P. F. Barbosa

Catastrophic antiphospholipid syndrome: clues to the pathogenesis from a series of 80 patients.

The antiphospholipid syndrome (APS), originally defined as the combination of venous or arterial thrombotic events, recurrent fetal loss, and, frequently, a moderate thrombocytopenia in association with antiphospholipid antibodies (aPL), was subsequently greatly expanded to include diverse conditions, for example, heart valve lesions, adrenal insufficiency, and pulmonary syndromes such as acute respiratory distress syndrome (ARDS), “capillaritis,” and pulmonary alveolar hemorrhage, among others (16, 17). It was then realized that several “microangiopathic syndromes” also existed, as opposed to large vessel occlusive disease. Single organs, such as the kidneys, heart, skin, and brain, have been affected by this “thrombotic microangiopathy” in the context of the “classic” or “simple” APS. The temporal occurrence of thrombotic events in patients with this classic APS usually extends over months or years. In 1992, the existence of a new “subset” was described in which multiple vascular occlusive events, usually affecting small vessels supplying organs and presenting over a short period of time, were the outstanding features. This subset was termed the “catastrophic” APS. Although large vessel occlusions were also present, their prevalence did not in any way approach that in patients with the classic APS. The occlusions occurred over days to several weeks, and more than 50% of patients usually succumbed despite seemingly adequate therapy, including anticoagulation, steroids, etc. (6). In 1998, a comprehensive review article with the clinical and laboratory description of 50 such patients was published (8). In the present paper we describe the clinical and serologic features of the largest series of patients with catastrophic APS hitherto reported, including 30 new cases from interested physicians in many different countries, as well as a comprehensive literature review of 50 additional recently published case reports with this syndrome. This new series, comprising a total of 80 patients, enables us to analyze further and clarify not only the clinical importance of this syndrome, but also its pathogenesis. 0025-7974/01/8006-0355/0 MEDICINE® 80: 355-77, 2001 Vol. 80, No. 6 Copyright

The Protective Role of HLA-DRB1∗13 in Autoimmune Diseases

Autoimmune diseases (AIDs) are characterized by a multifactorial aetiology and a complex genetic background, with the MHC region playing a major role. We genotyped for HLA-DRB1 locus 1228 patients with AIDs-213 with Systemic Lupus Erythematosus (SLE), 166 with Psoriasis or Psoriatic Arthritis (Ps + PsA), 153 with Rheumatoid Arthritis (RA), 67 with Systemic Sclerosis (SSc), 536 with Multiple Sclerosis (MS), and 93 with Myasthenia Gravis (MG) and 282 unrelated controls. We confirmed previously established associations of HLA-DRB1∗15 (OR = 2.17) and HLA-DRB1∗03 (OR = 1.81) alleles with MS, HLA-DRB1∗03 with SLE (OR = 2.49), HLA-DRB1∗01 (OR = 1.79) and HLA-DRB1∗04 (OR = 2.81) with RA, HLA-DRB1∗07 with Ps + PsA (OR = 1.79), HLA-DRB1∗01 (OR = 2.28) and HLA-DRB1∗08 (OR = 3.01) with SSc, and HLA-DRB1∗03 with MG (OR = 2.98). We further observed a consistent negative association of HLA-DRB1∗13 allele with SLE, Ps + PsA, RA, and SSc (18.3%, 19.3%, 16.3%, and 11.9%, resp., versus 29.8% in controls). HLA-DRB1∗13 frequency in the AIDs group was 20.0% (OR = 0.58). Although different alleles were associated with particular AIDs, the same allele, HLA-DRB1∗13, was underrepresented in all of the six diseases analysed. This observation suggests that this allele may confer protection for AIDs, particularly for systemic and rheumatic disease. The protective effect of HLA-DRB1∗13 could be explained by a more proficient antigen presentation by these molecules, favouring efficient clonal deletion during thymic selection.

HLA in Portuguese systemic lupus erythematosus patients and their relation to clinical features.

Systemic lupus erythematosus (SLE) is a clinically heterogeneous disease translating the different genetic and environmental factors involved. Polymorphisms at several loci, including the major histocompatibility complex (MHC), have been associated worldwide with SLE, although inconsistencies exist among these studies mainly due to genetic heterogeneity between populations and sample characteristics. The aim of the present study was to investigate in Portuguese SLE the association of HLA‐DRB1 alleles with clinical patterns of the disease and severity. Two hundred eighteen Portuguese patients with SLE—42% of whom had kidney involvement—were studied for HLA‐DRB1. Clinical and laboratory manifestations were correlated with HLA allele frequencies. HLA‐DRB1u2003*u200303 allele frequency was significantly higher in SLE patients—as a whole and as either with or without renal involvement—compared to controls, while HLA‐DRB1u2003*u200309 and DRB1u2003*u200313 allele frequencies were decreased. Regarding the relationship with the presence or absence of specific clinical manifestations, it was only found that HLA‐DRB1u2003*u200308 allele frequency was increased in patients with neurological involvement. No association with the presence or absence of anti‐dsDNA, anti‐sm or antiphospholipid antibodies, or antiphospholipid syndrome, was observed. These results were reproducible when analysis was repeated only with patients with more than 5 years of evolution. As in other populations HLA‐DRB1u2003*u200303 is a susceptibility allele in Portuguese SLE patients, while HLA‐DRB1u2003*u200309 and DRB1u2003*u200313 alleles may be protective alleles, not only for the disease, but for the development of nephritis. No correlations with the different clinical manifestations were found, except with the neurological system.