Doppler fetal mechanical PR interval prolongation with positive maternal anti‐RNP but negative SSA/Ro and SSB/La auto‐antibodies

Abstract

Keywordsfetal atrio-ventriculat block; fetal Doppler; PR interval; systemic lupus erythematosus Cutaneous neonatal lupus can occur with negative SSA/Ro or SSB/La but positive non-SSA/ SSB ribonucleoprotein (RNP) maternal autoantibodies (Provost et al., 1987). No fetalcardiac manifestations, however, have been reported in association with isolated maternal RNP autoantibodies. We report the first association of transient first-degree atrioventricular block (AVB) in a fetus exposed to maternal anti-RNP in the absence of SSA/Ro-SSB/La autoantibodies. CASE REPORTA 27-year-old mother with a history of systemic lupus erythematosus (SLE) underwent an obstetric ultrasound and the 22-week fetus was noted to have hypoplasia of the middle phalanx of the fifth digit and multiple cardiac echogenic foci. The mother was diagnosed with SLE at 20 years old and had received steroids for arthritis in the past. However, for the last 2 years before this pregnancy, she was in remission and on no medications. Because of the findings at 22 weeks of gestation, she was referred for a fetal echocardiogram that demonstrated a normal heart rate with regular rhythm and 1 : 1 atrioventricular conduction. As maternal antibodies were pending, we proceeded to measure a Doppler mechanical PR interval (MPRI) and found it to be normal at 132 ms (normal 120 ± 10 ms with 99th percentile at 150 ms) (Glickstein et al., 2004). Additionally, there were three echogenic intracardiac foci: two in the left ventricle and one in the right ventricle. Otherwise, there was no tricuspid regurgitation or any other intracardiac abnormalities, and there was no pericardial effusion or other fluid collections. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptAt 31 weeks of gestation, a second fetal echocardiogram demonstrated the MPRI to be 146 ms (+2 to +3 SD), and the other cardiac findings remained normal. The maternal antibodies were reported as negative for SSA/Ro and SSB/La.For confirmation, maternal sera were retested and again found to be absent in anti-SSA/Ro or anti-SSB/La reactivity. A third fetal echocardiogram at 32 weeks of gestation demonstrated prolongation of the MPRI at 156 ms (Figures 1 and 2), but otherwise normal echocardiographic findings. A third evaluation of the maternal sera was performed at the New York University School of Medicine's CLIA-approved immunology laboratory and the research laboratory of one of the authors (JPB) using recombinant proteins La48, Ro52 and Ro60 as previously described (Clancy et al., 2005). Although antibodies to all components of the SSA/Ro-SSB/La complex were confirmed to be negative; however, antibodies to RNP were confirmed in high titer (14 848 EU with a negative value <19 EU).Subsequent weekly fetal echocardiograms demonstrated that the MPRI was consistently >150 ms until 36 weeks of gestation when it normalized at 136 ms. The baby had a normal delivery. At 6 h of life, the physical exam, the electrocardiographic PR interval (104 ms), and echocardiogram were normal. The infant continues...

The clinical spectrum of autoimmune congenital heart block

“…However, all reported cases of auto-immune CHB associated with anti-RNP autoantibodies have been mothers who were also positive for anti-Ro or anti-La autoantibodies, and we identified only one case of a transient type I CHB in an anti-RNP-antibody-positive mother who was negative both for anti-Ro and anti-La antibodies. 59 …”

Neonatal Lupus

“…These cases had the classic rash of NL, but not CHB. There was one report of cardiac injury associated with anti-RNP in the absence of anti-SSA/Ro-SSB/La, which presented as transient fi rst degree block that spontaneously reversed [ 103 ].…”

Pregnancy outcomes in mixed connective tissue disease: a multicentre study

“…As the data on eligibility were dichotomous (eligible: yes/no), inter rater agreement at both the title and abstract review stage and the full article review stage was determined by calculation of Cohen's kappa coefficient (k=0.92). Fourteen studies were included [5,[8][9][10][11][12][13][14][15][16][17][18][19][20], the search strategy is presented in Figure 1.…”