A serological marker for neonatal lupus erythematosus

British Journal of Dermatology (1982) 107, 377-382.

Clinical and Laboratory Investigations

A serological marker for neonatal lupus erythematosus W.L.WESTON, CATHERINE HARMON*, CAROL PEEBLES§, D.MANCHESTERf H.L.FRANCO, J.CHUFF AND D.A.NORRIS Departments of Dermatology, *Rheiimatology and fPediatrics, University of Colorado School of Medicine, Denver, Colorado, U.S.A. Accepted for publication 16 March 1982

SUMMARY

Precipitating antibodies to cellular antigens, designated SS-A(Ro), were found in the sera of seven of eight infants with lupus erythematosus, but they were not found in seventy-one control infants. Neonatal lupus is a rare syndrome with fewer than ioo cases reported in the English literature (Bremers et al.t 1979; Brunjes, Zike & Julian, 1961; Brustein ei al., 1977; Draznin et ai, 1979; East & Lumpkin, 1969; Epstein & Litt, 1961; Esscher & Scott, 1979; Franco el al, 1981; Goldberg & Diamond, i973;Hardy er a/., 1979; Jackson, 1964; Kephart, Hood & Provost, 1981; Levy et al., 1976; McCuistion & Schoch, 1954; Motoya, Horino & Fukui, 1971; Nathan & Snapper, 1958; Nice, 1962; Nolan, Shulman & Victoria, 1979; Reed, May & Tuffanelli, 1967; Rendall & Wilkinson, 1978; Soltani, Pacernick & Lorincz, i974; Vonderheid ei a/., 1976; Wagenhals & Burgeson, 1953; Winkler, Nora & Nora, 1977). The affected infants have discoid skin lesions, with or without congenital heart block, but they rarely meet the criteria for systemic lupus erythematosus (SLE), such as those of the American Rheumatism Association. We have observed 8 infants in the past 5 years with the neonatal lupus syndrome and describe our experience with this rare syndrome. The purpose of this report is to describe a serological marker for the syndrome, the presence of precipitating antibodies to cellular antigens, designated SS-ACRo) (Alspaugh & Tan, 1975; Alspaugh, Talal & Tan, 1976; Alspaugh & Maddison, 1979; Clark, Reichlin & Tomasi, 1969, Provost et al., 1977). This marker was detected in the sera of seven of the eight affected infants and in none of the sera of seventy-one control infants of a similar age (0-5 months). METHODS

Subjects Sera from eight unrelated infants from age i week to 3 months were obtained by venepuncture. Correspondence: William L.Weston, M.D., University of Colorado School of Medicine, Deparunent of Dermatology/Box B153, 4200 East Ninth Avenue, Denver, CO 80262, U.S.A. OOO7-0963/82/1000-0377S02.00 :P> 1982 British Association of Dermatologists

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TABLE 1. Clinical and laboratory features of infants with neonatal lupus

Infant I

Race Negro

Discoid Congenital skin heart Sex lesions block F

Yes

No

FANA

Immunodiffusion

Mother's symptoms

Speckled +

SS-A>i:33

None

RAP

n

Caucasian

F

Yes

Yes

Speckled +

111

Hispanic

F

Yes

No

Speckled +

SS-Ai>:32 SS-B>i:33

Ncme

vn

Negro Caucasian Caucasian Negro

M F F F

No Yes Yes No

Yes No No Yes

Speckled + Negative Speckled + Speckled +

SS-B> 1:32 SS-A>i:32 SS-A>i:32 SS-A>i:32 SS-A > Neat

VIII

Caucasian

F

Yes

No

Speckled +

SS-A>i:32

IV V VI

None

Dry mouth None Sjogren's syndrome SLE with renal disease and arthritis Dry mouth

The clinical and laboratory data on these infants are summarized in Table i. An additional important feature is the history that four of the six infants had skin lesions that were sun-induced. Four of the six infants with discoid skin lesions had a skin biopsy compatible with the histological changes of lupus. Skin immunofluorescence for the presence of granular immunoreactants at the dermal-epidermal junction was positive in two of three infants tested. The male infant designated IV died of severe cardiac disease within the first month of life. Autopsy revealed extensive fibrosis of the entire heart. Controls We obtained sera from seventy-one infants aged 0-5 months. Thirty-eight were female and thirty-three were male. Control subjects included sera from forty-five healthy infants (group A), from four itifants with reactive erythemas such as erythema annulare and erythema nodosum (group B), from thirteen infants with documented congenital infection (group C), and from nine acutely ill infants hospitalized with fevers of unknown origin (group D). Anti-nuclear antibodies Indirect fluorescent nuclear antibody tests were performed on all patients' sera with the use of a mouse kidney substrate and with a HEp-2 continuous cell line (Alspaugh et al., 1976; Greenwald, Peebles & Nakamura, 1978; Tan, 1979). The more sensitive HEp-2 substrate was used to examine all sera obtained from control subjects. Sera were diluted 1132 in phosphate buffered saline for HEp-2 substrates, and 1:4, 1:16, 1:64 and 1:256 for mouse kidney substrates, and examined with an epi-illuminated fluorescent microscope (Greenwald et al., 1978; Tan, 1979). Titres greater than 1132 for HEp-2 substrates and greater than 1164 for mouse kidney substrates were considered significant. Immunodiffusion Autoantibodies to cellular antigens SS-A (Ro) were identified by their precipitin reactions with cellular antigens in immunodiffusion. An extract of a human lymphoblastoid cell line called Wilwas used as the tissue source of soluble antigen (Alspaugh &. Tan, 1975; Alspaugh et al.^ 1976).

Serological marker for neonatal LE 379 Wih is a continuously growing diploid lymphoycte line obtained from a patient with hereditary spherocytosis. Cells were grown in suspension in Eagle's minimal essential medium, sonicated and then centrifuged at 105,000^ for 20 min with the supernatant used as the source of antigen. The entire procedure was performed at 4 C. To demonstrate precipitating antibodies in human sera a double diffusion method was used (Greenwald et aL, 1978; Tan, 1979). For each group of precipitating sera reference sera known to contain antibodies to SS-A(Ro) and SS-B(La) were used and placed in wells adjacent to unknown sera in order to examine for lines of identity or non-identity with reference sera (Greenwald et al., 1978; Tan, 1979). Antibodies to Sm, a non-histone acidic nuclear glycoprotein, and RNP were tested in immunodiffusion against nuclear antigens in rabbit thymus extract (Greenwald et al., 1978). Radioitnmunoassay

Antibody activity against native deoxyribonucleic acid (DNA) was determined by radioimmunoassay by the millipore filter technique (Greenwald et al., 1978). Statistical analysis Sera from infants with neonatal lupus were compared to sera from controls by the two-tailed Fisher's exact test (Colton, 1974). RESULTS

Seven of the eight infants had sera that gave a speckled positive ANA pattern, and seven of the eight demonstrated precipitating antibodies to SS-A(Ro) antigens (Table 2). This was significantly different from the control infants {P