Aims: To report circulating and mucosa-deposited anti-basement membrane zone autoantibodies in a series of six ectodermal dysplasia patients with severe bilateral cicatrising conjunctivitis and blindness due to both corneal disease and intractable surface inflammation. We also report clinical improvement with steroid-sparing systemic immunosuppression combined with clearance of bacterial colonisation.
Methods: Conjunctival and buccal immunohistopathology, and serological analysis using a panel of epithelial basement membrane zone proteins including the bullous pemphigoid antigen 180 (BP180) were carried out as part of an ocular pemphigoid work-up in each patient. The degree of photophobia, conjunctival inflammation and visual acuity were monitored to evaluate the response to immunosuppression. The mean duration of follow-up was 31 (SD 6) months.
Results: Four of the six patients showed positive immunopathology: direct immunofluorescence testing of the conjunctiva in one patient demonstrated linear IgA deposition along the basement membrane zone, and IgG and IgM in the buccal mucosa of another patient. Circulating autoantibodies to BP180 were detected in two other patients. Treatment with systemic immunosuppression, combined with clearance of bacterial colonisation, reduced the severity of photophobia and degree of conjunctival inflammation in 5/6 (83%) patients.
Conclusions: Systemic immunosuppression, used as steroid-sparing therapy, combined with clearance of bacterial colonisation can control inflammation and disabling photophobia, and allow improvement in vision, in a subgroup of ectodermal dysplasia patients who have severe cicatrising conjunctivitis which shares clinical and immunopathological features with ocular mucous membrane pemphigoid.
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The ectodermal dysplasias are a large group of disorders which include ectrodactyly, ectodermal dysplasia, cleft lip and palate (EEC) syndrome, and are characterised by dry skin, sparse hair, dystrophic nails, hypoplastic teeth, and sweat gland anomalies.1 Recognised ophthalmic features of ectodermal dysplasias include absence of meibomian glands,2 3 lacrimal drainage abnormalities,4 corneal vascularisation and perforations,5–7 dry eye symptoms3 and conjunctivitis.4 7 8
Conjunctivitis in ectodermal dysplasia has previously been attributed to infection secondary to lacrimal drainage problems,7 or to blepharoconjunctivitis.8 In other cases, the aetiology of the keratoconjunctivitis has been obscure.2 Conjunctival scarring, along with entropion and secondary trichiasis, are recognised features of the subtype EEC syndrome,2 7 9 10 but the presence of circulating or mucosa-deposited anti-basement membrane autoantibodies associated with bilateral cicatrising conjunctivitis in these patients has not, to our knowledge, been previously reported.
This article presents new findings regarding the immunopathology of chronic bilateral cicatrising conjunctivitis in ectodermal dysplasia, and discusses insights that this reveals about the potential triggers for autoimmune conjunctivitis. We also report a new approach of combined steroid-sparing immunosuppression and clearance of bacterial colonisation to treat these patients, who are blind from both the corneal disease and intractable surface inflammation, and present significant difficulties in management.
PATIENTS AND METHODS
Patients and investigations
All six ectodermal dysplasia patients had been referred to the External Disease Service at Moorfields Eye Hospital between March 2003 and September 2004 with disabling bilateral conjunctivitis unresponsive to topical therapy and poor vision.
Upper and lower conjunctival fornix depth was measured with a fornix gauge.11 As part of the work-up for cicatrising conjunctivitis clinically resembling ocular mucous membrane pemphigoid (MMP), conjunctival and buccal mucosal biopsies for direct immunofluorescence12 and histopathology (conjunctival only) were taken. Serological testing for circulating anti-epithelial basement membrane autoantibodies was carried out by indirect immunofluorescence on monkey oesophagus and human salt split skin for IgG and IgA, as well as by non-conventional diagnostic techniques including an IgG ELISA for reactivity with recombinant BP180 NC16A (bullous pemphigoid antigen 180 kDa, 16th non-collagenous domain A), and immunoblotting studies testing for reactivity to a panel of cell-derived and recombinant proteins reported as target antigens in mucous membrane pemphigoid,13–15 including the soluble ectodomain of BP180 (also known as LAD-1, first described as a target antigen in Linear IgA Disease), laminin 5 and type VII collagen. Serological screening for autoimmune connective tissue diseases was also carried out. Lid and conjunctival microbiological cultures and sensitivities were taken at each clinic visit. The mean duration of follow-up was 31 (SD 6) months.
Immunosuppressive and antibiotic therapy strategy
The criterion for treatment with systemic therapy was when severe photophobia and conjunctival inflammation did not respond to at least 8 weeks of local therapy with topical steroids, antibiotics selected according to the lid and conjunctival cultures, and unpreserved lubricants. A stepladder strategy for steroid-sparing immunosuppression was employed, as described previously,16 17 consisting of a 4–6 week course of oral corticosteroids combined with one or more immunosuppressive agents. The least toxic agents were used first, and therapy was stepped up to more toxic agents if the conjunctival inflammation did not respond after 6–8 weeks. Blood pressure, weight, urinalysis and blood tests were evaluated regularly to screen for drug-related side effects. The degree of photophobia (graded 0–4), conjunctival inflammation (graded 0–4)18 and visual acuity were monitored.
The authors conducted a comprehensive search to identify all previous reports describing the immunopathological manifestations of ectodermal dysplasia and cicatrising conjunctivitis. English and non-English language articles were retrieved using a keyword and thesaurus search of MEDLINE (1966 onwards), EMBASE (1966 onwards) and the Web of Science Citation Index. The search terms included: ectodermal dysplasia and (Boolean) immunoglobulin, basement membrane immunoglobulin, fluorescent antibody test, cicatrix and (Boolean) conjunctivitis, cicatrising conjunctivitis. This was supplemented by manually searching the reference lists of all included studies. Reference books searched included major dermatological and ophthalmological texts.
The study was conducted with approval of the local research governance committee and with the informed consent of the patients.
The mean age was 39 (7) years (range 28–49) with a male:female ratio of 2:1. There was shortening of the upper conjunctival fornix in 8/12 (67%) eyes and of the lower fornix in 10/12 (83%) eyes (table 1). Advanced scarring and contracture with symblephara were present in 8/12 (83%) eyes. Entropion was present in 4/12 and trichiasis in 4/12 (33%) eyes. Meibomian gland orifices were absent in all eyelids, and no meibomian gland tissue could be detected by lid eversion at the slit lamp. Tear-film break-up time was reduced in all eyes. Schirmer’s I test without anaesthetic was reduced in both eyes of three patients.
Direct immunofluorescence testing (direct IF) showed linear immunoglobulin staining on the conjunctival biopsies (IgA) from case 4 (fig 1A), and the buccal biopsy (IgG, IgM) from case 2 (fig 1B). Circulating autoantibodies were detected in the serum of two additional patients: IgG autoantibodies reacting with the NC16A (16th non-collagenous A) domain of BP180 (bullous pemphigoid antigen of 180 kDa) in case 1, and IgA autoantibodies reacting against the soluble ectodomain of BP180 (also known as LAD-1 (linear IgA dermatosis antigen-1)) in case 5. Indirect immunofluorescence on human salt split skin and monkey oesophagus, and autoimmune connective tissue disease tests were negative in all patients. Conjunctival histopathology showed goblet cell depletion in thickened irregular epithelium, and a chronic inflammatory mononuclear infiltrate and scarring in the substantia propria in all cases.
Immunosuppression reduced conjunctival inflammation in 9/12 eyes (table 2, figs 2–4). Photophobia was markedly reduced in all patients during the course of treatment, but this deteriorated when the inflammation rebounded, or corneal perforations occurred. Improvement of visual acuity, including the ability to tolerate a contact lens for best vision, occurred in 4/12 eyes. Of the remaining eight eyes, visual acuity remained stable in five, and deteriorated in three eyes. Recurrent epithelial defects, corneal perforations and frequent corneal and conjunctival infections punctuated the treatment course in 5/12 eyes.
Immunosuppressive drugs were given according to the stepladder strategy previously described,16 17 and included prednisolone 1–1.5 mg/kg/day as a tapering course over 6 weeks (six patients), ciclosporin 3–5 mg/kg/day (five patients), dapsone 50–100 mg/day (four patients), azathioprine 1–2.5 mg/kg/day (three patients), mycophenolate 0.5–1 g twice daily (six patients) and cyclophosphamide 1–2 mg/kg/day (three patients) (table 2). A combination of two or more drugs was necessary to control inflammation in all patients. Changes in treatment were due to either intolerance or inadequate control of inflammation. For details, see Case Reports (available online).
Bacterial infection and colonisation were treated with 4 weeks of topical antibiotics to which the organisms were sensitive, followed by topical chlorhexidine 0.02% or polyhexamethylbiguanide (PHMB) if organisms were still cultured.
Anti-basement membrane zone autoantibodies were detected in four of the six ectodermal dysplasia patients with bilateral chronic cicatrising conjunctivitis in this series. The inflammation, photophobia and blepharospasm appeared to respond to steroid-sparing systemic immunosuppression combined with topical antibiotics, when it had failed to respond to topical steroids, antibiotics and lid hygiene alone.
Significance of the anti-basement membrane zone autoantibodies
Conjunctival cicatrisation is a recognised feature of the EEC syndrome, but to our knowledge the presence of anti-basement membrane zone autoantibodies has not previously been reported. The finding of basement membrane autoantibodies in four of the six patients with cicatrising conjunctivitis suggests that the pathogenesis may be similar to that occurring in mucous membrane pemphigoid (MMP), or may indicate a predisposition to developing a mucous membrane pemphigoid-like disease where the mucosal injury acts as a trigger. No symptoms or signs of ulceration or scarring of extraocular mucous membranes or skin were detected in any of the patients in this series. Ectodermal dysplasia may be associated with autoimmune disease,19 as in case 3 who had Addison disease, but there may also be no evidence of immunological dysfunction in other EEC patients.20
In addition to immunofluorescence techniques, we used serological diagnostic techniques, including immunoblot assay and ELISA to detect circulating autoantibodies to basement membrane zone antigens which have been reported to contain target epitopes in mucous membrane pemphigoid (MMP), as part of our work-up for cicatrising conjunctivitis resembling ocular mucous membrane pemphigoid. When indirect immunofluorescence microscopy is used, circulating antibodies against the epithelial basement membrane zone are detected in only about 50% of MMP sera.14 In comparison, when immunoblotting assays are used, autoantibodies can be detected in 75–100% of MMP sera.13 14 These assays are not currently used outside the research setting due to the costs involved.
Finding autoantibodies in these four patients may provide a rationale for the use of systemic immunosuppression, but steroid-sparing immunosuppression may also be helpful in patients in whom no immunoglobulin deposition is detected, as in case 3 in our series. Longitudinal follow-up of these cases, including those treated with immunosuppression and those not treated with immunosuppression, will help assess whether and how quickly cicatrisation progresses. Repeat fornix depth measurements in Case 5, whose conjunctival inflammation has been overall well controlled with systemic immunosuppression, have showed no change over the last 24 months.
Previous treatments reported
Conventional ocular treatment for patients with ectodermal dysplasia has addressed lid margin colonisation8 10 and the characteristic blepharitis, where the eyelids become thickened and inflamed despite the absence or paucity of meibomian glands. Lid hygiene, topical antibiotics and topical steroids or anti-inflammatory agents have had variable effects.7 10 21 Monitoring for glaucoma in these patients is not easy. The severe photophobia and blepharospasm makes examination very difficult, and in some cases examinations under anaesthesia are necessary. For this reason, we have avoided all but short-term use (ie, less than 1 month) of topical steroids in these patients.
Topical vitamin A therapy has been reported to reduce photophobia in a patient with hidrotic ectodermal dysplasia and corneal erosions.6 Systemic ciclosporin, topical mycophenolate and oral steroids have been used to prevent graft rejection following penetrating keratoplasty and keratolimbal allografting in two ectodermal dysplasia patients, but their effect on photophobia or conjunctival inflammation in these patients was not described.5
Effectiveness and safety of systemic immunosuppression
Systemic immunosuppression combined with topical antibiotic or antiseptic therapy appeared to reduce disabling photophobia and conjunctival inflammation in 5/6 (83%) of patients in this series. The chief rationale for systemic immunosuppression was the clinical dilemma of a prolonged active inflammatory state with poor response to topical therapy. Given the prolonged course of inflammation, immunosuppression was commenced as steroid-sparing therapy, to avoid the significant morbidity associated with long-term high-dose systemic corticosteroids. This is an uncontrolled case series, however, so the true value of the combined treatment approach cannot be assessed. Furthermore, topical immunosuppression using ciclosporin or tacrolimus could be considered. In the UK, our locally available preparation of ciclosporin is poorly tolerated (2% in oil), and topical tacrolimus is not available for ophthalmic use.
Recurrent corneal and conjunctival infections and colonisation by pathogenic organisms despite prophylactic topical antibiotics or antiseptic therapy was a recalcitrant problem for all patients, and was responsible for rebounds in conjunctival inflammation. Systemic immunosuppression appeared to be effective for several months, but then corneal perforations or a flare-up of conjunctival inflammation led to a change in medication. Most patients required two agents to control photophobia and inflammation, and three of the six have required the most toxic agent, cyclophosphamide. Systemic immunosuppression did not appear to impair the ability to overcome corneal or conjunctival infections, as all acute infections in this series of patients resolved. Whether immunosuppressive therapy had any effect on increasing the predisposition to developing such infections could not be evaluated in this study.
Adverse effects encountered during immunosuppression in our patients, all of which were reversible upon cessation of therapy, included renal impairment due to ciclosporin, nausea due to azathioprine and liver-function abnormalities due to mycophenolate and azathioprine. Although the sample size and duration of follow-up are not great enough to know how safe immunosuppressive treatment is in this group of patients, some information on the safety and risks associated with the treatment can be gained from our report of use of a similar immunosuppressive strategy in 115 patients with mucous membrane pemphigoid, where the duration of follow-up was up to 14 years.17 Furthermore, it is unknown how long the immunosuppressive therapy will be maintained for in these patients. In case 3, immunosuppression was stopped after 3 years as the ocular surface inflammation had been quiescent for 6 months.
Proposed pathogenesis of the cicatrising conjunctivitis
Patients developing conjunctival scarring as part of their disease process can be divided into two categories, and the patients with ectodermal dysplasia presented here may fit both of these: in the first category, chronic ocular mucosal injury precipitates conjunctival cicatrisation that may be progressive, as in atopic keratoconjunctivitis, rosacea and trachoma22 (cases 3, 6 in this report). In the second category, conjunctival cicatrisation may be associated with antibodies directed at the basement membrane, as in mucous membrane pemphigoid,12 which may be a final common pathway for a subset of patients with progressive conjunctival cicatrisation, including those with Stevens–Johnson syndrome23 and drug-induced ocular pemphigoid24 25 (cases 1, 2, 4, 5 in this report).
Possible factors involved in chronic mucosal injury in these patients with ectodermal dysplasia include: (1) recurrent lid and conjunctival infection due to microbial colonisation of the ocular surface; (2) recurrent conjunctival infection due to lacrimal drainage abnormalities; (3) lack of lipid and mucin in the tear film due to absent meibomian glands and reduced goblet cells. Goblet cells may be reduced as a consequence of inherent defects in the conjunctival epithelium as well as secondary to conjunctival fibrosis. In severe cases (eg, case 1), lacrimal ductule obstruction from conjunctival fibrosis leads to further instability of the tear film and surface epithelial destruction. Meibomian lipid may also function to trap and enfold micro-organisms, pollen or other organic matter, thereby rendering the entity isolated and harmless, and a lack of meibomian lipid may enable such particles to injure the mucosa;26 and (4) a primary defect of ectodermally derived conjunctival epithelium. Recent evidence from a mouse model of X linked anhydrotic ectodermal dysplasia supports the latter notion of ocular surface health being dependent on proteins such as ectodysplasin, which regulates and maintains ectoderm-derived tissues.27
Major visual disability in ectodermal dysplasia patients is attributed to severe photophobia and blepharospasm,21 along with blindness secondary to corneal vascularisation.7 Our patients were most improved when they were taking immunosuppression, and their conjunctival and eyelid cultures showed no growth. For this reason, we postulate that the ongoing conjunctival inflammation and associated conjunctival scarring in these patients may be due to an abnormal host response to bacterial colonisation or infection. Ongoing surface inflammation and limbitis may play a role in the pathogenesis of ocular surface failure and corneal vascularisation, which is the other major cause of visual impairment.
In conclusion, anti-basement membrane zone autoantibodies are detectable in a subgroup of ectodermal dysplasia patients with cicatrising conjunctivitis. We propose that clearance of bacterial colonisation, combined with suppression of the excessive inflammatory response by immunosuppressive therapy administered by experienced physicians, can improve the visual disability caused by intractable conjunctival inflammation and photophobia, and provide an opportunity for carrying out ocular surface reconstructive surgery to treat the blindness due to corneal disease.
Funding: This study was supported by the Special Trustees of Moorfields Eye Hospital, a Royal Australian & New Zealand College of Ophthalmologists/Advanced Medical Optics Scholarship and a University College London Graduate School Scholarship (VPJS).
Competing interests: None.
Ethics approval: Ethics approval was obtained from the local research governance committee.
Patient consent: Obtained.