Kappa light chain predominance in serum and cerebrospinal fluid from human immunodeficiency virus type 1 (HIV-1)-infected patients.

We measured kappa/lambda light chain ratios of Ig and IgG in 41 serum and 34 cerebrospinal fluid (CSF) samples from 47 patients at different clinical stages of human immunodeficiency virus type 1 (HIV-1) infection and in serum and CSF samples from control subjects. Both ratios were more elevated in HIV-1 seropositive subjects than controls. The elevation was more evident in samples from asymptomatic seropositive patients (ASP) than those from patients with acquired immunodeficiency syndrome (AIDS). In addition, there was a statistically significant elevation of Ig kappa/lambda ratios in ASP CSF compared to serum. We also delineated the light chain composition of oligoclonal IgG bands (OCB) by isoelectric focusing followed by immunofixation in CSF and serum samples from selected ASP and patients with AIDS who had neurological involvement. Five of six AIDS and all seven ASP samples had IgG OCB exclusively or predominantly of the kappa type. Four IgG OCB of the lambda type and one free lambda chain band were seen in CSF from a pediatric AIDS patient. The presence of an abnormally elevated kappa/lambda ratio correlated with the presence of IgG kappa OCB (p less than 0.02). We conclude that HIV-1 infection is associated with a kappa light chain predominance and with OCB mainly composed of kappa light chains.