  We discuss the photoionization of the intergalactic medium by early formed
quasars and propose a mechanism which could generate measurable temperature
fluctuations $\delta_{T }~=~\Delta T/T$ of the cosmic microwave background
(CMB). Early quasars produce individual ionized regions around themselves. We
evaluate both thermal and kinetic (first-order Doppler) Sunyaev-Zeldovich (SZ)
effects associated with those ionized regions.
