Reactivity against the BP180 ectodomain in patients with bullous pemphigoid, mucous membrane pemphigoid, multiple sclerosis and Parkinson disease.

The 16th non-collagenous domain (NC16A) of BP180 is the main antigenic target of autoantibodies in bullous pemphigoid (BP) and mucous membrane pemphigoid (MMP). Commercially available assays detect serum autoantibodies against NC16A in the majority of BP (80%-90%) and in approximately 50% of MMP patients. However, a standardized test system for detecting antibodies against other regions of BP180 is still lacking. Moreover, anti-BP180 autoantibodies have been found in neurological conditions such as multiple sclerosis and Parkinson disease. This study aimed at identifying primary epitopes recognized by BP autoantibodies on the BP180 ectodomain. Serum samples of 51 BP and 30 MMP patients both without anti-NC16A reactivity were included along with 44 multiple sclerosis and 75 Parkinson disease sera. Four overlapping His-tagged proteins covering the entire BP180 ectodomain (BP180(ec)1-4) were cloned, expressed, purified and tested for reactivity by immunoblot. IgG antibodies to BP180(ec)3 were detected in 98% of BP, 77% of MMP and 2% of normal human sera. Only weak reactivity was detected for neurological diseases against BP180(ec)1, BP180(ec)2 and BP180(ec)4, in 3%, 11% and 7% of tested multiple sclerosis sera, respectively. 8% of Parkinson disease sera reacted with BP180(ec)2 and 9% with BP180(ec)4. In conclusion, this study successfully identified epitopes recognized by BP autoantibodies outside the NC16A domain in pemphigoid diseases. These findings contribute to a better understanding of the immune response in BP and MMP with potential implications for a future diagnostic assay for NC16A-negative pemphigoid patients.

Autoantibody Detection for Diagnosis in Direct Immunofluorescence-Negative Mucous Membrane Pemphigoid: Ocular and Other Sites Compared.

PURPOSE: To assess whether a panel of serum pemphigoid autoantibody tests could be used to confirm an immunopathologic diagnosis of mucous membrane pemphigoid (MMP) in direct immunofluorescent negative (DIF-) MMP patients. DESIGN: Prospective cross-sectional study. PARTICIPANTS: Seventy-six patients with multisite MMP with 45 matched control participants. METHODS: Enzyme-linked immunosorbent assays (ELISAs) for BP180 and BP230 (MBL International), immunoglobulin A (IgA) A and immunoglobulin G indirect immunofluorescence (IIF) on human salt-split skin and the keratinocyte footprint assay for anti-laminin 332 antibodies. MAIN OUTCOME MEASURES: Sensitivity and specificity of autoantibody detection and significant differences for individual tests and test combinations for MMP involving different sites. RESULTS: All DIF- patients (24/73 [31.8%]) had either ocular-only disease or ocular involvement in multisite disease. Serum pemphigoid autoantibodies were detected in 29 of 76 MMP patients (38.2%) compared with 3 of 45 control participants (6.7%). Autoantibody reactivity detected by any 1 or more of the tests was present in 6 of 24 DIF- patients (25%) compared with 22 of 49 DIF positive (DIF+) patients (44.9%). Ocular-only MMP serum reactivity was not significantly different for any test or test combination compared with control participants, whereas DIF- multisite ocular MMP differed for 1 ELISA and 3 of 7 test combinations. By contrast, for DIF+ nonocular MMP patients, all the individual tests, apart from IgA IIF, and all test combinations were significantly different compared with those for control participants. For the entire MMP cohort, the sensitivity of all individual tests was low, having a maximum of 21.05% for BP180 reactivity but increasing to 38.16% for an optimal test combination. Disease activity was associated strongly with positive serologic findings. CONCLUSIONS: Pemphigoid serum autoantibody tests did not provide immunopathologic evidence of MMP in ocular-only MMP patients but showed limited value in DIF- multisite ocular MMP patients. The requirement for immunopathologic confirmation of MMP by autoantibody detection is inappropriate for DIF- ocular-only MMP patients, resulting in missed diagnoses, delayed therapy, and poor outcomes. Alternative diagnostic criteria for ocular-only MMP are required to exclude the other causes of scarring conjunctivitis until more sensitive and specific immunopathologic tests become available.

Fc-binding proteins enhance autoantibody-induced BP180 depletion in pemphigoid.

Immunoglobulins (Igs) consist of two antigen-binding regions (Fab) and one constant region (Fc). Protein A and protein G are bacterial proteins used for the purification of IgG by virtue of their high affinities for the Fc fragment. Rheumatoid factors are autoantibodies against IgG Fc fragments, which are present in the body under physiological conditions. Little is known about the influence of Fc-binding proteins on the pathogenicity of antibody-induced autoimmune diseases. Pemphigoid diseases are a group of autoimmune subepidermal blistering disorders that includes bullous pemphigoid and mucous membrane pemphigoid. IgGs targeting the non-collagenous NC16A domain of the 180-kDa bullous pemphigoid antigen (BP180) are known to induce skin fragility in mice and the depletion of BP180 in keratinocytes. In this study, mAb against NC16A in combination with Fc-binding proteins was found to enhance BP180 depletion. Although mAb against the C-terminus of BP180 does not show pathogenicity in vivo or in vitro, mAb treatment with Fc-binding proteins clearly induced skin fragility in mice and BP180 depletion in keratinocytes. Anti-BP180 mAbs and Fc-binding proteins were colocalized in the cytoplasm and at the basement membrane zone. Cell adhesion strengths were decreased in parallel with BP180 amounts. Clinically, bullous pemphigoid patients had higher rheumatoid factor titers than controls. Anti-BP180 mAb in combination with high-titer rheumatoid factor serum was found to enhance BP180 depletion. Furthermore, saliva from mucous membrane pemphigoid patients contained larger quantities of bacteria and Fc-binding proteins than controls. Our results suggest that Fc-binding proteins (rheumatoid factor or protein G) may enhance the pathogenicity of autoantibodies in pemphigoid diseases. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Targeting interleukin 4 receptor α: A new approach to the treatment of cutaneous autoimmune bullous diseases?

Bullous pemphigoid, mucous membrane pemphigoid, and pemphigus vulgaris are different cutaneous autoimmune blistering diseases, with complex pathogenic mechanisms. In all of them, a type-2 response is thought to have a central role. Interleukin 4 and Interleukin 13 are crucial cytokines in type-2 response. Treatment of these conditions is often challenging. Dupilumab, a recombinant fully human IgG4 monoclonal antibody with binding specificity to human interleukin-4 receptor IL-4Rα, has the potential to inhibit both IL-4 and IL-13. We propose IL-4Rα as a theoretical drug target for cutaneous autoimmune bullous diseases.

The direct binding of collagen XVII and collagen IV is disrupted by pemphigoid autoantibodies.

The basement membrane zone (BMZ) is framed by hemidesmosomes and extracellular matrix (ECM) including collagen IV (COL4). Hemidesmosomes are multiprotein complexes that include collagen XVII (COL17). BMZ proteins can be targeted in autoimmune subepidermal blistering diseases, e.g., pemphigoid targeting COL17. The blistering mechanisms in pemphigoid have not been fully elucidated, especially in mucous membrane pemphigoid (MMP), which mainly affects the mucosa. In this study, we showed that oral lesions in pemphigoid may be attributed to the inhibition of protein-protein interactions by autoantibodies. Using immunoprecipitation, we revealed that COL17 directly binds to COL4 in normal human keratinocytes and normal human oral keratinocytes. In particular, the C-terminus of COL17 is binding site to COL4 in oral keratinocytes. The precise COL4-binding region on COL17 was determined by protein-protein binding assay to be from amino acid Gly1175 to Asp1340 on the C-terminus. MMP-IgG or mAb recognizing the C-terminus hindered the interaction of COL17 with COL4 in oral keratinocytes. Furthermore, keratinocyte adhesion strength to COL4-coated plates was significantly reduced by the treatment of mAb against the C-terminus. In addition, the inflammatory infiltrates around perilesions were significantly less in MMP compared to BP. These results indicate that pemphigoid IgG targeting the C-terminus plays a pathogenic role in blister formation in the oral mucosa to inhibit protein interactions with less inflammation.

Circulating bullous pemphigoid autoantibodies in the setting of negative direct immunofluorescence findings for bullous pemphigoid: A single-center retrospective review.

BACKGROUND: Bullous pemphigoid (BP) autoantibody levels are generally elevated in patients with BP but can be present nonspecifically in patients without BP. OBJECTIVE: To analyze the clinical findings of patients with elevated BP180 or BP230 autoantibody levels and negative direct immunofluorescence (DIF) study findings. METHODS: We retrospectively reviewed records of patients seen at our institution during January 1, 2005-December 31, 2015, who were positive for BP180 or BP230 autoantibodies and had a negative DIF study finding. These patients' demographic characteristics and BP180 and BP230 levels were compared with those of a BP control group who were positive for BP180 or BP230 autoantibodies and had positive DIF study findings. RESULTS: We identified 208 patients with BP autoantibodies but without positive DIF study findings. These patients' mean age and enzyme-linked immunosorbent assay values were significantly lower than those of the control group. Dermatitis was the most common final clinical diagnosis. Of the 208 patients, 41 (19.7%) had at least 2 years' follow-up. Four patients had positive DIF results upon repeating the test and ultimately received pemphigoid diagnoses. LIMITATIONS: Retrospective design with limited follow-up. CONCLUSION: Patients might harbor serum BP autoantibodies in the context of a wide range of dermatoses. Low positive BP180 and BP230 autoantibody levels should not be overinterpreted as evidence for BP in the setting of a negative DIF.

The identification of autoantigens in mucous membrane pemphigoid using immortalized oral mucosal keratinocytes.

BACKGROUND: Mucous membrane pemphigoid (MMP) is a rare chronic autoimmune subepithelial blistering disorder, targeting multiple basement membrane zone (BMZ) proteins including collagen XVII (COL17). Circulating autoantibodies of MMP are often undetected due to their lower titers. The oral mucosa is a valuable substrate for the detection of autoantibodies in MMP patients. However, obtaining normal human oral mucosa is more difficult than obtaining normal human skin. We established immortalized normal human oral mucosal keratinocytes (OMKs) and performed immunoblotting using immortalized OMK lysate for detecting autoantigens in MMP. METHODS: Immortalized OMKs were generated from primary OMKs using E6/E7 proteins of HPV. We compared the protein expression levels of major BMZ proteins between primary OMKs and immortalized OMKs. We performed immunoblotting to detect autoantigens using cell lysates from immortalized OMKs in 30 MMP patients. RESULTS: There were no significant differences between primary OMKs and immortalized OMKs in terms of protein expression levels of the BMZ proteins, including COL17, laminin 332, integrin α6/ß4, collagen VII, and collagen IV. Cell lysates of immortalized OMKs effectively identified MMP autoantigens in 60% (18/30) of MMP sera. We found an interesting case of MMP whose autoantibodies preferentially reacted to the 120-kD protein that is an ectodomain of COL17. CONCLUSION: We demonstrated that a cell lysate of immortalized OMKs is a reliable substrate for the detection of MMP autoantigens. This newly developed immunoblotting analysis method promises to contribute to the diagnosis of MMP.

Mucous membrane pemphigoid and oral blistering diseases.

The autoimmune blistering disorders present with variable frequency in the oral cavity. Recognition of their key clinical features at presentation is important, as there are many causes of oral ulceration. Careful history-taking, clinical examination, an understanding of pathogenesis and appropriate investigations are essential. With the exception of the rare genodermatoses that may lead to blistering and oral ulceration, the majority of patients have an acquired disorder. These include the rare autoimmune blistering diseases mucous membrane pemphigoid (MMP), pemphigus vulgaris (PV), linear IgA disease, epidermolysis bullosa acquisita and paraneoplastic pemphigus. Important clinical differential diagnoses include erythema multiforme, which may be mistaken for PV in appearance, while oral lichen planus may be indistinguishable from MMP. Angina bullosa haemorrhagica may also present with tense haemorrhagic bullae, and in the absence of diagnostic tests, requires an astute clinical diagnosis based upon the history. Newer laboratory techniques have facilitated identification of target antigens and epitopes in the autoimmune blistering diseases, particularly in MMP. Current interest is in whether these relate to clinical presentation and outcomes. There have also been recent investigations into the use of saliva as an alternative medium to serum for the diagnosis of oral vesiculobullous lesions. Assessment of disease severity and measurement of quality of life at presentation and subsequent follow-up is paramount to interpreting therapeutic response. Furthermore, combining these scores with serological and/or salivary biomarkers is valuable in the assessment of clinical response. In this paper, we discuss MMP and its important differential diagnoses.

Mucous membrane pemphigoid-associated paronychia with onychomadesis.

BACKGROUND: Mucous membrane pemphigoid (MMP) is an autoimmune blistering disease that is notoriously difficult to treat. Nail involvement in MMP is rare. CASE PRESENTATION: We report on a 58 years old man with severe MMP who presented with onychomadesis. CONCLUSION: To our knowledge, mucous membrane pemphigoid associated paronychia and onychomadesis have not been reported before. We believe it is important for dermatologists to be aware of this entity.

[Anti-laminin 332 mucous membrane pemphigoid with irreversible ocular and tracheobronchial involvement : Delayed diagnosis of a severe autoimmune bullous disease]. / Anti-Laminin-332-Schleimhautpemphigoid mit irreversiblem okulärem und tracheobronchialem Befall : Verspätete Diagnosestellung einer schweren bullösen Autoimmunerkrankung.

A 53-year-old man presented with a 37-year history of erosive and scarring mucosal lesions of several organs. An initial diagnosis of Stevens-Johnson syndrome was maintained for many years. Due to late correct diagnosis of an anti-laminin 332 mucous membrane pemphigoid and the fact that early, targeted, intensified immunosuppressive therapy was not initiated, the disease led to almost complete loss of vision and obstruction of airways.

Mucous Membrane Pemphigoid with Ocular Involvement: The Clinical Phenotype and Its Relationship to Direct Immunofluorescence Findings.

PURPOSE: This study explored the validity of the First International Consensus on Mucous Membrane Pemphigoid (MMP) guidance, which recommends that clinically indistinguishable patients, who have direct immunofluorescence (DIF)-negative biopsies, be excluded from a diagnosis of MMP. Misdiagnosis, or delayed diagnosis, of MMP with ocular involvement leads to the inappropriate use of topical therapy, the standard of care for causes of cicatrising conjunctivitis other than MMP, rather than systemic immunomodulatory therapy, resulting in irreversible clinical deterioration in patients with MMP. DESIGN: Prospective, cross-sectional study. PARTICIPANTS: Patients meeting the clinical criteria of ocular MMP, including those with positive and negative DIF findings. METHODS: A case report form was used to collect the demographic details, the clinical history, and the results of a detailed clinical assessment by ophthalmologists, otolaryngologists, dermatologists, and oral medicine specialists. All anatomic sites potentially affected by MMP were examined apart from the esophagus (and larynx in a subset). The DIF results were recorded. MAIN OUTCOME MEASURES: Differences between DIF-positive and -negative patients in demography, sites of involvement, and disease severity as determined by the degree of conjunctival scarring (using Tauber staging), central corneal disease (vascularization, scarring, ulceration, and conjunctivalization), history of conjunctival or lid surgery, and requirement for systemic immunotherapy at the time of screening. RESULTS: A total of 73 patients with ocular MMP were recruited, of whom 20 of 73 (27.4%) had ocular-only disease. There was no significant demographic or clinical difference between patients with positive and negative DIF results. This finding included differences in disease severity for which the only significant difference was that of more severe central corneal disease in DIF-negative patients. Asymptomatic disease at different sites was frequent. CONCLUSIONS: These findings do not support the classification of DIF-negative patients, meeting the clinical criteria for ocular MMP, as having a different disease. This category of patients should be accepted as having DIF-negative MMP, for clinical management purposes, with patients having inflamed eyes being treated with systemic immunomodulatory therapy. The frequent finding of asymptomatic ocular, oral, and nasopharyngeal MMP is clinically significant and implies that these sites should be routinely screened in asymptomatic patients.

Coexistence of mucous membrane pemphigoid, vitiligo, and hypothyroidism: A second report of a new multiple autoimmune syndrome.

Mucous membrane pemphigoid (MMP) is a rare immunobullous disease affecting the mucous membrane and skin. An association of MMP with other autoimmune disease is uncommon. Multiple autoimmune syndrome (MAS) is a subclass of autoimmune disorders with a coexistence of three or more autoimmune disorder in a single patient. The second report of the association of vitiligo, autoimmune thyroid disease, and MMP shows that this combination can be considered as a new type of MAS, although its mechanism and pathology are unknown.

Structured Diagnostic Approach and Risk Assessment in Mucous Membrane Pemphigoid with Oesophageal Involvement.

Oesophageal involvement in mucous membrane pemphigoid is considered rare, but it may be underdiagnosed. To assess the incidence of oesophageal involvement in a group of patients with newly diagnosed mucous membrane pemphigoid we retrospectively analysed the medical records of 30 consecutive patients with mucous membrane pemphigoid diagnosed between 2006 and 2016 at the Department of Dermatology, University Hospital Würzburg. Twenty-one patients (70%) reported symptoms indicative of oesophageal mucous membrane pemphigoid. Twelve patients (40%) underwent oesophagogastroduodenoscopy, and oesophageal pathology compatible with mucous membrane pemphigoid was endoscopically found in 9 cases (30%). In all patients indirect and direct immunofluorescence were performed. Patients with and without oesophageal involvement did not differ with regard to the results of indirect immunofluorescence on salt-split human skin and monkey oesophagus. Study results demonstrate the necessity of a standardized diagnostic work-up, including adequate tissue samples for direct immunofluorescence, to prevent underdiagnosis of oesophageal mucous membrane pemphigoid.

[Mucous membrane pemphigoid]. / Schleimhautpemphigoid.

Mucous membrane pemphigoid (MMP) is a pemphigoid disease defined by the presence of autoantibodies against the dermal-epidermal junction and predominant involvement of mucous membranes. Diagnosis is made by the clinical presentation and linear deposits of IgG and/or IgA and/or C3 at the dermal-epidermal junction by direct immunofluorescence microscopy of a perilesional biopsy. Circulating autoantibodies can be detected in most patients by indirect immunofluorescence microscopy on salt-split human skin as well as ELISA and immunoblotting with recombinant and cell-derived target antigens. For systemic treatment of MMP, corticosteroids, dapsone, mycophenolates, and azathioprine are applied. In severe cases and in cases with rapid disease progression cyclophosphamide, rituximab, high-dose intravenous immunoglobulins, and immunoadsorption are used. For the successful management of MMP patients, close cooperation with dentists, ophthalmologists, ENT specialists, gynecologists, and gastroenterologists is essential.

Spectrum of orocutaneous disease associations: Immune-mediated conditions.

There are a number of diseases that manifest both on the skin and the oral mucosa, and therefore the importance for dermatologists in clinical practice to be aware of these associations is paramount. In the following continuing medical education series, we outline orocutaneous disease associations with both immunologic and inflammatory etiologies.

Antigastric parietal cell and antithyroid autoantibodies in patients with desquamative gingivitis.

BACKGROUND: Desquamative gingivitis (DG) is principally associated with erosive oral lichen planus (EOLP), mucous membrane pemphigoid (MMP), and pemphigus vulgaris (PV). METHODS: Serum autoantibodies including antigastric parietal cell antibody (GPCA), antithyroglobulin antibody (TGA), and antithyroid microsomal antibody (TMA) were measured in 500 patients with DG, 287 EOLP without DG (EOLP/DG- ) patients, and 100 healthy control subjects. RESULTS: The 500 patients with DG were diagnosed as having EOLP in 455 (91%), PV in 40 (8%), and MMP in five (1%) patients. We found that 37.0%, 43.6%, and 42.6% of 500 patients with DG, 39.6%, 46.4%, and 45.1% of 455 EOLP with DG (EOLP/DG) patients, and 18.5%, 27.5%, and 30.3% of 287 EOLP/DG- patients had the presence of GPCA, TGA, and TMA in their sera, respectively. DG, EOLP/DG, and EOLP/DG- patients all had a significantly higher frequency of GPCA, TGA, or TMA positivity than healthy control subjects (all P-values < 0.001). Moreover, 455 EOLP/DG patients had a significantly higher frequency of GPCA, TGA, or TMA positivity than 287 EOLP/DG- patients (all P-values < 0.001). Of 210 TGA/TMA-positive patients with DG whose serum thyroid-stimulating hormone (TSH) levels were measured, 84.3%, 6.7%, and 9.0% patients had normal, lower, and higher serum TSH levels, respectively. CONCLUSION: We conclude that 73.4% DG, 77.1% EOLP/DG, and 47.4% EOLP/DG- patients may have GPCA/TGA/TMA positivity in their sera. Because part of GPCA-positive patients may develop pernicious anemia, autoimmune atrophic gastritis, and gastric carcinoma, and part of TGA/TMA-positive patients may have thyroid dysfunction, these patients should be referred to medical department for further management.

Immunopathogenic Oral Diseases: An Overview Focusing on Pemphigus Vulgaris and Mucous Membrane Pemphigoid.

Pemphigus vulgaris, mucosal pemphigoid (mucous membrane pemphigoid), lichen planus, discoid lupus erythematosus and erythema multiforme are a group of immune-mediated mucocutaneous disorders characterised clinically by the formation of blisters, erosions or ulcers. The oral mucosa is often affected, and sometimes the disease is limited to the mouth. The target antigens, autoreactive immune responses, microscopic features, treatment and prognosis vary from one disease to the other. Treatment aims to eliminate exogenous risk factors, suppress the pathogenic immuno-inflammatory reactions, promote healing and prevent infection. The aim of this article is to provide the general dental practitioner with a succinct overview of the diagnostic, clinical, aetiopathogenic features and characteristics of, as well as treatment guidelines for oral pemphigus vulgaris and oral mucosal pemphigoid. Early diagnosis and treatment could prevent severe consequences of the disease in their full-blown forms.

[Foreign material in the gingival tissues admixed with a clinical picture of Mucous Membrane Pemphigoid: A coincidence or inter-related conditions?].

We present a case of a 74-year old female who complained of chronic vesicular and ulcerative lesions distributed on her gingivae. The lesions did not respond to conventional periodontal treatment. The clinical appearance was consistent - with vesiculo-bullous conditions, such as Pemphigus Vulgaris and Mucous Membrane Pemphigoid. These conditions have an auto- immune etiology, whereby pathologic auto-antibodies are generated against structures that constitute the epithelial cell-cell or cell-connective tissue attachment systems. Accurate diagnosis is mandatory due to the high risk, at least in part of them, to spread to extra- oral sites, such skin, eyes and other types of mucosae and cause severe morbidity and even death. Diagnosis is based on routine biopsy aimed to identify the characteristic histomorphological features and on direct immunofluorescence that highlights the type and pattern of the deposition of the auto-antibodies with the affected tissue. The present biopsy did not show features of a vesiculo-bullous condition. However, the presence of a foreign material in the form of fine granules was highlighted by polarized microscopy. Immunofluorescence revealed a %pattern of auto-antibodies that was supportive of Mucous Membrane Pemphigoid. In lack of involvement of any other oral site, the patient has been treated with local agents, as commonly accepted. The present case emphasizes the need to consult specialists from various disciplines, especially in those cases where the clinical response to a common practice is not as expected. Furthermore, diagnosis is not always straightforward, and sometimes a pathologic condition may be the "product" of more than one single etiology.

Salivary IgA and IgG antibodies to bullous pemphigoid 180 noncollagenous domain 16a as diagnostic biomarkers in mucous membrane pemphigoid.

BACKGROUND: Mucous membrane pemphigoid (MMP) is an uncommon mucocutaneous immunobullous disorder. Use of saliva for diagnosis by enzyme-linked immunosorbent assay (ELISA) using the noncollagenous (NC) domain 16a of bullous pemphigoid antigen II (BP180) is not well described. OBJECTIVE: To establish whether whole or parotid saliva is a suitable alternative to serum for diagnosis of MMP. METHODS: Precoated BP180-NC16a ELISA plates were used to test serum, and whole and parotid saliva for IgG, IgA and secretory IgA antibodies. Patients with MMP (n = 64) provided matched serum and whole saliva. In addition 18 of the MMP patients also provided matched parotid saliva. Healthy controls (n = 50) provided matched serum and whole saliva and 6 of these additionally provided matched parotid saliva. An additional 16 disease controls provided matched serum, and whole and parotid saliva. RESULTS: In whole saliva, IgG antibodies were detected in 11/64 (17%), IgA in 23/64 (36%) and a combined positivity in 29/64 (45%). In parotid saliva, IgA antibodies were found in 8/18 (44%). Serum IgG antibodies were detected in 27/64 (42%), serum IgA antibodies in 18/64 (28%) and a combined positivity in 33/64 (52%). Combined use of serum and saliva increased detection of specific antibodies by 30%. Control samples were all negative (positive predictive value of 100% for all tests). The negative predictive values were 62% for IgA saliva, 65% for IgG serum, 59% for IgA serum and 56% for IgG saliva. CONCLUSIONS: IgG and IgA antibodies may provide a suitable diagnostic marker in MMP. Assay of salivary IgA antibodies to NC16a offers a similar diagnostic predictive value to serum.