The role of pure diffuse mesangial hypercellularity in patients with proteinuria.

Background: Pure diffuse mesangial hypercellularity (DMH), in its primary form, is a relatively rare histological finding, and scant data exist in the literature regarding its clinical course and prognosis in nephrotic adults with this diagnosis.

Methods: We retrospectively analyzed the clinical and histological data of 8 out of 41 patients with the above diagnosis in regard to response to the treatment, outcome and prognostic indicators.

Results: Six patients received oral prednisolone as initial therapy, five of whom receiving it as monotherapy at first. The two other patients did not receive anything at all. Three out of the above six patients received prednisolone either with cyclophosphamide or with cyclosporine (CyA). Three patients responded with complete remission, two showed partial remission, and one did not respond at all. During follow-up, none of the patients with complete response appeared to have relapse. The two patients with initial partial response to steroids received CyA in combination with low dose of oral prednisolone. The other patient who did not respond at all from the beginning did not receive anything more due to his bad general condition. Plasma creatinine remained stable in those with complete or partial response to treatment. None of the clinical characteristics was found to be predictive of the degree of renal function impairment at the time of renal biopsy. The three patients with partial or no response were characterized by the severity of mesangial hypercellularity. Patients with complete or partial response to therapy did not differ with regard to age, plasma creatinine, and severity of proteinuria at biopsy. Presence of mesangial IgM was not associated with poor or satisfactory response. In general, no clinical feature at the time of biopsy was predictive of a response to therapy.

Conclusions: At present, it seems that adult patients with DMH and proteinuria represent a heterogeneous group with different clinical courses despite a similar morphological appearance in initial biopsies. We conclude that serial biopsies taken at regular intervals coupled with a longer follow-up may provide answers concerning the real intensity of DMH.