STABILITY OF IMMUNOBLOT PROFILE OF ANTI-SSA RO-SSB/LA ANTIBODIES OVERTIME IN MOTHERS WHOSE CHILDREN HAVE NEONATAL LUPUS/

Neonatal lupus is strongly associated with antibodies reactive with SS A/Ro-SSB/La proteins, independent of maternal disease activity or clas sification. We sought to determine whether the fine specificity of ant ibody profiles remains stable or evolves over time and whether these f indings relate to clinical status. Sera from 23 mothers whose children had neonatal lupus (22 heart block, one skin) were evaluated by SDS-i mmunoblot. For each mother two samples were available at least 13 mont hs apart; the mean duration of time between testing was 45 months +/- 27 S.D. (range 13-108 months). Twenty-two of the 23 initial profiles w ere identical to the results obtained in a later sample. The health st atus of seven (30%) of 23 mothers changed after the birth of the affec ted infant but the immunoblot specificity of the antibodies remained u nchanged. SLE was the initial and final diagnosis in the only mother w hose profiles differed, with development of weak reactivity to 48 kD S SB/La in addition to the 52 kD SSA/Ro after 14 months. In conclusion, the fine specificity of anti-SSA/Ro-SSB/La antibodies as assessed by i mmunoblot is highly stable for years. Progression of clinical status w as not associated with a concomitant change in antibody profile.