Multiple Myeloma: Modification and Adaptation of Plasma Cell Morphology Algorithm for the Prognosis of Congolese Patient

Abstract

Objectives: To determine the multiple myeloma (MM) prognostic formulas applicable in Congolese with many aberrant and/or immature plasma cells according to GOASGUEN’s plasma cell morphology algorithm (PMA). Methods: The prospective, observational and descriptive study was carried out at the Ngaliema Clinic in Kinshasa from July 2016 to December 2019. The variables studied were the plasma cell types and the prognosis groups according to GOASGUEN and ZANDECKI. The nucleolus, the chromatin and the N/C ratio of 2 for each plasma cell encountered in multiple myeloma are examined in order by asking three successive questions as follows: 1) Is the nucleolus present? If yes, we denote 1; if not, note 0; 2) Is the chromatin thin? If yes, we score 1; if not we score 0; 3) The N/C ratio is greater than 6, if so, 1 is noted; if not, we note 0. We obtain a number with 3 successive digits preceded by the letter P for each plasma cell. Results: The overall rate of immature plasma cells and aberrant plasma cells in MM among Congolese was high at 26.6%. Their integration in the prognostic formulas showed for group A" = 22 patients, group B" = 5 patients and group C" = 32 patients. Examination of plasma cell types in the deceased showed that 14/17 had a P001 plasma cell count ≥ 15%. Conclusion: The high rate of aberrant and/or immature plasma cells, the P001 plasma cell type at a rate ≥ 15%, found mostly in group C" with poor prognosis, are responsible for the aggressive nature of MM in Congolese Blacks.