Characteristics of patients with C1 esterase inhibitor deficiency: a single center study

Cutaneous Findings in Inborn Errors of Immunity: An Immunologist's Perspective

Cutaneous manifestations are common in patients with inborn errors of immunity (IEI)/primary immunodeficiency and could be due to infections, immune dysregulation, or lymphoproliferative/malign diseases. Immunologists accept some as warning signs for underlying IEI. Herein, we include noninfectious/infectious cutaneous manifestations that we come across in rare IEI cases in our clinic and provide a comprehensive literature review. For several skin diseases, the diagnosis is challenging and differential diagnosis is necessary. Detailed disease history and examination play a vital role in reaching a diagnosis, especially if there is a potential underlying IEI. A skin biopsy is sometimes necessary, especially if we need to rule out inflammatory, infectious, lymphoproliferative, and malignant conditions. Specific and immunohistochemical stainings are particularly important when diagnosing granuloma, amyloidosis, malignancies, and infections like human herpes virus-6, human herpes virus-8, human papillomavirus, and orf. Elucidation of mechanisms of IEIs has improved our understanding of their relation to cutaneous findings. In challenging cases, the immunological evaluation may lead the approach when there is a specific primary immunodeficiency diagnosis or at least help to reduce the number of differential diagnoses. Conversely, the response to therapy may provide conclusive evidence for some conditions. This review raises awareness of concomitant lesions and expands the scope of the differential diagnosis of IEI and the spectrum of skin disease therapy by highlighting frequent forms of IEI-associated cutaneous manifestations. The manifestations given here will guide clinicians to plan for alternative use of diverse therapeutics in a multidisciplinary way for skin diseases.

The prevalence of hereditary angioedema in a Chinese cohort with decreased complement 4 levels

Objective

Hereditary angioedema (HAE) is a rare, life-threatening autosomal dominant disorder. We aimed to investigate the prevalence of HAE in a Chinese population with a decreased Complement 4 (C4) level.

Methods

All the patients present in Tongji Hospital with C4 below lower normal range were included from January 2019 to June 2020. The individual data were extracted from the database and categorized by diagnosis. Patients suspected of HAE were further evaluated by C1 inhibitor level and function test to confirm the HAE diagnosis.

Results

A total of 8226 patients were enrolled in our study, among whom 18 had symptoms similar to HAE and received C1 inhibitor level and function tests. Two (1 male and 1 female) of the 18 patients were identified as HAE patients. This means the prevalence of HAE was 2.43/10 000 among the C4-decreased population and 10.1/10 000 in the C4-decreased population with etiology undetermined. The 2 HAE patients had experienced skin and oropharynx edema attack and received tracheotomy. The female patient had a family history. Laboratory tests showed significant decrease of C4 and C1 inhibitor levels in the 2 patients, both of whom were diagnosed as type 1 HAE.

Conclusion

The prevalence of HAE is low in C4-decreased patients. In a large cohort, C4 level can serve as a practical indicator to screen the HAE patients, but further testing of C1 inhibitor activity and levels is needed to confirm the diagnosis of HAE.