Critères de classification : mode d'emploi pour le diagnostic de lupus systémique

Evaluation of the performance of immunoblot and immunodot techniques used to identify autoantibodies in patients with autoimmune diseases

Autoimmune diseases are pathological conditions in which the immune system mistakenly attacks its own tissues. This study evaluates the performance of two techniques, which are identifiers of autoantibody specifics: immunoblot and immunodot. This study was conducted in 300 patients of whom 62 were tested positive for antinuclear antibodies. The patients were initially screened for antinuclear antibodies using indirect immunofluorescence. Then, the identification of specific autoantibodies such as anti-extractable nuclear antigens (ENAs) was carried out using the immunoblot and immunodot techniques. The results showed that immunoblot and immunodot did not present a significant difference in their sensitivity against anti-SSA/52, SSB, CENP-B, PCNA, U1-snRNP, Jo-1, Pm-scl, and Mi-2 (p > 0.05). However, the two techniques showed a significant difference in their sensitivity toward autoantibodies anti-DNAn, anti-histone, anti-SmD1, and anti-ds-DNA (p < 0.05). The immunoblot data were in complete accordance with the immunodot data (100%) regarding the detection of autoantibodies such as anti SSA/52, SSB, CENP-B, PCNA, U1-snRP, Jo-1, Pm-scl, and Mi-2, 80% regarding SmD1, and 75% concerning ds-DNA. We should certainly pay closer attention to the efficiency of the techniques used in the diagnosis of autoimmune diseases.

[An acute psychotic episode revealing neuropsychiatric lupus with atypical brain MRI]

INTRODUCTION

The frequency of neuropsychiatric symptoms in systemic lupus varies between 14 and 75%. Their mechanisms are multiple and their non-specificity makes the etiological diagnosis more difficult. The MRI lesions are dominated by small white matter hyperintensities.

CASE REPORT

We report a case of 17-year-old girl without medical, surgical or familial past, who presented an acute psychotic episode with fever. The neurological examination showed a pyramidal syndrome. The brain MRI objectified diffuse, bilateral and symmetrical white and gray matter hyperintensities. The diagnosis of neuropsychiatric lupus was retained with association of more than four criteria among the 11 ARA revised criteria: pleural effusion, neuropsychiatric manifestations, anemia, lymphopenia and positive ANA. The treatment was based on corticosteroids. The evolution was fatal.

DISCUSSION

Psychiatric disorders are polymorphic and appear during the course of the disease or at diagnosis; they can be seen in 20% of cases and are a sign of a poor prognosis. Most often these disorders are a non-specific reaction, but severe clinical forms can be observed as suicidal risk or mood disorders (depression, mania...), or acute psychotic episode.

CONCLUSION

The diagnosis of neuropsychiatric lupus must be evoked systematically in atypical neuropsychiatric disorders especially when confronted with minimal biological and brain imaging abnormalities.

[Splenic marginal zone lymphoma and autoimmunity: report of six cases]

INTRODUCTION

Autoimmune manifestations are common in splenic marginal zone lymphoma (SMZL) and are sometimes the presenting feature of the disease. Autoimmune cytopenia (anemia, thrombocytopenia) are the most frequently reported autoimmune conditions. However, other immunological manifestations may be associated with SMZL.

METHODS

We report a retrospective case series of six patients with SMZL associated with autoimmunity.

RESULTS

Auto-immune manifestations were the presenting feature of lymphoma in four cases. Auto-immune manifestations included auto-immune cytopenia in three cases (two hemolytic anemia and one pancytopenia), thyroiditis in two cases, systemic lupus and Still's disease in one case each. Antinuclear antibodies were detected with a titre of 1/250 in three cases, and with a titre of 1/32,000 in the patient with systemic lupus. Testing for DNA antibodies was negative in all cases. Two patients had a circulating lupus anticoagulant, with portal venous thrombosis following splenectomy in one case. One patient had hypogammaglobulinemia. A monoclonal gammopathy was detected in three patients. All patients had spleen enlargement. Immunophenotyping of blood peripheral lymphocyte was typical in five out of the six cases. Bone marrow was infiltrated in five out of the six cases. Diagnosis was obtained by the combination of immunophenotyping and bone marrow histopathology in five cases, and by splenic histopathology in the remaining case. Hepatitis C virus serology was negative in all patient.

CONCLUSION

Autoimmune disease as systemic lupus or Still's disease may be associated with SMZL before its tumoral manifestations are evident. In this mode of presentation, spleen enlargement, hypogammaglobulinemia, monoclonal gammopathy, and multiple autoimmune diseases, should alert the physician.