Characterisation of anticytoplasmic antibodies and their clinical associations

A Case of Palmoplantar Keratoderma in the Constellation of Connective Tissue Diseases

Overlap syndrome is a clinical challenge and brings together a wide range of treatment options for the treating physician. Addressing each and every complaint of the patient is crucial. A 50-year-old female patient presented with skin thickening, blackening, and hyperkeratosis; dysphagia; joint pain; features of myopathy; Raynaud's phenomenon; and dry mouth. Inflammatory markers were raised along with a positive antinuclear antibody (ANA) with Golgi apparatus pattern, anti-Sjögren's-syndrome-related antigen A (anti-SSA)/Ro60 3+, anti-SSA/Ro52 3+, and anti-PM/Scl 2+ antibodies that suggested overlap syndrome. Although the patient had no respiratory complaints, a unique interstitial lung disease (ILD) pattern was noted during the evaluation. Skin manifestations were puzzling, but the histopathology analyses of skin biopsies taken from two different sites revealed distinguishing features of cutaneous lupus and dermatomyositis. Treatment with hydroxychloroquine, pilocarpine, nifedipine, methotrexate, and topical tacrolimus produced a dramatic improvement in the clinical features. This case highlights subtle and florid features of different autoimmune diseases. The hyperkeratotic skin changes were the most striking feature, but the whole evaluation process unveiled many rare presentations of known autoimmune conditions that can open doors to new areas of our understanding toward connective tissue diseases (CTDs). Our case report demonstrates significant heterogeneity in the ANA patterns, ILD patterns, clinical manifestations, and treatment approaches.

Antinuclear antibodies (ANA) patterns in paraneoplastic cerebellar degeneration during the course of disease and treatment protocols - A case report

Paraneoplastic cerebellar degeneration (PCD) is a rare disease that is triggered by an abnormal immune response to a malignant tumor by cross-reaction of antibodies. The low prevalence of this condition has not allowed for large-scale randomized controlled trials. Suspecting a paraneoplastic syndrome followed by rapid diagnosis is crucial before the symptoms irreversibely progress. Indirect immunofluorescence (IIF) with HEp-2 ​cells is currently the most widely used screening technique for the detection of a wide range of nuclear and cytoplasmatic autoantibodies. Here, we present a case of a female Caucasian patient, 61 years of age, who started having sudden symptoms of PCD starting April 2016 that progressed through the course of 10 months before the final diagnosis. Assuming that antinuclear antibodies (ANA) testing could give rise to suspicion of an underlying malignancy but also to an underlying autoimmune etiology of PCD, we followed the ANA patterns of the patient during the course of disease and treatment protocols. A total of four ANA follow ups were done on serum dilution 1:100 and all showed weak positive results on hepatic cells and a mix of similar patterns that, through the course of time, differed slightly on HEp-2 ​cells. Finding positive antinuclear or anticytoplasmic auto-antibodies might guide toward an extensive and useless search for a systemic autoimmune disease ignoring the possibility of searching for paraneoplastic-specific antibodies. An unspecified mix of patterns should not be ignored and might, through further research, show to be more valuable in the ANA screening than is the case now. Weak positive results should not mislead into thinking that there is no overall effect on health, since quite the opposite was the case here. In our example, neither the tumor response to treatment, neurological presentation nor the immunological treatment had a strong effect on the ANA patterns which remained almost identical throughout the course of disease and treatment. Ultrastructural and molecular events in the pathogenesis of the disease could have caused certain minor changes in the pattern but are not of clinical value at the moment and further research is needed.

Antisynthetase syndrome: An under-recognized cause of interstitial lung disease

Background:

Antisynthetase syndrome (AS) is an uncommon and under-recognised connective tissue disease characterized by the presence of antibodies to anti-aminoacyl t-RNA synthetase along with features of interstitial lung disease (ILD), myositis and arthritis. The aim of the current study is to describe our experience with management of AS.

Materials and Methods:

This was a 2-year (2013-2014) retrospective analysis of patients diagnosed with anti-Jo-1-related AS. The presence of anti-Jo-1 antibody was tested by the immunoblot assay. All patients underwent high-resolution computed tomography of the chest, transthoracic echocardiography and evaluation for inflammatory myositis. Transbronchial lung biopsies and muscle biopsies were obtained when clinically indicated.

Results:

Nine patients (mean age: 43.8 years) were diagnosed with anti-Jo-1-related AS. The median duration of symptoms before diagnosis of AS was 6 months. All patients were negative for antinuclear antibodies by indirect immunofluorescence. The prevalence of ILD, myositis and arthritis at presentation was 100%, 77.8% and 55.6%, respectively. The most common ILD pattern was non-specific interstitial pneumonia (n = 6) followed by organizing pneumonia (n = 2) and usual interstitial pneumonia (n = 1). ILD was the sole manifestation in two patients and was subclinical in two patients. Six patients had pleuropericardial effusions, three patients had pulmonary artery hypertension and two patients had venous thromboembolism. Eight of the nine patients improved after treatment with steroids and other immunosuppressants.

Conclusion:

Antisynthetase syndrome is an important and a treatable cause of ILD. Strong clinical suspicion is needed to achieve an early diagnosis.

Characterization for anti-cytoplasmic antibodies specificity by morphological and molecular techniques

PURPOSE

The aim of our study was the characterization of anti-cytoplasmic antibodies by home-made morphological and biochemical techniques. Indeed, indirect immunofluorescence (IIF) on HEp-2 cell line is not always exhaustive in relation to the complexity of the antigens involved.

METHODS

Nine serum samples with anti-cytoplasmic antibodies (2 anti-Golgi apparatus, 3 with diffuse pattern and 4 with lysosome/endosome-like pattern) were tested with fluorescent confocal microscopy, Western blot analysis and, when necessary, with electron microscopy technique.

RESULTS

Confirmation of the IIF staining pattern was performed in confocal microscopy by comparison with the respective antibody marker. The anti-endoplasmatic reticulum positivity was also confirmed by electron microscopy evaluation. Both anti-lysosome/endosome and anti-endoplasmatic reticulum positivity have been definitely identified by Western blot through clear reactivity with calreticulin and LC3B, respectively.

CONCLUSIONS

These results do not aim at representing a standard routine laboratory procedure. Electron microscopy evaluation cannot be proposed as a routine approach, but confocal microscopy technique may be offered in centralized reference laboratories. Newer technologies, especially multiplex immunoassay, can also lead to an easier identification of these autoantibodies, without recurring to a home-made immunoblotting. Only with a complete characterization we will be able to define the clinical relevance of anti-cytoplasmic antibodies, which are still considered as "esoteric" and not as "diagnostic" antibodies.

The relationship between antinuclear antibody data and antibodies against extractable nuclear antigens in a large laboratory cohort

BACKGROUND

Anti-extractable nuclear antigen antibodies (anti-ENA) have diagnostic significance in systemic rheumatic disease (SRD).

METHODS

Anti-ENA were tested in 1685/30,196 sera that were submitted sequentially for antinuclear antibody (ANA) testing. Frequency was stratified by ANA titer and pattern, by referral source, by submitted diagnosis and by patient age and sex.

RESULTS

Anti-ENA frequency increased with ANA titer (7.3% at < 32%-43.3% at ≥ 1024). Anti-histone (11.6%) and anti-SSA/SSB (13.9%) were the most frequent finding with a homo\xadgeneous pattern; anti-SSA/SSB (39.7%) and anti-RNP/anti-Sm (37.7%) were the most frequent finding with a speckled pattern. Sera with speckled, multiple and homogenous ANA patterns accounted for 92.6% of positive anti-ENA findings. At ANA titer ≥ 256, 29.2% of these sera were tested for anti-ENA, of which 41.2% were positive; frequency was higher with an accompanying diagnosis of SRD (53.5% vs. 36.5%, p < 0.004 by χ2-test) but not with referral by rheumatologists (43.5% vs. 35.9%) and did not differ by patient age or sex.

CONCLUSIONS

Reflexive anti-ENA testing may be helpful among sera with ANA titer ≥ 256 and homogeneous, speckled or multiple patterns, irrespective of referral source or accompanying diagnosis. Further work is needed to evaluate the clinical impact of this protocol.

Anti-proteasome activator 28alpha is a novel anti-cytoplasmic antibody in patients with systemic lupus erythematosus and Sjögren's syndrome

We evaluated the extent to which anti-proteasome activator (PA) 28alpha antibodies act as anti-cytoplasmic antibodies in systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS). Sera from 46 SLE patients without SS, 11 SLE patients with SS, and 45 primary SS patients were tested. Using anti-PA28alpha and anti-PA28gamma (Ki) antibodies purified from nitrocellulose membranes onto which recombinant PA28alpha and Ki had been transferred, the cellular distributions of the targeted antigens were analyzed immunohistochemically. In addition, the incidence of anti-PA28alpha antibodies was compared with those of other anti-cytoplasmic antibodies. Immunofluorescent staining showed that purified anti-PA28alpha antibodies reacted with the cytoplasm of HEp-2 cells, whereas purified anti-Ki antibodies reacted with nucleoplasm. Among the 15 SLE patients without SS, the six SLE patients with SS, and the 30 primary SS patients who were anti-cytoplasmic-antibody positive, anti-SS-A/Ro antibodies were the most frequently detected (53, 67, and 70%, respectively); anti-PA28alpha antibodies were, respectively, detected in 33, 50, and 40% of those patient groups, incidences that were higher than those of anti-ribosomal P, anti-smooth muscle and anti-mitochondrial M2 antibodies. These results show that anti-PA28alpha antibodies are major anti-cytoplasmic antibodies in patients with SLE and SS, and the distinct cellular distributions of PA28alpha and Ki suggest these proteins are associated with different cellular functions.

Relevance of complement fixing antinuclear antibodies

BACKGROUND

Connective tissue diseases (CTDs) are a heterogeneous group of disorders defined by the association of a variety of clinical manifestations with immunologic and other laboratory findings. Overlap of syndromes and aberrant findings appear rather frequently.

METHODS

Sera of eight antinuclear antibody (ANA) negative, cases of subacute cutaneous lupus erythematosus (SCLE) with antibodies to Ro (SS-A) and a ninth case with clinical and laboratory signs of Sjögren's syndrome and systemic lupus erythematosus (SLE) were tested for complement (C') fixing antinuclear antibodies (C-ANAs). The ninth case was examined in depth by direct immunofluorescence (DIF) and a two-step "C + DIF" test of biopsies for C' fixation to in vivo bound ANAs, as well as serum tests for C-ANA, ANA, and SCLE markers.

RESULTS

Sera of five of the eight ANA negative, Ro(SS-A) positive SCLE cases had C-ANAs. The ninth case, a 50-year-old woman with clinical and laboratory signs of Sjögren's syndrome and SLE, gave a strong positive C + DIF reaction in the skin biopsy for in vivo bound ANAs that fix C', but negative ANAs and C-ANAs in routine serum tests; they revealed antimitochondrial antibodies. Serum tests on normal skin, however, revealed weak ANA and strong C-ANA reactions with in vitro fixed C'.

CONCLUSIONS

ANA negative cases of SCLE or Sjögren's syndrome may have C-ANAs. A case with Sjögren's syndrome and signs of SLE had both in vivo and in vitro C' fixing ANAs. C-ANA tests can aid in the identification of such cases.