C-reactive protein in patients with lymphatic filariasis: increased expression on lymphocytes in chronic lymphatic obstruction.

Levels of C-reactive protein (CRP) were evaluated by enzyme immunoassay in patients infected with the filarial parasite Wuchereria bancrofti. Significantly elevated levels of CRP (P less than 0.001) were demonstrated in patients with chronic lymphatic pathology (CP; n = 18) compared to patients with asymptomatic microfilaremia (MF; n = 13) and normal volunteers (NV; n = 29). Serum levels of CRP showed an inverse correlation (rs = -0.37; P less than 0.05) with phosphocholine (PC)-containing filarial antigen that was present in the circulation of patients with bancroftian filariasis. Marked elevations in the percentage of CRP-binding lymphocytes were observed in patients with CP (mean = 44%; P less than 0.001) compared to those with MF (mean = 18%) or NV (mean = 3%). The increased percentage of surface CRP was not due to an abnormal change in major lymphocyte subset (CD5, CD4, CD8, or CD19). No significant correlation was noted between surface CRP and serum CRP; however, an inverse correlation was observed between surface CRP and PC-bearing circulating filarial Ag (rs = -0.64; P less than 0.001). Biosynthetic labeling and immunoprecipitation with anti-CRP antibodies indicated quantitative differences in the synthesis of CRP in patients with CP compared to MF and CP. Complexing of CRP with PC-containing Brugia malayi antigen (CRP-BmA) caused increased binding to normal lymphocytes (less than 8%), but not close to the extent seen in patients with CP (44%), suggesting de novo synthesis of CRP in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)