The Distribution of CD56 dim CD16 + and CD56 bright CD16 ) Cells are Associated with Prolactin Levels during Pregnancy and Menstrual Cycle in Healthy Women Erika A. Martı´nez-Garcı´a 1 , Pedro E. Sa ´ nchez-Herna ´ ndez 2 , Bernardo Chavez-Robles 3 , Lourdes Nun ˜ ez- Atahualpa 4 , Beatriz T. Martı´n-Ma ´ rquez 1 , Victor E. Arana-Argaez 1 , Trinidad Garcı´a-Iglesias 2 , Laura Gonza ´ lez-Lo ´ pez 5 , Jorge I. Gamez-Nava 6 , Marcelo H. Petri 1 , Juan Velazquez-Rodriguez 7 , Mario Salazar-Paramo 6 , Ingrid P. Davalos-Rodriguez 8 , Adrian Daneri-Navarro 2 , Mo ´ nica Va ´ zquez-Del Mercado 1,9 1 Instituto de Investigacio ´ n en Reumatologı ´a y del Sistema Mu ´ sculo Esquele ´ tico, CUCS, Universidad de Guadalajara, Jalisco, Me ´ xico; 2 Laboratorio de Inmunologı´a, CUCS, Universidad de Guadalajara, Jalisco, Me ´ xico; 3 Hospital Versalles, Guadalajara, Jalisco, Me ´ xico; 4 Universidad Auto ´ noma de Guadalajara, Jalisco, Me ´ xico; 5 HGR 110, IMSS, Guadalajara, Jalisco, Me ´ xico; 6 Unidad de Investigacio ´ n Me ´dica en Epidemiologı´a Clı ´nica, HECMNO, IMSS. Guadalajara, Jalisco, Me ´ xico; 7 Unidad de Investigacio ´ n Me ´ dica de Zacatecas, IMSS, Zacatecas, Me ´ xico; 8 Instituto de Gene ´ tica Humana, CUCS, Universidad de Guadalajara, CIBO, IMSS, Jalisco, Me ´ xico; 9 Hospital Civil ‘‘Dr. Juan I. Menchaca’’, Guadalajara, Jalisco, Me ´ xico Keywords Healthy women, menstrual cycle, NK cells, pregnancy, prolactin Correspondence Mo ´ nica Va ´ zquez-Del Mercado, Directora, Instituto de Investigacio ´n en Reumatologı´a y del Sistema Mu ´ sculo Esquele ´ tico, CUCS, Universidad de Guadalajara, Sierra Mojada # 950, CP 44340, Guadalajara, Jalisco, Me ´ xico. E-mail: dravme@hotmail.com Submitted June 13, 2010; accepted July 27, 2010 Citation Martı´nez-Garcı ´a EA, Sa ´ nchez-Herna ´ ndez PE, Chavez-Robles B, Nun ˜ ez-Atahualpa L, Martı ´n- Ma ´ rquez BT, Arana-Argaez VE, Garcı ´a-Iglesias T, Gonza ´ lez-Lo ´ pez L, Gamez-Nava JI, Petri MH, Velazquez-Rodriguez J, Salazar-Paramo M, Davalos-Rodriguez IP, Daneri-Navarro A, Va ´ zquez-Del Mercado M. The distribution of CD56 dim CD16 + and CD56 bright CD16 ) Cells are associated with prolactin levels during pregnancy and menstrual cycle in healthy women. Am J Reprod Immunol 2011; 65: 433–437 doi:10.1111/j.1600-0897.2010.00916.x Problem The pregnancy and menstrual cycle (MC) are the main physiologic events linked to the human reproduction. An adequate neuroendocrine axis is mandatory for the homeostasis in both events. To analyze the dis- tribution of NK, T, Treg cells, expression of their receptors and to associ- ate with hormone levels in pregnant and MC in healthy women. Method of Study We studied two groups of healthy women: 13 pregnant women fol- lowed up at 1st, 2nd and 3rd trimesters and 11 women in the 5th and 21st day of the MC. The distribution of NK, T, Treg cells population, expression of their receptors and hormone levels were quantified. Results In pregnant women, we found an association of NK cells CD56 dim CD16 + with prolactin levels. This finding was also was observed for CD56 brig- thCD16) being statistical significant during 1st trimester for both subpopu- lations. During MC, correlation of CD56 dim CD16 + , CD56 bright CD16 ) cells with prolactin in follicular and luteal phase was found. Conclusion This is the first report where these cell subpopulations have been ana- lyzed prospectively. Even we can argue the random effect for the small number of women is interesting that prolactin showed the more consis- tent correlation with CD56 dim CD16 + , CD56 brigth CD16 ) cells during both events studied. SHORT COMMUNICATION American Journal of Reproductive Immunology 65 (2011) 433–437 ª 2010 John Wiley & Sons A/S 433