Background Anti-synthetase syndromes (ASS) are a subset of idiopathic inflammatory myositis (IIM). Patients present with varying combinations of myositis, interstitial lung disease (ILD), Raynaud's phenomenon and arthritis.Anti Jo-1is the prototypical form of ASS.Non Jo-1 forms are increasing being recognized with anti PL-12 syndrome constituting around 2-3% of IIM patients. Data regarding anti PL-12 is rare and most cohorts report a nearly universal presence of ILD as well as infrequent muscle involvement which is mostly subclinical.The aim of this retrospective review was to determine diagnostic utility of various tests in anti PL-12 ASS patients seen in a single centre.
Objectives To determine nailfold capillaroscopic findings as well as identify unique laboratory characteristics in patients diagnosed with anti PL-12 ASS.
Methods A search was made among the database of all patients seen in the newly instituted department of rheumatology.Patients identified as having anti PL-12 ASS were identified and details recorded.
Results Three patients (Two women and one man) were diagnosed with anti PL-12 antisynthetase syndrome in a short span of 7 months. (July 2013 to December 2013). Their clinical and laboratory characteristics are detailed in the table. Mean age of the patients was 44.3 years.(46,36 & 51 yrs) All three patients had a symptom duration of around 1 month. All patients had fever, myalgia and arthralgia, though only the male patient had objective arhtritis.Objective muscle weakness varied from absent to moderately significant, however all patients demonstrated a normal CPK level.MRI (performed in 2 patients) demonstrated significant muscle oedema.Nailfold capillaroscopy demonstrated significantly high number of microhemorrhages and capillary dropouts. There were a number of megacapillaries as well. None of the patients demonstrated Raynaud's phenomenon.Despite a normal CPK, patients had a high LDH and borderline high ALT/AST.Patients demonstrated a significantly elevated level of inflammatory markers and leucocytosis.They also demonstrated a hyperglobulinemia (absolute or relative to serum albumin level), though there was an absence of reactive thrombocytosis.
Conclusions As in previous literature, patients with anti PL-12 ASS in this single centre cohort demonstrated minimal to moderate myositis.Similar to previous literature they demonstrated an elevated serum LDH level though the serum CPK level was uniformly normal.Nail fold capillaroscopic abnormalities and laboratory features of significant systemic inflammation except for absence of reactive thrombocytosis are described for the first time.
Disclosure of Interest None declared