Complement deficiency and systemic lupus erythematosus: consensus and dilemma

Rheumatologic and autoimmune manifestations in primary immune deficiency

PURPOSE OF REVIEW

Here we review the rheumatologic and autoimmune features of primary immune deficiencies with a focus on recently recognized genetic diseases, the spectrum of autoimmunity in PID, and targeted therapies.

RECENT FINDINGS

Primary immune deficiencies (PIDs) were initially described as genetic diseases of the immune system leading to susceptibility to infection. It is now well recognized that immune dysfunction and dysregulation also cause noninfectious complications including autoimmunity. The increased application of molecular testing for PID has revealed the diversity of clinical disease. Recent discoveries of diseases with prominent autoimmunity include activated phosphoinositide 3-kinase δ syndrome and PIDs caused by gain-of-function in STAT1 and STAT3. Similarly, identification of larger cohorts of patients with molecular diagnoses in more common PIDs, such as common variable immune deficiency (CVID), has led to increased understanding of the range of autoimmunity in PIDs. Understanding the molecular basis of these PIDs has the potential to lead to targeted therapy to treat associated autoimmunity.

SUMMARY

Autoimmunity and rheumatologic disease can be presenting symptoms and/or complicating features of primary immunodeficiencies. Evaluation for PIDs in patients who have early-onset, multiple, and/or atypical autoimmunity can enhance diagnosis and therapeutic options.

Systemic Lupus Erythematosus with Multiple Autoimmune Disease Presented with Extensive Peripheral Gangrene

Systemic lupus erythematosus (SLE) is an autoimmune disease and can be associated with other autoimmune diseases. SLE usually presents with skin change and rarely presents with gangrene. SLE gangrene usually involves the digits of upper extremities. We report the first case of SLE associated with an extremely rare constellation of neuromyelitis Optica (NMO) and diabetes mellitus type 1, presented with a rare form of the SLE gangrene which involves bilateral lower extremities up to midlegs, a case that has not yet been reported in the literature. Although SLE gangrene may respond to immunosuppressants, it has a high risk of complications that can end up with amputations.

Genetic analysis of complement component 9 (C9) polymorphisms with clearance of hepatitis B virus infection

BACKGROUND

The complement component 9 (C9), a major cytolytic protein in the complement system, plays an important role in the immunological process. However, associations between genetic variations of the complement factor and chronic hepatitis B virus infection still need to be investigated.

AIMS

We hypothesized that genetic variations in the complement component 9 gene can influence the clearance of chronic hepatitis B virus infection, hepatocellular carcinoma occurrence, and onset age of hepatocellular carcinoma. To investigate the relationship between complement component 9 variations and these disease phenotypes, we performed a case-control association analysis in a Korean population.

METHODS

Genetic variations were identified through direct DNA sequencing and genotyped using TaqMan assay (n = 1,103). In order to investigate the relationship of complement component 9 with chronic hepatitis B virus clearance and hepatocellular carcinoma occurrence, differences in SNP and haplotype frequency distributions were analyzed using logistic and multiple regression analyses with adjusted age and gender as covariates.

RESULTS

Although +23189C>T polymorphism in exon 4 and C9_ht2 [T-G-C-A-C] were significantly associated with clearance of chronic hepatitis B virus infection and hepatocellular carcinoma occurrence, the association signals were not retained after multiple testing corrections.

CONCLUSIONS

We conclude that variations in the complement component 9 gene are unlikely to influence clearance of chronic hepatitis B virus infection and hepatocellular carcinoma occurrence. Although this preliminary result provides meaningful information, further functional investigations in other genetic factors for pathway analyses are required.