Anti-PM/Scl Antibody-positive Systemic Sclerosis Complicated by Multiple Organ Involvement

Scleroderma autoantibodies in guiding monitoring and treatment decisions

PURPOSE OF REVIEW

One of the key clinical challenges of systemic sclerosis (SSc) is diversity in clinical presentation, organ involvement and disease progression. Antinuclear autoantibodies (ANA) are central to the diagnosis of SSc. ANA specificities associated with distinct clinical patterns of organ and skin involvement. Understanding of the molecular differences and pathogenesis of scleroderma has helped further inform clinical acumen. Here, we provide an update on ANA on clinical profiling, management and future direction of SSc.

RECENT FINDINGS

There has been further development in delineating clinical patterns in ANA, genetic susceptibility and antigen triggers predisposing to ANA subtypes. Sub-group analysis of recent clinical trials shows differing treatment responses to novel therapeutics.

SUMMARY

ANA subtyping is likely to be firmly embedded into future classification systems. Beyond informing current management and monitoring of scleroderma patients, ANA subsets have implication on future research and clinical trial design.

Increased L-Selectin on Monocytes Is Linked to the Autoantibody Profile in Systemic Sclerosis

Monocytes are known to be implicated in the pathogenesis of systemic sclerosis (SSc), as they exert prominent migratory, adhesive, and chemotactic properties. The aim of our study was to characterize the surface expression of adhesion/chemotactic molecules (CD62L, CD11b, CCR2, CCR5) on the SSc monocytes and determine correlations with the clinical presentation of SSc. We included 38 SSc patients and 36 healthy age-and sex-matched controls. Isolated monocytes, as well as in vitro serum-treated monocytes, were analyzed by flow cytometry; additionally, soluble CD62L was measured in serum. We found increased soluble CD62L in the SSc serum samples and increased CD62L on the surface of the SSc monocytes in the in the same set of patients. Among samples with determined SSc-specific autoantibodies, the surface CD62L was the lowest in patients positive for anti-PM/Scl autoantibodies and the highest in patients with anti-topoisomerase I autoantibodies (ATA). The treatment of isolated healthy monocytes with ATA-positive SSc serum resulted in increased surface CD62L expression. Moreover, surface CCR5 was reduced on the monocytes from SSc patients with interstitial lung disease but also, along with CCR2, negatively correlated with the use of analgesics/anti-inflammatory drugs and immunosuppressants. In conclusion, increased CD62L on SSc monocytes, particularly in ATA-positive patients, provides new insights into the pathogenesis of SSc and suggests CD62L as a potential therapeutic target.

A Japanese Patient with Anti-PM/Scl and Centromere Antibody-Positive Scleroderma-Amyopathic Dermatomyositis Overlap Syndrome Who Developed Renal Crisis

Anti-PM/Scl antibodies are associated with the overlap syndrome of systemic sclerosis and dermatomyositis/polymyositis (SSc-DM/PM), and are found in 50% of SSc-DM/PM cases in Europe and the United States, whereas they are rare in Japan. We report a case of an 80-year-old Japanese female with SSc-amyopathic dermatomyositis (ADM) overlap syndrome, who developed scleroderma renal crisis (SRC), a complication of SSc. She had positive antinuclear antibodies in a discrete-speckled and nucleolar pattern and anticentromere antibodies and anti-PM/Scl antibodies were confirmed by ELISA and immunoprecipitation, respectively. The incidence rate of SRC in SSc patients varies significantly depending on the specificity of autoantibodies, with the highest incidence of ~50% in anti-RNA polymerase III antibody positive patients, followed by ~10% in anti-PM/Scl and lower incidence of 0.45% in anticentromere antibody-positive cases. Anti-PM/Scl antibodies are uncommon in Japanese patients presumably due to its strong association with certain HLA haplotype that is rare in Japanese. Clinical significance of anti-PM/Scl antibodies in Japanese patients will need to be clarified with accumulation of cases in future studies.