Although common in patients with Gaucher disease, antibody abnormalities are not associated with disease severity, a large French study reports.
Still, monitoring these patients is important because they may develop blood malignancies such as non-Hodgkin’s lymphoma and multiple myeloma, the researchers said. Their findings also revealed that being older when diagnosed with Gaucher disease increased the risk of monoclonal gammopathy, which can make patients more susceptible to these cancers.
The study, “Immunoglobulin Abnormalities in Gaucher Disease: an Analysis of 278 Patients Included in the French Gaucher Disease Registry,” was published in the International Journal of Molecular Sciences.
Gaucher disease (GD) is associated with a higher risk of other conditions, such as Parkinson’s disease, as well as immunoglobulin (antibody) abnormalities that include polyclonal and monoclonal gammopathies.
Immunoglobulins are produced by plasma cells to specifically recognize and help destroy diverse threats, such as bacteria and viruses. Such antibodies may be overproduced in a condition called polyclonal gammopathy (PG), which can occur in many contexts, such as chronic inflammation, liver diseases, autoimmune diseases, infections, and malignancies.
Monoclonal gammopathy (MG) is characterized by abnormal production of antibodies from a small subset of plasma cells. It can be benign, malignant, or pre-malignant, such as its most common form called monoclonal gammopathy of undetermined significance (MGUS), which can progress into multiple myeloma.
These abnormalities occur frequently in GD patients, with previous reports suggesting a prevalence of up to 91% for PG and 35% for MG.
To better understand PG and MG in this patient population, the study assessed risk factors, disease progression, and response to treatments in a large group of GD patients, who were enrolled in the French GD Registry. Data from 278 GD patients were included, all with at least one test of antibody levels and/or data on the presence or absence of MG. Among these patients, 262 had type 1, three had type 2, and 13 had type 3. Mean age at diagnosis was 24.4 years and mean follow-up duration since diagnosis was 19 years.
Results showed that the prevalence was 48% for PG and 32% for MG, both in agreement with previous data. MG prevalence was higher compared to the general population (up to 3.2% among people older than 50), but the prevalence of MG subtypes was similar. Mean age at diagnosis was 35 years in PG and 49.7 years in MG.
Age at GD diagnosis was the only independent risk factor for developing MG. Those older than 30 were about 4.7 times more likely to have MG than younger patients.
Splenectomy (spleen removal) and other GD treatments — enzyme replacement therapy (ERT) and substrate reduction therapy (SRT) — did not decrease the risk of PG or MG. Also, having one of these disorders was not associated with GD severity, as risk of bone events or severe thrombocytopenia (low platelet count) did not correlate with either PG or MG.
During follow-up, malignant blood diseases occurred in six patients, one with multiple myeloma and five with non-Hodgkin’s lymphoma. In four cases, MG was diagnosed before or at the same time as the malignant disease.
Due to the limited number of malignancies, the team was not able to determine whether the risk of progression from MGUS to multiple myeloma was higher among GD patients, or if ERT or SRT can decrease the risk of such diseases among this patient population.
As such, the researchers wrote that “these patients should be monitored with caution regarding hematological [blood] malignancies, at least by respecting the usual guidelines for MGUS follow-up.”
“Efforts are still needed to better understand the pathophysiology [disease mechanisms] of these abnormalities in GD patients and the influence of specific treatment,” they added.
