POLM and Thrombocytopenia: Hematological analysis revealed moderate thrombocytopenia, with 403×109 platelets/ml in Polμ−/− mice, compared with 663×109 platelets/ml in wt counterparts (p<0.01, Figure 1B); this was associated with increased bleeding times (Figure S1) Thus peripheral blood populations other than B lymphocytes are altered in Polμ−/− mice.