Evidence of cerebrospinal fluid free kappa light chains in AIDS patients with Toxoplasma gondii encephalitis

Cerebrospinal fluid (CSF) free light chains of kappa or lambda (FLC kappa/l ambda) type were investigated by affinity mediated blotting technique (AMI) and ELISA in 28 patients of which nine with AIDS and Toxoplasma gondii enc ephalitis (AIDS, TE), 11 with AIDS with or without other CNS AIDS-related o pportunistic infections (non-TE AIDS) and eight control patients with or wi thout inflammatory neurological disorders (control group). CSF restricted o ligoclonal FLC bands either of k or lambda isotype or both were found by AM I in 18 (90%) out of 20 AIDS patients, while a CSF pattern predominantly ch aracterized by F kappa LC rather than F lambda LC was observed in eight (88 .8%) out of nine TE patients. No FLC components were detected in the matche d sera of TE or non-TE AIDS patients or in the CSF and sera from control gr oup. The anti-parasite-specific F kappa LC CSF/serum mean levels and the T. gondii-specific F kappa LC index values were found by ELISA to be signific antly more elevated in TE patients when compared to non-TE AIDS or control group. These findings suggest that the increased production of T. gondii-sp ecific F kappa LC could provide insights into pathogenesis of reactivated T E in immunocompromised patients and may have important diagnostic usefulnes s. (C) 2000 Elsevier Science BN. All rights reserved.