The following recommendations are based on personal experience following and managing CD55-deficiency patients. Follow-up and management of CD55-deficiency patients is determined by their disease manifestations and anti-complement treatment status.
Pre-symptomatic children should be monitored regularly by a pediatric gastroenterologist for timely detection of disease onset, which is essential for management and prevention of disease complications. Due to phenotypic heterogeneity, following onset of PLE symptoms, disease management should be tailored for each patient. In general, management of CD55-deficiency is multidisciplinary and should include gastroenterology, hematology, nutrition and development experts.
Anti-complement treatment has been shown to ameliorate disease manifestations, minimize complications and to improve the patients’ quality of life. Currently, eculizumab (Soliris, Alexion Pharmaceuticals) is the only FDA-approved anti-C5 medication; it is indicated as a first-line treatment in other complementopathies, such as paroxysmal nocturnal hemoglobinuria (PNH) and atypical hemolytic uremic syndrome (aHUS). Medical professionals are encouraged to search ClinicalTrials.gov for clinical trials for treatment of CD55-deficiency or other disorders of complement system dysregulation.
- Gastroenterology: CD55-deficiency typically manifests with PLE and diarrhea, causing hypoalbuminemia, edema, abdominal pain, vomiting and malabsorption and an increased risk of intussusception and bowel obstruction. These manifestations are commonly exacerbated by high-fat diet due to intestinal lymphangiectasia. A low-fat diet with medium-chain triglyceride (MCT) supplementation may partially alleviate symptoms and reduce exacerbations. Anti-complement treatment with eculizumab resolves the gastrointestinal disease manifestations and reduces the risk of complications.
- Hematology: CD55-deficiency causes susceptibility to large-vein thrombosis, such as superior vena cava syndrome and Budd-Chiari syndrome. Patients developing thrombi should be referred to a hematologist, and anti-coagulation treatment should be considered. Anti-coagulation may be reconsidered in patients treated with eculizumab.
- Nutrition: Diarrhea and enteric protein loss often lead to malabsorption and malnutrition. Therefore, CD55-deficiency patients require dietary consultation for nutritional supplementation. A low-fat diet with MCT supplementation is indicated due to intestinal lymphagiectasia. Some patients may require a gastrostomy for feeding and micronutrient supplementation. Parenteral nutrition should be considered with caution in severe cases of intestinal failure, since a central-line may predispose to line thrombosis. The dietary restrictions may be lifted upon intestinal recovery in patients receiving eculizumab treatment.
- Growth and development: Malabsorption and intestinal failure may cause poor growth and development; therefore, children should be monitored for weight, stature and bone density. Patients treated with eculizumab are expected to recover age-appropriate growth parameters. If an increase in patient weight is observed, hypoalbuminemia and PLE exacerbation causing fluid retention should be considered.
- Laboratory: Patients should be monitored for serum levels of albumin, total protein, iron, hemoglobin, immunoglobulins, minerals and vitamins. Elevated stool α1-antitrypsin is indicative of PLE. PLE severity is best reflected by albumin and total protein levels, and may reflect disease exacerbation vs. stability. Albumin infusions and other supplementations may be indicated according to laboratory findings of deficiency. Albumin and total protein levels are expected to normalize within 1-2 months of eculizumab treatment initiation.