Immunoglobulin levels at diagnosis and outcomes of patients with chronic lymphocytic leukemia

This study aimed to investigate the relationship between immunoglobulin (Ig) levels and clinical outcomes in patients with chronic lymphocytic leukemia. 

This study concluded that levels of IgG and IgA at diagnosis are important prognostic markers for infection in these patients. 

Immunoglobulins (Ig) are a type of protein found in serum and cells of the immune system. They are also known as antibodies. They combine with substances that the body recognizes as foreign (such as bacteria and viruses). The 5 types of Ig are IgG, IgA, IgM, IgE, and IgD.  

The relationship between Ig levels at diagnosis and outcomes in patients with chronic lymphocytic leukemia (CLL) was unknown. 

This study involved 660 patients. 72% of patients had CLL, 13% had monoclonal B-cell lymphocytosis (MBL) and 14% had small lymphocytic leukemia (SLL). 511 patients had their first Ig level determined within 3 months of diagnosis. Of these patients, abnormal IgM, IgG and IgA levels were seen in 58% of patients with CLL, 27% of patients with MBL and 20% of patients with SLL.  

For CLL, IgG and IgA abnormal levels occurred with increasing frequency with advancing Rai stages. Rai stages are the staging of CLL. The frequency of IgM abnormalities was similar in all patient groups.  

Abnormal levels of IgG and IgA at diagnosis were independent predictors for future immunoglobulin replacement (when antibody levels are low). Abnormal IgA levels were associated with shorter time to first treatment and overall survival. 

This study concluded that both reduced and elevated levels of IgG and IgA at diagnosis are important prognostic markers for infection in CLL. It was also concluded that IgA is a marker of disease progression and survival.