Intravascular bone marrow accumulation in persistent polyclonal lymphocytosis: a misleading feature for B-cell neoplasm.

Persistent polyclonal B-cell lymphocytosis is usually reported in young smoking women. Whether this syndrome represents a premalignant or benign disease remains unclear. Indeed, because of the association of Bcl-2/IgH rearrangement and cytogenetic abnormalities, such cases may be misdiagnosed as the leukemic phase of a non-Hodgkin's lymphoma. We report eight new cases of persistent polyclonal B-cell lymphocytosis, which displayed a misleading bone marrow histological pattern, that is, intravascular B-cell infiltrate, constantly associated with Bcl-2 immunohistostaining, as seen in some lymphoma. We also show the absence or low expression of adhesion molecules on persistent polyclonal B-cell lymphocytes, suggesting that migration abnormalities might lead to bone marrow and peripheral blood accumulation. Although most cases presented multiple Bcl-2/IgH gene rearrangements and appeared to be polyclonal, oligoclonal expansion was identified in one out of eight patients, yet was not associated with clinical aggressiveness. The occasional reports of oligoclonal IgH and Bcl-2/IgH rearrangements in this disorder suggest that polyclonal expansion may be followed by the emergence of a predominant clone. However, the benign clinical course and lack of biological evolution in most cases imply that it is mandatory to distinguish this disorder from other malignant lymphoproliferations, so that unnecessary aggressive therapy can be avoided.

Clinical involvement of the tonsillar immune system in IgA nephropathy.

The temporal association of tonsillitis and hematuria or proteinuria in IgA nephropathy suggests that there might be a link between the physiological properties of the secondary lymphoid organ that tonsils represent and the mesangial deposition of IgA characteristic of this nephropathy. A number of clinical and ex-vivo data support this hypothesis. One of the earliest was the demonstration of the dimeric nature of mesangial IgA, composed of IgA monomers linked by a J chain, yet lacking the polyIg receptor acquired by secretory IgA during transcytosis through epithelial cells. This molecular structure is that of IgA synthesized in human tonsils, the epithelium of which lacks polyIg receptor. Moreover, tonsils from patients with IgA nephropathy display an abnormal partition of IgG and IgA producing plasma cells associated with a significantly developed web of high endothelial venules. IgA nephropathy could thus be in part related to an alteration of IgA precursors homing in tonsils. Tonsillectomy thus would present the advantage of removing an abnormally functioning source of dimeric IgA. Performed early enough in the course of the renal disease, tonsillectomy could suffice to halt the development of the nephropathy and restore the kidneys to health.

Isotypic antibody response to plaque anaerobes in periodontal disease.

BACKGROUND: It has been suggested that locally produced immunoglobulin (Ig)A could be more protective than IgG and that there could be a relationship between crevicular fluid-specific IgA levels and the onset of periodontal disease. This study was designed to investigate this hypothesis regarding specific immune responses towards 4 plaque anaerobes in gingival crevicular fluid and saliva from patients with periodontopathies and controls. METHODS: Gingival crevicular fluid (GCF) and whole saliva were collected from 35 adults with periodontitis and 24 periodontally healthy adults (controls). Antigens were extracted from Actinomyces actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, and Fusobacterium nucleatum and used to set up specific enzyme-linked immunosorbent assay (ELISA) tests to assess IgA and IgG levels to these microorganisms in the fluids collected. RESULTS: The crevicular fluid of periodontitis patients contained significantly higher levels of IgG to the 4 microorganisms tested than that of controls (P < 10(-6) for all comparisons). IgA levels to the 4 bacteria were statistically significantly much higher in control crevicular fluid (P < 10(-7) for all comparisons). Controls also had statistically significantly higher levels of specific salivary IgA than patients (P < 0.02 for all comparisons). CONCLUSIONS: These data support the potentially protective role of specific IgA directed to oral microorganisms involved in the onset and development of periodontal disease.