H1 histones are important not only for maintaining chromatin structure but also for gene expression. The biology of these histones is quiet complex because of various reasons like their existence in multiple isoforms, they undergoing various kinds of post translational modifications etc. Harshman et al. in their paper on H1 histones have described the genetics and interaction of these histones with various gene expression regulators.They have also discussed the various limitations of immunological agents. For more on this read the following paper :-
Harshman S.W. et al (2013) Nucleic Acid Research 41 (21) 9593-9609.