March 3, 2009
In an oral presentation at CROI 2009 in Montreal, Canada, Eric Engels of the US National Cancer Institute presented on the possible role of abnormal antibody fragments called immunoglobulin free light chains in predicting non-Hodgkin's lymphoma (NHL) in people living with HIV. NHL is an AIDS-associated cancer.
The risk for NHL increases as CD4 counts decline, though only a relatively small minority of people with HIV go on to develop NHL. The incidence of NHL has declined since the use of potent HIV therapy in the 1990s. To date, there are no tools to help determine who is at risk for developing NHL. Measuring immunoglobulin free light chains may be one such tool.
Engels and his collaborators identified 66 men from the Multicenter AIDS Cohort Study who had developed NHL. They then identified four control groups (men of similar race, age, CD4 count, etc.) who did not develop NHL for each of the 66 cases. Everyone had samples stored from one of two time points prior to NHL diagnosis.
Engels' group found that elevated kappa or lambda free light chains were strongly predictive, regardless of CD4 count, for developing NHL. Further, these abnormal antibody fragments were present years (in some cases up to five) before the development of NHL. Because the levels were elevated before developing NHL, this marker may be a useful tool for identifying someone at risk for developing NHL. Thus far, there are no data on the impact of potent HIV therapy on the marker or if it can be used in predicting a relapse of NHL.