MO173: Clinical Profile of Plasma Cell Dyscrasias and Their Renal Outcomes
Authors: Mulpuri Niharika , Attur Prabhu Ravindra , Prasad Nagaraju Shankar , Rangaswamy Dharshan , Ramachandra Rao Indu , Vinayak Shenoy Srinivas , Bhojaraja Mohan V 
Published: May 2022

Abstract

BACKGROUND AND AIMS
The involvement of kidney in plasma cell dyscrasias is widespread, often referred to as myeloma kidney. At the time of presentation, nearly 50% of patients have renal involvement which is associated with higher mortality [1, 2]. Multiple myeloma is more common in African Americans, with male predilection and median age about 65–70 years [3]. Two major causes of renal insufficiency are light chain cast nephropathy and hyperkalcaemia [4]. Flow cytometry plays an important role in diagnosis of plasma cell dyscrasias. Myeloma cells infrequently express CD19 and variable CD45 in contrast to normal plasma cells. Approximately 70% of myeloma cells will express CD56, which is typically negative in normal plasma cells and in plasma cell leukaemia [5]. Studies addressing the relation of flow cytometry parameters with respect to prognosis and outcome in plasma cell dyscrasias are sparse in Asian population. Hence, this research was conducted to study the clinical profile and correlation of flow cytometry parameters with renal outcomes in patients with plasma cell dyscrasias.

METHOD
All consecutive patients, aged above 18 years and diagnosed with plasma cell dyscrasias from January 2016 to June 2021 were included.

RESULTS
Of 165 patients, 115 were males (69.7%), with mean age 58.2 ± 6.4 years. Pallor was seen in 126 (76.4%), bone pains in 90 (54.5%), lytic lesions in 63 (38.2%) and fractures in 37 (22.4%) patients. Severe anaemia (&lt;7 g/ dL) was seen in 35 (21.2%) patients. At presentation, deranged renal parameters with eGFR &lt; 60 mL/min/1.73 m2 were seen in 89 (53.9%) patients, of which 55 (61.8%) patients progressed to chronic kidney disease and 8 (8.9%) patients were continued on maintenance hemodialysis. Nephrotic syndrome presentation was seen in 26 (15.8%) patients. Infections were seen in 65 (39.4%) patients, of which most common infections were respiratory (25, 38.5%), blood stream (18, 27.7%) and urinary tract (12, 18.5%) infections. Serum free light chains were more than 800 mg/L in 71 patients, of them high kappa and lambda levels are seen in 41 (24.8%), and 30 (18.2%) patients, respectively. Most common immunoglobulin seen was IgG (63.6%), followed by IgA (15.8%) and IgE (2.4%). Flow cytometry parameters are shown in Table 1.
Remission was attained with chemotherapy in 139 patients (64.3%), and bone marrow transplantation was done in 27 patients (16.4%). Relapse of disease was seen in 31 patients (18.8%) and worsening of renal parameters at relapse was seen in 15 (48.4%) patients. A total of 35 (21.2%) patients expired. Correlation of flow cytometry parameters with renal outcomes showed presence of CD56 with worse renal outcomes (P = .032), and presence of CD117 with favourable renal outcomes (P = .003) with statistical significance. Presence of CD56 and CD138 had increased risk of mortality with significant P value (P = .04, P = .01, respectively).

CONCLUSION
Flow cytometry parameters may play a role in predicting the prognosis and renal outcomes in patients of plasma cell dyscrasias. Our study showed presence of CD56 with worse renal outcome and mortality, while CD117 presence with favourable renal outcome.
Table 1. Flow cytometry parameters in patients with plasma cell dyscrasias CD markers (n = 165) Present Absent CD19 21/165 (12.7%) 144/165 (87.3%) CD38 53/165 (32.1%) 112/165 (67.9%) CD45 46/165 (27.9%) 119/165 (73.9%) CD56 134/165 (81.2%) 31/165 (18.8%) CD117 86/165 (52.1%) 79/165 (48.9%) CD138 46/165 (27.9%) 119/165 (73.9%) KAPPA 93/165 (56.4%) 72/165 (44.6%) LAMBDA 71/165 (43%) 94/165 (57%)