Dr. Hermelijn H. Smits

Associate Professor


  • Immunology
  • Parasitology
  • Pulmonology


Dr. Hermelijn Smits is heading her own research group focusing on the exploitation of helminth-induced immunoregulatory mechanisms for therapeutic purposes in prevention and treatment of allergic asthma. 

She is combining basic and clinical research in which key elements include:

- identification of helminth-induced regulation of the host immune system and allergic airway responses
- identification of helminth-derived molecules responsible for immune regulation
- phenotyping of inflammatory processes that lead to allergic airway diseases and identify key processes for targeting

The ultimate goal is to combine the newly acquired information on novel strategies to prevent the development of allergic airway disease and stop the increasing prevalence of allergic asthma among children.


Dr. Hermelijn Smits studied Biology at the University of Utrecht and did her PhD-studies at the Academic Medical Center, University of Amsterdam on microbial priming of the human immune system and modulation of allergen-specific immune responses. She did a post-doc in the lab of Prof. B. Lambrecht (currently at VIB, Ghent, Belgium) on microbial priming and protection against allergic airway diseases in different mouse models. 

She obtained prestigious personal grants (VENI (2006) and VIDI (2014)) from ZonMW and LUMC (Gisela Thier fellow (2006)) to build her own research group focusing on immune regulation by worms and their protection against allergic airway diseases at the Dept of Parasitology. Throughout her career, Dr. Hermelijn Smits has received continuous financial support from the Dutch Lung Foundation for several research projects and a national consortium (2015). She was involved in several EU consortia (Gabriel, IDEA, TheSchistoVac). Currently, she is leading an international consortium on asthma prevention (AWWA -2018) within the programme ‘Accelerate’ of the Dutch Lung Foundation. She is actively involved in campaigns to explain her research to the general public and to patients.

She has been committee member and chair of the ‘Young Investigators’ (2010-2012) within the Netherlands Society of Respiratory Science (NRS), committee member of the Task Force on ‘Training Young Investigators’ (2015). She is the chair of the working group on Infections and Allergy in the EAACI (2015) and will be a member of the scientific programme committee of the Dutch Society of Immunology (NVVI - 2019). She is on the evaluation board of the ZonMw ‘Off Road’ programme.

Alongside the regular curricular teaching, Dr. Hermelijn Smits is also actively involved in teaching the next generation of researchers by setting up the NRS national Lung course for PhD-students and the new advanced LIFI course on ‘Immunology, Infections and Tolerance’. She is the coordinator of the half minor ‘Infections in Health and Disease’.     

Research interest

The research interest of Dr. Hermelijn Smits is centred around the role of the Hygiene Hypothesis, or nowadays preferably called the ‘Old Friends’ Hypothesis as an explanation for the increase in inflammatory diseases, such as childhood allergic asthma in the past 50 years. During her PhD studies she investigated how probiotics could influence the function of human dendritic cells to induce tolerance. She shifted her focus to the role of helminths, because they are regarded as the master regulators of the host immune system and because of the strong associations with protection, found in field studies. She demonstrated that in particular chronic schistsosome infections were protective against experimental allergic airway inflammation and that a novel schistosome-induced subset, regulatory B cells, were responsible. Current studies focus more on the molecular analysis of schistosome-induced regulatory mechanisms and molecules that can be used for novel therapies of lung diseases such as allergic asthma.

In addition to the fundamental and molecular studies, Dr. Hermelijn Smits has also studied regulatory cells in schistosome-infected people in Gabon, and in allergic asthma patients. Current studies focus on the phenotyping of regulatory immune responses during immunotherapy of allergic diseases and the analysis of local inflammatory immune responses following allergen challenge in the nose by novel technologies, such as Cytof, RNAseq and ATACseq. The overarching goal is to identify immune signatures specific for early phases of allergic airway responses and deduct whether those are susceptible for modulation by helminth-derived molecules and/or regulatory mechanisms. 



Key publications

An updated list of all publications can be found on Pubmed and Google Scholar.


Leids Universitair Medisch Centrum
Gebouw 1
Kamer P4-37

Albinusdreef 2
2333 ZA Leiden
Tel: +31 71 526 5070

Postzone P4-Q
Postbus 9600
2300 RC Leiden

E-mail: h.h.smits@lumc.nl