Table 2.

Summary of immunostaining of CLDN10, CLDN16, and CLDN19 in the human renal tubules and collecting system

	Megalin/LRP2		UMOD			NKCC2			NCC	NCX1	AQP2	AE1	Pendrin
	Cortex	OSOM	Cortex	OSOM	ISOM	Cortex	OSOM	ISOM	Cortex	Cortex	Cortex, OSOM, ISOM	Cortex, OSOM, ISOM	Cortex
CLDN10	*	*	***	***	***				0	0	0	$	$
CLDN16	0	0				***	***	*	0		0	$	$
CLDN19	0/very rare	*	***	***	***				*,£	**,£	***	***	***

Localization was determined by costaining for the following specific markers in immunofluorescence: megalin/LDL receptor-related protein 2 (LRP2), uromodulin (UMOD), Na⁺-K⁺-2Cl⁻ cotransporter (NKCC2), Na⁺-Cl⁻ cotransporter (NCC), Na⁺/Ca²⁺ exchanger isoform 1 (NCX1), aquaporin-2 (AQP2), Cl⁻/${\text{HCO}}_3^{-}$

anion exchanger isoform 1 (AE1), and pendrin. ISOM, inner stripe of the outer medulla; OSOM, outer stripe of the outer medulla. *, **, and ***, Expression with increasing intensity. 0, Expression absent or below the limit of detection. $, Costainings for AE1-CLDN10, pendrin-CLDN10, AE1-CLDN16, and pendrin-CLDN16 were not performed in human kidney sections because we did not find any CLDN10 and CLDN16 staining in tubules expressing AQP2. £, We could not determine whether CLDN19 is expressed at tight junctions in the human distal convoluted tubule and connecting tubule for technical reasons and despite multiples tries.