Abnormal frequency of the memory B cell subsets and plasmablasts in patients with congenital severe hemophilia A:correlation with “Inhibitor” formation
	    		
		   		
		   			
		   		
	    	
    	 
    	10.1007/s44313-024-00017-7
   		
        
        	
        	
        	
        		- Author:
	        		
		        		
		        		
			        		Omid Reza ZEKAVAT
			        		
			        		
			        		
			        			1
			        			
			        		
			        		
			        		
			        		
			        		;
		        		
		        		
		        		
			        		Yasaman MOVAHEDNEZHAD
			        		
			        		;
		        		
		        		
		        		
			        		Amin SHAHSAVANI
			        		
			        		;
		        		
		        		
		        		
			        		Sezaneh HAGHPANAH
			        		
			        		;
		        		
		        		
		        		
			        		Negin SHOKRGOZAR
			        		
			        		;
		        		
		        		
		        		
			        		Hossein GOLMOGHADDAM
			        		
			        		;
		        		
		        		
		        		
			        		Mehdi KALANI
			        		
			        		;
		        		
		        		
		        		
			        		Mohammad Reza BORDBAR
			        		
			        		;
		        		
		        		
		        		
			        		Nargess ARANDI
			        		
			        		
		        		
		        		
		        		
		        		
		        			
			        		
			        		Author Information
			        		
		        		
		        		
			        		
			        		
			        			1. Hematology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
			        		
		        		
	        		
        		 
        	
        	
        	
        		- Publication Type:RESEARCH
 
        	
        	
            
            
            	- From:Blood Research
	            		
	            		 2024;59():16-
	            	
            	
 
            
            
            	- CountryRepublic of Korea
 
            
            
            	- Language:English
 
            
            
            	- 
		        	Abstract:
			       	
			       		
				        
				        	 Background:Development of antibodies against infused Factor VIII (FVIII) or "inhibitors" represents a major challenge following FVIII replacement therapy in patients with hemophilia A (HA). Recent studies have shown that certain cellular compartments of the immune system contribute to the production of such antibodies. Herein, we determined the frequency of class-switched CD19+IgD−CD27+ on-class-switched CD19+IgD+CD27+ memory B cell subsets and CD19 + CD27hiCD38hi plasmablasts in patients with severe HA and their association with the development of inhibitors in these patients. 
				        	
				        
				        	Methods:This cross-sectional case–control study enrolled 32 patients with severe HA, including 8 with and 24 without inhibitors, and 24 healthy individuals. The frequencies of the memory B cell subsets and plasmablasts were determined using flow cytometry. 
				        	
				        
				        	Results:The frequency of CD19+IgD+CD27+ non-class-switched memory B cells was significantly lower in patients with HA (including both patients with and without inhibitors) than in healthy controls. The percentages of both CD19+IgD−CD27+ class-switched and CD19+IgD+CD27+ non-class-switched memory B cells did not differ significantly between patients with and without inhibitors. HA patients with inhibitors had significantly higher proportions of CD19+CD27hiCD38hi plasmablasts than the control group as well as the inhibitor (-) ones. No significant correlation was observed between the inhibitor levels with the percentages of memory B cell subsets and plasmablasts. 
				        	
				        
				        	Conclusion:This study is the first to demonstrate a dysregulated proportion of CD19+IgD+CD27+ non-class-switched memory B cells and CD19+CD27hiCD38hi plasmablasts in patients with severe HA. Therefore, strategies targeting memory B-cell/plasmablast differentiation may have promising outcomes in the management of inhibitor formation in patients with severe HA.