A rapid test for the detection of a B-cell marker (D8/17) in rheumatic fever patients.

A new, rapid blood test for the detection of B-cell markers in patients with rheumatic fever (RF) was applied to 10 patients with RF, 26 of their family members and 14 normal subjects. Three-hundred microliters of blood was obtained by finger-pricking from each subject and submitted to the immunofluorescence technique using three different antibodies, i.e., D8/17 monoclonal ascites antibody, FIRC-conjugated goat anti-mouse IgM (mu chain specific) and phycoerythrin-conjugated murine anti-HLA-DR antibody. D8/17 lymphocytes (green stain) and B-lymphocytes (red stain) were counted using a double-filter microscope. The percentage of positive cells was 20-64% (average 38.5%) in patients, siblings, fathers and mothers, 4.5% in 12 normal controls and 27.5% in the other 2 controls with a family history of RF. In 90% of the families studied, the patients had the highest percentage of positive cells. We conclude that this rapid test can be used as an aid for RF diagnosis and possibly to detect siblings who are at risk to develop the disease.