ADA2 deficiency (DADA2) as an unrecognised cause of early onset polyarteritis nodosa and stroke: a multicentre national study

OBJECTIVES

To analyse the prevalence of CECR1 mutations in patients diagnosed with early onset livedo reticularis and/or haemorrhagic/ischaemic strokes in the context of inflammation or polyarteritis nodosa (PAN). Forty-eight patients from 43 families were included in the study.

METHODS

Direct sequencing of CECR1 was performed by Sanger analysis. Adenosine deaminase 2 (ADA2) enzymatic activity was analysed in monocyte isolated from patients and healthy controls incubated with adenosine and with or without an ADA1 inhibitor.

RESULTS

Biallelic homozygous or compound heterozygous CECR1 mutations were detected in 15/48 patients. A heterozygous disease-associated mutation (p.G47V) was observed in two affected brothers. The mean age of onset of the genetically positive patients was 24 months (6 months to 7 years). Ten patients displayed one or more cerebral strokes during their disease course. Low immunoglobulin levels were detected in six patients. Thalidomide and anti-TNF (tumour necrosis factor) blockers were the most effective drugs. Patients without CECR1 mutations had a later age at disease onset, a lower prevalence of neurological and skin manifestations; one of these patients displayed all the clinical features of adenosine deaminase 2deficiency (DADA2) and a defective enzymatic activity suggesting the presence of a missed mutation or a synthesis defect.

CONCLUSIONS

DADA2 accounts for paediatric patients diagnosed with PAN-like disease and strokes and might explain an unrecognised condition in patients followed by adult rheumatologist. Timely diagnosis and treatment with anti-TNF agents are crucial for the prevention of severe complications of the disease. Functional assay to measure ADA2 activity should complement genetic testing in patients with non-confirming genotypes.

Elevations of neutrophil proteinase 3 in serum of patients with Wegener's granulomatosis and polyarteritis nodosa

OBJECTIVE

To determine serum levels of proteinase 3 (PR3) in normal subjects and patients with Wegener's granulomatosis (WG), polyarteritis nodosa (PAN), chronic renal failure, and systemic lupus erythematosus (SLE).

METHODS

Serum levels of PR3 were measured by enzyme-linked immunosorbent assay employing a monospecific rabbit polyclonal antibody against PR3.

RESULTS

Quantifiable levels of PR3 were detected in all serum samples examined, including those of normal subjects. Marked elevations of serum PR3, which decreased with treatment, were found in patients with active WG. Patients with PAN, SLE, and chronic renal failure also showed elevated levels of PR3.

CONCLUSION

Quantitating serum PR3 may be useful in the management of patients with WG and other connective tissue diseases.

Cutaneous periarteritis nodosa. Hepatitis B surface antigen-containing immunocomplexes and polymorphonuclear-leukocyte lysosomal enzyme release

In a patient with cold-induced cutaneous periarteritis nodosa, cryoprecipitation of a circulating hepatitis B surface antigen-containing immunocomplex resulted in phagocytosis by neutrophils and monocytes with prominent vacuolation of the cells and extracellular release of lysosomal enzymes. We believe this immunocomplex attached itself to the cell membrane and induced vacuolation and degranulation in normal neutrophils.

Muscle involvement in polyarteritis nodosa: report of a patient presenting clinically as polymyositis and review of the literature

Muscle symptoms, especially myalgias, appear to be common in patients with polyarteritis nodosa (PAN). We describe a patient who presented with a generalized myopathy and elevated creatine kinase (CK) suggestive of polymyositis. However, subsequent exploratory surgery for an acute abdomen revealed colonic perforation on the basis of PAN. A review of the literature suggests that generalized myopathy and elevated CK are uncommon features of PAN. A muscle biopsy can be a helpful procedure to secure the diagnosis in patients with PAN especially those with myopathies. Strategies for optimizing the choice of biopsy site are discussed.