Effect of anti-GM-CSF treatment prior to the onset of arthritis on individual limb involvement. Data are from the experiment in Fig. 1 where mice were treated intraperitoneally with either 300 ?g anti-GM-CSF or 300 ?g isotype control every second day from days 21 to 31. (a) The number of mice that developed arthritis in a given number of limbs is presented. Anti-GM-CSF (n = 9) versus isotype control mice (n = 10) (P = 0.048; multiway chi-squared). There were no anti-GM-CSF-treated mice with all four limbs affected. (b) The number of individual limbs from arthritic mice only with a particular clinical score (severity) is presented. For the anti-GM-CSF-treated group, n = 20 limbs (5 mice); for the isotype control-treated group, n = 36 limbs (9 mice). There were no limbs from anti-GM-CSF-treated mice with a clinical score of 3. GM-CSF, Granulocyte macrophage-colony stimulating factor.