E1Lymphocytopenia in pseudo-lupus-erythmetaosus syndrome

HLA-DR4 and Gm 1;21 haplotypes are associated with pseudolupus induced by venopyronum dragées

The phenotypic frequencies of human major histocompatibility complex class I, II, and III antigens and immunoglobulin allotypes (Gm factors) were determined in 56 patients (55 women, 1 man) who had lupus-like disease induced by venopyronum dragées. The findings in these patients were compared with those of a control group. We found a significant increase of HLA-DR4 (57.1% versus 26.5%, relative risk [RR] 3.7) and a decrease of HLA-DR3 (3.6% versus 19.1%, RR 0.16) in the patient group. In addition, the haplotype Gm 1;21 (60.7% versus 32.9%, RR 3.2), and the phenotype Gm 1,3;5,21 (46.4% versus 25.8%, RR 2.5) were significantly increased. Both the haplotype Gm 1;21 and the phenotype Gm 1,3;5,21 are associated with HLA-DR4 in pseudolupus patients but not in controls. The coincidence of HLA-DR4 and Gm 1;21 markedly increases the risk of acquiring pseudolupus (RR 6.9). We conclude that the pathogenesis of pseudolupus is influenced by at least 2 independent genetic factors. A similar HLA association has been described in hydralazine-induced lupus, and this suggests a common pathogenic mechanism.

[Immune reactions in pseudo-lupus-syndrome. A long-term study (author's transl)]

23 patients with proven pseudolupus-syndrome were observed over a period of five years; titers of specific antimitochondrial antibodies (AMA) were tested in a follow-up study after the last intake of Venopyronum-Dragees (VPD), a drug combination of plant glycosides, horse-chestnut extracts and phenopyrazone. Cellular immune reactions against the eliciting drug, depended on the date of the acute phase and were examined in two patients after reexposure. High titers in the acute phase decreased rapidly in most of the cases within the first six months. After reexposure with VPD, AMA rose within three days up to the five fold compared with the initial titer. Only the analgetic component of VPD, phenopyrazone, was able to induce a significant increase of AMA-titer after reexposure. A specific cellular sensitivity to this substance could be demonstrated by lymphocyte stimulation in the presence of a phenopyrazone containing drug preparation. There was no chronic course of the disease; clinical exazerbation could be observed only after new intake of the drug. The analysis of drug history shows, that other pyrazolone containing drugs may also be able to induce a pseudolupus-syndrome.