (CLE) and photosensitivity. The aim of this study was to investigate cutaneous Ro52 expression in CLE patients and to examine whether UVR might modulate Ro52. Ro52 expression was assessed by immunohistochemistry in biopsies derived from CLE lesions (n=25), nonlesional (n=7), and healthy control skin using four anti-Ro52 mAbs generated by us. Ro52 expression was also analyzed in psoriatic, lichenoid, and eczematous lesions. It was increased in the epidermis of spontaneous CLE lesions as compared with unaffected skin of patients and healthy controls. High epidermal Ro52 expression was also observed in other inflammatory dermatoses investigated. Ro52 was upregulated in experimentally photoprovoked CLE lesions as observed by immunohistochemistry in sequential biopsies, which was confirmed in vitro both at the mRNA and protein levels by exposing cultured patient-derived primary keratinocytes to UVR. In conclusion, Ro52 expression is upregulated in keratinocytes in inflammatory skin conditions and in response to UVR. High Ro52 expression might lead to the breaking of tolerance and the generation of Ro52 autoantibodies in genetically susceptible subjects. Further, the upregulation of Ro52 in keratinocytes after sun exposure might also be a triggering factor for skin lesions in patients with Ro52 antibodies.

Sunlight triggers cutaneous lupus through a CSF-1-dependent mechanism in MRL-Fas(lpr) mice

Sunlight (UVB) triggers cutaneous lupus erythematosus (CLE) and systemic lupus through an unknown mechanism. We tested the hypothesis that UVB triggers CLE through a CSF-1-dependent, macrophage (Mø)-mediated mechanism in MRL-Fas(lpr) mice. By constructing mutant MRL-Fas(lpr) strains expressing varying levels of CSF-1 (high, intermediate, none), and use of an ex vivo gene transfer to deliver CSF-1 intradermally, we determined that CSF-1 induces CLE in lupus-susceptible MRL-Fas(lpr) mice, but not in lupus-resistant BALB/c mice. UVB incites an increase in Møs, apoptosis in the skin, and CLE in MRL-Fas(lpr), but not in CSF-1-deficient MRL-Fas(lpr) mice. Furthermore, UVB did not induce CLE in BALB/c mice. Probing further, UVB stimulates CSF-1 expression by keratinocytes leading to recruitment and activation of Møs that, in turn, release mediators, which induce apoptosis in keratinocytes. Thus, sunlight triggers a CSF-1-dependent, Mø-mediated destructive inflammation in the skin leading to CLE in lupus-susceptible MRL-Fas(lpr) but not lupus-resistant BALB/c mice. Taken together, CSF-1 is envisioned as the match and lupus susceptibility as the tinder leading to CLE.

Kutaner Lupus erythematodes

Cutaneous lupus erythematosus (CLE) is a heterogenous disorder with a wide range of skin manifestations. Therefore, it has been difficult to develop a unifying concept for classifying CLE from the dermatologic perspective in the past. In 2004, the classification system was updated and includes now acute CLE (ACLE), subacute CLE (SCLE), chronic CLE (CCLE), and intermittent CLE (ICLE). Additional rarely described variants are not listed as separate entities but are included in the classical forms. Diagnosis of the different subtypes of CLE is made by considering genetic, clinical, histopathologic, and immunoserologic findings, with a systematic analysis of individual criteria. In the past years, the etiology and pathogenesis of CLE has been subject of intensive research and it has been shown by several groups that exogenous factors, such as ultraviolet light and drugs, can induce CLE. The first part of this review will enable the reader to identify the various clinical manifestations of CLE and to employ characteristic criteria to assess differential diagnostic considerations.

Immunoglobulin M predominance in cutaneous lupus erythematosus

BACKGROUND

Direct immunofluorescence (DIF) is a valuable tool in the diagnosis of cutaneous lupus erythematosus (LE). Our goal was to characterize the most frequent immune reactants in the skin biopsies of cutaneous LE and identify the most common immunofluorescence staining patterns.

METHODS

DIF results of immunoglobulin G (IgG), IgA, IgM, C3, and fibrinogen from 199 patients between 1989 and 1998 were retrospectively analyzed. Confirmatory clinical and serological diagnosis of LE subtype was available for 95 patients. Intensity of staining was ranked from 0 to 4+ but only included as significant if >/=2+. Laboratory values were gathered and analyzed for all patients who had distinct granular immune deposition for Ig and/or complement.

RESULTS

The most commonly detected individual Ig was IgM in 149 (75%) specimens. IgM and C3 combination was the most common pair expressed with 98 (49%) specimens. The most common triplet was IgM, C3, and fibrinogen in 63 (32%) specimens. The most common quadruplet was the combination of IgG, IgM, C3, and fibrinogen in 42 (21%) specimens. All the five immunoreactants were detected in only 25 (13%) specimens. Systemic LE patients had a higher percent of abnormal laboratory values compared to discoid LE (DLE) and subacute LE (SCLE) patients (p = 0.02). Fibrinogen staining was found to be significantly higher in DLE patients and lowest in SCLE patients (p = 0.05).

CONCLUSIONS

This study demonstrates a marked predominance of IgM +/- C3 in cutaneous LE. When used in conjunction with other data, DIF is an extremely powerful tool in the routine evaluation of the LE patient. Our report emphasizes the importance of IgM expression in the diagnosis of LE by DIF and how positive staining with multiple conjugates can raise its sensitivity.

Immunopathology of vesicular cutaneous lupus erythematosus in the rough collie and Shetland sheepdog: a canine homologue of subacute cutaneous lupus erythematosus in humans

Clinical and histological features of an erosive disease in the rough collie and Shetland sheepdog are most consistent with a vesicular variant of cutaneous lupus erythematosus (VCLE). This paper reports the immunopathological findings of canine VCLE using samples from 17 affected dogs. Lesional skin sections were stained with monoclonal antibodies specific for CD3 (11 dogs) or a panel of monoclonal antibodies specific for leukocyte antigens (two dogs). Apoptotic cells were detected using the TUNEL method in 12 cases. Direct (14 dogs) and indirect immunofluorescence tests (five dogs) were also performed. Circulating antibodies to extractable nuclear antigens (ENA) were surveyed in 11 dogs by immunoblotting and ELISA. The predominant cells at the dermal-epidermal interface were identified as CD3(+) T lymphocytes expressing CD4 or CD8 and CD1(+) dendritic antigen presenting cells. In 7/12 dogs (58%), apoptosis of basal keratinocyte nuclei was present. Up-regulation of MHCII and ICAM-1 was observed on basal keratinocytes from the two dogs examined. Direct immunofluorescence revealed deposition of immunoglobulins bound to the cytoplasm of keratinocytes (6/14 dogs; 43%), to the dermal-epidermal junction (7/14 dogs; 50%), or to superficial dermal venules (13/14 dogs; 93%). Circulating IgG auto-antibodies targeting one or more ENA were detected in nine (82%) and eight (73%) of 11 dogs by immunoblotting and ELISA, respectively. These auto-antibodies recognized Ro/SSA and/or La/SSB in four (36%) and six (55%) of 11 dogs respectively by these two methods. Altogether, results of these studies provide evidence supporting the hypothesis that canine VCLE is an immunological homologue of subacute cutaneous lupus erythematosus in humans.

Histopathologic findings in lupus erythematosus tumidus: review of 80 patients

BACKGROUND

In a recent study, we demonstrated that lupus erythematosus (LE) tumidus (LET) is a distinct subset of cutaneous LE (CLE), which is clinically characterized by erythematous, urticaria-like, nonscarring plaques in sun-exposed areas.

OBJECTIVE

Our purpose was to analyze skin biopsy specimens from 80 patients with this disease and to determine whether it could be differentiated from other variants of CLE on histopathologic grounds.

METHODS

Skin biopsy specimens from 53 primary and 38 UVA- and/or UVB-induced lesions of 80 patients with LET were examined and compared with skin biopsy specimens from patients with discoid LE (DLE) and subacute CLE (SCLE).

RESULTS

Specimens from LET lesions showed a characteristic and diagnostic pattern of perivascular and periadnexal cellular infiltrates in the papillary and reticular dermis composed almost entirely of lymphocytes. In some cases, few scattered neutrophils were present. Furthermore, interstitial mucin deposition was observed in all specimens, as confirmed by colloidal iron staining. In contrast to discoid LE and subacute CLE lesions, epidermal atrophy or alteration at the dermoepidermal junction was not detected.

CONCLUSION

Skin lesions of patients with LET present with specific histopathologic features, and the differences compared with subacute CLE and discoid LE further support the concept to consider LET as a separate entity of CLE.

Mannose binding lectin (MBL) polymorphisms associated with low MBL production in patients with dermatomyositis

One theory for the pathophysiology of photosensitive autoimmune skin diseases is that photoinduction of tumor necrosis factor alpha (TNFalpha) secretion leads to keratinocyte apoptosis and translocation of previously sequestered cellular antigens that then activate the immune system. We previously found an association of the overproducing TNFalpha-308 A variant with adult dermatomyositis and with subacute cutaneous lupus erythematosus. Here we focused on mannose binding lectin (MBL), which is one of several proteins involved in clearance of apoptotic cells and could thereby lessen photosensitive autoimmunity. We examined three variant MBL polymorphisms associated with decreased MBL protein (Asp54, Glu57, and the LX promoter polymorphism) in adult dermatomyositis, subacute cutaneous lupus erythematosus, and discoid lupus, and controls. The variant Asp54 allele was positively associated with adult dermatomyositis in a dose-responsive fashion (p=0.0004), as was the Glu57 allele (p=0.004). None of the three variant MBL alleles considered individually was significantly associated with either subacute cutaneous lupus erythematosus or discoid lupus. In adult dermatomyositis patients homozygous for the wild-type TNFalpha-308G allele (GG), i.e., presumably without elevated TNFalpha production, 69% had at least two of the MBL polymorphisms, versus 20% of healthy GG controls (p=0.0011). Combinations of low-producing MBL variants were over-represented in adult dermatomyositis in a dose-responsive fashion (p=0.0002). In adult dermatomyositis patients with one variant TNFalpha-308 A allele (GA), 46% had at least two MBL polymorphisms, versus 7% of GA controls (p=0.0077). Thus, low-producing MBL genes are very strongly associated with adult dermatomyositis. Our model is that genetic polymorphisms leading to overproduction of apoptotic keratinocytes and then impaired clearance of these cells contribute to the pathogenesis of adult dermatomyositis, a photoinduced autoimmune skin disease.

Cutaneous lupus erythematosus: a review

This article will review and update information about the pathogenesis, clinical presentation, diagnosis, and treatment of cutaneous lupus erythematosus. Lupus erythematosus (LE) can present as a skin eruption, with or without systemic disease. Cutaneous LE is subdivided into chronic cutaneous LE, subacute cutaneous LE and acute LE. The prevalence of systemic lupus erythematosus (SLE) is 17-48/100,000 population worldwide. Skin disease is one of the most frequent clinical complaints of patients suffering from SLE. It has been found to occur in up to 70% of patients during the course of the disease. The most frequent mucocutaneous manifestations of SLE are malar rash (40%), alopecia (24%), and oral ulcers (19%). It has been suggested that risk factors that are more likely to signal transition of cutaneous into systemic LE are high ANA titers (> 1:320) and the presence of arthralgias. CLE patients who exhibit these symptoms should be monitored closely, since they may be at increased risk to develop SLE.

Ulcerative dermatosis of the Shetland sheepdog and rough collie dog may represent a novel vesicular variant of cutaneous lupus erythematosus

A syndrome of ulcerative dermatitis (UDSSC) previously has been described as unique to the Shetland sheepdog and rough collie dog. The pathogenesis of this disease is poorly understood and it has been suggested that it may be a variant of canine dermatomyositis (DM) which is also seen in these breeds. Information on the clinical presentation and previous medical history was collected from five Shetland sheepdogs and three rough collie dogs previously diagnosed with UDSSC. Characteristic features of the disease were adult onset in the summer months with annular, polycyclic and serpiginous ulcerations distributed over sparsely haired areas of the body. Skin biopsies taken from active lesions were compared in a blinded fashion with histological sections from seven Shetland sheepdogs and one rough collie with DM. Dermatomyositis was characterized histologically as a cell poor interface dermatitis associated with follicular atrophy. In contrast, the lesional pattern of UDSSC is that of a lymphocyte-rich interface dermatitis and folliculitis with vesiculation at the dermal-epidermal junction. The authors conclude that these represent two distinct diseases and that UDSSC may be a vesicular form of cutaneous lupus erythematosus seen in the adult rough collie dog and Shetland sheepdog.

Association of a promoter polymorphism of tumor necrosis factor-alpha with subacute cutaneous lupus erythematosus and distinct photoregulation of transcription

Ultraviolet irradiation stimulates keratinocytes and dermal fibroblasts to release cytokines involved in apoptosis and immunomodulation, such as tumor necrosis factor-alpha and interleukin-1alpha. Recent work has associated the -308A polymorphism of the human tumor necrosis factor-alpha promoter with systemic lupus erythematosus and adverse outcomes in several infectious diseases. To explore the role of this polymorphism in ultraviolet-induced disease, we used two approaches. First, we examined its prevalence in individuals with different ultraviolet sensitivity. Compared with healthy controls, there was a substantially increased prevalence of -308A in subacute cutaneous lupus erythematosus, an extremely photosensitive form of cutaneous lupus erythematosus, but not in discoid lupus erythematosus, a less photosensitive form. Next, to examine molecular regulation by tumor necrosis factor -308A, cultured 3T3 fibroblasts were transiently transfected with chloramphenicol acetyl transferase reporter constructs under the control of either -308A or the wild-type -308G promoter. Without added interleukin-1alpha the two constructs produced similar baseline chloramphenicol acetyl transferase activity and similar responses to ultraviolet. The responses to interleukin-1alpha, a photoinduced cytokine, were markedly different: interleukin-1alpha without ultraviolet produced a 15-fold increase in chloramphenicol acetyl transferase transcription from the -308A construct without affecting the wild-type -308G. Interleukin-1alpha plus ultraviolet B caused a remarkable 300-fold increase in -308A chloramphenicol acetyl transferase transcription over baseline, while increasing the wild type to <15% of this level. These results indicate a clear difference between the two promoters, including a striking synergy between ultraviolet B and added interleukin-1alpha in the induction of transcription by the tumor necrosis factor-alpha -308A promoter. Overall, our findings indicate a strong linkage between the -308A polymorphism and subacute systemic lupus erythematosus, which is likely to directly contribute to the photosensitivity of these patients.

Pemphigus foliaceus in association with systemic lupus erythematosus, and subsequent lymphoma in a cocker spaniel

A seven-year-old neutered male cocker spaniel was presented with an 11-month history of generalised bacterial dermatitis. There were skin lesions over the entire body, which were round, slightly raised and encrusted. Skin biopsies were collected and the histological findings were consistent with pemphigus foliaceus. Immunohistochemical staining by the indirect immunoperoxidase method was positive, with desmosomal deposition of immunoglobulin (Ig) G. Haematological analysis revealed a regenerative anaemia and profound thrombocytopenia, while a Coombs' test was positive for polyvalent canine Coombs' reagent and anti-dog IgG. An antinuclear antibody test was positive, with a titre of 10,240. An ophthalmic examination demonstrated low tear production (keratoconjunctivitis sicca). Seven months after initial referral, the dog was re-presented with severe generalised peripheral lymphadenopathy. Radiographic evaluation of the thorax and abdomen revealed enlarged cranial mediastinal and sublumbar lymph nodes. Tru-Cut biopsy from an enlarged lymph node confirmed the diagnosis of lymphoma, which was phenotyped as a B-cell tumour. The diagnosis in this case was systemic lupus erythematosus, with the unusual feature of pemphigus foliaceus, and subsequent development of B-cell lymphoma. The case adds further to knowledge of the protean clinical presentations of canine autoimmune diseases and provides additional evidence for the potential association between autoimmunity and immune-system neoplasia in this species.

A Central Role for αβ T Cells in the Pathogenesis of Murine Lupus

We have previously shown that female transgenic mice expressing IFN-γ in the epidermis, under the control of the involucrin promoter, develop inflammatory skin disease and a form of murine lupus. To investigate the pathogenesis of this syndrome, we generated female IFN-γ transgenic mice congenitally deficient in either αβ or γδ T cells. TCRδ−/− transgenics continued to produce antinuclear autoantibodies and to develop severe kidney lesions. In contrast, TCRβ−/− IFN-γ transgenic mice failed to produce antinucleosome, anti-dsDNA, or antihistone autoantibodies, and kidney disease was abolished. Both αβ- and γδ-deficient transgenics continued to develop IFN-γ-associated skin disease, lymphadenopathy, and splenomegaly. The data show that the autoantibody-mediated pathology of murine lupus in IFN-γ transgenic mice is completely αβ T cell dependent and that γδ T cells cannot drive autoantibody production. These results imply that production of antinuclear autoantibodies in IFN-γ transgenic animals is Ag driven, and we identified clusters of apoptotic cells in the epidermis of the mice as a possible source of self Ags. Our findings emphasize the relevance of this murine lupus model to the human disease.