Thread by @TransfusionWM

First transfusion session of the day @BritSocHaem . BBTS session chaired by @mikefmurphy looking at red cell genotyping. Dr Megan Delaney is going to take us through when red cell genotyping should be undertaken #BSH2019

In the setting of AIHA, providing matched blood can avoid the need for multiple adsorptions (if pt only receiving blood in your institution) #BSH2019

Phenotyping may not be possible with a strong warm autoab therefore genotyping may be useful #BSH2019

Difficult to prove that matching for important antigens prevents alloimmunisation in AIHA #BSH2019

Daratumumab (antiCD38) targets red cells and causes panreactive antibody screens. Ideally need to phenotype patients prior to treatment #BSH2019

If no extended phenotype pre rx with dara, molecular typing will be useful #BSH2019

Can also treat cells with DTT to destroy the dara. BUT some blood group antigens are also destroyed #BSH2019 (K and k particularly) #BSH2019

Dr Delaney advocates
No prev abs : kell match
Prev abs : extended match

Genotyping also useful for patients with D variants. Some D variants can form anti D and others "can't". So important to know which variant the patient has #BSH2019

Review of which D types should be treated as D neg according to the available literature #BSH2019
onlinelibrary.wiley.com/doi/full/10.11…

Slide courtesy of Megan Delaney

Markov model used by Kacker et al. to follow women through their lifetime and use genotyping to distinguish treatment approach. Found to be marginally cost saving #BSH2019
ncbi.nlm.nih.gov/pmc/articles/P…

In sickle cell anaemia we should be fully Rh matching in order to reduce risk of alloimmunisation. High rate of C/c and E/e variants in this population #BSH2019

D gene is thought to be a historical duplication of the CE gene; many similarities and parts of the genes have been 'exchanged' over time. RhD/CR hybrid allele in 24% sickle patients who are C positive, and 30% made anti-C #BSH2019

This is probably one of the most compelling reasons to genotype patients, argues Dr Delaney #BSH2019

Genotyping remains a tool for select groups of patients. No benefit still in the vast majority of patients #BSH2019

Dr Shubha Allard makes the point that dara is now being used for indications other than myeloma, and we need to find ways to reach non-haematology clinicians #BSH2019