Klein Lab

Inborn errors of immunity (IEI) are rare genetic diseases of the immune system, characterized by immunodeficiency, autoimmunity, autoinflammation, or predisposition to cancer. With our dynamic team of clinicians, bioinformaticians and lab-based biologists, we aim to explore PIDs and identify their underlying genetic cause(s). Through clinical and molecular investigation of IEIs, we and other groups have been able to greatly advance our understanding of the cell biology and biochemistry orchestrating the proper functioning of the immune system.

A key step in understanding PIDs is whole genome sequencing (WGS) of patients’ genomic DNA and state-of-the-art computational analysis. However, given the enormous genetic variability between individuals, such an analysis typically generates a number of potential gene candidates that must then be further investigated to assess their potential biological relevance and functional consequence(s). This is achieved through state of the art in vitro and in vivo laboratory based studies, specifically tailored for the gene of interest and the patient disease and phenotype. This factor demands from our researchers a substantial level of versatility, presenting them with a unique challenge and opportunity to continually adapt, update and enhance their skills. Ultimately, utilizing our worldwide network of collaborators, we aim to find additional patients with similar phenotypes and genotypes.

Our established and growing patient databases are key for these projects. By virtue of large international networks such as the Care-for-Rare Alliance and the Very-Early-Onset Inflammatory Bowel Disease Consortium we are in the privileged position to reach important milestones and to continuously expand our projects. We have successfully identified a number of novel genes associated with inherited defects of cells of the innate and adaptive immune system, adding to our understanding of these diseases and approaches available for their treatment. Our work now continues to identify new immune pathologies, their underlying genetic and biology, and improvements in the manner in which they are treated.

References:

Abdollahpour H, Appaswamy G, Kotlarz D, Diestelhorst J, Beier R, Schaffer AA, Gertz EM, Schambach A, Kreipe HH, Pfeifer D, Engelhardt KR, Rezaei N, Grimbacher B, Lohrmann S, Sherkat R, Klein C (2012) The phenotype of human STK4 deficiency. Blood 119: 3450-3457. PubMed

Bahrami E, Witzel M, Racek T, Puchalka J, Hollizeck S, Greif-Kohistani N, Kotlarz D, Horny HP, Feederle R, Schmidt H, Sherkat R, Steinemann D, Gohring G, Schlegelbeger B, Albert MH, Al-Herz W, Klein C (2017) Myb-like, SWIRM, and MPN domains 1 (MYSM1) deficiency: Genotoxic stress-associated bone marrow failure and developmental aberrations. The Journal of allergy and clinical immunology. PubMed

Kotlarz D, Ziętara N, Uzel G, Weidemann T, Braun CJ, Diestelhorst J, Krawitz PM, Robinson PN, Hecht J, Puchałka J, Gertz EM, Schäffer AA, Lawrence MG, Kardava L, Pfeifer D, Baumann U, Pfister E-D, Hanson EP, Schambach A, Jacobs R, Kreipe H, Moir S, Milner JD, Schwille P, Mundlos S, Klein C (2013) Loss-of-function mutations in the IL-21 receptor gene cause a primary immunodeficiency syndrome. The Journal of experimental medicine 210: 433-443. PubMed

Schober T, Magg T, Laschinger M, Rohlfs M, Linhares ND, Puchalka J, Weisser T, Fehlner K, Mautner J, Walz C, Hussein K, Jaeger G, Kammer B, Schmid I, Bahia M, Pena SD, Behrends U, Belohradsky BH, Klein C, Hauck F (2017) A human immunodeficiency syndrome caused by mutations in CARMIL2. Nature communications 8: 14209. PubMed

Li Y, Führer M, Bahrami E, Socha P, Klaudel-Dreszler M, Bouzidi A, Liu Y, Lehle AS, Magg T, Hollizeck S, Rohlfs M, Conca R, Field M, Warner N, Mordechai S, Shteyer E, Turner D, Boukari R, Belbouab R, Walz C, Gaidt MM, Hornung V, Baumann B, Pannicke U, Al Idrissi E, Ali Alghamdi H, Sepulveda FE, Gil M, de Saint Basile G, Hönig M, Koletzko S, Muise AM, Snapper SB, Schwarz K, Klein C, Kotlarz D (2019).Human RIPK1 deficiency causes combined immunodeficiency and inflammatory bowel diseases. PNAS 15;116(3):970-975. Pubmed

Gene therapy has emerged as a new paradigm of targeted and personalized treatment severe inborn errors of immunity, including the Wiskott Aldrich Syndrome (WAS). WAS is a complex life-threatening PID characterized by recurrent pyogenic, viral and fungal infections, thrombocytopenia and autoimmunity. It is an X-linked disorder caused by loss of function mutations in the gene encoding the Wiskott-Aldrich syndrome protein (WASP). WASP-deficiency leads to multiple dysfunctions in different subgroups of leukocytes, including defective T and B cell function, disturbed formation of the NK cell immunological synapse and impaired migratory responses in all leukocyte subgroups.

In 2004, we initiated a hematopoietic stem cell gene therapy trial using a γ-retroviral vector to reconstitute WASP expression. Ten patients with severe WAS were enrolled. 9 out of ten patients showed sustained engraftment and correction of WASP expression in lymphoid and myeloid cells and platelets as well as resolution of immunodeficiency, autoimmunity, and bleeding diathesis. Several years after gene therapy however, patients developed clonal hematopoietic disorders such as myelodysplastic syndromes and acute leukemias as a consequence of insertional mutagenesis. Our study showed hematopoietic stem cell gene therapy for WAS is feasible and effective, but the use of γ-vectors is associated with a substantial risk of leukemogenesis. We now hypothesize that WAS is associated with decreased genomic stability and continue to work on the development of both efficacious and safe techniques for the genetic engineering of HSC, to cure WAS and other primary immunodeficiency diseases. We make use of novel large animal models and CRISPR-Cas9-mediated gene editing to secure physiological gene expression and to minimize unwanted side-effects.

References:

Boztug K, Dewey RA, Klein C (2006) Development of hematopoietic stem cell gene therapy for Wiskott-Aldrich syndrome. Curr Opin Mol Ther 8: 390-395. PubMed

Boztug K, Schmidt M, Schwarzer A, Banerjee PP, Diez IA, Dewey RA, Bohm M, Nowrouzi A, Ball CR, Glimm H, Naundorf S, Kuhlcke K, Blasczyk R, Kondratenko I, Marodi L, Orange JS, von Kalle C, Klein C (2010) Stem-cell gene therapy for the Wiskott-Aldrich syndrome. The New England journal of medicine 363: 1918-1927. PubMed

Braun CJ, Boztug K, Paruzynski A, Witzel M, Schwarzer A, Rothe M, Modlich U, Beier R, Gohring G, Steinemann D, Fronza R, Ball CR, Haemmerle R, Naundorf S, Kuhlcke K, Rose M, Fraser C, Mathias L, Ferrari R, Abboud MR, Al-Herz W, Kondratenko I, Marodi L, Glimm H, Schlegelberger B, Schambach A, Albert MH, Schmidt M, von Kalle C, Klein C (2014) Gene therapy for Wiskott-Aldrich syndrome--long-term efficacy and genotoxicity. Science translational medicine 6: 227ra233. PubMed