Clinical Specialist Services Care Group Department of ...

[Pages:2]Clinical Specialist Services Care Group Department of Pathology - Immunology

MYOSITIS SCREEN Screen includes:

- Mi-2, Ku, PM-Scl100, PM-Scl75, Jo-1, SRP, PL-7, PL-12, EJ, OJ, Ro-52

Specific Information

Laboratory

Immunology

Specimen type

Serum

Container

- Standard - Paediatric - Neonates

4.0 mL White top yellow ring Vacuette 2.5 mL Yellow top white ring Reduced draw 0.8 mL Ochre top MiniCollect

Clinical information Special considerations and limitations Reference ranges Clinical significance of test

Please supply sufficient clinical information necessary for test interpretation Myositis is rare and antibodies are found in about half of patients.

Normal result = Negative Mi-2 antibodies are typically found in patients with steroid responsive dermatomyositis. They are rare in polymyositis. Mi-2 antibodies recognise nuclear helicase and homogenous staining on Hep2 slides is usually seen. Mi-2 antibodies are invariably of high titre and show no variation during the course of the disease or treatment.

Antibodies to PM-Scl75 and PM-Scl100 antigen are found in 50-70% of patients with the polymyositis/scleroderma overlap syndrome. PM-Scl75 is seen in 8% of patients with myositis and 3% of patients with systemic sclerosis but 25% of patients with scleroderma/myositis overlap syndrome. PM-Scl100 is not as closely associated with systemic sclerosis as PM-Scl75. Strong nucleolar staining with weak, fine speckled, nucleoplasmic staining can be seen on Hep2 immunofluorescence.

Ku antibodies are seen in a variety of diseases including systemic lupus erythematosus, mixed connective tissue disease, scleroderma and the polymysitis/scleroderma overlap syndrome. They are also seen in patients with pulmonary hypertension. They show fine speckled nuclear and nucleolar staining on Hep2 immunofluorescence and are of little diagnostic value.

Jo-1 (Histidyl tRNA synthetase) antibodies are found in 20-40% of patients with aggressive polymyositis, usually in association with interstitial lung disease and arthralgia. Whilst the majority of Jo-1 antibodies will demonstrate a fine granular cytoplasmic pattern on IIF with Hep 2 cell substrate, up to 40% may be IIF negative.

PL-7 (Threonyl tRNA synthetase ) and PL-12 (Alanyl tRNA synthetase) belong to the same family of aminoacyl-tRNA synthetases (ARS) as Jo-1. Antibodies against ARS are associated with polymyositis and dermatomyositis, they are also seen in antisynthetase syndrome (ASS) recognized as a spectrum of myositis, interstitial pneumonia, non-erosive arthritis, fever and Raynaud's phenomena. PL-12 may be associated with lung disease in the absence of clinically apparent myositis

Anti-Ro52 are the most common ENA specificity amongst autoimmune diseases. They can be seen in Sj?gren's syndrome, SLE, cutaneous lupus erythematosus, neonatal lupus and primary biliary cirrhosis.

Signal recognition peptide (SRP) antibodies can be found in approximately 5% of polymyositis and dermatomyositis cases. They are also markers for necrotising myopathy which shows similar skin changes to dermatomyositis but has more acute symptoms including muscle pain/weakness and interstitial lung disease.

EJ (glycyl) and OJ (Isoleucyl) are markers for polymyositis and may be found in

Index no: QF/ND/IM/HB.028 Editor: Rebecca Haycox

Page 1 of 2

Version no. 1 Date of issue: May 2017

Clinical Specialist Services Care Group Department of Pathology - Immunology

Availability of testing Turnaround time

interstitial lung fibrosis, in overlap syndrome, arthritis and Raynaud's syndrome. EJ may also be observed in SLE. Routine referred: Protein Reference Unit, Sheffield

Approx. 21 working days

General Information

Optimal time and

Collect using aseptic technique

method of

collection

Volume / quantity

Minimum 1 mL or one full neonatal container

requirements

Transportation

Please see "Safe Working Practice for Courier/Taxi Drivers Carrying Pathological Specimens" (SF/PA/GP/004) and "Use and Maintenance of the Pneumatic Air Tube

System (PTS)" (LP/PA/GR/021)

Storage

Specimens that cannot be transported or processed immediately should be refrigerated (2-8?C).

Consent information

The trust consent policy requires that the patient has been informed of the possible use of their specimens by the pathology laboratories for quality control, education or research as part of the quality management system. If the patient declines use other

than for the tests specifically requested, please indicate by marking the box provided

on the front of the request form.

Information for

Please see NHS Choices website

patients

Index no: QF/ND/IM/HB.028 Editor: Rebecca Haycox

Page 2 of 2

Version no. 1 Date of issue: May 2017

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