Defining a normal reference range for B cells: A key to diagnosing humoral inborn errors of immunity

B cells are integral components of the adaptive immune response that develop in distinct stages, producing various subsets with specialized roles. Abnormal B cell subsets development is associated with humoral inborn errors of immunity (IEI) and so assessment of B cell subsets is a component of humoral IEI diagnosis and should be compared to a reference range which is age- and population-specific although relatively few studies on B-cell subsets have been published in Africa populations when compared with other populations and not all studies evaluate the same subsets or in the same age-groups. This highlights the need for local studies to establish locally relevant reference ranges.