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BackgroundImmunocompromised patients have an increased risk of developing severe COVID disease, as well as a tendency to suboptimal responses to vaccines. The objective of this study was to evaluate the specific cellular and humoral adaptive immune responses of a cohort of kidney transplant recipients (KTR) after 3 doses of mRNA-1273 vaccine and to determinate the main factors involved.MethodsProspective observational study in 221 KTR (149 non infected), 55 healthy volunteers (HV) and 23 dialysis patients (DP). We evaluated anti-spike (by quantitative chemiluminescence immunoassay) and anti-nucleocapsid IgG (ELISA), percentage of TCD4+ and TCD8+ lymphocytes producing IFNγ against S-protein by intracellular flow cytometry after Spike-specific 15-mer peptide stimulation and serum neutralizing activity (competitive ELISA) at baseline and after vaccination.ResultsAmong COVID-19 naïve KTR, 54.2% developed cellular and humoral response after the third dose (vs 100% in DP and 91.7% in HV), 18% only showed cell-mediated response, 22.2% exclusively antibody response and 5.6% none. A correlation of neutralizing activity with both the IgG titer (r=0.485, p1000/mm3 [4.68 (1.72-12.73, p=0.003], eGFR>30 mL/min [7.34(2.72-19.84), pConclusionsKTR presented poor cellular and humoral immune responses following vaccination with mRNA-1273. The immunosuppression degree and kidney function of these patients play an important role, but the only modifiable factor with a high impact on humoral immunogenicity after a booster dose was an immunosuppressive therapy including a mTOR inhibitor. Clinical trials are required to confirm these results.

Cytotoxic CD8 T cells are crucial for the host antigen-specific immune response to viral pathogens. Here we report the identification of an essential role for the serine/arginine-rich splicing factor (SRSF) 1 in CD8 T cell homeostasis and function. Specifically, SRSF1 is necessary for the maintenance of normal CD8 T lymphocyte numbers in the lymphoid compartment, and for the proliferative capacity and cytotoxic function of CD8 T cells. Furthermore, SRSF1 is required for antigen-specific IFN-γ cytokine responses in a viral infection challenge in mice. Transcriptomics analyses of Srsf1-deficient T cells reveal that SRSF1 controls proliferation, MAP kinase signaling and IFN signaling pathways. Mechanistically, SRSF1 controls the expression and activity of the Mnk2/p38-MAPK axis at the molecular level. Our findings reveal previously unrecognized roles for SRSF1 in the physiology and function of cytotoxic CD8 T lymphocytes and a potential molecular mechanism in viral immunopathogenesis.

Kurds are living at Middle East region comprising several countries (38 million people) and also have emigrated to Asia, Europe and America. Kurds from Iran have been HLA typed in the present work from Saqqez and Baneh towns, Kordestan province, Iran. Origin of Kurds is considered autochthonous from Anatolia and surrounding mountains :they have been referred as "the mountain people" by classic Persian, Greek and Roman authors. Present day Turks are also autochthonous from Anatolia, but they were not recognized by classical authors as living in the mountains and they speak a language of Asian origin that was imposed to Anatolia by a "elite" invasion without a noticeable high Asian gene input. Most frequent class I and class II HLA alleles found in Iranian Kurds population are: HLA-A*24:02, A*02:01 and HLA-B*35:01, and HLA-DRB1*11:01, DRB1*03:02 and HLA-DQB1*03:01; also, most frequent HLA extended haplotypes from this Iran Kurdish sample are not shared with Iranians but with Mediterranean, Turkish and Caucasus people. This is confirmed by Neighbour-Joining and correspondence analysis studied together with the corresponding populations. Finally, our studies show that both Kurds and Turks are genetically original from Anatolian Peninsula and surrounding countries and that an apparent Asian genetic or Aryan invasion does not exist in the area.

Background. Reduced TCRζ chain surface has been reported in T cells from patients with different inflammatory conditions and cancer. However, the causes of this diminished expression in cancer remain elusive. Methods. T cell-enriched populations of blood or tissue (tumoral and nontumoral) origin from 44 patients with gastric adenocarcinoma and 33 healthy subjects were obtained. Samples were subjected to cytofluorimetry, Western blot analysis, TCRζ cDNA sequencing experiments, measurement of TCRζ mRNA levels, and caspase-3 activity assays. Results. Cytofluorimetry revealed a decreased TCRζ expression in T cells of patients, assessed either as percentage of cells expressing this chain (blood: control subjects 99.8 ± 0.1 % , patients 98.8 ± 1.1 % P < 0.001 ; tissue: control subjects 96.7 ± 0.9 % , patients tumoral tissue 67.9 ± 27.0 % , patients nontumoral tissue 82.8 ± 12.6 % , P = 0.019 ) or mean fluorescence intensity (MFI) value (blood: control subjects 102.2 ± 26.0 ; patients 58.0 ± 12.3 , P = 0.001 ; tissue: control subjects 99.4 ± 21.4 ; patients tumoral tissue 41.6 ± 21.4 ; patients nontumoral tissue 62.3 ± 16.6 , P = 0.001 ). Other chains pertaining to the TCR-CD3 complex (CD3ε) showed no significant differences (MFI values). Subsequent TCRζ cDNA sequencing experiments or measurements of TCRζ mRNA levels disclosed no differences between patients and control subjects. Evaluation of caspase-3 activity showed higher levels in T cell extracts of patients, and this activity could be decreased by 70% with the use of the inhibitor Ac-DEVD-FMK, although CD3ζ expression levels did not recover. Conclusions. These results further place the defect responsible for the low TCRζ expression in cancer at the posttranscriptional level and suggests contrary to what has been proposed in other pathologies that elevated caspase-3 activity is not the causative agent.

HLA-G immune modulatory genes and molecules are presently being studied by a widespread number of research groups. In the present study, we do not aim to be exhaustive since the number of manuscripts published every year is overwhelming. Instead, our aim is pointing out facts about HLA-G function, polymorphism and pathology that have been confirmed by several different researchers, together with exposing aspects that may have been overlooked or not sufficiently remarked in this productive field of study. On the other hand, we question whether performing mainly studies on HLA-G and disease associations is going to give a clear answer in the future, since 40 years of study of classical HLA molecules association with disease has still given no definite answer on this issue.

Objective Lymphopenia is a frequent clinical manifestation and risk factor for infections in SLE, but the underlying mechanisms are not fully understood. We previously identified novel roles for the RNA-binding protein serine arginine-rich splicing factor 1 (SRSF1) in the control of genes involved in signalling and cytokine production in human T cells. SRSF1 is decreased in T cells from patients with SLE and associates with severe disease. Because SRSF1 controls the expression of apoptosis-related genes, we hypothesized that SRSF1 controls T cell homeostasis and, when reduced, leads to lymphopenia. Methods We evaluated SRSF1 expression in T cells from SLE patients by immunoblots and analysed its correlation with clinical parameters. T cell conditional Srsf1 knockout mice were used to evaluate lymphoid cells and apoptosis by flow cytometry. Quantitative PCR and immunoblots were used to assess Bcl-xL mRNA and protein expression. SRSF1 overexpression was performed by transient transfections by electroporation. Results We found that low SRSF1 levels correlated with lymphopenia in SLE patients. Selective deletion of Srsf1 in T cells in mice led to T cell lymphopenia, with increased apoptosis and decreased expression of the anti-apoptotic Bcl-xL. Lower SRSF1 expression correlated with low Bcl-xL levels in T cells and lower Bcl-xL levels associated with lymphopenia in SLE patients. Importantly, overexpression of SRSF1 rescued survival of T cells from patients with SLE. Conclusion Our studies uncovered a previously unrecognized role for SRSF1 in the control of T cell homeostasis and its reduced expression as a molecular defect that contributes to lymphopenia in systemic autoimmunity.

HLA-G is a non-classical HLA class I molecule with immunomodulatory properties. It was initially described at the maternal-fetal interface, and it was later found that this molecule was constitutively expressed on certain immuneprivileged tissues, such as cornea, endothelial and erythroid precursors, and thymus. The immunosuppressive effect of HLA-G is exerted through the interaction with its cognate receptors, expressed on immunocompetent cells, like ILT2, expressed on NK, B, T cells and APCs; ILT4, on APCs; KIR, found on the surface of NK cells; and finally, the co-receptor CD8. Because of these immunomodulatory functions, HLA-G has been involved in several processes, amongst which organ transplantation, viral infections, cancer progression, and autoimmunity. HLA-G neo-expression on tumors has been recently described in several types of malignancies. In fact, tumor progression is tightly linked to the presence of the molecule, as it exerts its tolerogenic function, inhibiting the cells of the immune system and favoring tumor escape. Several polymorphisms in the 3’UTR region condition changes in HLA-G expression (14bp and +3142C/G, among others), which have been associated with both the development and outcome of patients with different tumor types. Also, in recent years, several studies have shown that HLA-G plays an important role in the control of autoimmune diseases. The ability of HLA-G to limit the progression of these diseases has been confirmed and, in fact, levels of the molecule and several of its polymorphisms have been associated with increased susceptibility to the development of autoimmune diseases, as well as increased disease severity. Thus, modulating HLA-G expression in target tissues of oncology patients or patients with autoimmune diseases may be potential therapeutic approaches to treat these pathological conditions.

Georgia (or Sakartvelo in its own language) is a South Caucasus Mts. country with its easternmost part is enigmatically named Iberia, like the Iberian Peninsula, which may refer to rivers "Kura" and "Ebro" or their valleys respectively. Most of their inhabitants speak Georgian which is included within Dene-Caucasian group and Usko-Mediterranean subgroup of languages. The latter includes Basque, Berber, ancient Iberian-Tartessian, Etruscan, Hittite, Minoan Lineal A and others. In the present paper, HLA class II -DRB1 and -DQB1 alleles has been studied and extended haplotypes calculated. Most frequent haplotypes are also of Mediterranean origin (i. e.: (A*02-B*51)-DRB1*11:01-DQB1*03:01, (A*02-B*51)-DRB1*13:01-DQB1*06:03, or (A*24-B*35)-DRB1*01:01-DQB1*05:01) and DA genetic distances show that closest world populations to Georgians are Mediterraneans. Georgians also show common extended haplotypes ((A*02-B*51)-DRB1*11:01-DQB1*03:01, (A*02-B*13)-DRB1*07:01-DQB1*02:01 and (A*03-B*35)-DRB1*11:01-DQB1*03:01) with Svan people, a secluded population in North Georgia mountains. We can conclude that Georgians belong to a very old Mediterranean substratum according to both linguistics (Usko Mediterranean languages) and HLA genetics.

The presence of cells with regulatory functions in patients with cancer is one of the mechanisms whereby the immune system cannot confront tumor growth. We sought to determine the prevalence of immunoregulatory Tcell subpopulations, expressing the latency TGFβ-associated peptide (LAP), in patients with gastric adenocarcinoma. T cells were enriched from blood or gastric tissue (tumoral, TT or tumor-free, TF) samples from 22 patients, 6 with early (EGC) and 16 with advanced gastric cancer (AGC). CD4, CD8, LAP, FoxP3 and IFN-γ were measured by cytometry. CD8 + LAP + cells were increased at tumoral sites, especially in early stages of the disease, as compared to tumor-free explants (EGC 5.28 % [4.67–6.64]*; AGC 2.90 % [1.37–4.44]; TF 3.14 % [2.33–4.16]; *p < 0.05 vs TF). Likewise, the LAP+/CD8 + LAP- ratio is increased in gastric samples from patients with early disease (EGC 0.38 [0.30–0.45]*, AGC 0.12 [0.07–0.14]; TF 0.12 [0.09–0.31]; *p < 0.05 vs AGC). Disease progression is accompanied by decreased LAP membrane expression and, probably, increased LAP secretion, therefore limiting the response to the tumor.

HLA-G is a non-classical class I HLA molecule that induces tolerance by acting on receptors of both innate and adaptive immune cells. When overexpressed in tumors, limits surveillance by the immune system. The HLA-G gene shows several polymorphisms involved in mRNA and protein levels. We decided to study the implication of two polymorphisms (rs371194629; 14bp INS/DEL and rs1063320; +3142 C/G) in paired tissue samples (tumoral and non-tumoral) from 107 Spanish patients with gastric adenocarcinoma and 58 healthy control individuals, to assess the possible association of the HLA-G gene with gastric adenocarcinoma susceptibility, disease progression and survival. The presence of somatic mutations involving these polymorphisms was also analyzed. The frequency of the 14bp DEL allele was increased in patients (70.0%) compared to controls (57.0%, p=0.025). In addition, the haplotype formed by the combination of the 14bp DEL/+3142 C variants is also increased in patients (54.1% vs 44.4%, p=0.034, OR=1.74 CI95% 1.05-2.89). Kaplan-Meier analysis revealed that 14bp DEL/DEL patients showed lower 5-year life-expectancy than INS/DEL or INS/INS (p=0.041). Adjusting for TNM staging (Cox regression analysis) disclosed a significant difference in death risk (p=0.03) with an expected hazard 2.6 times higher. Finally, no somatic mutations were found when comparing these polymorphisms in tumoral vs non-tumoral tissues, which indicates that this is a preexisting condition in patients and not a de novo, tumor-restricted, event. In conclusion, the variants predominant in patients were those increasing HLA-G mRNA stability and HLA-G expression, clearly involving this molecule in gastric adenocarcinoma susceptibility, disease progression and survival and making it a potential target for immunotherapeutic approaches.

Mexican Mixtec population from coastal Jamiltepec (Oaxaca) Amerindians was studied for its HLA profile. They show genetic characteristics close to Pacific Islanders and other Mexican Isthmus Amerindians (Mazatecans, Zapotecans and Mayas). Interestingly, this coastal Oaxaca Mixtec population is genetically closer to Mazatecans than to Oaxaca Mixtec from mountains according to HLA genes. Mixtec HLA frequent extended haplotype A*24:02-B*35:14-DRB1*16:02 has been also found in Jaidukama North Colombia forest Amerindians and in Guatemala Mayas; A*24:02, DRB1*04:03, DRB1*04:04 and DRB2*16:02 are frequent alleles also common to Pacific Inhabitants. Notwithstanding, Mixtecs show deep cultural and genetic roots with Mesoamerican Amerindians and all of them probably contributed to construct Monte Alban culture around an important Pyramid Complex close to Oaxaca City.

Background:HLA-G molecules are immunosuppressive and avoid fetal rejection by giving negative signals to maternal immune system from fetal trophoblast cell surface. HLA-G genes have been associated to different pathologies: Spontaneous abortions, autoimmunity, tumor progression, transplant rejection and infection. In addition, different World populations show remarkable different HLA-G allele frequencies in the allele that does not produce a full HLA-G molecule (HLA-G*05N); this allele is almost absent in studied Amerindians.Objectives:The aim is to study HLA-A.-B,-DRB1 and –G alleles and extended haplotypes in Amerindians for the first time. This may be useful to asses HLA-G epidemiology, association to disease and Preventive Medicine in Amerindians.Methods:HLA-A,-B and -DRB1 have been typed by using standard automatic protocols. HLA-G alleles have been detected by direct HLA-G exon 2, exon 3 and exon 4 DNA sequencing. Computer calculations have been done by specific standard methods.Results:HLA-A,-B,-DRB1 and –G extended haplotypes have been calculated in Amerindians for the first time. Also, their HLA-G frequencies have been compared with worldwide populations.Conclusion:Low frequencies of null HLA-G*01:05N allele are found in Amerindians. The extended haplotypes with this allele bear other typical Amerindian HLA-DRB1 alleles and its origin is discussed. HLA-G allele frequency profile is closer to that of Europeans than to that of Far East Asians. Our findings are useful to Preventive Medicine and Epidemiology associated to Fertility and HLA-G associated pathology and transplantation.

Quechua Amerindians established Inca Empire and chose Cuzco as their capital. Their language is closely related to that of Aymara ethnic group and both of them were originated from Titikaka Lake Altiplano area. In the present study we have analyzed Bolivian Quechua HLA profile and found that it has common characters with other Andean and Pacific Amerindians (Uros, Aymaras, Lamas, Mapuches, Athabascan), and Pacific Islanders, including Easter Islanders: relatively high frequency of HLA-A*24 (:02), class II haplotypes DRB1*08:02-DQB1*04:02, and DRB1*04:03-DQB1* 03:02. Titikaka Lake area prehistoric populations: Quechua, Aymaras and Uros are closely related according to HLA Nei DA genetic distances and other HLA traits: they built up Tiwanaku culture, which resembles that of Easter Island (i.e.: similar giant heads); later, Quechuas also moved to Cuzco. This genetic reletedness together with Easter Island and Titikaka Lake Tiwanaku (Bolivia, Peru) cultural common similarities support a prehistoric Pacific people/Amerindians gene flow.

Huastecos or Teenek Amerindians are presently living at North East Mexico (San Luis Potosi State). They have probably one of the most ancient culture of Mexico and Central America together with Mayas and Olmec groups with which also show close relationships. Proximity to Atlantic Ocean/Mexican Gulf originated that Spaniards had very early contact with them at about 1519 CE or before. In the present paper we have aimed to study HLA gene profile which may be useful for HLA and disease epidemiology and transplant programs in Teeneks. HLA-DRB1*04:07, -DRB1*14:06 and -DRB1*04:11 have been found in high frequency like in other Amerindian groups. High frequency typical Amerindians HLA extended haplotypes have been found, such as A*02-B*35-DRB1*04:07-DQB1*03:02; A*68-B*39-DRB1*04:07-DQB1*03:02 and A*02-B*39-DRB1*04:07-DQB1*03:02; also new haplotypes have been described, like A*02-B*52-DRB1*04:11-DQB1*03:02, A*68-B*35-DRB1*14:02-DQB1*03:01 and A*68-B*40-DRB1*16:02-DQB1*03:01. Genetic proximity is observed not only to linguistically close Mayans, but also to Mazatecans, Mixtecans and Zapotecans, who speak an altogether different languages; it shows once more that genes and languages do not correlate. This population was greatly diminished after European contact between 1500 and 1600 years CE; in fact, North and South America First Inhabitants population was brought from 80 down to 8 million people because of diseases (i.e.: measles, smallpox or influenza), slavery and war.

Mexican Mayo Amerindians live in southern Sonora and North Sinaloa states. They probably come from North or are related to First American Inhabitants established further North. A non-related sample of them have volunteered to HLA study in order to achieve a profile useful for their epidemiology and future transplant interstate programs, in addition to ascertain ancestry and anthropological studies. HLA typing was carried out by a standard methodology. HLA-B*48 allele(s) was found, which is characteristic of Pacific Amerindians and Pacific Islanders/southern Asians. Also, HLA-A*24 (most likely HLA-A*24:02) shows specific high frequencies in this population and also in indigenous people, like Aleuts, Alaska Yupik, Japan, Taiwan, Australia, New Zealand, Papua New Guinea, southern China and other Pacific Islands. Other Andean Amerindians also show a high HLA-A*24:02 frequencies. This confirms our previous results of a possible direct gene flow between Pacific Islanders/southern Asians and Amerindians. In addition, typical Amerindian haplotypes have been found in high frequency like HLA-A*24-B*39-DRB1*04:07-DQB1*03:02, HLA-A*02-B*35-DRB1*04:07-DQB1*03:02 and HLA-A*24-B*35-DRB1*04:07-DQB1*03:02, and new haplotypes are also described like HLA-A*02-B*35-DRB1*14:06-DQB1*03:01, HLA-A*02-B*48-DRB1*04:04-DQB1*03:02, and HLA-A*02-B*08-DRB1*04:07-DQB1*03:02. This study also supports that Americas peopling was not only carried out through Bering Strait but also through Pacific and Atlantic Oceans in an earlier time than proposed.

Gorgan (Iran) have been studied for HLA-A, -B, -C, -DRB1 and -DQB1 genes for the first time. They are Turkmen and originated in East Asia around Altai Mts; they originally spoke a Turk language classified within the Turkish-Oguz group. Peripheral blood samples were collected from Gorgan City (Iran) and HLA typed by standard methodology. HLA allele frequencies were compared with 7984 chromosomes of other World populations and it was shown existence of admixture of Siberian and Mediterranean HLA characters in this population, probably due to longlasting contact with Persians. Three new HLA extended haplotypes were found: A*01:01-B*35:01-DRB1*03:01-DQB1*02:01, A*30:01-B*13:01-DRB1*15:01-DQB1*02:01 and A*31:01-B*35:01-DRB1*15:01-DQB1*03:01. Gorgan (Iran) were most close to Chuvashians (Noth Caspian Sea, Russia) and Siberians, like Tuvinians, Mansi and Buryats in Neighbour Joining and Vista analyses. It is established a relationship of this population with Kurgan (Gorgan, Iran) archaeological mounds culture. However, their kinship with Scythians (2nd century BC) and Sarmatians (4th century AD) is obscure although both of them spoke a Persian language.

Mapuche Amerindians live now widespread in Central South Chile and Argentina and speak “Mapudungun”, an unclassified language. A group of Chilean Mapuche was studied for HLA genes using standard techniques. Typical Amerindian HLA genes and haplotypes are found in the population, like HLA-DRB1*14:02, −08:02 and class II haplotype DRB1*08:02-DQB1*04:02. However, these and other genes are also common in Pacific Islanders. Thus, relatedness of First America Inhabitants with some Pacific Islanders is stressed. Evidences of Pacific and Atlantic cultural and genetic exchange, probably in both directions, and California Man settlements found since 130,000 years ago makes it necessary a revision of Americas peopling. This study may be also useful for medical Mapuche use in Transplantation and HLA and disease Epidemiology.

Wayu Amerindians live around Guajira Peninsula shared by Colombia and Venezuela. Wayu from Colombia have been studied for their HLA profile and these data put in context with both genetic and cultural relatedness to Pacific Islanders. HLA-A*24 and HLA-B*35 (most likely HLA-A*24:02 and HLA-B*35:05) and HLA-DRB1*04:03 and HLA-DQB1*03:02 are shared both by Wayu and other Amerindians and Pacific Islanders in specific high frequency. Our findings further suggest a genetic relationship between Amerindians (also Wiwa/Arsario and Chimila from Colombia; Uros from Peru) and Pacific Islanders. Titikaka Lake (Peru/Bolivia) Amerindians (Aymara, Uros and Quechua) share also cultural traits, like Tiwanaku (Titikaka Culture giant statues) and Easter Island Culture giant statues or “Moais”.

We have studied Wiwa/Sanja Amerindians HLA-A, -B, -C, -DRB1 and DQB1 allele frequencies and extended haplotypes in 52 unrelated individuals from “El Encanto” town at Guanachaca riverside. High frequency alleles were in general present in other Amerindian populations. Also, three extended haplotypes and eight ones were respectively both “new found” and already described in Amerindians from North, Central and South America, including Lakota-Sioux, Mayas, Teeneks, Quechua and Aymaras. Analyses of HLA-A*24:02 and -C*01:02 Wiwa high frequency alleles suggested a specific relatedness with another Amerindian and Pacific Islander ethnic groups (these two particular alleles bearing in high frequencies); they include New Zealand Maoris, Taiwanese, Japanese, Papua New Guinea, and Samoans among others. This may indicate that selective forces are maintaining these two alleles high frequency within this wide American/Pacific area.

HLA-A, -B, -C and -DRB1 alleles and haplotypes have been studied in a group of Aleuts from Bering Island (Commander Islands, Russia). Many of their ancestors were original from other Aleutian Islands, like Attu and Atka Islands (USA) and may have had a low degree of admixture with Russians. HLA haplotypes are found to be specific and quite different from other First North America Inhabitants (including Amerindians, Na-Dene and Eskimo), as it was previously shown in a less numerous Aleut population. HLA-A*24:02 is found in a very high frequency; this character is shared by Pacific and Amerindian populations. In conclusion, HLA, other genetic markers, anthropological and linguistic traits make Aleuts to be different from First America Inhabitants and closer to Europeans and Asians: specifically Aleut relatedness has been found with Scandinavian Saami (Lapps) and Finns and Baikal Lake area Buryats, where all of them may have initialing being originated.

Uros people live in floating reed islands in Titikaka Lake in front of Puno town (Peru). They could have started Tiwanaku culture and shared genes and culture with Pacific Islanders; it is particularly relevant the giant hat covered men statues found in both Tiwanaku at Titikaka Lake shore and Easter Island (3700 km far from Chile in Pacific Ocean). These giants monoliths are very similar one another and unique in America and Pacific Islands. The following HLA alleles are shared in a specifically high frequency between Uros and Pacific Islanders : HLA-A*24:02, HLA-B*35:05, HLA-B*48:01, HLA-DRB1*04:03, HLA-DRB1*08:02 and HLA-DRB1*09:01. Uros also have 3 unique HLA haplotypes: A*24:02-B*15:04 − DRB1*14:02-DQB1*03:01, A*68:01:02-B*35:05-DRB1*04:03-DQB1*03:02, A*24:02-B*48:01-DRB1*04:03-DQB1*03:02. Also Uros seem to be one of the most ancient population in Titikaka Lake that could have started Tiwanaku culture. Prehistoric contacts between Amerindians and Pacific Islanders are strongly suggested by genetic and cultural traits. It is not discarded that Uros could have come from Pacific Islands: Uros show melanic skin and are dolichocephalic; in contrast, surrounding Aymara people have a clear skin and are brachicephalic. The Kon-Tiki project led by Thor Heyerdahl showed that a simple sailing is possible between Peru and Polynesia Islands; also, the most ancient skull found in America is of black origin: Luzia, suggesting that first America peopling was also carried out by Black/coloured people.

HLA-A,-B,-C,-DRB1 and -DQB1 alleles have been studied in Chimila Amerindians from Sabana de San Angel (North Colombian Coast) by using high resolution molecular typing. A frequent extended haplotype was found:HLA-A*24:02-B*51:10-C*15:02-BRB1*04:07-DQB1*03:02 (28.7%) which has also been described in Amerinndian Mayos Mexican population (Mexico, California Gulf, Pacific Ocean). Other haplotypes had already been found in Amerindians from Mexico (Pacific and Atlantic Coast), Peru (highlands and Amazon Basin), Bolivia and North USA. A geographic pattern according to HLA allele or haplotype frequencies is lacking in Amerindians, as already known. Also, five new extended haplotypes were found in Chimila Amerindians. Their HLA-A*24:02 high frequencies characteristic is shared with aboriginal populations of Taiwan; also, HLA-C*01:02 high frequencies are found in New Zealand Maoris, New Caledonians and Kimberly Aborigines from Australia. Finally, this study may show a model of evolutionary factors acting and rising one HLA allele frequency (-A*24:02), but not in others that belong to the same or different HLA loci.

Original San Basilio de Palenque population (North Colombia) fled from Spanish traders that carried them as slaves and they funded in nearby Maria Mountains a fortified town (Palenque). They started helping new Africans brought as slaves to flee and join them. Most of them spoke a Bantu-Congo language and nowadays they speak the only one extant Bantu-Spanish Creole language. Spanish Crown was forced to issue a decree declaring them free (1691 CE), more than 100 years before than Haiti Republic existed. HLA-A, -B, -DRB1 and -DQB1 alleles were studied and further computer procedures were performed with Arlequin 3.5 software. No Amerindian or Europeans gene flow to this population was found. However, three specific HLA extended haplotypes are found in this population, which may reflect an isolation from other Africans or Afro-Americans also. This may be due to the maintenance of their own African culture, and even their unique Creole language.

HLA-G and HLA-A frequencies have been analysed in Amerindians from Ecuador. HLA-G allele frequencies are found to be closer to those of other Amerindians (Mayas from Guatemala and Uros from Peru) and closer to European ones than to Far East Asians groups, particularly, regarding to HLA-G*01:04 allele. HLA-G/-A haplotypes have been calculated for the first time in Amerindians. It is remarkable that HLA-G*01:05N "null" allele is found in a very low frequency (like in Amerindian Mayas and Uros) and is also found in haplotypes belonging to the HLA-A19 group of alleles (HLA-A*30, -A*31, -A*33). It was previously postulated that HLA-G*01:05N appeared in HLA-A*30/-B*13 haplotypes in Middle East Mediterraneans. It may be hypothesized that in Evolution, HLA-G*01:05N existed primarily in one of the HLA extant or extinct -A19 haplotype, whether this haplotype was placed in Middle East or other World areas, including America. However, the highest present day HLA-G*01:05N frequencies are found in Middle East Mediterraneans.

America First Inhabitants population (Amerindians, Na Dene and Eskimos) underwent a drastic population reduction and gene exchange after Europeans and Africans arrival after 1492 AD. Barranquilla population may be a good model to study present day population admixture in South America. HLA-A, -B and -DRB1 DNA typing has been performed in 188 unrelated individuals originated in the area and speak Spanish language; they showed apparent European/African and mixed characters. HLA genetic European/African features were found and only 1.85% Amerindian one. This contrasts with neighboring Cuban population where 10% HLA Amerindian characters appear.